# Patent

## Title
Non-combustible reinforced cementitious lightweight panels and metal frame system for flooring

## Abstract

A flooring system including horizontal metal framing members, for example, C-joists, U-joists, open web joists, HAMBRO or other metal frame systems that support a reinforced, lightweight, dimensionally stable SCP panel. The flooring system is non-combustible, water durable, mold and rot resistant, termite resistant and is capable of resisting shear loads equal to or exceeding shear loads provided by plywood or oriented strand board panels. The panels employ one or more layers of a continuous phase resulting from the curing of an aqueous mixture of inorganic binder, for example, calcium sulfate alpha hemihydrate, hydraulic cement, an active pozzolan and lime. The continuous phase is reinforced with glass fibers and contains lightweight filler particles, for example, ceramic microspheres.

## Background
This claims the benefit of US provisional patent application number U.S. Provisional Patent Application No. 60/647,015, filed Jan. 27, 2005 and U.S. provisional patent application No. 60/640,174 filed Dec. 30, 2004, both of which are incorporated herein by reference in their entirety.


FIELD OF THE INVENTION
This invention relates generally to a flooring system comprising metal framing and lightweight structural cementitious panels, termed here as SCP panels, in residential and commercial construction. More particularly, the invention relates to a non-combustible flooring system, having panels mechanically or adhesively fastened to steel frame flooring systems. The panels provide a shear resistant diaphragm and axial load carrying floor element. The system provides the following advantageous performance attributes when used with steel framing: non-combustibility, water durability, mold resistance, high specific strength and stiffness, economy of building design that results in speed of assembly, reduced foundation size due to reduced building weight, and increased ratios of useable building volume for a given building footprint.
BACKGROUND OF THE INVENTION
Interior residential and light commercial flooring systems commonly include plywood or oriented strand board (OSB) nailed to a wooden frame. OSB consists of pieces of wood glued together. However, costs of lumber and labor required for installing wooden floors and framing components have risen with time. Wooden floors and framing components are also susceptible to water damage, fire damage, insect damage and rotting. Additional problems specifically associated with wooden floor joists include stability and quality.
Typical floor construction methods include installing “header” members (rim joists) on the top of support walls that may be fabricated from, for example, concrete blocks, wood or metal studs. In wood frame construction, the header members typically comprise wood beams that are supported on edge on the wall. Other wood beam members, commonly referred to as joists, are used to span from wall to wall between the headers and are usually connected to the headers by nails. The joists are typically arranged parallel to each other with 8′′, 16′′ or 24′′ between their respective centers, depending upon the load characteristics that the floor must accommodate. A sheathing material such as plywood or OSB is then fastened to the upper edges of the joists using nails, screws or other mechanical fasteners to form the floor surface. To prevent the joists from twisting or moving laterally, small pieces of wood, known as blocking pieces, are commonly nailed between adjacent joists to form, in many instances, X-shaped braces between the joists. Insulation is sometimes installed between the joists and sheathing, drywall, plasterboard, etc. is then applied to the bottom of the joists to form a ceiling for the space located under the floor joist system. When connecting the joists to their respective headers, the carpenter must first measure and mark the headers to establish the desired joist spacing. After the headers are installed, the joists must be properly nailed to the headers by a carpenter. If the carpenter has access to the opposite side of the header from which the joist is to be installed, the nails are hammered through the header into the end of the respective joist. If, however, the carpenter cannot access the opposite side of the header, nails must be inserted at an angle (commonly referred to as “toe-nailing”) through the joist and into the header. Care must be taken to avoid inadvertently splitting the joist and to ensure that the nails extend through the joist and into the header a sufficient distance. Such attachment process can be time consuming and may require the use of skilled labor which can also lead to increase construction costs. If toe-nailing is not structurally acceptable, another piece, called a joist hanger is added which also increases labor and material costs.
Framing in metal, both when building out commercial spaces as well as residential structures, is becoming more and more common. Probably the best known and most prevalent method of framing in metal involves the use of metal channeling, typically rolled from sheet steel and sometimes aluminum. These metal framing members or studs, often used to erect and reinforce commercial and residential structures, are channels having a substantially C-shaped cross section with a broad web (base) and narrow flanges (sides) of uniform height. To enhance the stud or framing member's strength and rigidity, the edges of the flanges of the C-channel component are bent over to form lips parallel to the plane of the C-channel base to form the C-shaped component.
The outside dimensions of the metal framing members and studs, and the weight or gauge of the member or stud, vary. Typically the members are fabricated to be approximately 4 inches wide by 2 inches deep, corresponding thereby to the width and depth of wood framing and stud members, in which case the lips may extend 1⁄4 to 1⁄2 inch from the sides of the studs. Fourteen to 20 gauge metal may be used for light gauge, residential construction and commercial wall construction. Heavier metal gauges are used in some residential and commercial framing and particularly in multiple story commercial construction.
There has developed a variety of methods for connecting and securing metal frames and wall studs. At the most basic level, metal studs are inserted into and secured within metal tracks by drilling, screwing, or welding from the outside wall of the track into an adjoining metal stud. Similarly, commercially available devices for interconnecting metal framing members, as for example tie brackets, shear connectors and plate connectors, typically use screws and bolts applied from the outside of the track or stud member inwards.
Metal studs and framing members have been modified to include saw or punch slots, tabs and brackets intended to facilitate the interconnection of these studs and framing member to adjoining studs and framing members and/or to cross-bars and other non-framing members that serve to reinforce the studs and framing members. Known connectors, including bracket, plate and tie connectors, presently used to tie together and interconnect metal studs, are generally drilled and screwed on site.
U.S. Pat. No. 6,799,407 discloses, a system for interconnecting metal framing members, tracks and studs by way of a variety of connectors and tracks. The connectors are specially configured and designed to fit within and interlock with the framing members, tracks and studs. The connectors serve to secure one member, track or stud to another member, track or stud, by fasteners applied from within the connector outwards into the non-surface aspects of the member, track or stud. The tracks are specially configured to utilize the novel connectors of the present invention to interconnect with other tracks or studs using fasteners applied from both the inside out, and the outside in, in three dimensions, while still leaving the surface aspects of tracks and studs free of fastener heads or other protrusions. It employs traditional C-channel shaped framing members or studs, made of sheet steel or aluminum. According to the system, the C-channel members comprise many or all framing components for commercial and residential construction as, for example, wall studs, tracks, headers, hips, floor joists, ceiling joists, roof trusses, fascia, stud blocking, etc. The framing members or studs are tied together by a collection of more than twenty-eight structurally related metal connectors specially configured and grooved to interlock within the familiar C-channel framing member. These connectors are secured to the studs using fasteners, typically self-tapping screws, inserted from within the connectors, through the connectors, and outward into the adjoining member or stud. Its system for interconnecting metal framing members, tracks and studs that can employ a member or stud of uniform dimension and that results in a frame having a smooth, continuous outer surface, devoid of protruding fasteners heads. This includes a system of interconnecting metal framing members in which fasteners are applied from the inside of the members outward, allowing the members to be secured by workers working entirely from within the building. The metal framing members, tracks and studs are interconnected in at least two, and often three, dimensions for additional strength and durability. Its connectors for interconnecting metal framing members and studs interlock within the framing members, tracks and studs that can be screwed and secured safely on site, without significant risk that the connector will be grabbed and spun by a powered drill or bit.
U.S. Pat. No. 5,687,538 discloses a structural framing member with a C-shaped cross section comprising of a main planar surface and two planar side walls at right angles. The side walls present an inwardly turned lip formed substantially parallel to the base. The capacity of the metal framing joist sections is increased by embossing longitudinal stiffeners perpendicular to the top and bottom side walls, with a minimum depth of 0.01′′ (0.025 cm), continuous along the face of the main planar surface for the full length of the section. By bridging these longitudinal stiffeners with, but not limiting to, diagonal embossed stiffeners, a series of adjoining geometric shapes between longitudinal chords has been created to increase the rigidity of the web via adjoining geometric stiffeners which will carry the load by axial deformation rather than pure shear deformation.
U.S. Pat. No. 6,418,964 to Daudet et al, incorporated herein by reference, discloses floor joists and floor header systems made of metal. The system may include a joist rim that has at least one attachment tab integrally formed therein to facilitate attachment of a joist to the joist rim. Reinforcing ribs are preferably provided adjacent the attachment tabs for providing desired structural integrity to the attachment tab connection. The system may also include a C-shaped joist that has a plurality of oval-shaped openings to enable components such as ducts, wires, piping, etc. to pass there through. The joists may also be provided with a plurality of mounting holes that are adapted to accommodate wire retainer members for supporting insulation between respective joists. The system may also include preformed blocking members that are sized to extend between adjacent joists and be attached thereto to provide lateral support to the joists.
It is known to place plywood or OSB on cold formed, light gauge steel C-joists or steel open web bar joists. However, plywood and OSB are combustible.
U.S. Pat. No. 6,620,487 to Tonyan et al., incorporated herein by reference in its entirety, discloses a reinforced, lightweight, dimensionally stable structural cement panel (SCP) capable of resisting shear loads when fastened to framing equal to or exceeding shear loads provided by plywood or oriented strand board panels. The panels employ a core of a continuous phase resulting from the curing of an aqueous mixture of calcium sulfate alpha hemihydrate, hydraulic cement, an active pozzolan and lime, the continuous phase being reinforced with alkali-resistant glass fibers and containing ceramic microspheres, or a blend of ceramic and polymer microspheres, or being formed from an aqueous mixture having a weight ratio of water-to-reactive powder of 0.6/1 to 0.7/1 or a combination thereof. At least one outer surface of the panels may include a cured continuous phase reinforced with glass fibers and containing sufficient polymer spheres to improve nailability or made with a water-to-reactive powders ratio to provide an effect similar to polymer spheres, or a combination thereof.
U.S. Pat. No. 6,241,815 to Bonen, incorporated herein by reference in its entirety, also discloses formulations useful for SCP panels.
U.S. patent application Ser. No. 10/666,294, incorporated herein by reference, discloses a multi-layer process for producing structural cementitious panels (SCP's or SCP panels), and SCP's produced by such a process. After one of an initial deposition of loosely distributed, chopped fibers or a layer of slurry upon a moving web, fibers are deposited upon the slurry layer. An embedment device mixes the recently deposited fibers into the slurry, after which additional layers of slurry, then chopped fibers are added, followed by more embedment. The process is repeated for each layer of the board, as desired.
For use in construction, SCP panels should meet building code standards for shear resistance, load capacity, water-induced expansion and resistance to combustion, as measured by recognized tests, such as ASTM E72, ASTM 661, and ASTM C 1185 or equivalent, as applied to structural plywood sheets. SCP panels are also tested under ASTM E-136 for non-combustibility—plywood does not meet this test.
The SCP panel should be capable of being cut with the circular saws used to cut wood.
The SCP panel should be dimensionally stable when exposed to water, i.e., it should expand as little as possible, preferably less than 0.1% as measured by ASTM C 1185.
The SCP panel should provide a bondable substrate for exterior finish systems.
The SCP panel should be non-combustible as determined by ASTM E136.
After curing for 28 days, the flexural strength of a 0.75 inch (19. mm) thick SCP panel having a dry density of 65 to 90 lb/ft3 (1041 kg/m3) after being soaked in water for 48 hours should be at least 1000 psi (7 MPa), e.g. at least 1300 psi (9 MPa) preferably at least 1650 psi (11.4 MPa), more preferably at least 1700 psi (11.7 MPa), as measured by ASTM C 947. The panel should retain at least 75% of its dry strength.
In heavier commercial construction it is also common to form a floor by a “level pan” technique including laying steel I-beams or steel joists, e.g., open web bar joists, horizontally and then supporting a pan on the I-beams or joists and filling the pan with cement. Typically the pan has a corrugated bottom surface. However, this is expensive and time consuming.
There is a need for an economical, easy to assemble, durable and non-combustible total framing and flooring system.
SUMMARY OF THE INVENTION
The present invention relates to a system for residential and light commercial construction including a metal frame and lightweight SCP panel flooring. This flooring is made from a mixture of inorganic binder and lightweight fillers. Selecting a combination of a metal frame with SCP panels achieves a synergy of a completely non-combustible flooring system. By a fully non-combustible horizontal shear diaphragm on light gauge cold rolled metal frame is meant a system in which all elements pass ASTM E-136. For example, the floor system may include SCP panels employed with a metal floor framing system employing any standard light-gauge steel C-channels, U-channels, I-beams, square tubing, and light-gauge prefabricated building sections, such as floor trusses or open web bar joists.
The present SCP horizontal floor diaphragm system may have a higher specific stiffness than a floor system of open web bar joists, metal deck and poured in place concrete or precast plank with a topping slab on load bearing walls. Specific stiffness is defined as the unit weight of a floor system in lbs/sq. ft. to satisfy a design deflection requirement and at least one corresponding strength requirement for a particular span and loading condition. Strength in this definition is flexural strength and/or shear strength for vertical and/or horizontal loads on the floor. Vertical loads include live and/or dead loads. Horizontal (transverse) loads include loads applied by wind and/or seismic action.
For instance, a comparison can be made of systems including a 20 foot span designed to withstand live loads and dead loads of 40 pounds per square foot with a floor deflection in inches calculated as less than ((20 feet×12 inches/foot)/360) inches, i.e., 0.667 inches. An embodiment of the present system having a horizontal diaphragm of 3⁄4 inch thick SCP panels installed on a 20 foot span of metal framing joists, and having a lower unit weight than a 20 foot span floor system of open bar joists, a floor diaphragm of corrugated metal deck and a concrete slab, may have a higher specific stiffness than the floor system of open bar joists, the floor diaphragm of corrugated metal deck and the concrete slab.
The present invention may also provide higher specific stiffness than wooden floor systems.
The present system having a horizontal shear diaphragm on light gauge cold rolled metal frame also is typically water durable. Preferably the horizontal shear diaphragm load carrying capacity of a system of the present invention will not be lessened by more than 25% (more preferably will not be lessened by more than 20%) when exposed to water in a test wherein a 2 inch head of water is maintained over 3⁄4 inch thick SCP panels fastened on a 10 foot by 20 foot metal frame for a period of 24 hours. In this test, the 2 inch head is maintained by checking, and replenishing water, at 15 minute intervals.
Preferably the system of the present invention will not absorb more than 0.7 pounds per square foot of water when exposed to water in a test wherein a 2 inch head of water is maintained over 3⁄4 inch thick SCP panels fastened on a 10 foot by 20 foot metal frame for a period of 24 hours. In this test, the 2 inch head is maintained by checking, and replenishing water, at 15 minute intervals.
Also, combining non-combustible SCP panels with metal framing results in an entire system which resists swelling due to moisture. Preferably in the system of the present invention a 10 foot wide by 20 foot long by 3⁄4 inch thick diaphragm of the SCP panels attached to a 10 foot by 20 foot metal frame will not swell more than 5% when exposed to a 2 inch head of water maintained over the SCP panels fastened on the metal frame for a period of 24 hours. In this test, the 2 inch head is maintained by checking, and replenishing water, at 15 minute intervals.
Also, the present floor system of a horizontal diaphragm of SCP panel on metal frame leads to a mold and mildew resistant floor system. Preferably every component of the system of the present invention meets ASTM G-21 in which the system achieves approximately a rating of 1 and meets ASTM D-3273 in which the system achieves approximately a rating of 10. Preferably the system of the present invention supports substantially zero bacteria growth when clean.
Another preferred attribute of the present floor system of a horizontal diaphragm of SCP panel on metal frame is that preferably it is inedible to termites.
The system of the present invention may employ single layer or multi-layer SCP panels. In the multi-layer SCP panel the layers may be the same or different. For example, the SCP panel may have an inner layer of a continuous phase and at least one outer layer of a continuous phase on each opposed side of the inner layer, wherein at least one outer layer on each opposed side of the inner layer has a higher percentage of glass fibers than the inner layer. This has the ability to stiffen, strengthen and toughen the panel.
A potential advantage of the present system is that, due to its being lightweight and strong, the combination of the present floor system of a horizontal diaphragm of 3⁄4 inch thick SCP panel on metal frame permits efficient use of building volume for a given building footprint to permit maximization of building volume for the given building footprint. Thus, the present system may allow for more efficient building volume to allow more floor to ceiling height or even a greater number of floors in zoning areas with building height restrictions.
The lightweight nature of this system typically avoids the dead load associated with metal pan deck/poured concrete systems. Less dead load also allows building comparable size structures on less stable soil possessing relatively low bearing capacities.
In contrast to plywood, the present system potentially has the advantage of potentially being non-directional. In other words, the panels of the present system may be placed with their long dimension parallel or perpendicular to the metal joists of the frame without losing strength or load carrying characteristics. Thus, the ability of the system to support dead and live loads without breaking is the same regardless of the orientation of the SCP panel on the metal framing.
Another potential advantage of the present system over plywood is that the present system has greater compressive strength. For buildings with multiple floors, constructed such that the building walls rest upon the floor, the walls place increasingly greater compressive forces on the lower floors. Thus, the greater compressive strength of the present system assists in withstanding these compressive forces.
Moreover, adding gypsum drywall or other sound attenuating material can improve the sound insulation provided by the SCP floors. This can especially reduce IIC (impact noise). Typical materials to add include floor underlayment panels (to make a floor which is non-combustible from the bottom), FIBEROCK brand interior panels (available from US Gypsum Corporation, Chicago, Ill.)(to make a non-combustible floor), LEVELROCK brand floor underlayment (available from US Gypsum Corporation, Chicago, Ill.)(to make a non-combustible floor), or acoustical plaster (to make a non-combustible floor). An acoustic ceiling may also be applied to the underside of the floor-joists. The ceiling panels are attached to resilient channels or a suspension grid.
As the thickness of the board affects its physical and mechanical properties, e.g., weight, load carrying capacity, racking strength and the like, the desired properties vary according to the thickness of the board. Thus, for example, the desired properties which a shear rated panel with a nominal thickness of 0.75 inches (19.1 mm) should meet include the following.
When used for floors, a typical panel when tested according to ASTM 661 and American Plywood Association (APA) Test Method S-1 over a span of 16 inches (406.4 mm) on centers, typically has an ultimate load capacity greater than 400 lbs (182 kg), e.g. greater than 550 lbs (250 kg), under static loading, an ultimate load capacity greater than 400 lbs (182 kg) under impact loading and a deflection of less than 0.125 inches (3.2 mm), typically less than 0.078 inches (1.98 mm), under both static and impact loading with a 200 lb (90.9 kg) load.
A 4×8 ft, 3⁄4 inch thick panel (1.22×2.44 m, 19.1 mm thick) typically weighs no more than 156 lbs (71 kg) and preferably no more than 144 lbs (65.5 kg).
Typical compositions for embodiments of panels of the present invention which achieve the combination of low density, improved flexural strength, and nailability/cuttability comprise inorganic binder (examples—gypsum-cement, Portland cement or other hydraulic cements) having, distributed throughout the full thickness of the panel, selected glass fibers, lightweight fillers (examples—hollow glass microspheres, hollow ceramic microspheres and/or perlite uniformly), and superplasticizer/high-range water reducing admixtures (examples—polynapthalene sulfonates, poly acrylates, etc.).
The panels may be single layer panels or multilayer panels. A typical panel is made from a mixture of water and inorganic binder with the selected glass fibers, lightweight ceramic microspheres and superplasticizer throughout the mixture. Other additives such as accelerating and retarding admixtures, viscosity control additives may optionally be added to the mixture to meet the demands of the manufacturing process involved.
A single or multi layer panel may also be provided with a sheet of mesh, e.g. fiber glass mesh if desired.
In embodiments having multiple (two or more) layers, the composition of the layers may be the same or different. For example, a multi-layer panel structure may be created to contain at least one outer layer having improved nailability and cutability. This is provided by using a higher water-to-reactive powder (defined below) ratio in making the outer layer(s) relative to the core of the panel. A small thickness of the skin coupled with a small dosage of polymer content may improve the mailability without necessarily failing the non-combustibility test. Of course, high dosages of polymer content would lead to failure of the product in the non-combustibility test.
The glass fibers can be used alone or in combination with other types of non-combustible fibers such as steel fibers.
As previously discussed, there is a need for a light, noncombustible flooring system to replace wood frames sheathed with plywood or OSB flooring panels. There is also a need for a light economical replacement for flooring systems constructed with poured concrete on metal pan deck by the “level pan” technique.
The SCP panels may float on the joists or be connected to the joists mechanically or by adhesive. Connecting the SCP panels directly or indirectly to the metal framing may achieve a composite action such that the metal framing and panels work together to carry greater loads.
In its method respects, the present invention comprises a method of making the non-combustible flooring system of the present invention, comprising placing the SCP panel on metal flooring elements.
The present invention has an unexpected advantage in cold weather performance. Conventional cementitious panels can be brittle in cold weather. Thus, installing such panels in cold weather would require careful handling by the construction workers during installation. However, in the present system the SCP panels can preferably withstand being installed on metal flooring elements when the ambient temperature is less than 32 degrees F. (0 degrees C.), or even less than 20 degrees F. (minus 7.5 degrees C) without cracking. This is a very significant advantage because it facilitates building in harsh climates in winter thus increasing builder productivity. The present SCP panels can preferably withstand being subjected to normal rough treatment during installation at these cold temperatures. For instance, at these cold temperatures placing the SCP panel may include a step of dropping the panel on the metal flooring elements, e.g., trusses, such that at least one end of the panel falls in free fall at least 2 feet, typically at least 3 feet, for example, 2 to 3 feet or 3 to 6 feet without cracking. For example, this occurs when one end of the panel is placed on one or more metal flooring elements and then the opposing other end is released to drop in free fall on one or more metal flooring elements.
Another unexpected advantage is that the present invention achieves a 2 hour fire resistance rating according to ASTM E-119 by employing the SCP panel, for example 3⁄4 inch or 1 inch SCP panel, on U-shaped channel framing.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic side view of a metal C-joist for employing with a structural cementitious panel (SCP) panel in the non-combustible flooring system of the present invention.
FIG. 2 is a perspective view of a single layer SCP panel for employing with metal framing in the non-combustible flooring system of the present invention.
FIG. 3 is a fragmentary cross-section of a multi-layer SCP panel for employing with metal framing in the system of the present invention.
FIG. 4 shows a perspective view of a typical tongue-and-groove SCP panel of the present invention supported on C-joist metal framing wherein the C-joist metal framing is supported on a header (not shown).
FIGS. 5A-5C illustrate a typical design and dimensions of tongue and groove employed in a 3⁄4 inch (19.1 mm) thick SCP panel (with dimensions in inches).
FIG. 6 is a fragmentary perspective view of the SCP panels supported on C-joist metal framing of FIG. 4 in the non-combustible flooring system of the present invention.
FIG. 7A is a perspective view of an SCP panel supported on a corrugated sheet in the non-combustible flooring system of the present invention.
FIG. 7B is a cross-sectional view of the SCP panel of FIG. 7A supported on a corrugated sheet wherein the SCP panel is secured over insulation material in the non-combustible flooring system of the present invention.
FIG. 7C shows a perspective view of SCP panels of FIG. 7A attached to the flat portions of corrugated sheet.
FIG. 7D is a side view of the SCP panel of FIG. 7C prior to use and shows that prior to use adhesive strips are covered with removable protective strips.
FIG. 8 shows assembled metal, e.g., steel, floor framing.
FIG. 9 shows attachment of the C-joist metal framing members to the header.
FIG. 10 shows an enlarged view of a portion of the frame of FIG. 8.
FIG. 11 shows a test SCP panel floor system configuration attached to the metal frame of FIG. 8.
FIGS. 12, 13, 14 and 15 show enlarged views of respective portions of the floor of FIG. 11.
FIG. 16 shows the frame of FIG. 8 having the attached floor of FIG. 9 mounted on a floor diaphragm testing apparatus.
FIG. 17 shows an enlarged view of a portion of the apparatus of FIG. 16.
FIG. 18 shows experimental load versus deflection data from a floor diaphragm test using a 3⁄4 inch structural cement panel (SCP panel) from an example employing the floor diaphragm testing apparatus of FIG. 16.
FIG. 19 shows a photograph of the SCP panel and metal frame floor mounted on the test apparatus of FIG. 16 at design load.
FIG. 20 shows a photograph of the SCP panel and metal frame floor mounted on the test apparatus of FIG. 16 at failure.
FIG. 21 is a diagrammatic elevational view of an apparatus which is suitable for performing the present process.
FIG. 22 is a perspective view of a slurry feed station of the type used in the present process.
FIG. 23 is a fragmentary overhead plan view of an embedment device suitable for use with the present process.
FIG. 24 shows a Floor Diaphragm test using a 3⁄4 inch thick SCP panel in a dry test.
FIG. 25 shows a Floor Diaphragm test using a 3⁄4 inch thick SCP panel in a wet test.
FIG. 26 shows a hypothetical SCP structural floor system employing 3⁄4 inch thick SCP sheathing on a 12 inch deep metal joist.
FIG. 27 shows a hypothetical precast plank system.
FIG. 28 shows a hypothetical bar joist/deck/slab system having a 3 inch thick concrete topping on 9/16 inch 22 gauge corrugated metal deck on a 14 inch deep K3 bar joist.
FIG. 29 shows a hypothetical plywood sheathing on a wood joist system.



