Abstract:
A method and structure for constructing a waterproof concrete structure using a central core of rigid foam attached to exterior castings, cemented together and anchored to a foundation.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This patent application claims the priority of U.S. Provisional Patent Application No. 60/486,884, inventor Bruce L. Riley, filed on Jul. 10, 2003 and entitled Component Modular Foam Based System For Construction Of Concrete Structures. 
     
    
     FIELD OF THE INVENTION  
       [0002]     A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the U.S. Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.  
         [0003]     This invention relates to concrete structures and more particularly to a method and apparatus for constructing a concrete structure having a solid foam core, forming a water-resistant structure that is particularly amenable to applications where water is used, such as for a decorative fountain.  
       BACKGROUND OF THE INVENTION  
       [0004]     Concrete structures such as buildings, outdoor barbeques, shower stalls and swimming pools are typically constructed by first assembling forms to hold the concrete in place. Armature, usually in the form of a matrix of steel rebar is then placed in the form to give the concrete added tensile strength, different sections of armature may need to be spliced together with steel wire. Concrete is then poured over the armature, immersing the armature. Alternatively, after the armature is completed, a mesh of steel, burlap or nylon netting may be placed over the armature and tied to it. This mesh provides a surface to hold the concrete in place over the surface of the structure. A first structural layer of concrete may be poured over the mesh and allowed to harden.  
         [0005]     For situations requiring waterproofing, an elastomeric waterproof coating may then be applied to the structural concrete coat. A final, textured concrete coat might be applied to the structural coat and textured and colored to give a desired appearance.  
         [0006]     A solid concrete wall may be constructed in a similar fashion but sheet forms such as plywood must typically be used to hold the concrete in place while it dries and hardens. An alternative to solid concrete construction, where the strength of solid rebar armature-reinforced concrete is not required, is using a wood and mortar or stucco construction. A stucco wall, for example, is usually built by constructing a wood frame, covering the wood frame with a waterproof membrane such as tar paper, covering the tar paper with a mesh and troweling or spraying on one or more layers of mortar or concrete over the mesh. The wall is structurally supported by the wood frame and the concrete layer is added to provide the strength and imperviousness of masonry.  
         [0007]     The construction of naturalistic artificial rock structures, such as fountains surrounding a swimming pool requires a more specialized construction. There has been a trend in swimming pool design to incorporate naturalistic elements into the surrounding deck, such as waterfalls and rocks, such that the pool looks like a natural mountain pond or tropical grotto.  
         [0008]     A common swimming pool waterfall construction technique employs concrete footings reinforced with steel rebar. The footings are first anchored to the ground and then an armature or steel skeleton in the desired general shape of the naturalistic artificial rock structure is anchored to the footings. This process is laborious and expensive, the armature is laboriously formed by bending the steel rebar into the basic shape of the desired finished structures. When the armature is shaped to form a resulting enclosed structure, framework such as wood bracing and steel-reinforced concrete support columns must frequently be used in the internal area to reinforce the artificial rock structure and ensure structural integrity.  
         [0009]     There are other methods for building naturalistic waterfalls and other artificial rock structures but they too have drawbacks. Natural rock itself can simply be cemented together to make the structures, but natural rock is heavy and difficult to move; it is expensive to buy and to transport, it is difficult to work with. Natural rock it also requires a high degree of skill to ensure that a structurally sound artificial rock structure is built, and, natural rock tends to be difficult to seal against water. Natural rock also tends to leak water when used alone to build a waterfall or basin.  
         [0010]     An alternative to constructing these artificial rock structures is to use preformed plastic or urethane waterfalls and rocks and simply affix around the pool. These structures tend to be unconvincing though and fake in appearance. Moreover, these preformed plastic and urethane structures are also flimsy and structurally weak and tend to fade and crack under the stress of sun or from people climbing on them. These fake rocks are just for decoration they usually do not incorporate steel-reinforced concrete.  
         [0011]     The foregoing methods of constructing concrete and concrete-covered structures require a high degree of skill to shape the finished product, to place the forms correctly and particularly to ensure the integrity of the waterproofing of the concrete. These methods are also wasteful because the forms must be discarded or stored after use, and a given shape must be repeatedly reconstructed from the same forms when a similar construction is subsequently undertaken. The present methods are also labor-intensive, time-consuming because they require that forms to be set, the armature and mesh to be placed and, after the concrete is poured, the removal of the forms. Finally, the above methods are difficult to design by engineers and difficult to inspect by building inspectors, because they are frequently custom jobs.  
         [0012]     An improved method for producing easily constructed water-resistant structures for such applications is taught in U.S. Pat. No. 6,581,349, Riley, titled Method And Manufacture For Constructing Watertight Concrete Structures. In that patent a method is taught of using rigid plastic shells faced with armature such as rebar. The shells are wired to each other and covered with a layer of cementatious material. Castings are usually added to the cement-covered shell structure and bonded with additional concrete. Castings are pre-cast impressions made from the image of natural rock or a mold made to look like pre-cast rock. These castings may be hollow formed sheets and are usually made from concrete or fiber-embedded concrete.  
         [0013]     The Riley &#39;349 patent presents a much easier method for constructing such naturalistic fountains but requires some degree of skill and further labor to construct and complete the structure, such as a fountain.  
         [0014]     What is needed then is a less labor-intensive method that optimally will be lighter to reduce transportation costs for building naturalistic structures or waterproofed structures.  
       SUMMARY OF THE INVENTION  
       [0015]     A more economical construction method requiring less skill and time to construct a concrete structure has been developed. A concrete structure such as a fountain or more complicated structure may be constructed by providing one or more pieces of rigid foam to make a structural block. The structural foam block is anchored to a foundation pad, typically a concrete foundation pad. The block may be attached to the foundation pad with cement. The block may further have one or more anchoring holes extending through the foam block that can be filled with concrete, cement or the like to further anchor the block to the pad.  