DETAILED DESCRIPTION OF THE INVENTION
The frames may be any metal, e.g., steel or galvanized steel, framing systems suitable for supporting flooring. Typical frames include C-joists having openings therein for passing plumbing and electrical lines there through and headers for supporting the C-joists about the floor perimeter.
A typical C-joist 10 is shown in FIG. 1. The C-shaped joist has a joist web and an upper joist leg protruding from the joist web and a lower joist leg protruding from the joist web. Typically the joist web has one or more openings through the joist web for passing utility lines therethrough. U.S. Pat. No. 6,691,478 B2 to Daudet et al. discloses an example of a suitable metal flooring system.
FIG. 2 is a schematic perspective view of a single layer SCP panel 20 for employing with metal framing in the system of the present invention. The principal starting materials used to make such SCP panels are inorganic binder, e.g., calcium sulfate alpha hemihydrate, hydraulic cement, and pozzolanic materials, lightweight filler, e.g., one or more of perlite, ceramic microspheres, or glass microspheres, as well as superplasticizer, e.g., polynapthalene sulphonates and/or poly acrylates, water, and optional additives.
If desired the panel may have a single layer as shown in FIG. 2. However, the panel typically is made by a process which applies multiple layers which, depending upon how the layers are applied and cured as well as whether the layers have the same or different compositions, may or may not in the final panel product retain distinct layers. A multi-layer structure of a panel 21 having layers 22, 24, 26 and 28 is shown in FIG. 3. In the multi-layer structure the composition of the layers may be the same or different. The typical thickness of the layer(s) ranges between about 1/32 to 1.0 inches (about 0.75 to 25.4 mm). Where only one outer layer is used, it typically will be less than 3⁄8 of the total panel thickness.
Calcium Sulfate Hemihydrate
Calcium sulfate hemihydrate, which may be used in panels of the invention, is made from gypsum ore, a naturally occurring mineral, (calcium sulfate dihydrate CaSO4.2H2O). Unless otherwise indicated, “gypsum” will refer to the dihydrate form of calcium sulfate. After being mined, the raw gypsum is thermally processed to form a settable calcium sulfate, which may be anhydrous, but more typically is the hemihydrate, CaSO4.1⁄2H2O. For the familiar end uses, the settable calcium sulfate reacts with water to solidify by forming the dihydrate (gypsum). The hemihydrate has two recognized morphologies, termed alpha hemihydrate and beta hemihydrate. These are selected for various applications based on their physical properties and cost. Both forms react with water to form the dihydrate of calcium sulfate. Upon hydration, alpha hemihydrate is characterized by giving rise to rectangular-sided crystals of gypsum, while beta hemihydrate is characterized by hydrating to produce needle-shaped crystals of gypsum, typically with large aspect ratio. In the present invention either or both of the alpha or beta forms may be used depending on the mechanical performance desired. The beta hemihydrate forms less dense microstructures and is preferred for low density products. The alpha hemihydrate forms more dense microstructures having higher strength and density than those formed by the beta hemihydrate. Thus, the alpha hemihydrate could be substituted for beta hemihydrate to increase strength and density or they could be combined to adjust the properties.
A typical embodiment for the inorganic binder used to make panels of the present invention comprises of hydraulic cement such as Portland cement, high alumina cement, pozzolan-blended Portland cement, or mixtures thereof.
Another typical embodiment for the inorganic binder used to make panels of the present invention comprises a blend containing calcium sulfate alpha hemihydrate, hydraulic cement, pozzolan, and lime.
Hydraulic Cement
ASTM defines “hydraulic cement” as follows: a cement that sets and hardens by chemical interaction with water and is capable of doing so under water. There are several types of hydraulic cements that are used in the construction and building industries. Examples of hydraulic cements include Portland cement, slag cements such as blast-furnace slag cement and super-sulfated cements, calcium sulfoaluminate cement, high-alumina cement, expansive cements, white cement, and rapid setting and hardening cements. While calcium sulfate hemihydrate does set and harden by chemical interaction with water, it is not included within the broad definition of hydraulic cements in the context of this invention. All of the aforementioned hydraulic cements can be used to make the panels of the invention.
The most popular and widely used family of closely related hydraulic cements is known as Portland cement. ASTM defines “Portland cement” as a hydraulic cement produced by pulverizing clinker consisting essentially of hydraulic calcium silicates, usually containing one or more of the forms of calcium sulfate as an interground addition. To manufacture Portland cement, an intimate mixture of limestone, argallicious rocks and clay is ignited in a kiln to produce the clinker, which is then further processed. As a result, the following four main phases of Portland cement are produced: tricalcium silicate (3CaO.SiO2, also referred to as C3S), dicalcium silicate (2CaO.SiO2, called C2S), tricalcium aluminate (3CaO.Al2O3 or C3A), and tetracalcium aluminoferrite (4CaO.Al2O3.Fe2O3 or C4AF). Other compounds present in minor amounts in Portland cement include calcium sulfate and other double salts of alkaline sulfates, calcium oxide, and magnesium oxide. Of the various recognized classes of Portland cement, Type III Portland cement (ASTM classification) is preferred for making the panels of the invention, because of its fineness it has been found to provide greater strength. The other recognized classes of hydraulic cements including slag cements such as blast-furnace slag cement and super-sulfated cements, calcium sulfoaluminate cement, high-alumina cement, expansive cements, white cement, rapidly setting and hardening cements such as regulated set cement and VHE cement, and the other Portland cement types can also be successfully used to make the panels of the present invention. The slag cements and the calcium sulfoaluminate cement have low alkalinity and are also suitable to make the panels of the present invention.
Fibers
Glass fibers are commonly used as insulating material, but they have also been used as reinforcing materials with various matrices. The fibers themselves provide tensile strength to materials that may otherwise be subject to brittle failure. The fibers may break when loaded, but the usual mode of failure of composites containing glass fibers occurs from degradation and failure of the bond between the fibers and the continuous phase material. Thus, such bonds are important if the reinforcing fibers are to retain the ability to increase ductility and strengthen the composite over time. It has been found that glass fiber reinforced cements do lose strength as time passes, which has been attributed to attack on the glass by the lime which is produced when cement is cured. One possible way to overcome such attack is to cover the glass fibers with a protective layer, such as a polymer layer. In general, such protective layers may resist attack by lime, but it has been found that the strength is reduced in panels of the invention and, thus, protective layers are not preferred. A more expensive way to limit lime attack is to use special alkali-resistant glass fibers (AR glass fibers), such as Nippon Electric Glass (NEG) 350Y. Such fibers have been found to provide superior bonding strength to the matrix and are, thus, preferred for panels of the invention. The glass fibers are monofilaments that have a diameter from about 5 to 25 microns (micrometers) and typically about 10 to 15 microns (micrometers). The filaments generally are combined into 100 filament strands, which may be bundled into rovings containing about 50 strands. The strands or rovings will generally be chopped into suitable filaments and bundles of filaments, for example, about 0.25 to 3 inches (6.3 to 76 mm) long, typically 1 to 2 inches (25 to 50 mm).
It is also possible to include other non-combustible fibers in the panels of the invention, for example, steel fibers are also potential additives.
Pozzolanic Materials
As has been mentioned, most Portland and other hydraulic cements produce lime during hydration (curing). It is desirable to react the lime to reduce attack on glass fibers. It is also known that when calcium sulfate hemihydrate is present, it reacts with tricalcium aluminate in the cement to form ettringite, which can result in undesirable cracking of the cured product. This is often referred to in the art as “sulfate attack.” Such reactions may be prevented by adding “pozzolanic” materials, which are defined in ASTM C618-97 as “. . . siliceous or siliceous and aluminous materials which in themselves possess little or no cementitious value, but will, in finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to form compounds possessing cementitious properties.” One often used pozzolanic material is silica fume, a finely divided amorphous silica which is the product of silicon metal and ferro-silicon alloy manufacture. Characteristically, it has a high silica content and a low alumina content. Various natural and man-made materials have been referred to as having pozzolanic properties, including pumice, perlite, diatomaceous earth, tuff, trass, metakaolin, microsilica, ground granulated blast furnace slag, and fly ash. While silica fume is a particularly convenient pozzolan for use in the panels of the invention, other pozzolanic materials may be used. In contrast to silica fume, metakaolin, ground granulated blast furnace slag, and pulverized fly ash have a much lower silica content and large amounts of alumina, but can be effective pozzolanic materials. When silica fume is used, it will constitute about 5 to 20 wt. %, preferably 10 to 15 wt. %, of the reactive powders (i.e., hydraulic cement, calcium sulfate alpha hemihydrate, silica fume, and lime). If other pozzolans are substituted, the amounts used will be chosen to provide chemical performance similar to silica fume. Lightweight Fillers/Microspheres
The lightweight panels employed in systems of the present invention typically have a density of 65 to 90 pounds per cubic foot, preferably 65 to 85 pounds per cubic foot, more preferably 72 to 80 pounds per cubic foot. In contrast, typical Portland cement based panels without wood fiber will have densities in the 95 to 110 pcf range, while the Portland Cement based panels with wood fibers will be about the same as SCP (about 65 to 85 pcf).
To assist in achieving these low densities the panels are provided with lightweight filler particles. Such particles typically have an average diameter (average particle size) of about 10 to 500 microns (micrometers). More typically they have a mean particle diameter (mean particle size) from 50 to 250 microns (micrometers) and/or fall within a particle diameter (size) range of 10 to 500 microns. They also typically have a particle density (specific gravity) in the range from 0.02 to 1.00. Microspheres or other lightweight filler particles serve an important purpose in the panels of the invention, which would otherwise be heavier than is desirable for building panels. Used as lightweight fillers, the microspheres help to lower the average density of the product. When the microspheres are hollow, they are sometimes referred to as microballoons.
When the microspheres are hollow, they are sometimes referred to as microballoons.
The microspheres are either non-combustible themselves or, if combustible, added in sufficiently small amounts to not make the SCP panel combustible. Typical lightweight fillers for including in mixtures employed to make panels of the present invention are selected from the group consisting of ceramic microspheres, polymer microspheres, perlite, glass microspheres, and/or fly ash cenospheres.
Ceramic microspheres can be manufactured from a variety of materials and using different manufacturing processes. Although a variety of ceramic microspheres can be utilized as a filler component in the panels of the invention, the preferred ceramic microspheres of the invention are produced as a coal combustion by-product and are a component of the fly ash found at coal fired utilities, for example, EXTENDOSPHERES-SG made by Kish Company Inc., Mentor, Ohio or FILLITE® Brand ceramic microspheres made by Trelleborg Fillite Inc., Norcross, Ga. USA. The chemistry of the preferred ceramic microspheres of the invention is predominantly silica (SiO2) in the range of about 50 to 75 wt. % and alumina (Al2O3) in the range of about 15 to 40 wt. %, with up to 35 wt. % of other materials. The preferred ceramic microspheres of the invention are hollow spherical particles with diameters in the range of 10 to 500 microns (micrometers), a shell thickness typically about 10% of the sphere diameter, and a particle density preferably about 0.50 to 0.80 g/mL. The crushing strength of the preferred ceramic microspheres of the invention is greater than 1500 psi (10.3 MPa) and is preferably greater than 2500 psi (17.2 MPa).
Preference for ceramic microspheres in the panels of the invention primarily stems from the fact that they are about three to ten times stronger than most synthetic glass microspheres. In addition, the preferred ceramic microspheres of invention are thermally stable and provide enhanced dimensional stability to the panel of invention. Ceramic microspheres find use in an array of other applications such as adhesives, sealants, caulks, roofing compounds, PVC flooring, paints, industrial coatings, and high temperature-resistant plastic composites. Although they are preferred, it should be understood that it is not essential that the microspheres be hollow and spherical, since it is the particle density and compressive strength which provide the panel of the invention with its low weight and important physical properties. Alternatively, porous irregular particles may be substituted, provided that the resulting panels meet the desired performance.
The polymer microspheres, if present, are typically hollow spheres with a shell made of polymeric materials such as polyacrylonitrile, polymethacrylonitrile, polyvinyl chloride or polyvinylidine chloride, or mixtures thereof. The shell may enclose a gas used to expand the polymeric shell during manufacture. The outer surface of the polymer microspheres may have some type of an inert coating such as calcium carbonate, titanium oxides, mica, silica, and talc. The polymer microspheres have a particle density preferably about 0.02 to 0.15 g/mL and have diameters in the range 10 to 350 microns (micrometers). The presence of polymer microspheres may facilitate simultaneous attainment of low panel density and enhanced cutability and nailability.
Other lightweight fillers, for example glass microspheres, perlite or hollow alumino-silicate cenospheres or microspheres derived from fly ash, are also suitable for including in mixtures in combination with or in place of ceramic microspheres employed to make panels of the present invention.
The glass microspheres typically are made of alkali resistant glass materials and may be hollow. Typical glass microspheres are available from GYPTEK INC., Suite 135, 16 Midlake Blvd SE, Calgary, AB, T2X 2X7, CANADA.
In a first embodiment of the invention, only ceramic microspheres are used throughout the full thickness of the panel. The panel typically contains about 35 to 42 weight % of ceramic microspheres uniformly distributed throughout the thickness of the panel.
In a second embodiment of the invention, a blend of lightweight ceramic and glass microspheres is used throughout the full thickness of the panel. The volume fraction of the glass microspheres in the panel of the second embodiment of the invention will typically be in the range of 0 to 15% of the total volume of the dry ingredients, where the dry ingredients of the composition are the reactive powders (examples of reactive powders: hydraulic cement only; blend of hydraulic cement and pozzolan; or blend of hydraulic cement, calcium sulfate alpha hemihydrate, pozzolan, and lime), ceramic microspheres, polymer microspheres, and alkali-resistant glass fibers. A typical aqueous mixture has a ratio of water-to-reactive powders from greater than 0.3/1 to 0.7/1.
FIG. 4 shows a fragmentary perspective view of a typical tongue-and-groove SCP panel 20 of the present invention supported on C-joist metal framing 10 wherein the C-Joist metal framing 10 is supported on a header (not shown).
FIGS. 5A-5C illustrate a typical design and dimensions of tongue and groove employed in a 3⁄4 inch (19.1 mm) thick SCP panel 20.
SCP Panel and Metal Frame Systems
FIGS. 4 and 6 are perspective views of the single-layer SCP panel 20 supported on C-joist metal framing 10. For illustrative purposes a fastener (not shown) may be employed to attach the SCP panel to a C-joist. In practice the floor may be mechanically or adhesively attached to the C-joist or be not attached to the C-joist (i.e., be floating). Typically, the C-Joist framing is supported on a header or rim track (not shown).
FIG. 7A is a perspective view of SCP panels 116 of the present invention supported on a corrugated sheet 110 in a non-combustible flooring system of the present invention. In FIG. 7A the numeral 101 generally designates a composite flooring deck assembly comprising a corrugated sheet 102 supported from below by a joist (not shown) and secured from above by mechanical fasteners 104 to a diaphragm 106 of SCP panels 116. Corrugated sheet 102 typically has flat portions 108 and 110 of substantially equal length joined by connector portions 112 providing straight, parallel, regular, and equally curved ridges and hollows. This configuration has a substantially equal distribution of surface area of the corrugated sheet above and below a neutral axis 114 (as seen in FIG. 7B). Optionally the panels 116 have a tongue 118 and groove 120 formed on opposite edges thereof to provide for continuous interlocking of the flooring substrate panels 116 to minimize joint movement under moving and concentrated loads.
The embodiment of FIG. 7A involves a design using a system of corrugated steel decking, designed using steel properties provided by the Steel Deck Institute (SDI) applied over steel joists and girders. A ceiling (not shown), such as gypsum drywall mounted on DIETRICH RC DELUXE channels may be attached to the bottoms of the joists or ceiling tiles and a grid may be hung from the joists. An alternate is for the bottom surfaces of the steel to be covered with spray fiber or fireproofing materials. The steel joists which support the steel decking are any which can support the system. Typical steel joists may include those outlined by the SSMA (Steel Stud Manufacturer's Association) for use in corrugated steel deck systems, or proprietary systems, such as those sold by Dietrich as TRADE READY Brand joists. Joist spacing of 24 inches (61 cm) is common. However, spans between joists may be greater or less than this. C-joists and open web joists are typical.
In the particular embodiment of the invention illustrated in FIG. 7A, SCP panels 116 have sufficient strength to create a structural bridge over the wide rib openings 122. As illustrated in FIG. 7A, spaced screws 104, having screw heads 142 are oriented to form a series of generally triangular shaped horizontally disposed trusses (for example, truss Th shown as the horizontal line in FIG. 7B and a series of vertically disposed trusses Tv shown in FIG. 7B) between respective pairs of screws 104 throughout the length and width of spans between spaced joists (not shown) to increase the resistance to horizontal and vertical planar deflection of the deck.
FIG. 7B is a cross-sectional view of an SCP panel 116 of the present invention supported on a corrugated sheet wherein the SCP panel 116 is secured over insulation material in the non-combustible flooring system of the present invention. In the form of the invention illustrated in FIG. 7B the diaphragm 106 comprises the SCP panel 116 positioned over a sheet of insulation material 130. The diaphragm 106 is secured to upper ridge portions 108 of the corrugated sheet 102 by threaded screws 104 having upper portions 144 with enlarged heads 142. Sheet 130 of insulation material typically comprises incombustible foamed polystyrene or other suitable insulation material. For example, other insulation material such as polyurethane, fiberglass, cork and the like may be employed in combination with or in lieu of the polystyrene.
If desired, adhesive may be applied onsite or pre-applied and covered with removable strips to a side of the SCP panel, in place of or in addition to screws, for attaching the SCP panel to the flat portions 108 (FIG. 7B) of the corrugated sheet 102 or for attaching the SCP panel to other metal framing members, e.g., joists.
FIG. 7C shows another view of a floor of the present invention comprising SCP panels 116 placed on a corrugated metal sheet 102, having upper flat portions 108 and fastened mechanically (screws, etc.) or with adhesive applied onsite or pre-applied offsite.
FIG. 7D shows a side view of an embodiment of the SCP panel 116 that can be employed in the floor system of FIG. 7C having adhesive strips 145 pre-applied to the SCP panel 116 at locations for engaging at least a number of the upper flat portions 108. Prior to use the adhesive strips 145 are covered by removable tape 147. The adhesive strips 145 may also serve to dampen noise transfer.
The SCP panels may have a tongue and groove construction, which may be made by shaping the edges of the panel during casting or before use by cutting the tongue and groove with a router. For example, the tongue and groove of panel 77 may be tapered, as shown in FIGS. 5A-5C (with dimensions in inches), FIG. 7A or FIG. 14 (with dimensions in inches). The taper provides easy installation of the panels of the invention. The SCP floor panels are typically 0.75 to 1 inch thick. Any opposed pair of edges of the panels may be provided with mating tongue and groove construction.
Formulation of SCP Panels
The components used to make the shear resistant panels of the invention include hydraulic cement, calcium sulfate alpha hemihydrate, an active pozzolan such as silica fume, lime, ceramic microspheres, alkali-resistant glass fibers, superplasticizer (e.g., sodium salt of polynapthalene sulfonate), and water. Typically, both hydraulic cement and calcium sulfate alpha hemihydrate are present. Long term durability of the composite is compromised if calcium sulfate alpha hemihydrate is not present along with silica fume. Water/moisture durability is compromised when Portland cement is not present. Small amounts of accelerators and/or retarders may be added to the composition to control the setting characteristics of the green (i.e., uncured) material. Typical non-limiting additives include accelerators for hydraulic cement such as calcium chloride, accelerators for calcium sulfate alpha hemihydrate such as gypsum, retarders such as DTPA (diethylene triamine pentacetic acid), tartaric acid or an alkali salt of tartaric acid (e.g., potassium tartrate), shrinkage reducing agents such as glycols, and entrained air.
Panels of the invention will include a continuous phase in which alkali-resistant glass fibers and light weight filler, e.g., microspheres, are uniformly distributed. The continuous phase results from the curing of an aqueous mixture of the reactive powders, i.e., blend of hydraulic cement, calcium sulfate alpha hemihydrate, pozzolan, and lime), preferably including superplasticizer and/or other additives.
Typical weight proportions of embodiments of the reactive powders (inorganic binder), e.g., hydraulic cement, calcium sulfate alpha hemihydrate, pozzolan and lime, in the invention, based on dry weight of the reactive powders, are shown in TABLE 1. TABLE 1A lists typical ranges of reactive powders, lightweight filler, and glass fibers in compositions of the present invention.










TABLE 1









Weight Proportion (%)












Reactive Powder
Broad
Typical







Hydraulic Cement
20-55
25-40



Calcium Sulfate Alpha Hemihydrate
35-75
45-65



Pozzolan
 5-25
10-15



Lime
up to 3.5 or
0.75-1.25




0.2 to 3.5





















TABLE 1A








Typical Weight
Typical Weight



SCP Composition (dry basis)
Proportion (%)
Proportion (%)









Reactive Powder
35-70
35-68



Lightweight Filler
20-50
23-49



Glass Fibers
 5-20
 5-17










Lime is not required in all formulations of the invention, but it has been found that adding lime provides superior panels and it usually will be added in amounts greater than about 0.2 wt. %. Thus, in most cases, the amount of lime in the reactive powders will be about 0.2 to 3.5 wt. %.
In the first embodiment of an SCP material for use in the invention, the dry ingredients of the composition will be the reactive powders (i.e., blend of hydraulic cement, calcium sulfate alpha hemihydrate, pozzolan, and lime), ceramic microspheres and alkali-resistant glass fibers, and the wet ingredients of the composition will be water and superplasticizer. The dry ingredients and the wet ingredients are combined to produce the panel of the invention. The ceramic microspheres are uniformly distributed in the matrix throughout the full thickness of the panel. Of the total weight of dry ingredients, the panel of the invention is formed from about 49 to 56 wt. % reactive powders, 35 to 42 wt. % ceramic microspheres and 7 to 12 wt. % alkali-resistant glass fibers. In a broad range, the panel of the invention is formed from 35 to 58 wt. % reactive powders, 34 to 49 wt. % lightweight filler, e.g., ceramic microspheres, and 6 to 17 wt. % alkali-resistant glass fibers of the total dry ingredients. The amounts of water and superplasticizer added to the dry ingredients will be sufficient to provide the desired slurry fluidity needed to satisfy processing considerations for any particular manufacturing process. The typical addition rates for water range between 35 to 60% of the weight of reactive powders and those for superplasticizer range between 1 to 8% of the weight of reactive powders.
The glass fibers are monofilaments having a diameter of about 5 to 25 microns (micrometers), preferably about 10 to 15 microns (micrometers). The monofilaments typically are combined in 100 filament strands, which may be bundled into rovings of about 50 strands. The length of the glass fibers will typically be about 0.25 to 1 or 2 inches (6.3 to 25 or 50 mm) or about 1 to 2 inches (25 to 50 mm) and broadly about 0.25 to 3 inches (6.3 to 76 mm). The fibers have random orientation, providing isotropic mechanical behavior in the plane of the panel.
A second embodiment of an SCP material suitable for use in the invention contains a blend of ceramic and glass microspheres uniformly distributed throughout the full thickness of the panel. Accordingly, the dry ingredients of the composition will be the reactive powders (hydraulic cement, calcium sulfate alpha hemihydrate, pozzolan, and lime), ceramic microspheres, glass microspheres, and alkali-resistant glass fibers, and the wet ingredients of the composition will be water and superplasticizer. The dry ingredients and the wet ingredients will be combined to produce the panel of the invention. The volume fraction of the glass microspheres in the panel will typically be in the range of 7 to 15% of the total volume of dry ingredients. Of the total weight of dry ingredients, the panel of the invention is formed from about 54 to 65 wt. % reactive powders, 25 to 35 wt. % ceramic microspheres, 0.5 to 0.8 wt. % glass microspheres, and 6 to 10 wt. % alkali-resistant glass fibers. In the broad range, the panel of the invention is formed from 42 to 68 wt. % reactive powders, 23 to 43 wt. % lightweight fillers, e.g., ceramic microspheres, 0.2 to 1.0 wt. % glass microspheres, and 5 to 15 wt. % alkali-resistant glass fibers, based on the total dry ingredients. The amounts of water and superplasticizer added to the dry ingredients will be adjusted to provide the desired slurry fluidity needed to satisfy the processing considerations for any particular manufacturing process. The typical addition rates for water range between 35 to 70% of the weight of reactive powders, but could be greater than 60% up to 70% (weight ratio of water to reactive powder of 0.6/1 to 0.7/1), preferably 65% to 75%, when it is desired to use the ratio of water-to-reactive powder to reduce panel density and improve cutability. The amount of superplasticizer will range between 1 to 8% of the weight of reactive powders. The glass fibers are monofilaments having a diameter of about 5 to 25 microns (micrometers), preferably about 10 to 15 microns (micrometers). They typically are bundled into strands and rovings as discussed above. The length of the glass fibers typically is about 1 to 2 inches (25 to 50 mm) and broadly about 0.25 to 3 inches (6.3 to 76 mm). The fibers will have random orientation providing isotropic mechanical behavior in the plane of the panel.
A third embodiment of SCP material suitable for use in the invention, contains a multi-layer structure in the panel created where the outer layer(s) have improved nailability (fastening ability)/cutability. This is achieved by increasing the water-to-cement ratio in the outer layer(s), and/or changing the amount of filler, and/or adding an amount of polymer microspheres sufficiently small such that the panel remains noncombustible. The core of the panel will typically contain ceramic microspheres uniformly distributed throughout the layer thickness or alternatively, a blend of one or more of ceramic microspheres, glass microspheres and fly ash cenospheres.
The dry ingredients of the core layer of this third embodiment are the reactive powders (typically hydraulic cement, calcium sulfate alpha hemihydrate, pozzolan, and lime), lightweight filler particles (typically microspheres such as ceramic microspheres alone or one or more of ceramic microspheres, glass microspheres and fly ash cenospheres), and alkali-resistant glass fibers, and the wet ingredients of the core layer are water and superplasticizer. The dry ingredients and the wet ingredients will be combined to produce the core layer of the panel of the invention. Of the total weight of dry ingredients, the core of the panel of the invention preferably is formed from about 49 to 56 wt. % reactive powders, 35 to 42 wt. % hollow ceramic microspheres and 7 to 12 wt. % alkali-resistant glass fibers, or alternatively, about 54 to 65 wt. % reactive powders, 25 to 35 wt. % ceramic microspheres, 0.5 to 0.8 wt. % glass microspheres or fly ash cenospheres, and 6 to 10 wt. % alkali-resistant glass fibers. In the broad range, the core layer of the panel of this embodiment of the present invention is typically formed by about 35 to 58 wt. % reactive powders, 34 to 49 wt. % lightweight fillers, e.g., ceramic microspheres, and 6 to 17 wt. % alkali-resistant glass fibers, based on the total dry ingredients, or alternatively, about 42 to 68 wt. % of reactive powders, 23 to 43 wt. % ceramic microspheres, up to 1.0 wt. %, preferably 0.2 to 1.0 wt. %, other lightweight filler, e.g., glass microspheres or fly ash cenospheres, and 5 to 15 wt. % alkali-resistant glass fibers. The amounts of water and superplasticizer added to the dry ingredients will be adjusted to provide the desired slurry fluidity needed to satisfy the processing considerations for any particular manufacturing process. The typical addition rates for water will range between 35 to 70% of the weight of reactive powders but will be greater than 60% up to 70% when it is desired to use the ratio of water-to-reactive powders to reduce panel density and improve nailability and those for superplasticizer will range between 1 to 8% of the weight of reactive powders. When the ratio of water-to-reactive powder is adjusted, the slurry composition will be adjusted to provide the panel of the invention with the desired properties.
There is generally an absence of polymer microspheres and an absence of polymer fibers that would cause the SCP panel to become combustible.
The dry ingredients of the outer layer(s) of this third embodiment will be the reactive powders (typically hydraulic cement, calcium sulfate alpha hemihydrate, pozzolan, and lime), lightweight filler particles (typically microspheres such as ceramic microspheres alone or one or more of ceramic microspheres, glass microspheres and fly ash cenospheres), and alkali-resistant glass fibers, and the wet ingredients of the outer layer(s) will be water and superplasticizer. The dry ingredients and the wet ingredients are combined to produce the outer layers of the panel of the invention. In the outer layer(s) of the panel of this embodiment of the present invention, the amount of water is selected to furnish good fastening and cutting ability to the panel. Of the total weight of dry ingredients, the outer layer(s) of the panel of the invention preferably are formed from about 54 to 65 wt. % reactive powders, 25 to 35 wt. % ceramic microspheres, 0 to 0.8 wt. % glass microspheres, and 6 to 10 wt. % alkali-resistant glass fibers. In the broad range, the outer layers of the panel of the invention are formed from about 42 to 68 wt. % reactive powders, 23 to 43 wt. % ceramic microspheres, up to 1.0 wt. % glass microspheres (and/or fly ash cenospheres), and 5 to 15 wt. % alkali-resistant glass fibers, based on the total dry ingredients. The amounts of water and superplasticizer added to the dry ingredients are adjusted to provide the desired slurry fluidity needed to satisfy the processing considerations for any particular manufacturing process. The typical addition rates for water range between 35 to 70% of the weight of reactive powders and particularly greater than 60% up to 70% when the ratio of water-to-reactive powders is adjusted to reduce panel density and improve nailability, and typical addition rates for superplasticizer will range between 1 to 8% of the weight of reactive powders. The preferable thickness of the outer layer(s) ranges between 1/32 to 4/32 inches (0.8 to 3.2 mm) and the thickness of the outer layer when only one is used will be less than 3⁄8 of the total thickness of the panel.
In both the core and outer layer(s) of this embodiment of the present invention, the glass fibers are monofilaments having a diameter of about 5 to 25 microns (micrometers), preferably 10 to 15 microns (micrometers). The monofilaments typically are bundled into strands and rovings as discussed above. The length typically is about 1 to 2 inches (25 to 50 mm) and broadly about 0.25 to 3 inches (6.3 to 76 mm). The fiber orientation will be random, providing isotropic mechanical behavior in the plane of the panel.
A fourth embodiment of SCP material for use in the present invention provides a multi-layer panel having a density of 65 to 90 pounds per cubic foot and capable of resisting shear loads when fastened to framing and comprising a core layer of a continuous phase resulting from the curing of an aqueous mixture, a continuous phase resulting from the curing of an aqueous mixture comprising, on a dry basis, 35 to 70 weight % reactive powder, 20 to 50 weight percent lightweight filler, and 5 to 20 weight % glass fibers, the continuous phase being reinforced with glass fibers and containing the lightweight filler particles, the lightweight filler particles having a particle specific gravity of from 0.02 to 1.00 and an average particle size of about 10 to 500 microns (micrometers); and at least one outer layer of respectively another continuous phase resulting from the curing of an aqueous mixture comprising, on a dry basis, 35 to 70 weight % reactive powder, 20 to 50 weight percent lightweight filler, and 5 to 20 weight % glass fibers, the continuous phase being reinforced with glass fibers and containing the lightweight filler particles, the lightweight filler particles having a particle specific gravity of from 0.02 to 1.00 and an average particle size of about 10 to 500 microns (micrometers) on each opposed side of the inner layer, wherein the at least one outer layer has a higher percentage of glass fibers than the inner layer.
Making a Panel of the Invention
The reactive powders, e.g., blend of hydraulic cement, calcium sulfate alpha hemihydrate, pozzolan, and lime), and lightweight filler, e.g., microspheres, are blended in the dry state in a suitable mixer.
Then, water, a superplasticizer (e.g., the sodium salt of polynapthalene sulfonate), and the pozzolan (e.g., silica fume or metakaolin) are mixed in another mixer for 1 to 5 minutes. If desired, a retarder (e.g., potassium tartrate) is added at this stage to control the setting characteristics of the slurry. The dry ingredients are added to the mixer containing the wet ingredients and mixed for 2 to 10 minutes to form smooth homogeneous slurry.
The slurry is then combined with glass fibers, in any of several ways, with the objective of obtaining a uniform slurry mixture. The cementitious panels are then formed by pouring the slurry containing fibers into an appropriate mold of desired shape and size. If necessary, vibration is provided to the mold to obtain good compaction of material in the mold. The panel is given required surface finishing characteristics using an appropriate screed bar or trowel.
One of a number of methods to make multi-layer SCP panels is as follows. The reactive powders, e.g., blend of hydraulic cement, calcium sulfate alpha hemihydrate, pozzolan, and lime), and lightweight filler, e.g., microspheres, are blended in the dry state in a suitable mixer. Then, water, a superplasticizer (e.g., the sodium salt of polynapthalene sulfonate), and the pozzolan (e.g., silica fume or metakaolin) are mixed in another mixer for 1 to 5 minutes. If desired, a retarder (e.g., potassium tartrate) is added at this stage to control the setting characteristics of the slurry. The dry ingredients are added to the mixer containing the wet ingredients and mixed for 2 to 10 minutes to form a smooth homogeneous slurry.
The slurry may be combined with the glass fibers in several ways, with the objective of obtaining a uniform mixture. The glass fibers typically will be in the form of rovings that are chopped into short lengths. In a preferred embodiment, the slurry and the chopped glass fibers are concurrently sprayed into a panel mold. Preferably, spraying is done in a number of passes to produce thin layers, preferably up to about 0.25 inches (6.3 mm) thick, which are built up into a uniform panel having no particular pattern and with a thickness of 1⁄4 to 1 inch (6.3 to 25.4 mm). For example, in one application, a 3×5 ft (0.91×1.52 m) panel was made with six passes of the spray in the length and width directions. As each layer is deposited, a roller may be used to assure that the slurry and the glass fibers achieve intimate contact. The layers may be leveled with a screed bar or other suitable means after the rolling step. Typically, compressed air will be used to atomize the slurry. As it emerges from the spray nozzle, the slurry mixes with glass fibers that have been cut from a roving by a chopper mechanism mounted on the spray gun. The uniform mixture of slurry and glass fibers is deposited in the panel mold as described above.
If desired the outer surface layers of the panel may contain polymer spheres, or be otherwise constituted, in order that the fasteners used to attach the panel to framing can be driven easily. The preferable thickness of such layers will be about 1/32 inches to 4/32 inches (0.8 to 3.2 mm). The same procedure described above by which the core of the panel is made may be used to apply the outer layers of the panel.
Other methods of depositing a mixture of the slurry and glass fibers will occur to those familiar with the panel-making art. For example, rather than using a batch process to make each panel, a continuous sheet may be prepared in a similar manner, which after the material has sufficiently set, can be cut into panels of the desired size. The percentage of fibers relative to the volume of slurry typically constitutes approximately in the range of 0.5% to 3%, for example 1.5%. Typical panels have a thickness of about 1⁄4 to 1-1⁄2 inches (6.3 to 38.1 mm).
Another method of making panels of the present invention is by using the process steps disclosed in U.S. patent application Ser. No. 10/666,294 incorporated herein by reference. U.S. patent application Ser. No. 10/666,294, incorporated herein by reference, discloses after one of an initial deposition of loosely distributed, chopped fibers or a layer of slurry upon a moving web, fibers are deposited upon the slurry layer. An embedment device compacts the recently deposited fibers into the slurry, after which additional layers of slurry, then chopped fibers are added, followed by more embedment. The process is repeated for each layer of the board, as desired. Upon completion, the board has a more evenly distributed fiber component, which results in relatively strong panels without the need for thick mats of reinforcing fibers, as taught in prior art production techniques for cementitious panels.
More specifically, U.S. patent application Ser. No. 10/666,294 discloses a multi-layer process for producing structural cementitious panels, including: (a.) providing a moving web; (b.) one of depositing a first layer of loose fibers and (c.) depositing a layer of settable slurry upon the web; (d.) depositing a second layer of loose fibers upon the slurry; (e.) embedding the second layer of fibers into the slurry; and (f.) repeating the slurry deposition of step (c.) through step (d.) until the desired number of layers of settable fiber-enhanced slurry in the panel is obtained.
FIG. 21 is a diagrammatic elevational view of an apparatus which is suitable for performing the process of U.S. patent application Ser. No. 10/666,294. Referring now to FIG. 21, a structural panel production line is diagrammatically shown and is generally designated 310. The production line 310 includes a support frame or forming table 312 having a plurality of legs 313 or other supports. Included on the support frame 312 is a moving carrier 314, such as an endless rubber-like conveyor belt with a smooth, water-impervious surface, however porous surfaces are contemplated. As is well known in the art, the support frame 312 may be made of at least one table-like segment, which may include designated legs 313. The support frame 312 also includes a main drive roll 316 at a distal end 318 of the frame, and an idler roll 320 at a proximal end 322 of the frame. Also, at least one belt tracking and/or tensioning device 324 is preferably provided for maintaining a desired tension and positioning of the carrier 314 upon the rolls 316, 320.
Also, in the preferred embodiment, a web 326 of Kraft paper, release paper, and/or other webs of support material designed for supporting slurry prior to setting, as is well known in the art, may be provided and laid upon the carrier 314 to protect it and/or keep it clean. However, it is also contemplated that the panels produced by the present line 310 are formed directly upon the carrier 314. In the latter situation, at least one belt washing unit 328 is provided. The carrier 314 is moved along the support frame 312 by a combination of motors, pulleys, belts or chains which drive the main drive roll 316 as is known in the art. It is contemplated that the speed of the carrier 314 may vary to suit the application.
In the apparatus of FIG. 21, structural cementitious panel production is initiated by one of depositing a layer of loose, chopped fibers 330 or a layer of slurry upon the web 326. An advantage of depositing the fibers 330 before the first deposition of slurry is that fibers will be embedded near the outer surface of the resulting panel. A variety of fiber depositing and chopping devices are contemplated by the present line 310, however the preferred system employs at least one rack 331 holding several spools 332 of fiberglass cord, from each of which a cord 334 of fiber is fed to a chopping station or apparatus, also referred to as a chopper 336.
The chopper 336 includes a rotating bladed roll 338 from which project radially extending blades 340 extending transversely across the width of the carrier 314, and which is disposed in close, contacting, rotating relationship with an anvil roll 342. In the preferred embodiment, the bladed roll 338 and the anvil roll 342 are disposed in relatively close relationship such that the rotation of the bladed roll 338 also rotates the anvil roll 342, however the reverse is also contemplated. Also, the anvil roll 342 is preferably covered with a resilient support material against which the blades 340 chop the cords 334 into segments. The spacing of the blades 340 on the roll 338 determines the length of the chopped fibers. As is seen in FIG. 21, the chopper 336 is disposed above the carrier 314 near the proximal end 322 to maximize the productive use of the length of the production line 310. As the fiber cords 334 are chopped, the fibers 330 fall loosely upon the carrier web 326.
Next, a slurry feed station, or a slurry feeder 344 receives a supply of slurry 346 from a remote mixing location 347 such as a hopper, bin or the like. It is also contemplated that the process may begin with the initial deposition of slurry upon the carrier 314. The slurry is preferably comprised of varying amounts of Portland cement, gypsum, aggregate, water, accelerators, plasticizers, foaming agents, fillers and/or other ingredients, and described above and in the patents listed above which have been incorporated by reference for producing SCP panels. The relative amounts of these ingredients, including the elimination of some of the above or the addition of others, may vary to suit the use.
While various configurations of slurry feeders 344 are contemplated which evenly deposit a thin layer of slurry 346 upon the moving carrier 314, the preferred slurry feeder 344 includes a main metering roll 348 disposed transversely to the direction of travel of the carrier 314. A companion or back up roll 350 is disposed in close parallel, rotational relationship to the metering roll 348 to form a nip 352 there between. A pair of sidewalls 354, preferably of non-stick material such as Teflon® brand material or the like, prevents slurry 346 poured into the nip 352 from escaping out the sides of the feeder 344.
The feeder 344 deposits an even, relatively thin layer of the slurry 346 upon the moving carrier 314 or the carrier web 326. Suitable layer thicknesses range from about 0.05 inch to 0.20 inch. However, with four layers preferred in the preferred structural panel produced by the present process, and a suitable building panel being approximately 0.5 inch, an especially preferred slurry layer thickness is approximately 0.125 inch.
Referring now to FIGS. 21 and 22, to achieve a slurry layer thickness as described above, several features are provided to the slurry feeder 344. First, to ensure a uniform disposition of the slurry 346 across the entire web 326, the slurry is delivered to the feeder 344 through a hose 356 located in a laterally reciprocating, cable driven, fluid powered dispenser 358 of the type well known in the art. Slurry flowing from the hose 356 is thus poured into the feeder 344 in a laterally reciprocating motion to fill a reservoir 359 defined by the rolls 348, 350 and the sidewalls 354. Rotation of the metering roll 348 thus draws a layer of the slurry 346 from the reservoir.
Next, a thickness monitoring or thickness control roll 360 is disposed slightly above and/or slightly downstream of a vertical centerline of the main metering roll 348 to regulate the thickness of the slurry 346 drawn from the feeder reservoir 357 upon an outer surface 362 of the main metering roll 348. Also, the thickness control roll 360 allows handling of slurries with different and constantly changing viscosities. The main metering roll 348 is driven in the same direction of travel “T” as the direction of movement of the carrier 314 and the carrier web 326, and the main metering roll 348, the backup roll 350 and the thickness monitoring roll 360 are all rotatably driven in the same direction, which minimizes the opportunities for premature setting of slurry on the respective moving outer surfaces. As the slurry 346 on the outer surface 362 moves toward the carrier web 326, a transverse stripping wire 364 located between the main metering roll 348 and the carrier web 326 ensures that the slurry 346 is completely deposited upon the carrier web and does not proceed back up toward the nip 352 and the feeder reservoir 359. The stripping wire 364 also helps keep the main metering roll 348 free of prematurely setting slurry and maintains a relatively uniform curtain of slurry.
A second chopper station or apparatus 366, preferably identical to the chopper 336, is disposed downstream of the feeder 344 to deposit a second layer of fibers 368 upon the slurry 346. In the preferred embodiment, the chopper apparatus 366 is fed cords 334 from the same rack 331 that feeds the chopper 336. However, it is contemplated that separate racks 331 could be supplied to each individual chopper, depending on the application.
Referring now to FIGS. 21 and 23, next, an embedment device, generally designated 370 is disposed in operational relationship to the slurry 346 and the moving carrier 314 of the production line 310 to embed the fibers 368 into the slurry 346. While a variety of embedment devices are contemplated, including, but not limited to vibrators, sheep's foot rollers and the like, in the preferred embodiment, the embedment device 370 includes at least a pair of generally parallel shafts 372 mounted transversely to the direction of travel “T” of the carrier web 326 on the frame 312. Each shaft 372 is provided with a plurality of relatively large diameter disks 374 which are axially separated from each other on the shaft by small diameter disks 376.
During SCP panel production, the shafts 372 and the disks 374, 376 rotate together about the longitudinal axis of the shaft. As is well known in the art, either one or both of the shafts 372 may be powered, and if only one is powered, the other may be driven by belts, chains, gear drives or other known power transmission technologies to maintain a corresponding direction and speed to the driving roll. The respective disks 374, 376 of the adjacent, preferably parallel shafts 372 are intermeshed with each other for creating a “kneading” or “massaging” action in the slurry, which embeds the fibers 368 previously deposited thereon. In addition, the close, intermeshed and rotating relationship of the disks 372, 374 prevents the buildup of slurry 346 on the disks, and in effect creates a “self-cleaning” action which significantly reduces production line downtime due to premature setting of clumps of slurry.
The intermeshed relationship of the disks 374, 376 on the shafts 372 includes a closely adjacent disposition of opposing peripheries of the small diameter spacer disks 376 and the relatively large diameter main disks 374, which also facilitates the self-cleaning action. As the disks 374, 376 rotate relative to each other in close proximity (but preferably in the same direction), it is difficult for particles of slurry to become caught in the apparatus and prematurely set. By providing two sets of disks 374 which are laterally offset relative to each other, the slurry 346 is subjected to multiple acts of disruption, creating a “kneading” action which further embeds the fibers 368 in the slurry 346.
Once the fibers 368 have been embedded, or in other words, as the moving carrier web 326 passes the embedment device 370, a first layer 377 of the SCP panel is complete. In the preferred embodiment, the height or thickness of the first layer 377 is in the approximate range of 0.05-0.20 inches. This range has been found to provide the desired strength and rigidity when combined with like layers in a SCP panel. However, other thicknesses are contemplated depending on the application.
To build a structural cementitious panel of desired thickness, additional layers are needed. To that end, a second slurry feeder 378, which is substantially identical to the feeder 344, is provided in operational relationship to the moving carrier 314, and is disposed for deposition of an additional layer 380 of the slurry 346 upon the existing layer 377.
Next, an additional chopper 382, substantially identical to the choppers 336 and 366, is provided in operational relationship to the frame 312 to deposit a third layer of fibers 384 provided from a rack (not shown) constructed and disposed relative to the frame 312 in similar fashion to the rack 331. The fibers 384 are deposited upon the slurry layer 380 and are embedded using a second embedment device 386. Similar in construction and arrangement to the embedment device 370, the second embedment device 386 is mounted slightly higher relative to the moving carrier web 314 so that the first layer 377 is not disturbed. In this manner, the second layer 380 of slurry and embedded fibers is created.
Referring now to FIG. 21, with each successive layer of settable slurry and fibers, an additional slurry feeder station 344, 378 followed by a fiber chopper 336, 366, 382 and an embedment device 370, 386 is provided on the production line 310. In the preferred embodiment, four total layers (see for example, the panel 21 of FIG. 3) are provided to form the SCP panel. Upon the disposition of the four layers of fiber-embedded settable slurry as described above, a forming device 394 is preferably provided to the frame 312 to shape an upper surface 396 of the panel. Such forming devices 394 are known in the settable slurry/board production art, and typically are spring-loaded or vibrating plates which conform the height and shape of the multi-layered panel to suit the desired dimensional characteristics.
The panel which is made has multiple layers (see for example layers 22, 24, 26, 28 of panel 21 of FIG. 3) which upon setting form an integral, fiber-reinforced mass. Provided that the presence and placement of fibers in each layer are controlled by and maintained within certain desired parameters as is disclosed and described below, it will be virtually impossible to delaminate the panel.
At this point, the layers of slurry have begun to set, and the respective panels are separated from each other by a cutting device 398, which in the preferred embodiment is a water jet cutter. Other cutting devices, including moving blades, are considered suitable for this operation, provided that they can create suitably sharp edges in the present panel composition. The cutting device 398 is disposed relative to the line 310 and the frame 312 so that panels are produced having a desired length, which may be different from the representation shown in FIG. 21. Since the speed of the carrier web 314 is relatively slow, the cutting device 398 may be mounted to cut perpendicularly to the direction of travel of the web 314. With faster production speeds, such cutting devices are known to be mounted to the production line 310 on an angle to the direction of web travel. Upon cutting, the separated panels 321 are stacked for further handling, packaging, storage and/or shipment as is well known in the art.
In quantitative terms, the influence of the number of fiber and slurry layers, the volume fraction of fibers in the panel, and the thickness of each slurry layer, and fiber strand diameter on fiber embedment efficiency has been investigated. In the analysis, the following parameters were identified:
vT=Total composite volume
vs=Total panel slurry volume
vf=Total panel fiber volume
vf,l=Total fiber volume/layer
vT,l=Total composite volume/layer
vs,l=Total slurry volume/layer
Nl=Total number of slurry layers; Total number of fiber layers
Vf=Total panel fiber volume fraction
df=Equivalent diameter of individual fiber strand
lf=Length of individual fiber strand
t=Panel thickness
tl=Total thickness of individual layer including slurry and fibers
ts,l=Thickness of individual slurry layer
nf,l, nf1,l, nf2,l=Total number of fibers in a fiber layer
sf,lP, sf,lP, sf2,lP=Total projected surface area of fibers contained in a fiber layer
Sf,lP, Sf1,lP, Sf2,lP, =Projected fiber surface area fraction for a fiber layer.
Projected Fiber Surface Area Fraction, Sf,lP 
Assume a panel composed of equal number of slurry and fiber layers. Let the number of these layers be equal to Nl, and the fiber volume fraction in the panel be equal to Vf.
In summary, the projected fiber surface area fraction, Sf,lP of a layer of fiber network being deposited over a distinct slurry layer is given by the following mathematical relationship:




  
    S
    
      f
      ,
      l
    
    P
  
  =
  
    
      
        4
        ⁢
        
          V
          f
        
        ⁢
        t
      
      
        π
        ⁢
        
          
        
        ⁢
        
          N
          l
        
        ⁢
        
          d
          f
        
      
    
    =
    
      
        4
        ⁢
        
          
        
        ⁢
        
          V
          f
        
        *
        
          t
          
            s
            ,
            l
          
        
      
      
        π
        ⁢
        
          
        
        ⁢
        
          
            d
            f
          
          ⁡
          
            (
            
              1
              -
              
                V
                f
              
            
            )
          
        
      
    
  




where, Vf is the total panel fiber volume fraction, t is the total panel thickness, df is the diameter of the fiber strand, Nl is the total number of fiber layers and ts,l is the thickness of the distinct slurry layer being used.
Accordingly, to achieve good fiber embedment efficiency, the objective function becomes keeping the fiber surface area fraction below a certain critical value. It is noteworthy that by varying one or more variables appearing in the Equations 8 and 10, the projected fiber surface area fraction can be tailored to achieve good fiber embedment efficiency.
Different variables that affect the magnitude of projected fiber surface area fraction are identified and approaches have been suggested to tailor the magnitude of “projected fiber surface area fraction” to achieve good fiber embedment efficiency. These approaches involve varying one or more of the following variables to keep projected fiber surface area fraction below a critical threshold value: number of distinct fiber and slurry layers, thickness of distinct slurry layers and diameter of fiber strand.
Based on this fundamental work, the preferred magnitudes of the projected fiber surface area fraction, Sf,lP have been discovered to be as follows:
Preferred projected fiber surface area fraction, Sf,lP<0.65
Most preferred projected fiber surface area fraction, Sf,lP<0.45
For a design panel fiber volume fraction, Vf, achievement of the aforementioned preferred magnitudes of projected fiber surface area fraction can be made possible by tailoring one or more of the following variables—total number of distinct fiber layers, thickness of distinct slurry layers and fiber strand diameter. In particular, the desirable ranges for these variables that lead to the preferred magnitudes of projected fiber surface area fraction are as follows:
Thickness of Distinct Slurry Layers in Multiple Layer SCP panels ts,l 
Preferred thickness of distinct slurry layers, ts,l≦0.20 inches
More Preferred thickness of distinct slurry layers, ts,l≦0.12 inches
Most preferred thickness of distinct slurry layers, ts,l≦0.08 inches
Number of Distinct Fiber Layers in Multiple Layer SCP panels, Nl 
Preferred number of distinct fiber layers, Nl≧4
Most preferred number of distinct fiber layers, Nl≧6
Fiber Strand Diameter, df 
Preferred fiber strand diameter, df≧30 tex
Most preferred fiber strand diameter, df≧70 tex
In using the panels as structural subflooring or flooring underlayment, they preferably will be made with a tongue and groove construction, which may be made by shaping the edges of the panel during casting or before use by cutting the tongue and groove with a router. Preferably, the tongue and groove will be tapered, as shown in FIGS. 3 and 4A-C, the taper providing easy installation of the panels of the invention.
Properties
The SCP panel metal frame system of the present invention preferably has one or more of the properties listed in TABLE 2.












TABLE 2






ASTM

Preferred




Physical
Test

Target
Typical


Characteristics
Method
Unit
Value
Range
Notes







Non-Combustibility
E-136
Weight
≦50%
≦50%
From Sec. 8, E-136




Loss




Temp
≦54° F.
≦54°
From Sec. 8, E-136




Rise




30
No
No flaming
From Sec. 8, E-136




seconds
flaming


Water Durability


Flex. Strength of


Sheathing


Dry
C-947
psi
≧1800
1400-3500


Wet
C-947
psi
≧1650
1300-3000


AMOE of Sheathing


Dry

ksi
≧700
 600-1000


Wet

ksi
≧600
550-950


Screw Withdrawal


(screw size: #8 wire


15⁄8 inch screw


with 0.25 inch


diameter head


minimum)


1⁄2′′ Panel-Dry
D-1761
pounds
352
250-450
Equiv. to American







Plywood Assoc. (APA)







S-4


1⁄2′′ Panel-Wet
D-1761
pounds
293
200-400
% of force for SCP







relative to OSB 82%; %







of force for SCP relative







to Plywood 80%


3⁄4′′ Panel-Dry
D-1761
pounds
522
450-600
Equiv. to American







Plywood Assoc. (APA)







S-4


3⁄4′′ Panel-Wet
D-1761
pounds
478
450-550
% of force for SCP







relative to OSB 82%; %







of force for SCP relative







to Plywood 80%


Lateral Screw


Resistance


(screw size: #8 wire


15⁄8 inch screw


with 0.25 inch


diameter head


minimum)


1⁄2′′ Panel-Dry
D-1761
pounds
445
350-550
Equiv. to APA S-4


1⁄2′′ Panel-Wet
D-1761
pounds
558
400-650
% of force for SCP







relative to OSB 73; % of







force for SCP relative to







Plywood 82%


3⁄4′′ Panel-Dry
D-1761
pounds
414
400-500
Equiv. to APA S-4


3⁄4′′ Panel-Wet
D-1761
pounds
481
400-500
% of force for SCP







relative to OSB 73; % of







force for SCP relative to







Plywood 82%


Static & Impact Test


(3⁄4 inch thick SCP)


Ultimate


Static
E-661
pounds
1286
1000-1500
APA S-1; 16 o.c. Span







Rating ≧550 lbs.


Following
E-661
pounds
2206
1500-3000
APA S-1; 16 o.c. Span


Impact




Rating ≧400 lbs


Deflection under 200 lb


Load


Static
E-661
inches
0.014
0.010-0.060
APA S-1;







16 o.c. Span







Rating ≦0.078′′


Following
E-661
inches
0.038
0.020-0.070
APA S-1;


Impact




16 o.c. Span Rating







≦0.078′′


Uniform Load


3⁄4′′ Panel-Dry
E-330
psf
330
300-450
16 o.c. Span Rating ≧330 psf


Linear Expansion


1⁄2′′ to 3⁄4′′
APA P-1
%
≦0.1
≦0.1
APA P-1 requires ≦0.5%


Panel


Water Absorption


1⁄2′′ Panel
APA PRP-
%
11.8
 7 to 15
% water absorption of



108



SCP relative to 1⁄2 inch







thick OSB: 51.5%,







% water absorption of







SCP relative to 1⁄2 inch







thick Plywood: 46.2%


3⁄4′′ Panel
APA PRP-
%
10.8
 7 to 15
% water absorption of



108



SCP relative to







OSB: 51.3%,







% water absorption of







SCP relative to







Plywood: 48.1%


Thickness Swell


1⁄2′′ Panel
APA PRP-
%
2.3
1 to 5
% water absorption of



108



SCP relative to 1⁄2 inch







thick OSB: 22.2%, %







water absorption of SCP







relative to 1⁄2 inch thick







Plywood: 7.8%


3⁄4′′ Panel
APA PRP-
%
2.4
1 to 5
% water absorption of



108



SCP relative to







OSB: 22.2%, % water







absorption of SCP







relative to Plywood: 7.8%


Mold & Bacteria


Resistance


1⁄2 to 3⁄4′′ Panel
G-21

1
1
OSB & Plywood have







food source


1⁄2 to 3⁄4′′ Panel
D-3273

10
10
OSB & Plywood have







food source


Termite Resistance


1⁄2 to 3⁄4′′ Panel


No
No food





food
source





source


Horizontal Design


Shear Capacity of


the Floor Diaphragm


3⁄4′′ Panel-
E-455
pounds
487.2
 300-1000
Performance relates to


10′ × 20′ Floor

per linear

Typically
panel properties,




foot

400-800
joist depth & spacing and







fastener type and spacing


System Fire


Resistance


5⁄8 to 3⁄4′′ SCP
E-119
Time
1 hr
1 to 1.5 hr.
Nominal 4′′ deep stud,


Panel on one side of


and 10 min.

24′′ O.C.,


metal frame




batt insulation, 1 layer







5⁄8′′ FIRECODE Gypsum







Board available from







USG.


3⁄4′′ Panel SCP on
E-119
Time
2 hr-9 min.
2 hr.
Nominal 10′′ deep joist,


one side of metal




24′′ O.C.,


frame




batt insulation, 1 layer







5⁄8′′ FIRECODE Gypsum







Board available from







USG









Horizontal Design Shear Capacity in Table 2 provides for a safety factor of 3.
A typical 3⁄4 inch (19 mm) thick panel when tested according to ASTM 661 and APA S-1 test methods over a span of 16 inches (406.4 mm) on centers, has an ultimate load capacity greater than 550 lb (250 kg), under static loading, an ultimate load capacity greater than 400 lb (182 kg) under impact loading, and a deflection of less than 0.078 inches (1.98 mm) under both static and impact loading with a 200 lb (90.9 kg) load.
Typically, the flexural strength of a panel having a dry density of 65 lb/ft3 (1041 kg/m3) to 90 lb/ft3 after being soaked in water for 48 hours is at least 1000 psi (7 MPa), e.g. 1300 psi (9 MPa), preferably 1650 psi (11.4 MPa), more preferably at least 1700 psi (11.7 MPa) as measured by the ASTM C 947 test.
Typically the SCP horizontal floor diaphragm system has a higher specific stiffness than a floor system of open web bar joists, metal deck and poured in place concrete or precast plank with a topping slab on load bearing walls.
Typically the horizontal shear diaphragm load carrying capacity of the system will not be lessened by more than 25%, preferably not be lessened by more than 20%, or not be lessened by more than 15%, or not be lessened by more than 10% when exposed to water in a test wherein a 2 inch head of water is maintained over 3⁄4 inch thick SCP panels fastened on a 10 foot by 20 foot metal frame for a period of 24 hours.
Typically the system will not absorb more than 0.7 pounds per square foot of water when exposed to water in a test wherein a 2 inch head of water is maintained over 3⁄4 inch thick SCP panels fastened on a 10 foot by 20 foot metal frame for a period of 24 hours.
Typically an embodiment of the present system having a 10 foot wide by 20 foot long by 3⁄4 inch thick diaphragm of the SCP panels attached to a 10 foot by 20 foot metal frame will not swell more than 5% when exposed to a 2 inch head of water maintained over the SCP panels fastened on the metal frame for a period of 24 hours.
Typically, every component of the present system meets ASTM G-21 in which the system achieves approximately a 1 and meets ASTM D-3273 in which the system achieves approximately a 10. Also, typically the present system supports substantially zero bacteria growth when clean. Also, typically the present system is inedible to termites.
Due to its being lightweight and strong, this combination of the present floor system of a horizontal diaphragm of 3⁄4 inch thick SCP panel on metal frame permits efficient use of building volume for a given building footprint to permit maximization of building volume for the given building footprint. The lightweight nature of this system avoids the dead load associated with pan/cement systems. Less dead load allows building comparable size structures on less stable soil. Moreover, the system may be non-directional, in that the panels of the system may be placed with their long dimension parallel or perpendicular to the metal joists of the frame without losing strength or load carrying characteristics, wherein the ability of the system to support dead and live loads without failure is the same regardless of the orientation of the SCP panel on the metal framing. Also, a potential advantage of the present system is that it may have greater compressive strength. This is useful in building where the walls of the structure rest on portions, e.g., the perimeter of the floor diaphragm formed by the panels. As multiple stories are added the weight of those stories can exert very high compressive forces on the lower floor panels.
The present invention has an unexpected advantage in cold weather performance. Conventional cementitious panels can be brittle in cold weather. Thus, installing such panels in cold weather would require careful handling by the construction workers during installation. However, in the present system the SCP panels can preferably withstand being installed on metal flooring elements when the ambient temperature is less than 32 degrees F. (0 degrees C.), or even less than 20 degrees F (minus 7.5 degrees C) without cracking. This is a very significant advantage because it facilitates building in harsh climates in winter thus increasing builder productivity. The present SCP panels can preferably withstand being subjected to normal rough treatment during installation at these cold temperatures. For instance, at these cold temperatures placing the SCP panel may include a step of dropping the panel on the metal flooring elements, e.g., trusses, such that at least one end of the panel falls in free fall at least 2 feet, typically at least 3 feet, for example 3 to 6 feet, without cracking. For example, this occurs when one end of the panel is placed on one or more metal flooring elements and then the opposing other end is released to drop in free fall on one or more metal flooring elements.
EXAMPLE 1
An experiment was conducted for fire endurance testing on comparative structural sheathing in the small-scale horizontal furnace (SSHF). Five samples, 1⁄2 inch (13 mm). Structural Cement Panel (SCP) of a composition of the present invention, 3⁄4 in. (19mm) VIROC panel, 1⁄2 in. (13 mm) NOVATECH panel, 15/32 in. (12 mm) plywood (grade A-C) and 31/64 in. (12 mm) Oriented Strand Board (OSB), were tested as part of 4 ft. by 4 ft. assemblies.
Each assembly was constructed of metal framing, 358, 20 gauge CR runners and ST studs spaced 24 in. on center. The test material was applied to the exposed surface and one layer of USG's SHEETROCK 5⁄8 in. (16 mm) FIRECODE Type SCX gypsum wallboard was applied to the unexposed surface for each of the five tests. The exposed surface material is applied perpendicular to the studs with a joint at the mid-span of the assembly. Thermocouples were placed in both cavities underside of the exposed panel and on the unexposed surface for temperature comparison of the assemblies. The furnace temperatures were controlled to the ASTM E119 Time/Temperature Curve. Temperature measurements were made of the finish rating and the unexposed surface for the duration of the test. Observations were made as to the estimated condition of the exposed surface during the test. Standard ASTM E119 temperature limits for the thermocouple readings were 250° F. (136° C.) above ambient for the average and 325° F. (183° C.) above ambient for the individual were used as control limits. The purpose of the testing was to provide a relative comparison of the performance of product material in the fire test. The procedure does not provide a fire endurance rating for a system.
The formulation of the SCP panels used in the small-scale horizontal furnace test (Example 1 and Example 3) is as follows in TABLE 2A:









TABLE 2A







Weight Proportion (%)



















Reactive Powder Blend




Reactive Powder Blend



Portland Cement
29



Calcium Sulfate Alpha Hemihydrate
58



Silica Fume
12



Lime
1



SCP Cementitious Composition



Ingredient



Portland Cement
12.3



Calcium Sulfate Alpha Hemihydrate
24.7



Silica Fume
5.1



Lime
0.4



Ceramic Microspheres
26.4



Superplasticizer
1.9



Water
21.9



Alkali-Resistant Glass Fibers1
7.2







1Weight proportion corresponds to 3.06% volume fraction of AR Glass Fibers in the composite



Length of glass fibers used in the small-scale horizontal furnace test - 40 mm.






The results from testing of the five samples can be found in TABLE 3. Both the average (A) and the individual (I) readings are in minutes when the temperature criteria limits were exceeded during each test. The SCP board has a composition of a panel of the present invention.







TABLE 3







Data Summary for Examples 1-5











SSHF


Unexposed
Exposed


Exam-

Finish
Surface
Surface


ple

Rating
(Overlimit/
Condition:


No.
Sample ID
(Minutes)
Minutes)
End of Test





1
1⁄2 in.
09:24 (A)
46:05 (A)
Intact



(13 mm) SCP
10:05 (l)
46:16 (l)
Low Shrinkage



board


2
3⁄4 in. (19 mm)
19:16 (A)
48:42 (A)
Intact



VIROC board
21.52 (l)
47:49 (l)
Moderate






Shrinkage


3
1⁄2 in. (13 mm)
12:52 (A)
46 42 (A)
Panel



NOVATECH
13 27 (l)
47:13 (l)
Delamination



board


No Fall Off


4
 15/32 in. (12 mm)
 6:40 (A)
23:42 (A)
Board



Plywood board
 7:10 (l)
23:31 (l)
Fall Off



(A-C Grade)


5
 31/64 in. (12 mm)
 6:50 (A)
24.25 (A)
Board



OSB board
 8:12 (l)
23:30 (I)
Fall Off









EXAMPLE 1 SAMPLE CONSTRUCTION
Size 48 in. (122 cm) by 48-5⁄8 in. (124 cm)
Studs: 358 ST, 20 gauge Spacing: 24 in. (61 cm) on center
Runners: 358 CR, 20 gauge; Cavity: Void
Facing: (Fire Side) One layer 1⁄2 in. (13 mm) USG Structural Cement Panel (SCP)

    
    
        (Unexposed Side) One Layer 5⁄8 in. (16 mm) SHEETROCK® FIRECODE® (Type X) Panel
    
    


Table 4 lists the boards employed in this example as test materials. The boards were subjected to heating as presented in Table 5. Observations from this heating are presented in Table 6.







TABLE 4







Example 1 Test Materials











SHEETROCK ®




Brand Wallboard



1⁄2′′ (13 mm) SCP
5⁄8′′ × 48′′ × 120′′



1⁄2′′ × 48′′ × 96′′
(16 mm ×



(13 mm × 122 cm ×
122 cm × 305 cm)



244 cm)
Type C





Lbs/1000 sq. ft
2736
2290


Average board thickness,
 0.528 (13.4)
 0.620 (15.7)


in. (mm)


Average density, pcf (g/cc)
62.128 (0.995)
44.332 (0.710)


Average panel weight, lbs.
 22.46 (10.19)
 37.13 (16.84)


(kgs.)
















TABLE 5







Example 1 Temperature Information










Average
Individual





Unexposed Surface
324° F. (182° C.)
399° F. (229° C.)


Limiting Temperature Criteria


Degrees 79° F. (29° C.) Ambient


Unexposed Surface

TC #4 at


Temperature Limits Reached
46:05
46:16


Finish Rating
323° F. (182° C.)
398° F. (229° C.)


Limiting Temperature Criteria


Degrees 79° F. (29° C.) Ambient


Finish Rating

TC #8 at


Temperature Limits Reached
 9:24
10:05









FIRE TEST DURATION: 70 MIN. 0 SEC.
TEST TERMINATED—No Board Fall Off







TABLE 6







Example 1 Observations









Time
Furnace



(Min:Sec)
Pressure
Observations












 4:00
+0.10
The exposed board is very light tan in color.


12:00
+0.07
Very light smoke and steam vapor emitting from




unexposed surface.


18:00
+0.08
Butt joint opening is at estimated 1/16 inch max.




More smoke and steam vapor emitting from




unexposed surface.


22:00
+0.08
Very heavy smoke and steam vapor emitting from




unexposed surface. Exposed board looks good and




is in place.


30:00
+0.06
Butt joint opening is at estimated 1⁄8 inch max.


33:00
+0.08
Board sag in between the studs is at estimated 1⁄8




inch to 1⁄4 inch max.


38:00
+0.07
Light smoke and steam vapor emitting from




unexposed surface.


41:00
+0.10
Board sag in between the studs is at estimated 1⁄8




to 1⁄4 inch max.


48:00
+0.07
Butt joint opining is at 3/16 to 1⁄4 inch max.


51:00
+0.08
Board sag in between the studs is at estimated 1⁄2




inch max.


53:00
+0.09
Can hear audible sound of paper burning on




unexposed surface.


63:00
+0.08
Board sag in between the studs is at estimated 1⁄2




to 5⁄8 inch max.


70:00

Test terminated. No board fall off.









EXAMPLE 2 SAMPLE CONSTRUCTION
Size 48 in. (122 cm) by 48-5⁄8 in. (124 cm)
Studs: 358 ST, 20 gauge Spacing: 24 in. (61 cm) on center
Runners: 358 CR, 20 gauge; Cavity: Void
Facing: (Fire Side) One layer 3⁄4 in. VIROC Board

    
    
        (Unexposed Side) One Layer 5⁄8 in. (16 mm) SHEETROCK® FIRECODE® (Type X) Panel
    
    


Table 7 lists the boards employed in this example as test materials. The boards were subjected to heating as presented in Table 8. Observations from this heating are presented in Table 9.







TABLE 7







Example 2 Test Materials











SHEETROCK ®



VIROC Board
Brand Wallboard



3⁄4′′ × 48′′ × 485⁄8′′
5⁄8′′ × 48′′ × 120′′



(13 mm × 122 cm ×
(16 mm × 122 cm ×



124 cm)
305 cm) Type X





Lbs/1000 sq. ft
—
2290


Average board
0.760 (19)
 0.620 (15.7)


thickness, inches


(mm)


Average density,
83.00 (1.33)
44.344 (0.710)


pcf (g/cc)


Average panel
22.46 (10.19)
 37.13 (16.84)


weight, lbs.


(kgs.)
















TABLE 8







Example 2 Temperature Information










Average
Individual





Unexposed Surface
323° F. (182° C.)
398° F. (229° C.)


Limiting Temperature Criteria


Degrees 73° F. (26° C.) Ambient


Unexposed Surface

TC #4 at


Temperature Limits Reached
48:42
47:49


Finish Rating
325° F. (183° C.)
400° F. (230° C.)


Limiting Temperature Criteria


Degrees 79° F. (29° C.) Ambient


Finish Rating

TC #8 at


Temperature Limits Reached
19:16
21:52









FIRE TEST DURATION: 60 MIN. 0 SEC.
TEST TERMINATED—No Board Fall Off







TABLE 9







Example 2 Observations









Time




(Min:Sec)
Furnace Pressure
Observations












2:30
+0.08
The butt joint is smoking and is dark brown in color. Smoke




emitting from unexposed surface.


6:00
+0.08
Exposed board is charred and black in color. Butt joint




opening is an estimated 1⁄8 inch max. Board crack by west




perimeter by center stud.


9:00
+0.08
Exposed board is lightly flaming on the entire surface. Butt




joint opening is at estimated 3/16 inch to 1⁄4 inch max.




Board sag is at estimated 1⁄4 inch to 3⁄8 inch max.


12:30
+0.08
Board sag is at estimated 1⁄2 inch to 3⁄4 inch max. Butt joint




opening is at estimated 1⁄2 inch max. and is peeling away




towards fire. Surface is still lightly flaming.


18:00
+0.08
Board is still flaming on entire surface. Smoke and steam




vapor is emitting from unexposed surface.


19:30
+0.08
Butt joint opening is at estimated 1 inch max. and peeling




away. Board sag is estimated 11⁄2 inch max. Exposed board




is still flaming.


24:00
+0.08
Butt joint opening is at estimated 11⁄2 to 2 inches max. The




west board has a crack across the center by stud. Center




board screws have pulled away from center stud.


29:00
+0.08
Crack opening in the center of the west board is at estimated




1⁄2 inch max. Board sag is at estimated 21⁄2 to 3 inches




max. The board is still flaming. Smoke and steam vapor are




emitting from unexposed surface.


34:00
+0.07
Board sag is at estimated 4 inches max. East board has a




crack at the center by the stud.


40:00
+0.08
West board is sagged towards fire an estimated 5 inches




max. East board crack opening is an estimated 5⁄8 inches




max. Board is still flaming.


43:00
+0.08
Board sample is peeling away towards fire at estimated 5-6




inches max. The sample cavity is seen due to board peel




away.


50:00
+0.0
Board sag is at estimated 6 to 7 inches max. and still peeling




towards fire. Butt joint opening is at estimated 3 inches max.




East and west center board cracks are at estimated 11⁄2




inches max.


60:00

Test terminated. No board fall off.









EXAMPLE 3 SAMPLE CONSTRUCTION
Size 48 in. (122 cm) by 48-5⁄8 in. (124 cm)
Studs: 358 ST, 20 gauge Spacing: 24 in. (61 cm) on center
Runners: 358 CR, 20 gauge; Cavity: Void
Facing: (Fire Side) One layer 1⁄2 inch NovaTech Board

    
    
        (Unexposed Side) One Layer 5⁄8 in. (16 mm) SHEETROCK® FIRECODE® (Type X) Panel
    
    


Table 10 lists the boards employed in this example as test materials. The boards were subjected to heating as presented in Table 11. Observations from this heating are presented in Table 12.







TABLE 10







Example 3 Test Materials











SHEETROCK ®



NovaTech Board
Brand Wallboard



3⁄4′′ × 48′′ × 485⁄8′′
5⁄8′′ × 48′′ × 120′′



(13 mm × 122 cm ×
(16 mm × 122 cm ×



124 cm)
305 cm) Type X















Lbs/1000 sq. ft
3163
2298



Average board
 0.531 (13)
 0.620 (15.7)



thickness, in. (mm)



Average density,
71.544 (1.15)
44.517 (0.713)



pcf (g/cc)



Average panel
 25.90 (11.75)
 37.25 (16.9)



weight, lbs. (kgs.)

















TABLE 11







Example 3 TEMPERATURE INFORMATION










Average
Individual













Unexposed Surface
324° F. (182° C.)
399° F. (229° C.)


Limiting Temperature Criteria


Degrees 74° F. (26° C.) Ambient


Unexposed Surface
46:42
TC #2 at


Temperature Limits Reached

47:13


Finish Rating
326° F. (183° C.)
401° F. (231° C.)


Limiting Temperature Criteria


Degrees 76° F. (27° C.) Ambient


Finish Rating
12:52
TC #8 at


Temperature Limits Reached

13:27









FIRE TEST DURATION: 70 MIN. 0 SEC.;
TEST TERMINATED—Board Delamination, No Board Fall Off







TABLE 12







Example 3 Observations









Time
Furnace



(Min:Sec)
Pressure
Observations





 2:30
+0.07
Exposed south half of west board popped apart and




delaminated and has fallen off. Estimated 1⁄4 inch of board




thickness is still in place at the cold junction. Exposed glass




fibers are seen on remaining board.


 8:00
+0.07
Light smoke and steam vapor emitting from unexposed surface.


18:00
+0.08
More smoke and steam vapor emitting from unexposed




surface. More board cracks by center stud screws


24:00
+0.07
Heavy smoke and steam vapor emitting from unexposed




surface. Butt joint is at estimated 3/16 to 1⁄4 inch max.




Northeast corner board is peeling away towards furnace and is




estimated at 1⁄4 inch max. Board thickness is falling off


32:00
+0.07
Less smoke and steam vapor emitting from unexposed surface.


35:00
+0.07
Butt joint opening is at estimated 3⁄8 inch max.


37:00
+0.08
Estimated 1⁄4 inch thick by 12 inch by 24 inch Board has




fallen at corner of north east board


45:30
+0.08
Very light smoke and steam vapor is emitting from unexposed




surface. Exposed board sag is at estimated 1⁄2 to 5⁄8 inch max


53:00
+0.07
Butt joint opening is at estimated 3⁄8 inch to 1⁄2 inch max.


57:00
+0.08
Unexposed wall board is starting to get brown in color over




butt joint location. Very little smoke and steam vapor emitting from




unexposed surface


61:00
+0.07
Board sag is at estimated 1 to 11⁄2 inches max.


63:00
+0.10
Hair cracks starting on southeast section of board


65:00
+0.09
Butt joint opening is at estimated 1⁄2 inches max.


67:00
+0.10
More exposed board peeling at northeast section. Total board




delamination is an estimated 15% max


70:00

Test terminated. Some board delamination. No board fall off.









EXAMPLE 4 SAMPLE CONSTRUCTION
Size 48 in. (122 cm) by 48-5⁄8 in. (124 cm)
Studs: 358 ST, 20 gauge; Spacing: 24 in. (61 cm) on center
Runners: 358 CR, 20 gauge; Cavity: Void
Facing: (Fire Side) One layer 15/32 inch (12mm) Plywood (A/C) Board

    
    
        (Unexposed Side) One Layer 5⁄8 in. (16 mm) SHEETROCK® FIRECODE® (Type X) Panel
    
    


Table 13 lists the boards employed in this example as test materials. The boards were subjected to heating as presented in Table 14. Observations from this heating are presented in Table 15.







TABLE 13







Example 4 Test Materials











SHEETROCK ®



Plywood Board
Brand Wallboard



 15/32′′ × 48′′ × 485⁄8′′
5⁄8′′ × 48′′ × 120′′



(16 mm × 122 cm ×
(16 mm × 122 cm ×



124 cm)
305 cm) Type X













Lbs/1000 sq. ft
1644
2283


Average board thickness,
 0.499 (12.6 mm)
 0.619 (16)


in. (mm)


Average density, pcf (g/cc)
39.544 (0.633)
44.242 (0.709)


Average panel weight, lbs.
 52.50 (28.8)
 37.00 (16.78)


(kgs.)
















TABLE 14







Example 4 Temperature Information










Average
Individual













Unexposed Surface
323° F. (182° C.)
398° F. (229° C.)


Limiting Temperature Criteria


Degrees 73° F. (26° C.) Ambient


Unexposed Surface
23:42
TC #3 at


Temperature Limits Reached

23:31


Finish Rating
325° F. (183° C.)
400° F. (230° C.)


Limiting Temperature Criteria


Degrees 76° F. (27° C.) Ambient


Finish Rating
 6:40
TC #7 at


Temperature Limits Reached

7:10









FIRE TEST DURATION: 32 MIN. 0 SEC.
TEST TERMINATED—Board Fall Off







TABLE 15







Example 4 Observations









Time
Furnace



(Min:Sec)
Pressure
Observations












0:30
+0.06
Exposed boards are black in color, burnt charred surface.


2:00
+0.04
Heavy smoke emitting from unexposed surface.


4:00
+0.08
Exposed boards are flaming. Very heavy smoke emitting from




unexposed surface.


6:00
+0.08
Butt joint opening is at estimated 1⁄4 in. max.


8:00
+0.08
Very heavy flaming seen through furnace view ports. Sample can




not be seen.


9:00
+0.07
Exposed 1⁄2 inch plywood has fallen in furnace. Cavity is now




exposed.


14:00 
+0.08
Still very heavy smoke and steam vapor emitting from unexposed




surface.


19:00 
+0.08
The exposed wallboard has hairline haze cracking seen from




exposed cavity.


28:00 
+0.07
Less smoke and steam vapor emitting from unexposed surface.




The unexposed side wallboard is now brown in color.


32:00 

Test terminated. Board has fallen off.









EXAMPLE 5 SAMPLE CONSTRUCTION
Size 48 in. (122 cm) by 48-5⁄8 in. (124 cm)
Studs: 358 ST, 20 gauge; Spacing: 24 in. (61 cm) on center
Runners: 358 CR, 20 gauge; Cavity: Void
Facing: (Fire Side) One layer 31/64 inch Oriented Strand Board (OSB)

    
    
        (Unexposed Side) One layer 5⁄8 in. (16 mm) SHEETROCK® FIRECODE® (Type X) panel.
    
    


Table 16 lists the boards employed in this example as test materials. The boards were subjected to heating as presented in Table 17. Observations from this heating are presented in Table 18.







TABLE 16







Example 5 Test Materials











SHEETROCK ®



OSB Board
Brand Wallboard



 15/32′′ × 48′′ × 485⁄8′′
5⁄8′′ × 48′′ × 120′′



(12 mm × 122 cm ×
(16 mm × 122 cm ×



124 cm)
305 cm) Type X













Lbs/1000 sq. ft
1644
2283


Average board thickness,
 0.499 (12.6 mm)
 0.619 (0.157)


in. (cm)


Average density, pcf (g/cc)
39.544 (0.633)
44.242 (0.709)


Average panel weight, lbs.
 52.50 (28.8)
 37.00 (16.78)


(kgs.)
















TABLE 17







Example 5 Temperature Information










Average
Individual













Unexposed Surface
327° F. (184° C.)
402° F. (231° C.)


Limiting Temperature Criteria


Degrees 77° F. (28° C.)Ambient


Unexposed Surface
24:25
TC #3 at


Temperature Limits Reached

23:30


Finish Rating
330° F. (186° C.)
405° F. (233° C.)


Limiting Temperature Criteria


Degrees 80° F. (30° C.) Ambient


Finish Rating
 6:50
TC #8 at


Temperature Limits Reached

8:12









FIRE TEST DURATION: 32 MIN. 0 SEC.
TEST TERMINATED—Board Fall Off







TABLE 18







Example 5 Observations









Time
Furnace



(Min:Sec)
Pressure
Observations












 1:00
+0.02
Exposed board is smoking and black in color


 1:30
+0.08
Smoke is heavy, emitting from unexposed surface


 3:00
+0.07
The entire board is flaming. Surface is hard.


 5:00
+0.08
Butt joint opening is at estimated 1⁄8 to 1⁄4 inches max.


 6:00
+0.08
Very heavy smoke emitting from unexposed surface.


 8:00
+0.15
Board sag is at estimated 1 inch max. Still is flaming.


 9:30
+0.08
Exposed board has fallen out. Remaining perimeter boards still




flaming. Exposed wallboard is seen from exposed cavity.


15:00
+0.07
Still heavy smoke and steam emitting from unexposed surface.


19:00
+0.08
Board crack running along the center stud on the unexposed surface.


23:00
+0.07
Smoke and steam is starting to decrease at unexposed surface.


25:00
+0.08
Unexposed board crack running the stud length is at estimated




1⁄8 inches max.


29:00
+0.07
Hairline haze cracking is seen on wallboard viewed from




exposed cavity.


31:00
+0.07
The unexposed surface wallboard is now dark brown in color.




Little smoke and steam vapor emitting from unexposed surface.


32:00

Test terminated. Board has fallen off.









EXAMPLE 6
This example determines the horizontal diaphragm strength of a single floor diaphragm constructed as explained below using a Prototype 3⁄4 inch thick SCP panel by ASTM E 455-98 Static Load Testing of Framed Floor or Roof Diaphragm Construction for Buildings, single beam method.
Test Specimen Materials
A. Floor Diaphragm Materials:
Prototype 3⁄4′′ SCP—Structural Cement Panel of the present invention reinforced with fiberglass strands. A “V”-groove and tongue is located along the 8′ dimension of the 4′×8′ sheets. The formulation used in the SCP panel examples of this floor diaphragm test is listed in TABLE 18A.










TABLE 18A







Ingredient
Weight Proportion (%)
















Reactive Powder Blend










Portland Cement
29



Calcium Sulfate Alpha Hemihydrate
58



Silica Fume
12



Lime
1







SCP Cementitious Composition










Portland Cement
12.2



Calcium Sulfate Alpha Hemihydrate
24.4



Silica Fume
5.1



Lime
0.4



Ceramic Microspheres
27.4



Superplasticizer
1.9



Water
24.2



Alkali-Resistant Glass Fibers1
4.4







1Weight proportion corresponds to 1.8% volume fraction of Alkali Resistant Glass Fibers in the composite.



Length of glass fibers used in the floor diaphragm test - 36 mm.






Fasteners—#8-18×1-5⁄8′′ long BUGLE HEAD GRABBER SUPER DRIVETM screws spaced 6′′ o.c. along the perimeter, and 12′′ o.c. in the field of the panels. All fasteners were placed a minimum of 3⁄4 inches in from panel edges and 1⁄2 inch in from seams. At panel corners the fasteners were inset 2 inches.
Adhesive—ENERFOAM SF polyurethane foam adhesive manufactured by Flexible Products Company of Canada, Inc. was applied to all butt-joints, and tongue and groove joints. One (1) 3⁄8′′ bead was applied to the bottom of the groove before setting into place. A 3⁄8′′ gap was left at the butt-joint to allow one (1) 3⁄8 bead of adhesive to be applied in the gap, before sliding the joint together.
B. Floor Framing:
FIG. 8 shows assembled metal, e.g., steel, floor framing. This includes the following parts:
A. Transverse Joists 150-16 gauge×10 inches deep×10 foot long Trade ReadyTM Joists manufactured by Dietrich Industries. The joists were stamped Dietrich TDW5 W 10 IN×L 10 FT 28324013 16 GAUGE G60 50KSI.
B. Longitudinal Rim Track 152-16 gauge×10- 3/16′′ deep×16′ long manufactured by Dietrich Industries with pre-bent joist attachment locations spaced at 24′′ o.c. The track was stamped Dietrich TD16 W 91⁄4 IN×L 16 FT 28323858 16 GAUGE 3RD FI.
C. 0.125′′ thick×2′′×2′′ steel angles 154 (FIG. 10) are located on each of the transverse end joists 156 spaced starting at the bearing side and spanning up to 3 inches from the load side angel and fixed to the respective end transverse joists with # 10-1′′ DRIVALL screws at 6′′ o.c.
D. Fasteners
#10-16×3⁄4′′ long hex-head, DRIVALL screws for attaching framing.
#10-16×3⁄4′′ long wafer head, self-drilling screws for attaching to framing 6′′ o.c. around the outermost edge and on both sides of the butt joints.
Test Specimen Construction
One (1) test sample was constructed to an overall dimension of 10′-0′′×20′-0′′. FIG. 8 shows a perspective view of the metal frame.
FIG. 9 shows an enlarged view of a portion of the frame of FIG. 8.
FIG. 10 shows an enlarged view of a portion AA of the frame of FIG. 8.
FIG. 11 shows a top view of the SCP panels 120 (with panel dimensions), but manufactured to have tongue and groove edges (not shown) similar to those of FIG. 5a, attached to the metal frame.
FIGS. 12, 13, 14 and 15 show enlarged views of respective portions BB, CC, DD and EE of the floor of FIG. 11.
A. The joists were attached to the rim track using three (3) hex head #10-16×3⁄4′′ long Drivall screws into the side of the joist through the pre-bent tab and one (1) #10-16×3⁄4′′ long wafer head self-drilling screws through the top of rim track into the joist, at each end. 0.078′′ thick×11⁄2′′×4′′ steel angles 151 which are 5′′ long were also fastened to the respective joist 1′′ o.c. with 3⁄4 inch long DRIVALL screws and one 3⁄4 inch long DRIVALL screw to the rim track.
B. 11⁄2 inch×25⁄8 inch×213⁄4 inch KATZ blocking 158 with a 2 inch long×13⁄4 inch tab on each end was fastened to the bottom of the joists across the center line of the floor. The blocking 158 was attached using (1) #10-16×3⁄4′′ long Drivall screw through the end of each Katz blocking member 158. In particular, the Katz blocking 158 is located between transverse joints 50 by being positioned staggered on either side of the midpoint and attached by one #10-16×3⁄4 inch long DRIVALL screw per tab.
C. Additional horizontal blocking was added, in two locations, to the rim track 152 on the load side to strengthen the rim track 152 for point loading purposes. Namely, 24 inch blocking 157 for load support is provided along the longitudinal rim track between a number of transverse joists 150. 20 inch long blocking 159 is fixed between each transverse end joist and the respective penultimate transverse end joist generally along the longitudinal axis of the frame with four #10-16×3⁄4 inch long DRIVALL screws on each end.
D. The frame was squared and then the prototype SCP panel was fastened to it as shown in FIG. 11. The prototype SCP was fastened at 6′′ o.c. around the perimeter inset 2′′ from the corners, and 12 inches o.c. in the field with #8-18×1-5⁄8 inch long Bugle head GRABBER SUPER DRIVETM screws (winged self drilling screws 162). Care was taken to ensure that the fasteners were kept flush or slightly below the surface of the prototype SCP and also did not strip out in the steel framing. At the butt-joints and tongue and groove locations, a 3⁄8 inch bead of ENERFOAM SF polyurethane foam adhesive manufactured by Flexible Products Company of Canada, Inc. was applied in the joint.
E. 1⁄8′′×2′′×2′′ angle iron was then fastened to the end joists flush to the bottom of the joists to minimize crumpling of the joists at the bearings and to represent the top plate member. An additional 6 inches long angle was fastened at the bearing side of the end joists flush to the top of the joist also to minimize crumpling.
F. The test sample set for a minimum of 36 hours to allow the adhesive to cure.
G. FIG. 16 shows the test sample 80, made of frame 160 of FIG. 8 having the attached floor 120 of FIG. 9, supported by appliance rollers 70 at 2 foot on center (o.c.) around the perimeter of the sample 80 on a concrete floor 98 (FIG. 17).
FIG. 17 shows an enlarged view of portion FF of FIG. 16. A bearing support 74, 84 was placed at both ends of the test sample 80. Three (3) loading cylinders 80 were located on the opposite side of the test sample 80. The load was applied from the cylinders through steel-beams, to six (6) 18′′ bearing blocks to uniformly apply the load to the floor test sample 80. Five (5) dial indicators were placed along the bearing side of the test sample 80 to measure deflections. FIG. 17 shows hold down 92 provided with spacers 90. A gap 96 of about 1⁄8 inch, and an 18 inch load block 94. The hold down 92 is mounted in cement 98. Another hold down 82 is provided at the other end of the test sample 80. The hold down 92 is supported on solid rollers 72.
Test Equipment
A. Three (3) ENERPAC Model P-39 hydraulic hand pumps.
B. Three (3) ENERPAC Model RC-1010 hydraulic cylinders.
C. Five dial indicators: 2 inches movement—0.001 inch increments.
D. Three (3) Omega digital meters.
E. Three (3) Omega pressure transducers.
F. Three (3) 6 ft. I-beams.
G. Five (5) rigid bearings bolted to floor.
Procedure
A. The loads were generated using three (3) 1-1⁄2 inch diameter×10 inches stroke hydraulic cylinders, one at each load point. The applied forces were measured with three (3) digital meters and pressure transducers. A permanent record of the applied forces was made on the attached data sheets.
B. The loads were generated by applying hydraulic pressure to create mechanical force until the required load was indicated on the digital meters.
C. The entire floor assembly was loaded in increments of 700 lbs. Each load was held for 1 minute before the deflection readings were taken. After the 14,000 lbs. deflection reading was taken, the assembly was then loaded at a rate of approximately 2800 pounds per minute, until a failure occurred.
FIG. 19 shows a photograph of the SCP panel and metal frame floor mounted on the test apparatus of FIG. 16 at design load.
FIG. 20 shows a photograph of the SCP panel and metal frame floor mounted on the test apparatus of FIG. 16 at failure.
Test Results
TABLE 19 shows the results of a Floor Diaphragm Test of applying loads to the above-described entire floor assembly. The floor having a width of 120 inches.
Using a factor of safety of 3.0 the following values were obtained.
 Ultimate Load=14,618.5 lbs./10.0 ft.=1,461.8 PLF (pounds per linear foot)
Design Shear=1461.8/3.0 safety factor=487.2 PLF
Design shear is calculated by dividing the ultimate load by a safety factor of 3.
Table 20 shows Resultant Deflection occurring due to the application of loads to the floor. FIG. 18 graphs the data of Table 20. FIG. 18 shows experimental load versus deflection data from the floor diaphragm test using 3⁄4 inch structural cement panel (SCP panel) employing the floor diaphragm testing apparatus of FIG. 16.
Table 21 shows average bearing deflection from applying loads at bearing points to the test sample floor.
Based on the data obtained from this single test sample a design shear of 487.2 PLF (pounds per linear foot) can be achieved from the above-described single floor diaphragm sample constructed as follows:







TABLE 19







Floor Diagram Test


Floor Width: 120 inches; Design Load: 420 P.L.F. (estimated)









Floor Test Loads











Loading
Total Ceiling
Load No. 1
Load No. 2
Load No. 3


Increments
Load (lbs.)
(lbs.)
(lbs.)
(lbs.)














No Load
0
0
0
0


1
700
233
233
233


2
1400
467
467
467


3
2100
700
700
700


4
2800
933
933
933


5
3500
1167
1167
1167


6
4200
1400
1400
1400


7
4900
1633
1633
1633


8
5600
1867
1867
1867


9
6300
2100
2100
2100


10
7000
2333
2333
2333


11
7700
2567
2567
2567


Design Load
8400
2800
2800
2800


13
9100
3033
3033
3033


14
9800
3267
3267
3267


15
10500
3500
3500
3500


16
11200
3733
3733
3733


17
11900
3967
3967
3967


18
14000
4667
4667
4667


Ultimate Load
29237
9717
9750
9770


Design Load


487.3 P.L.F.
















TABLE 20







Temp. & Humidity During Construction: 71 deg. F./32% Temp. & Humidity During


Test: 73 deg. F./35%


Sample Description: Prototype 3⁄4 inch SCP adhered to 16 gauge- 10 inches steel joists, using


ENERFOAM SF polyurethane foam adhesive









Floor Test Loads










Time

Clear Span














Load/
Loading
Load
Indicator #2
Indicator #3
Indicator #4
Resultant
















Reading
Increments
(lbs.)
Reading
Deflection
Reading
Defl.
Reading
Defl.
Deflection*



















9:30
No Load
0
0.100

0.100

0.100




9:31/9:32
1
700
0.168
0.068
0.155
0.055
0.133
0.033
0.003


9:33/9:34
2
1400
0.185
0.085
0.169
0.069
0.151
0.051
0.005


9:35/9:36
3
2100
0.203
0.103
0.185
0.085
0.163
0.063
0.009


9:37/9:38
4
2800
0.219
0.119
0.199
0.099
0.174
0.074
0.013


9:39/9:40
5
3500
0.231
0.131
0.210
0.110
0.184
0.084
0.016


9:41/9:42
6
4200
0.242
0.142
0.222
0.122
0.194
0.094
0.021


9:43/9:44
7
4900
0.253
0.153
0.233
0.133
0.204
0.104
0.025


9:45/9:46
8
5600
0.265
0.165
0.244
0.144
0.214
0.114
0.030


9:47/9:48
9
6300
0.276
0.176
0.255
0.155
0.224
0.124
0.034


9:49/9:50
10
7000
0.288
0.188
0.267
0.167
0.234
0.134
0.039


9:51/9:52
11
7700
0.300
0.200
0.279
0.179
0.244
0.144
0.045


9:53/9:54
Design
8400
0.311
0.211
0.290
0.190
0.255
0.155
0.050



Load


9:55/9:56
13
9100
0.321
0.221
0.302
0.202
0.264
0.164
0.057


9:57/9:58
14
9800
0.334
0.234
0.314
0.214
0.275
0.175
0.062


 9:59/10:00
15
10500
0.346
0.246
0.327
0.227
0.290
0.190
0.067


10:01/10:02
16
11200
0.359
0.259
0.343
0.243
0.306
0.206
0.076


10:03/10:04
17
11900
0.373
0.273
0.360
0.260
0.327
0.227
0.084


10:05/10:06
18
14000
0.412
0.312
0.413
0.313
0.387
0.287
0.111





Mode of Failure: End #2 - butt joint separation on the 4′ sheet in the middle row, and at the 951⁄2′′ sheet on the load side as the tongue and groove joint slipped. Secondary Failure - Board shear approximately 6′ in from the end on the bearing side (See FIG. 20).


*The resultant deflection is equal to the average deflection of the bearings minus the greatest point of deflection across the clear span. FIG. 18 shows the data graphically.
















TABLE 21







Time

Bearing Points
Average












Load/
Loading
Load
Indicator #1
Indicator #5
Bearing














Reading
Increments
(lbs.)
Reading
Deflection
Reading
Defl.
Deflection

















9:30
No Load
0
0.000

0.100




9:31/9:32
1
700
0.080
0.080
0.125
0.025
0.053


9:33/9:34
2
1400
0.096
0.096
0.132
0.032
0.064


9:35/9:36
3
2100
0.113
0.113
0.138
0.038
0.076


9:37/9:38
4
2800
0.127
0.127
0.145
0.045
0.086


9:39/9:40
5
3500
0.137
0.137
0.151
0.051
0.094


9:41/9:42
6
4200
0.145
0.145
0.158
0.058
0.102


9:43/9:44
7
4900
0.152
0.152
0.165
0.065
0.109


9:45/9:46
8
5600
0.158
0.158
0.171
0.071
0.115


9:47/9:48
9
6300
0.166
0.166
0.177
0.077
0.122


9:49/9:50
10
7000
0.174
0.174
0.183
0.083
0.129


9:51/9:52
11
7700
0.179
0.179
0.190
0.090
0.135


9:53/9:54
Design
8400
0.185
0.185
0.195
0.095
0.140



Load


9:55/9:56
13
9100
0.191
0.191
0.200
0.100
0.146


9:57/9:58
14
9800
0.197
0.197
0.207
0.107
0.152


 9:59/10:00
15
10500
0.203
0.203
0.217
0.117
0.160


10:01/10:02
16
11200
0.208
0.208
0.226
0.126
0.167


10:03/10:04
17
11900
0.214
0.214
0.238
0.138
0.176


10:05/10:06
18
14000
0.227
0.227
0.278
0.178
0.203









EXAMPLE 7
This example determines the effect of water exposure on the horizontal diaphragm strength of an assembly using 3⁄4′′ inch thick SCP panel by ASTM E455-98 Static Load Testing of Framed Floor or Roof Diaphragm Construction for Buildings, single beam method.
Test Specimen Materials
A. Floor Diaphragm Materials:
3⁄4 inch SCP panel reinforced with fiberglass strands. A “V”-groove and tongue are located along the 8′ dimension of the 4 foot×8 foot sheets.
Fasteners employed included #8-18×1-5⁄8 inch long Bugle head GRABBER SUPER DRIVE screws, available for GRABBER Construction Products, spaced 6 inches on center along the perimeter, and 12 inches on center in the field of the panels. All fasteners were placed a minimum of 3⁄4 inches in from the panel edges and 1⁄2 inches from the seams. At panel corners the fasteners were inset 2 inches. See FIG. 11 for fastener locations.
B. Floor Framing:
Joists included CSJ 16 gauge×8 inches deep×10 foot rim track manufactured by Dietrich Industries.
Test Specimen Construction
Four (4) test samples were constructed to an overall dimension of 10′-0′′×20′-0′′ as was the test sample described above in Example 6. FIG. 8 shows a perspective of the metal frame.
However, the frame was squared and then the prototype SCP panel was fastened to it as shown in FIG. 11. The prototype SCP was fastened at 6′′ o.c. around the perimeter and inset 2′′ from the corners, 12′′ o.c. in the field with #8-18×1-5⁄8′′ long Bugle head Grabber SuperDrive screws (winged self drilling screws 162). Care was taken to ensure that the fasteners were kept flush or slightly below the surface of the prototype SCP and also did not strip out in the steel framing. In contrast to the test sample of Example 6, at the butt-joints and tongue and groove locations, a 3⁄8 inch bead of ENERFOAM SF polyurethane foam adhesive manufactured by Flexible Products Company of Canada, Inc. was not applied in the joint.
Test Equipment
A. Four (4) ENERPAC Model P-39 hydraulic hand pumps
B. Four (4) ENERPAC Model RC-1010 hydraulic cylinders
C. Five (5) dial indicators 2′′ movement—0.001 increments
D. Four (4) OMEGA digital meters
E. Four (4) OMEGA pressure transducers
F. Four (4) 6 ft I-Beams
G. Six (6) rigid bearings bolted to the floor
Procedure
A. Two of the test assemblies were tested in an “as received”, or dry condition and two samples were tested after a 1′′ head of water was present for a minimum of 24 hours.
B. The loads were generated using four (4) 1-1⁄2′′ diameter hydraulic cylinders, one at each loading point. The applied forces were measured with four (4) calibrated digital meters and pressure transducers. A permanent record of the applied forces was made on the attached data sheets.
C. The loads were generated be applying hydraulic pressure to create mechanical force until the required load was indicated on the digital meters.
D. The entire floor assembly was loaded in increments of 700 lbs. Each load was held for 1 minute before the deflection readings were taken. After the 14000 lb deflection reading was taken, the assembly was then loaded at a rate of approximately 2800 pounds per minute, until a failure occurred.
Test Results
TABLES 22-38 and FIGS. 24 and 25 show the results of the floor diaphragm tests of applying loads to the above described entire floor assembly. The floor having a width of 120 inches. FIG. 24 shows the data of Dry Test 1 and Dry Test 2. FIG. 25 shows data from Wet Test 1 and Wet Test 2.
Using a factor of safety of 3.0, the following values were obtained.
Average ultimate load of dry samples=15,908.2 lb/10 ft=1,590.8 PLF
Design Shear of dry samples=1,590.8 PLF/3.0 safety factor=530.2 PLF
Average ultimate load of wet samples=14,544.5 lb/10 ft=1,454.4 PLF
Design Shear of wet samples=1,454.4 PLF/3.0 safety factor=484.8 PLF
These results indicate than approximately a 91% retention of diaphragm strength after continuous exposure to water for a 24 hour time period.







TABLE 22







Floor Diaphragm Test; Floor width 120 inches;


Design Load 420 P.L.F. (Dry Test 1)









Floor Test Loads













Total
Load
Load

Load


Loading
Ceiling
No. 1
No. 2
Load No. 3
No. 4


Increments
Load (lbs.)
(lbs.)
(lbs.)
(lbs.)
(lbs.)















No Load
0
0
0
0
0


 1
700
175
175
175
175


 2
1400
350
350
350
350


 3
2100
525
525
525
525


 4
2800
700
700
700
700


 5
3500
875
875
875
875


 6
4200
1050
1050
1050
1050


 7
4900
1225
1225
1225
1225


 8
5600
1400
1400
1400
1400


 9
6300
1575
1575
1575
1575


10
7000
1750
1750
1750
1750


11
7700
1925
1925
1925
1925


Design Load
8400
2100
2100
2100
2100


13
9100
2275
2275
2275
2275


14
9800
2450
2450
2450
2450


15
10500
2625
2625
2625
2625


16
11200
2800
2800
2800
2800


17
11900
2975
2975
2975
2975


18
14000
3500
3500
3500
3500


Ultimate Load
28,665
7,039
7,317
7,262
7,047





Design Load 477.8 P.L.F.


There are two design loads in this table. To set up the test and size the test equipment you initially hypothesize t first design load, here 420 P.L.F. The measured 477.8 P.L.F. is the actual Design Load determined from actual measurements and adding a safety factor.













TABLE 23







Floor Diaphragm Test (Dry Test 1)


Clear Span












Load
Load
Indicator #2
Indicator #3
Indicator #4
RESULTANT















Increment
(lbs.)
Reading
Deflection
Reading
Deflection
Reading
Deflection
DEFLECTION*


















No Load
0
0.154
—
0.084
—
0.094
—
—


 1
700
0.187
0.033
0.128
0.044
0.148
0.054
0.044


 2
1400
0.225
0.071
0.165
0.081
0.182
0.088
0.081


 3
2100
0.244
0.090
0.187
0.103
0.202
0.108
0.103


 4
2800
0.260
0.106
0.211
0.127
0.223
0.129
0.127


 5
3500
0.275
0.121
0.228
0.144
0.242
0.148
0.144


 6
4200
0.291
0.137
0.250
0.166
0.265
0.171
0.166


 7
4900
0.308
0.154
0.274
0.190
0.292
0.198
0.190


 8
5600
0.325
0.171
0.295
0.211
0.316
0.222
0.211


 9
6300
0.338
0.184
0.309
0.225
0.326
0.232
0.224


10
7000
0.354
0.200
0.327
0.243
0.341
0.247
0.241


11
7700
0.369
0.215
0.344
0.260
0.356
0.262
0.258


Design
8400
0.386
0.232
0.362
0.278
0.372
0.278
0.276


Load


13
9100
0.402
0.248
0.380
0.296
0.385
0.291
0.293


14
9800
0.425
0.271
0.405
0.321
0.410
0.316
0.313


15
10500
0.454
0.300
0.442
0.358
0.449
0.355
0.325


16
11200
0.495
0.341
0.490
0.406
0.502
0.408
0.348


17
11900
0.512
0.358
0.521
0.437
0.535
0.441
0.367


18
14000
0.569
0.415
0.596
0.512
0.614
0.520
0.422





Temp. and Humidity During Construction: 65° F./31%


Temp. and Humidity During Test: 65° F./31%


Sample Description 3⁄4 inch SCP panel fastened to 16 gauge - 10 inch steel joints


Mode of failure: Several of the butt-joints opened up in several locations causing cement board core failure at the fasteners along the edges of the cement board.


*The resultant deflection is equal to the average deflection of the bearings minus the greatest point of deflection across the clearspan.













TABLE 24







Floor Diaphragm Test (Dry Test 1)










Bearing Points
AVERAGE











Load
Load
Indicator #1
Indicator #5
BEARING













Increment
(lbs.)
Reading
Deflection
Reading
Deflection
DEFLECTION

















No Load
0
lbs
0.069
—
0.266
—
—


 1
700

0.069
0.000
0.266
0.000
0.000


 2
1400

0.069
0.000
0.266
0.000
0.000


 3
2100

0.069
0.000
0.266
0.000
0.000


 4
2800

0.069
0.000
0.266
0.000
0.000


 5
3500

0.069
0.000
0.266
0.000
0.000


 6
4200

0.069
0.000
0.266
0.000
0.000


 7
4900

0.069
0.000
0.266
0.000
0.000


 8
5600

0.069
0.000
0.266
0.000
0.000


 9
6300

0.070
0.001
0.267
0.001
0.001


10
7000

0.072
0.003
0.267
0.001
0.002


11
7700

0.072
0.003
0.267
0.001
0.002


Design Load
8400

0.073
0.004
0.267
0.001
0.003


13
9100

0.075
0.006
0.267
0.001
0.004


14
9800

0.083
0.014
0.268
0.002
0.008


15
10500

0.094
0.025
0.307
0.041
0.033


16
11200

0.105
0.036
0.346
0.080
0.058


17
11900

0.107
0.038
0.369
0.103
0.071


18
14000

0.114
0.045
0.402
0.136
0.091





Bearing Indictors 2, 3 and 4 (labeled “Clear Span”) of Table 23 are the instruments along the test specimen in the area between the support points at the two opposed ends of the frame.


Bearing Indicators 1 and 5 of Table 24 are at the support points of this test specimen.













TABLE 25







Floor Diaphragm Test; Floor width 120 inches; Design Load 420 P.L.F.


(Dry Test 2)


Floor Test Loads














Load


Load


Loading
Total Ceiling
No. 1
Load No. 2
Load No. 3
No. 4


Increments
Load (lbs.)
(lbs.)
(lbs.)
(lbs.)
(lbs.)















No Load
0
0
0
0
0


 1
700
175
175
175
175


 2
1400
350
350
350
350


 3
2100
525
525
525
525


 4
2800
700
700
700
700


 5
3500
875
875
875
875


 6
4200
1050
1050
1050
1050


 7
4900
1225
1225
1225
1225


 8
5600
1400
1400
1400
1400


 9
6300
1575
1575
1575
1575


10
7000
1750
1750
1750
1750


11
7700
1925
1925
1925
1925


Design
8400
2100
2100
2100
2100


Load


13
9100
2275
2275
2275
2275


14
9800
2450
2450
2450
2450


15
10500
2625
2625
2625
2625


16
11200
2800
2800
2800
2800


17
11900
2975
2975
2975
2975


18
14000
3500
3500
3500
3500


Ultimate
34,968
8,900
8,653
8,715
8,700


Load





Design Load 582.8 P.L.F.













TABLE 26







Floor Diaphragm Test (Dry Test 2)










Clear Span













Load

Indicator #2
Indicator #3
Indicator #4
RESULTANT















Increment
Load (lbs.)
Reading
Deflection
Reading
Deflection
Reading
Deflection
DEFLECTION*


















No Load
  0 lbs.
0.290
—
0.127
—
0.231
—
—


 1
 700 lbs.
0.322
0.032
0.156
0.029
0.250
0.019
0.028


 2
1400 lbs.
0.342
0.052
0.178
0.051
0.270
0.039
0.050


 3
2100 lbs.
0.365
0.075
0.202
0.075
0.292
0.061
0.073


 4
2800 lbs.
0.381
0.091
0.222
0.095
0.312
0.081
0.092


 5
3500 lbs.
0.398
0.108
0.244
0.117
0.334
0.103
0.113


 6
4200 lbs.
0.414
0.124
0.265
0.138
0.354
0.123
0.133


 7
4900 lbs.
0.429
0.139
0.285
0.158
0.375
0.144
0.152


 8
5600 lbs.
0.446
0.156
0.307
0.180
0.396
0.165
0.173


 9
6300 lbs.
0.463
0.173
0.328
0.201
0.415
0.184
0.192


10
7000 lbs.
0.478
0.188
0.345
0.218
0.433
0.202
0.209


11
7700 lbs.
0.493
0.203
0.363
0.236
0.450
0.219
0.225


Design
8400 lbs.
0.510
0.220
0.486
0.259
0.471
0.240
0.247


Load


13
9100 lbs.
0.525
0.235
0.404
0.277
0.490
0.259
0.265


14
9800 lbs.
0.543
0.253
0.429
0.302
0.513
0.282
0.289


15
10500 lbs. 
0.562
0.272
0.454
0.327
0.540
0.309
0.313


16
11200 lbs. 
0.581
0.291
0.478
0.351
0.564
0.333
0.337


17
11900 lbs. 
0.600
0.310
0.500
0.373
0.585
0.354
0.358


18
14000 lbs. 
0.655
0.365
0.565
0.438
0.640
0.409
0.421





Temp. and Humidity During Construction: 70° F./50%


Temp. and Humidity During Test: 70° F./48%


Sample Description: 3⁄4 inch SCP panel fastened to 16 gauge - 8 inch steel joints


Mode of failure: Several of the butt-joints opened up in several locations causing cement board core failure at the fasteners along the edges of the cement board.


*The resultant deflection is equal to the average deflection of the bearings minus the greatest point of deflection across the clearspan.













TABLE 27







Floor Diagram Test (Dry Test 2)










Bearing Points
AVERAGE











Indicator #1
Indicator #5
BEARING













Load
Load

De-

De-
DE-


Increment
(lbs.)
Reading
flection
Reading
flection
FLECTION
















No Load
0
0.124
—
0.201
—
—


 1
700
0.125
0.001
0.202
0.001
0.001


 2
1400
0.125
0.001
0.203
0.002
0.002


 3
2100
0.127
0.003
0.203
0.002
0.003


 4
2800
0.128
0.004
0.203
0.002
0.003


 5
3500
0.129
0.005
0.204
0.003
0.004


 6
4200
0.131
0.006
0.205
0.004
0.005


 7
4900
0.132
0.007
0.206
0.005
0.006


 8
5600
0.134
0.010
0.206
0.005
0.007


 9
6300
0.136
0.012
0.207
0.006
0.009


10
7000
0.137
0.013
0.208
0.006
0.009


11
7700
0.139
0.015
0.208
0.007
0.011


Design
8400
0.141
0.017
0.208
0.007
0.012


Load


13
9100
0.141
0.017
0.208
0.007
0.012


14
9800
0.143
0.019
0.208
0.007
0.013


15
10500
0.145
0.021
0.209
0.008
0.015


16
11200
0.145
0.021
0.209
0.008
0.015


17
11900
0.147
0.023
0.209
0.008
0.016


18
14000
0.150
0.026
0.209
0.008
0.017





Temp. and Humidity During Construction: 70° F./50%


Temp. and Humidity During Test: 70° F./48%


Sample Description: 3⁄4 inch SCP panel fastened to 16 gauge - 8 inch steel joints


Mode of failure: Several of the butt-joints opened up in several locations causing cement board core failure at the fasteners along the edges of the cement board.


*The resultant deflection is equal to the average deflection of the bearings minus the greatest point of deflection across the clearspan.













TABLE 28







Floor Diaphragm Test (Wet Test 1); Floor width 120 inches;


Design Load 420 P.L.F.


Floor Test Loads













Total
Load


Load


Loading
Ceiling
No. 1
Load No. 2
Load No. 3
No. 4


Increments
Load (lbs.)
(lbs.)
(lbs.)
(lbs.)
(lbs.)















No Load
0
0
0
0
0


 1
700
175
175
175
175


 2
1400
350
350
350
350


 3
2100
525
525
525
525


 4
2800
700
700
700
700


 5
3500
875
875
875
875


 6
4200
1050
1050
1050
1050


 7
4900
1225
1225
1225
1225


 8
5600
1400
1400
1400
1400


 9
6300
1575
1575
1575
1575


10
7000
1750
1750
1750
1750


11
7700
1925
1925
1925
1925


Design
8400
2100
2100
2100
2100


Load


13
9100
2275
2275
2275
2275


14
9800
2450
2450
2450
2450


15
10500
2625
2625
2625
2625


16
11200
2800
2800
2800
2800


17
11900
2975
2975
2975
2975


18
14000
3500
3500
3500
3500


Ultimate
27,893
7,097
6,878
6,850
7,068


Load





Design Load 464.9 P.L.F.













TABLE 29







Floor Diaphragm Comparison Test (Wet Test 1)










Clear Span













Load
Load
Indicator #2
Indicator #3
Indicator #4
RESULTANT















Increment
(lbs.)
Reading
Deflection
Reading
Deflection
Reading
Deflection
DEFLECTION*


















No Load
0
0.211
—
0.185
—
0.268
—
—


1
700
0.239
0.028
0.208
0.023
0.287
0.019
0.023


2
1400
0.245
0.034
0.225
0.040
0.293
0.025
0.040


3
2100
0.267
0.056
0.239
0.054
0.316
0.048
0.053


4
2800
0.287
0.076
0.260
0.075
0.336
0.068
0.073


5
3500
0.304
0.093
0.280
0.095
0.354
0.086
0.093


6
4200
0.320
0.109
0.300
0.115
0.372
0.104
0.113


7
4900
0.335
0.124
0.318
0.133
0.388
0.120
0.131


8
5600
0.354
0.143
0.339
0.154
0.405
0.137
0.152


9
6300
0.369
0.158
0.356
0.171
0.421
0.153
0.168


10 
7000
0.388
0.177
0.378
0.193
0.441
0.173
0.188


11 
7700
0.405
0.194
0.398
0.213
0.458
0.190
0.207


Design Load
8400
0.430
0.219
0.426
0.241
0.481
0.213
0.230


13 
9100
0.469
0.258
0.463
0.278
0.508
0.240
0.252


14 
9800
0.500
0.289
0.497
0.312
0.536
0.268
0.275


15 
10500
0.521
0.310
0.522
0.337
0.558
0.290
0.298


16 
11200
0.545
0.334
0.549
0.364
0.582
0.314
0.323


17 
11900
0.569
0.358
0.579
0.394
0.610
0.342
0.351


18 
14000
0.635
0.424
0.668
0.483
0.692
0.424
0.431





Temp. and Humidity During Construction: 65° F./31%


Temp. and Humidity During Test: 65° F./31%


Sample Description 3⁄4 inch SCP panel fastened to 16 gauge - 8 inch steel joints


Several of the butt-joints opened up in several locations causing cement board core failure at the fasteners along the edges of the cement board.


*The resultant deflection is equal to the average deflection of the bearings minus the greatest point of deflection across the clearspan.













TABLE 30







Floor Diaphragm Test (Wet Test 1)










Bearing Points
AVERAGE











Indicator #1
Indicator #5
BEARING













Load
Load

Deflec-

Deflec-
DEFLEC-


Increment
(lbs.)
Reading
tion
Reading
tion
TION
















No Load
0
0.199
—
0.341
—
—


1
700
0.199
0.000
0.342
0.001
0.001


2
1400
0.199
0.000
0.342
0.001
0.001


3
2100
0.199
0.000
0.343
0.002
0.001


4
2800
0.199
0.000
0.345
0.004
0.002


5
3500
0.199
0.000
0.345
0.004
0.002


6
4200
0.199
0.000
0.345
0.004
0.002


7
4900
0.199
0.000
0.346
0.005
0.002


8
5600
0.199
0.000
0.346
0.005
0.002


9
6300
0.200
0.001
0.347
0.006
0.003


10 
7000
0.203
0.004
0.347
0.006
0.005


11 
7700
0.204
0.005
0.348
0.007
0.006


Design
8400
0.214
0.015
0.348
0.007
0.011


Load


13 
9100
0.244
0.045
0.349
0.008
0.027


14 
9800
0.265
0.066
0.349
0.008
0.037


15 
10500
0.268
0.069
0.350
0.009
0.039


16 
11200
0.272
0.073
0.351
0.010
0.042


17 
11900
0.275
0.076
0.352
0.011
0.044


18 
14000
0.289
0.090
0.355
0.014
0.052





Temp. and Humidity During Construction: 65° F./31%


Temp. and Humidity During Test: 65° F./31%


Sample Description 3⁄4 inch SCP panel fastened to 16 gauge - 8 inch steel joints


Several of the butt-joints opened up in several locations causing cement board core failure at the fasteners along the edges of the cement board.


*The resultant deflection is equal to the average deflection of the bearings minus the greatest point of deflection across the clearspan.













TABLE 31







Floor Diaphragm Test (Wet); Floor Width; Design Load 420


P.L.F. (Wet Test 2)


Floor Test Loads













Total







Ceiling
Load
Load No.


Loading
Load
No. 1
2
Load No. 3
Load No. 4


Increments
(lbs.)
(lbs.)
(lbs.)
(lbs.)
(lbs.)















No Load
0
0
0
0
0


1
700
175
175
175
175


2
1400
350
350
350
350


3
2100
525
525
525
525


4
2800
700
700
700
700


5
3500
875
875
875
875


6
4200
1050
1050
1050
1050


7
4900
1225
1225
1225
1225


8
5600
1400
1400
1400
1400


9
6300
1575
1575
1575
1575


10 
7000
1750
1750
1750
1750


11 
7700
1925
1925
1925
1925


Design
8400
2100
2100
2100
2100


Load


13 
9100
2275
2275
2275
2275


14 
9800
2450
2450
2450
2450


15 
10500
2625
2625
2625
2625


16 
11200
2800
2800
2800
2800


17 
11900
2975
2975
2975
2975


18 
14000
3500
3500
3500
3500


Ultimate
30,285
7,327
7,707
7,740
7,511


Load





Design Load 504.8 P.L.F.













TABLE 32







Floor Diaphragm Comparison Test (Wet Test 2)










Clear Span













Load
Load
Indicator #2
Indicator #3
Indicator #4
RESULTANT















Increment
(lbs.)
Reading
Deflection
Reading
Deflection
Reading
Deflection
DEFLECTION*


















No Load
0
0.166
—
0.136
—
0.129
—
—


1
700
0.180
0.014
0.144
0.008
0.140
0.011
0.007


2
1400
0.193
0.027
0.156
0.020
0.150
0.021
0.019


3
2100
0.210
0.044
0.173
0.037
0.167
0.038
0.035


4
2800
0.228
0.062
0.192
0.056
0.181
0.052
0.054


5
3500
0.240
0.074
0.210
0.074
0.195
0.066
0.071


6
4200
0.268
0.102
0.233
0.197
0.213
0.084
0.094


7
4900
0.312
0.146
0.270
0.134
0.237
0.108
0.130


8
5600
0.337
0.171
0.293
0.157
0.255
0.126
0.152


9
6300
0.370
0.204
0.326
0.190
0.280
0.151
0.184


10 
7000
0.387
0.221
0.345
0.209
0.295
0.166
0.201


11 
7700
0.406
0.240
0.367
0.231
0.314
0.185
0.223


Design
8400
0.423
0.257
0.386
0.250
0.330
0.201
0.241


Load


13 
9100
0.440
0.274
0.406
0.270
0.351
0.222
0.260


14 
9800
0.451
0.285
0.427
0.291
0.368
0.239
0.279


15 
10500
0.471
0.309
0.448
0.312
0.387
0.258
0.298


16 
11200
0.491
0.325
0.468
0.332
0.405
0.276
0.316


17 
11900
0.512
0.346
0.494
0.358
0.429
0.300
0.341


18 
14000
0.569
0.393
0.553
0.417
0.482
0.353
0.396





Temp. and Humidity During Construction: 70° F./50%


Temp. and Humidity During Test: 70° F./48%


Sample Description: 3⁄4 inch SCP panel fastened to 16 gauge - 8 inch steel joints


Mode of failure: The butt-joints on the load side of the floor at end #1 opened up causing core failure to the cement board around the screws along the joint. The screws along the end joist at end #1 pulled through the cement board due to core


*The resultant deflection is equal to the average deflection of the bearings minus the greatest point of deflection across the clearspan.













TABLE 33







Floor Diaphragm Test (Wet Test 2)










Bearing Points
AVERAGE











Load

Indicator #1
Indicator #5
BEARING













Incre-
Load
Read-
Deflec-
Read-
Deflec-
DEFLEC-


ment
(lbs.)
ing
tion
ing
tion
TION

















No
0
lbs
0.075
—
0.110
—
—


Load


1
700
lbs.
0.077
0.002
0.110
0.000
0.001


2
1400

0.078
0.003
0.110
0.000
0.002


3
2100

0.078
0.003
0.111
0.001
0.002


4
2800

0.078
0.003
0.111
0.001
0.002


5
3500

0.079
0.004
0.112
0.002
0.003


6
4200

0.079
0.004
0.112
0.002
0.003


7
4900

0.080
0.005
0.113
0.003
0.004


8
5600

0.083
0.008
0.113
0.003
0.006


9
6300

0.084
0.009
0.114
0.004
0.007


10 
7000

0.086
0.011
0.115
0.005
0.008


11 
7700

0.087
0.012
0.115
0.005
0.009


Design
8400

0.089
0.014
0.115
0.005
0.010


Load


13 
9100

0.090
0.015
0.116
0.006
0.011


14 
9800

0.092
0.017
0.118
0.008
0.013


15 
10500

0.095
0.020
0.119
0.009
0.015


16 
11200

0.097
0.022
0.120
0.010
0.016


17 
11900

0.099
0.024
0.120
0.010
0.017


18 
14000

0.105
0.030
0.123
0.013
0.022





Bearing Indictors 2, 3 and 4 (labeled “Clear Span”) of Table 32 are the instruments along the test specimen in the area between the support points at the two opposed ends of the frame.


Bearing Indicators 1 and 5 of Table 33 are at the support points of this test specimen.













TABLE 34







Water Absorption Results - 3⁄4 inch thick SCP panel












Weight
Weight

Weight



Before
After
Weight
Gain


Specimen
Soak
Soak
Gain
Percentage





A
2069.0 g
2082.3 g
13.3 g 
0.6%


B
2109.1 g
2112.6 g
3.5 g
0.2%


C
2145.0 g
2149.9 g
4.9 g
0.2%








Average Water Absorption
0.3%





This data is for moisture content tests done on specimens A, B and C which are 12 inch × 12 inch specimens of the SCP panel of the composition tested in the above “Wet” and “Dry” tests. In the moisture content tests the specimens are soaked 24 hours under a two inch head of water.













TABLE 35







Moisture Content 3⁄4 inch thick SCP panel










Before Soak Test
After Soak Test
















Weight of


Weight of





Weight
samples


samples



After
before
Weight
Weight
after
Weight



Drying
soak
Loss
Loss
soak
Loss
Weight Loss


Specimen
(g)
(g)
(g)
Percentage
(g)
(g)
Percentage





A
1801.9
2069.0
267.1
12.9%
2082.3
280.4
13.5%


B
1875.5
2109.1
230.6
10.9%
2112.6
234.1
11.1%


C
1904.5
2145.0
240.5
11.2%
2149.9
245.4
11.4%


Average



11.7%


12.0%


Moisture


Content
















TABLE 36







Board Expansion 3⁄4 inch thick SCP panel


(dimensions in inches)













Specimen
Width 1
Width 2
Thick 1
Thick 2
Thick 3
Thick 4
















A - Before
12.146
11.907
0.717
0.715
0.697
0.704


Soak


A - After Soak
12.146
11.907
0.717
0.715
0.697
0.704


Difference
0.000
0.000
0.000
0.000
0.000
0.000


B - Before
12.072
11.940
0.710
0.740
0.732
0.715


Soak


B - After Soak
12.072
11.940
0.710
0.740
0.732
0.715


Difference
0.000
0.000
0.000
0.000
0.000
0.000


C - Before
12.065
11.970
0.755
0.740
0.730
0.750


Soak


C - After Soak
12.065
11.970
0.755
0.740
0.730
0.750


Difference
0.000
0.000
0.000
0.000
0.000
0.000









EXAMPLE 8
stiffness to Weight Ratio and Depth of Structure
Stiffness to Weight Ratio:
For a given span (in the range from 10 feet to 40 feet), live load (in the range from 20-100 psf) and deflection criteria (maximum of L/240 with total load), an SCP/Steel Frame floor structure will meet the structural requirements having less dead load than the traditional corrugated metal deck/concrete or pre-cast plank systems. As an example, using the following design criteria:

    
    
        20 foot span on continuous bearing wall supports
        Live load of 80 pounds per square foot
        Building use to be light commercial to multi-family residential
        Deflection criteria—total load L/240
    
    


Schematic drawings of the different systems in the comparison are included in FIGS. 26, 27, 28 and 29. These are all hypothetical systems for which the calculations of stiffness to weight ratio were based on the physical characteristics of the components of these systems.
FIG. 26 shows an SCP structural floor system 400 employing 3⁄4 inch thick SCP panel 402 as sheathing on a 12 inch deep metal joist 410. The SCP panel 402 has a thickness “H2” of 3⁄4 inches (1.9 cm). The metal joist 410 has a thickness “H3” of 12 inches (30.5) for a combined thickness “H3” of 12-3⁄4 inches (32.4 cm).
FIG. 27 shows a precast plank system including a precast panel 420 having a thickness “H4” of 6 inches (15.2 cm).
FIG. 28 shows a bar joist/deck/slab system 430 having a concrete topping having a thickness “H6” of 3 inches (7.6 cm) on 9/16 inch (1.4 cm) 22 gauge corrugated metal deck on a K3 bar joist having a depth “H7” of 14 inches (35.6 cm) for a total thickness “H5” of 17- 9/16 inches (44.6 cm).
FIG. 29 shows a system 440 including a plywood sheathing 444 having a thickness “H8” of 3⁄4 inches (1.9 cm) on a wood joist having a depth “H9” of 20 inches (50.8 cm) for a total depth “H10” of 20-3⁄4 inches (52.7 cm).
A comparison of dead loads and depth of structure for the different systems is shown below in Table 37. The calculations of dead load are given in Tables 38-41.







TABLE 37







Comparison of Dead Loads and Depth of Structure for Different Systems












Dead Load
Depth of Structure



Floor Structural System
(psf)
(inches)















SCP System
9.0
12.751



Pre-Cast Plank
49.0
6.02



Bar Joist/Deck/Slab
30.4
17.03



Plywood/Wood Joist
6.1
20.754







Notes:



112′′ deep C joist and 3⁄4′′ thick SCP floor sheathing



26′′ deep pre-cast plank - no topping slab



314′′ deep K3 steel bar joist and 3′′ concrete topping



420′′ deep TJI L90 wood joist and 3⁄4′′ plywood sheathing













TABLE 38







Calculations of Dead Load for An


SCP System to Satisfy Structural Criteria








Material Item
Dead Load (lbs per square foot)





3⁄4′′ Thick SCP Panel
4.7


Steel Framing
4.3


12′′ C joists, 14 gauge, 24′′ O.C.


Bridging, 16 gauge, 2 per joist


(3,760 each × 2 lf × 4.773 lb/ft)


Rim Track: 2000 lf × 4.773 lb/ft



Total
9.0
















TABLE 39







Calculations of Dead Load for


Pre-Cast Plank System to Satisfy Structural Criteria








Material Item
Dead Load (lbs per square foot)





6′′ Thick Hollow Core Pre-Cast Plank
49.0


(Assumes no topping slab)



Total
49.0
















TABLE 40







Calculations of Dead Load for Bar Joist/Deck/Slab System


to Satisfy Structural Criteria








Material Item
Dead Load (lbs per square foot)











3′′ Lightweight Concrete Topping
27.0


 9/16′′ Corrugated Metal Deck
1.5


14′′ Deep K3 Metal Bar Joists
1.9


Total
30.4
















TABLE 41







Calculations of Dead Load for Plywood/Wood Joist System


Required to Satisfy Structural Criteria








Material Item
Dead Load (lbs per square foot)





3⁄4′′ Thick Plywood panel
2.3


TJI L 90 - 20′′ Deep Wood Joist 3′′
2.7


Rim board - 11⁄2′′ × 20′′
0.3


2000 lf* on perimeter


(2000 lf × 0.125 ft × 1.67 ft × 40 pcf)


Blocking (3,760 ea. × 2 lf × 5.3 lbs/ft)
0.8


Total
6.1





*lf stands for linear feet.






Also, for a given span (in the range from 10 feet to 40 feet), live load (in the range from 20-100 psf) and deflection criteria (maximum L/240 with total load), the SCP/Steel Frame structural floor assembly will result in more useable building volume per square foot of building footprint than the traditional metal bar joist/corrugated metal deck/concrete or the plywood/wood joist system. Additionally, the SCP/Steel Frame structural floor assembly is non-combustible; the plywood/wood joist system is not.
A hypothetical example shows the advantage of the present invention in increasing useable building volume, given the design criteria used in the stiffness to weight ratio example, the SCP floor system has a depth of 123⁄4 inches, the bar joist/corrugated deck/slab has a depth of 17 inches and the wood joist system has a depth of 203⁄4 inches. For a building with 50,000 square feet of floor space, the present invention results in a potential increase in useable building volume for the SCP system compared to metal bar joist and deck or wood joists and plywood as listed below in Table 42.







TABLE 42







Potential Increase in Useable Building Volume Using SCP


versus Bar Joist/Deck/Topping Slab or Plywood/Wood Joist











Potential Increase In




Useable Bldg Volume



System Depth
if SCP is Used


Floor Structural System
(inches)
(cubic feet)












SCP System
12.75
—


Bar Joist/Deck/Slab
17
17,708


Plywood/Wood Joist
20.75
33,333









While a particular embodiment of the system employing a horizontal diaphragm of fiber-reinforced structural cement panels on a metal frame has been shown and described, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.

## Claims

1. A non-combustible flooring system for construction comprising:
metal screw fasteners with winged drillers;
a metal frame;
a horizontal shear diaphragm fastened by the fasteners to the metal frame, the horizontal shear diaphragm comprising a reinforced, lightweight, dimensionally stable cementitious panel;
the cementitious panel having a density of 65 to 90 pounds per cubic foot and capable of resisting shear loads when fastened to the metal frame and comprising a continuous phase resulting from the curing of an aqueous mixture comprising, on a dry basis,
49 to 68 weight % of a blend of reactive powders,
23 to 36.1 weight % uniformly distributed lightweight filler particles, and
5 to 20 weight % uniformly distributed alkali-resistant glass fibers, and
optional superplasticizer;
the continuous phase being uniformly reinforced with the glass fibers and uniformly containing the lightweight filler particles,
the lightweight filler particles comprising ceramic microspheres and optionally at least one member selected from the group consisting of glass microspheres, fly ash cenospheres or perlite, each on a dry basis, the lightweight filler particles having a particle specific gravity of from 0.02 to 1.00 and an average particle size of about 10 to 500 microns (micrometers),
a layer of Type X fire rated gypsum wallboard attached to a side of the metal frame opposed to the shear diaphragm to form a second diaphragm,
wherein the winged drillers are located above the point and below the first threads of the screw and protrude laterally from a shaft of the screw, and
wherein the flooring system meets the 2 hour fire resistance test rating under ASTM E-119 (effective 2003),
wherein the blend of reactive powders comprises, on a dry basis,
45 to 75 wt. % calcium sulfate alpha hemihydrate,
20 to 40 wt. % Portland cement,
0.2 to 3.5 wt. % lime, and
5 to 25 wt. % of an active pozzolan comprising silica fume,
wherein the flooring system has a horizontal design shear capacity of the floor shear diaphragm of 300 to 1000 pounds per linear foot,
wherein the cementitious panel has a thickness of about 1⁄2 to 11⁄2 inches.

2. The system of claim 1, wherein the glass fibers have a diameter of about 10 to 15 microns and lengths of 1 to 2 inches, and the aqueous mixture comprises, on a wet basis,
12.2-12.3 weight % portland cement,
24.4-24.7 weight % calcium sulfate alpha hemihydrate,
5.1 weight % silica fume,
0.4 weight % lime,
26.4-27.4 weight % ceramic microspheres,
1.9 weight % superplasticizer,
21.9-24.2 weight % water, and
4.4-7.2 weight % alkali-resistant glass fibers.

3. The system of claim 1, wherein the ceramic microspheres have at least one feature selected from the group consisting of a mean particle size from 50 to 250 microns and a particle size range of 10 to 500 microns.

4. The system of claim 1, wherein the aqueous mixture the panel has been formed from consists of, on a dry basis:
58 to 68 wt. % said reactive powders,
6 to 17 wt. % said alkali-resistant glass fibers, and
23 to 34 wt. % said lightweight filler particles, and
optional said superplasticizer;
wherein said lightweight filler particles consist of ceramic microspheres and up to 1.0 wt. % filler particles selected from the group consisting of glass microspheres, fly ash cenospheres or perlite,
wherein the reactive powders consist of, on a dry basis:
65 to 75 wt. % calcium sulfate alpha hemihydrate,
20 to 25 wt. % Portland cement,
0.75 to 1.25 wt. % lime, and

10 to 15 wt. % silica fume active pozzolan.

5. The system of claim 4, wherein the aqueous mixture contains, on a dry basis, 7 to 12 wt. % alkali-resistant glass fibers, wherein the horizontal shear diaphragm is supported on light gauge cold rolled metal frame comprising metal joists.

6. The system of claim 5,
wherein the ceramic microspheres have at least one feature selected from the group consisting of a mean particle size from 50 to 250 microns and falling within a particle size range of 10 to 500 microns,
wherein the panels are 1⁄2 inch (12.5 mm) thick, and the system having the 1⁄2 inch (12.5 mm) thick panels fastened to said light gauge cold rolled metal frame when tested according to ASTM D-1761-88, effective 1988 (reapproved 2000), has a dry lateral screw resistance of 350 to 550 pounds,
wherein the glass fibers are monofilaments having a diameter of about 5 to 25 microns (micrometers) and a length of about 0.25 to 3 inches (6.3 to 76 mm),
wherein the flexural strength of a said panel having a dry density of 65 lb/ft3 to 95 lb/ft3 (1041 to 1522 kg/m3) after being soaked in water for 48 hours is at least 1650 psi (11.4 MPa) as measured by the ASTM C 947-03 test, effective 2003,
wherein the system has a horizontal design shear capacity of the floor diaphragm of 400 to 1000 pounds per linear foot.

7. The system of claim 6, wherein the metal frame is 16 gauge steel.

8. The system of claim 1, wherein the filler comprises the ceramic microspheres and optionally at least one member selected from the group consisting of uniformly distributed glass microspheres and fly ash cenospheres having an average diameter of about 10 to 350 microns (micrometers) and, wherein the glass fibers are monofilaments having a diameter of about 5 to 25 microns (micrometers) and a length of about 0.25 to 3 inches (6.3 to 76 mm).

9. The system of claim 1, wherein the aqueous mixture comprises, on a dry basis:
54 to 58 wt. % said reactive powders,
5 to 15 wt. % said glass fibers,
33.8 to 36.1 wt. % said lightweight filler particles consisting of ceramic microspheres, and up to 1.0 wt. % of the glass microspheres,
the ceramic microspheres having a particle density of 0.50 to 0.80 g/mL; and
optional superplasticizer.

10. The system of claim 1, wherein the panel comprises a core comprising the continuous phase resulting from the curing of the aqueous mixture, and
further comprising at least one outer layer, each said outer layer comprising a second continuous phase resulting from the curing of a second aqueous mixture comprising, on a dry basis,
49 to 68 weight % a second blend of reactive powders,
23 to 36.1 weight % uniformly distributed lightweight filler particles comprising uniformly distributed ceramic microspheres, and
5 to 20 weight % uniformly distributed alkali-resistant glass fibers, and optional superplasticizer,
the second blend of reactive powders comprising, on a dry basis,
45 to 75 wt. % calcium sulfate alpha hemihydrate,
20 to 40 wt. % Portland cement,
0.2 to 3.5 wt. % lime, and
5 to 25 wt. % of an active pozzolan comprising silica fume,

the second continuous phase being uniformly reinforced with the alkali-resistant glass fibers, and the lightweight filler particles comprising ceramic microspheres having a particle specific gravity of from 0.02 to 1.00 and an average particle size of about 10 to 500 microns (micrometers),
at least one outer layer having reduced phase density relative to the core.

11. The system of claim 10, wherein the second aqueous mixture the outer layer(s) has been formed from comprises, each on a dry basis:
58 to 68 wt. % said second blend of reactive powders,
6 to 17 wt. % said glass fibers and
23 to 34 wt. % said lightweight filler particles comprising ceramic microspheres and up to 1.0 wt. % of glass microspheres having an average diameter of about 10 to 350 microns (micrometers), and
optional superplasticizer.

12. The system of claim 1, wherein the cementitious panel has a thickness of 3⁄4 inch and the 3⁄4 inch (19 mm) thick panel when tested according to ASTM 661-88 and APA S-1 test methods, effective as of 1988 (reapproved 1997) and Aug. 12, 1980, respectively, over a span of 16 inches (406.4 mm) on centers, has an ultimate load capacity greater than 400 lb (1810 kg), under static loading, an ultimate load capacity greater than 400 lb (182 kg) under impact loading, and a deflection of less than 0.125 inches (1.98 mm) under both static and impact loading with a 200 lb (90.9 kg) load.

13. The system of claim 1, wherein the flexural strength of a panel having a dry density of 65 lb/ft3 (1041 kg/m3) to 90 lb/ft3 after being soaked in water for 48 hours is at least 1650 psi (11.4 MPa) as measured by the ASTM C 947-03 test, effective as of 2003.

14. The system of claim 1, wherein the blend of reactive powders consists of, on a dry basis:
65 to 75 wt. % calcium sulfate hemihydrate,
20 to 25 wt. % Portland cement,
0.75 to 1.25 wt. % lime, and
10 to 15 wt. % silica fume active pozzolan.

15. The system of claim 1, wherein the panels are 3⁄4 inch (19 mm) thick, and the horizontal shear diaphragm load carrying capacity of the system will not be lessened by more than 25% when exposed to water in a test wherein a 2 inch head of water is maintained over the 3⁄4 inch thick panels fastened on a 10 foot by 20 foot metal frame for a period of 24 hours.

16. The system of claim 1, wherein the panels are 3⁄4 inch (19 mm) thick, and the system will not absorb more than 0.7 pounds per square foot of water when exposed to water in a test wherein a 2 inch head of water is maintained over the 3⁄4 inch thick panels fastened on a 10 foot by 20 foot metal frame for a period of 24 hours.

17. The system of claim 1, wherein the panels are 3⁄4 inch (19 mm) thick, and a 10 foot wide by 20 foot long by 3⁄4 inch thick diaphragm of the panels attached to a 10 foot by 20 foot said metal frame will not swell more than 5% when exposed to a 2 inch head of water maintained over the panels fastened on the metal frame for a period of 24 hours.

18. The system of claim 1, wherein the panel comprises:
a core layer comprising the continuous phase, the continuous phase comprising 5 to 17 wt % glass fibers, on a dry basis, and
at least one outer layer of respectively a second continuous phase resulting from the curing of a second aqueous mixture comprising, on a dry basis,
49 to 68 weight % second blend of reactive powder,
23 to 36.1 weight percent lightweight filler comprising ceramic microspheres, and
7 to 20 weight % alkali-resistant glass fibers, and
optional superplasticizer;
the second blend of reactive powders consisting of, on a dry basis,
45 to 75 wt. % calcium sulfate alpha hemihydrate,
20 to 40 wt. % Portland cement,
0.2 to 3.5 wt. % lime, and
5 to 25 wt. % of silica fume,

the second continuous phase being reinforced with glass fibers and containing the lightweight filler particles, the lightweight filler particles having a particle specific gravity of from 0.02 to 1.00 and an average particle size of about 10 to 500 microns (micrometers) on each opposed side of the inner layer,
wherein the at least one outer layer has a higher percentage of glass fibers than the inner layer.

19. The system of claim 1, wherein, the system is non-directional, in that the panels of the system may be placed with their long dimension parallel or perpendicular to the metal joists of the frame without losing strength or load carrying characteristics, wherein the ability of the system to support dead and live loads without failure is the same regardless of the orientation of the SCP panel on the metal framing.

20. The system of claim 1, wherein the system has a horizontal design shear capacity of the floor diaphragm of 400 to 800 pounds per linear foot.

21. The system of claim 1, wherein the horizontal shear diaphragm is supported on light gauge cold rolled metal frame comprising metal joists.

22. The system of claim 1, wherein the light gauge cold rolled metal frame comprises a corrugated metal sheet.

23. The system of claim 1, wherein the metal screw fasteners with winged drillers are winged self-drilling screws.

24. The system of claim 1, wherein the panels are 1⁄2 inch (12.5 mm) thick, and the system having the 1⁄2 inch (12.5 mm) thick panels fastened to said light gauge cold rolled metal frame when tested according to ASTM D-1761-88, effective 1988 (reapproved 2000), has a dry lateral screw resistance of 350 to 550 pounds.

25. The system of claim 1, wherein the panels are 3⁄4 inch (19.05 mm) thick, and the system having the 3⁄4 inch (19.05 mm) thick panels fastened to said light gauge cold rolled metal frame when tested according to ASTM D-1761-88, effective 1988 (reapproved 2000), has a dry lateral screw resistance of 400 to 500 pounds.

26. A method of providing a 2 hour fire resistance test rating under ASTM E-119, effective 2003 to a building structure comprising:
making a non-combustible flooring system as flooring of the building structure, said making step comprising forming a horizontal shear diaphragm supported on a metal frame, the system comprising:
metal bugle head screw fasteners with winged drillers;
the metal frame;
the horizontal shear diaphragm fastened by the fasteners to the metal frame,
the horizontal shear diaphragm comprising the reinforced, lightweight, dimensionally stable structural cementitious panel;
the cementitious panel having a density of 65 to 90 pounds per cubic foot and capable of resisting shear loads when fastened to the metal frame and comprising a continuous phase resulting from the curing of an aqueous mixture comprising, on a dry basis.
49 to 68 weight % of a blend of reactive powders,
23 to 36.1 weight % uniformly distributed lightweight filler particles, and
5 to 20 weight % uniformly distributed alkali-resistant glass fibers, and
optional superplasticizer;
the continuous phase being uniformly reinforced with the glass fibers and uniformly containing the lightweight filler particles,
the lightweight filler particles comprising ceramic microspheres and optionally at least one member selected from the group consisting of glass microspheres, fly ash cenospheres or perlite, each on a dry basis, the lightweight filler particles having a particle specific gravity of from 0.02 to 1.00 and an average particle size of about 10 to 500 microns (micrometers),
a layer of Type X fire rated gypsum wallboard attached to a side of the metal frame opposed to the shear diaphragm to form a second diaphragm,
wherein the winged drillers are located above the point and below the first threads of the screw and protrude laterally from a shaft of the screw, and
wherein the flooring system meets the 2 hour fire resistance test rating under ASTM E-119 (effective 2003),
wherein the blend of reactive powders comprises, on a dry basis,
45 to 75 wt. % calcium sulfate alpha hemihydrate,
20 to 40 wt. % Portland cement,
0.2 to 3.5 wt. % lime, and
5 to 25 wt. % of an active pozzolan comprising silica fume,
wherein the flooring system has a horizontal design shear capacity of the floor shear diaphragm of 300 to 1000 pounds per linear foot, and
the frame comprising metal joists,
said forming comprising:
placing the panel on metal joists of the metal frame;
attaching the structural cementitious panel on the metal joists with bugle head screws with winged drillers, the winged drillers located above the point and below the threads of the screw and protruding laterally from a shaft of the screw; and
attaching the layer of Type X fire rated gypsum wallboard to the side of the frame opposed to said horizontal shear diaphragm to form a second horizontal diaphragm,
wherein the flooring system meets the 2 hour fire resistance test rating under ASTM E-119 (effective 2003), the cementitious panel has a thickness of about 1⁄2 inch to 1 1⁄2 inches.

27. The method of making the non-combustible flooring system of claim 26, comprising placing the panel on said metal joists when the ambient temperature is less than 32 degrees F. (0 degrees C.), wherein the panel has a thickness of about 1⁄4 inch to 1 1⁄2 inches (6.3 to 38.11 mm),
wherein the flexural strength of the panel having a dry density of 65 lb/ft3 (1041 kg/m3) to 90 lb/ft3 after being soaked in water for 48 hours is at least 1650 psi (11.4 MPa) as measured by the ASTM C 947-03 test, effective as of 2003.

28. The method of claim 26, comprising placing the panel on said metal joists when the ambient temperature is less than 20 degrees F. (minus 7.5 degrees C.), wherein the panels are 3⁄4 inch (19 mm), and the horizontal shear diaphragm load carrying capacity of the system will not be lessened by more than 25% when exposed to water in a test wherein a 2 inch head of water is maintained over the 3⁄4 inch thick panels fastened on a 10 foot by 20 foot metal frame for a period of 24 hours,
wherein the 3⁄4 inch (19 mm) thick panel when tested according to ASTM 661-88 and APA S-1 test methods, effective as of 1988 (reapproved 1997) and Aug. 12, 1980, respectively, over a span of 16 inches (406.4 mm) on centers, has an ultimate load capacity greater than 400 lb (1810 kg), under static loading, an ultimate load capacity greater than 400 lb (182 kg) under impact loading, and a deflection of less than 0.125 inches (1.98 mm) under both static and impact loading with a 200 lb (90.9 kg) load.

29. The method of claim 26, wherein said placing step comprises placing the panel to lie on said metal joists when the ambient temperature is less than 32 degrees F. (0 degrees C.) by dropping the panel on the metal framing elements such that at least one end of the panel falls at least 2 feet.

30. The method of claim 26, wherein said placing step comprises placing the panel to lie on said metal joists when the ambient temperature is less than 32 degrees F. (0 degrees C.) by dropping the panel on the metal framing elements such that at least one end of the panel falls 2 to 3 feet.

31. The method of claim 26, wherein the metal screw fasteners with winged drillers are winged self-drilling screws.

32. The method of claim 26, wherein water is added to form the aqueous mixture in a range of between 35 to 70% of the weight of reactive powder.

33. The method of claim 26, wherein water is added to form the aqueous mixture in a range of between 60 to 70% of the weight of reactive powder.

34. The method of claim 26, wherein the aqueous mixture consists of, on a dry basis:
58 to 68 wt. % reactive powders,
6 to 17 wt. % alkali-resistant glass fibers, and
23 to 34 wt. % lightweight filler particles, and
optional superplasticizer;
wherein said lightweight filler particles consist of ceramic microspheres and up to 1.0 wt. % filler particles selected from the group consisting of glass microspheres, fly ash cenospheres or perlite,
wherein the reactive powders consist of, on a dry basis:
65 to 75 wt. % calcium sulfate alpha hemihydrate,
20 to 25 wt. % Portland cement,
0.75 to 1.25 wt. % lime, and
10 to 15 wt. % silica fume active pozzolan.

35. The method of claim 34, wherein the aqueous mixture contains 7 to 12 wt. % alkali-resistant glass fibers, wherein the horizontal shear diaphragm is supported on light gauge cold rolled metal frame comprising metal joists.

36. The method of claim 34, wherein water is added to form the aqueous mixture in a range of between 35 to 70% of the weight of reactive powder.

37. The method of claim 34, wherein the ceramic microspheres have at least one feature selected from the group consisting of a mean particle size from 50 to 250 microns and falling within a particle size range of 10 to 500 microns,
wherein the panels are 1⁄2 inch (12.5 mm) thick, and the system having the 1⁄2 inch (12.5 mm) thick panels fastened to said light gauge cold rolled metal frame when tested according to ASTM D-1761-88, effective 1988 (reapproved 2000), has a dry lateral screw resistance of 350 to 550 pounds,
wherein the glass fibers are monofilaments having a diameter of about 5 to 25 microns (micrometers) and a length of about 0.25 to 3 inches (6.3 to 76 mm),
wherein the flexural strength of a said panel having a dry density of 65 lb/ft3 to 95 lb/ft3 (1041 to 1522 kg/m3) after being soaked in water for 48 hours is at least 1650 psi (11.4 MPa) as measured by the ASTM C 947-03 test, effective 2003,
wherein the system has a horizontal design shear capacity of the floor diaphragm of 400 to 1000 pounds per linear foot,
wherein the metal frame is 16 gauge steel.

38. The method of claim 26, wherein the aqueous mixture comprises, on a dry basis:
54 to 58 wt. % of the reactive powders,
5 to 15 wt. % of the glass fibers,
33.8 to 36.1 wt. % of the lightweight filler particles consisting of ceramic spheres with up to 1.0 wt. % of the glass microspheres, the ceramic microspheres having a particle density of 0.50 to 0.80 g/mL, each on a dry basis;
and optional superplasticizer.