         [0016]     The structural foam block is provided is sized in the general shape of the desired structure. After it is affixed to the foundation pad it is partially or fully covered with one or more castings, made from fiber-reinforced/fiber-embedded concrete for example, which are affixed to the structural foam block with a closed-cell liquid foam that expands and hardens as it cures. The castings may further be more securely attached to the structural foam block by affixing wiring to the castings and also placing the wires in the anchoring holes to be covered by the concrete.  
         [0017]     In this way the castings will partially or fully cover the structural foam block. The castings may be further affixed to the concrete structure by filling any remaining voids between the castings and the structural foam block with a cementations material.  
         [0018]     In one embodiment the castings are formed to appear like natural rock. The invention is particularly useful with respect to making outdoor structures, where it may be desirous to have the structure appear as natural rock. The castings may be prepared by being pre-cast from an impression made from a natural rock, or even from a mold artistically made to look like natural rock. Using a waterproof liquid foam is advisable in this environment.  
         [0019]     There are a wide variety of liquid foams that are suitable to affixing the components of the invention together. There are urethane foams, latex foams, phenolic foams and other organic foams, to name a few. Gernerally, the foam is a liquid or foamy slurry that is sprayed on and expands and hardens as it cures, bonding the casting to the structural foam block. A liquid foam that cures to produce a waterproof barrier will provide additional waterproofing.  
         [0020]     If the intended concrete structure is be significantly weight-bearing, rebar armature can be added to secure support the castings and/or secure the structure to the foundation.  
         [0021]     The invention may be particularly suitable for building an outdoor structure, such as outdoor water fountain for a swimming pool for example. A water pump can be incorporated near or within the concrete structure, the water pump moves water through a riser pipe to a higher point on structure, an upper casting, so that the water will then fall into a basin such as a pond or swimming pool, to be then be recirculated by the pump.  
         [0022]     In this respect, before more fully explaining at least one embodiment of the invention in detail it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.  
         [0023]     Accordingly, although exemplary embodiments of the invention have been shown and described, it is to be understood that all the terms used herein are descriptive rather than limiting, and that many changes, modifications, and substitutions may be made by one having ordinary skill in the art without departing from the spirit and scope of the invention. Further objects and advantages of the invention will become apparent to one skilled in the art by reading and understanding the following detailed description and the drawings to which it refers. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]      FIGS. 1A and 1B  are top and side views of the rigid foam used as a core for the present structure.  
         [0025]      FIG. 2  is a perspective view of a casting of the present invention.  
         [0026]      FIG. 3  is a side cutaway view of an embodiment of the present invention.  
         [0027]      FIG. 4  is a photograph of a side view of the present invention under construction.  
         [0028]      FIGS. 5A and 5B  are photographs of up an upper view of  FIG. 4 .  
         [0029]      FIG. 6  is a photograph of up a rear upper view of  FIG. 4 .  
         [0030]      FIG. 7  is a photograph of up an alternative embodiment of the present invention under construction.  
         [0031]      FIG. 8  is a cutaway schematic view of the side of a fountain built as an embodiment of the present invention. 
     
    
     DESCRIPTION OF THE INVENTION  
       [0032]     The following description, and the figures to which it refers, are provided for the purpose of describing examples and specific embodiments of the invention only and are not intended to exhaustively describe all possible examples and embodiments of the invention.  
         [0033]     Referring now to  FIGS. 1A and 1B  a concrete structure such as a fountain is formed by providing a rigid foam block  21  anchored to a concrete foundation pad  23 . An example of such a foam block is one made of an extruded polystyrene such as Styrofoam®, made by the Dow chemical company of Midland, Mich. Another closed cell extruded or molded/expanded polystyrene or polyethylene or other structural foam product with generally equivalent properties may be used as well. Styrofoam® and its equivalents, hereafter referred to as styrofoam, provides excellent water resistance, high insulation value and superior compressive strength.  
         [0034]     In this embodiment the single rigid block of foam  21  is used and the anchoring is achieved by using a styrofoam block forming a void, an anchoring hole  25 , passing through the styrofoam block  21 . The styrofoam block  21  is carved or otherwise shaped to the desired general shape of the completed structure. The styrofoam block  21  is then placed on the concrete foundation pad  23 . An initial layer of concrete may be used to cement the styrofoam block  21  to the foundation pad  23 .  
         [0035]     Referring now to  FIG. 2 , foam-filled castings  27  of a variety of shapes are provided. As noted above castings are pre-cast impressions made from the a impression mold of natural rock or a mold artistically made to look like rock. Castings are typically made using a latex mold which was in turn made from an impression of natural rock. The castings are optimally made from fiber-reinforced/fiber-embedded concrete (FRC) and filled with closed-cell foam  29 . The castings are preferably colored and treated for water resistance.  
         [0036]     The foam in the castings is usually applied as a liquid foam and allowed to harden. Liquid foam insulation can be applied from small spray containers as a liquid or in larger quantities as a pressure sprayed (foamed-in-place) product. There are also liquid foam materials that are poured from a container. These types of foam expand and harden as the chemical mixture cures and conform to the shape of the cavity to fill and seal it thoroughly. These are generally urethane foams but latex, phenolic, and organic based foams are available too.  
         [0037]      FIG. 3  is a schematic of the invention with parts in their relative configuration.  FIGS. 4-7  are photographs of the component parts of an actual construction of the invention.  FIG. 4  is a side view of the construction of a water fountain structure. The upper casting  31  is lined with the foam  29 .  FIG. 5  details the anchor hole  25  centrally located in the styrofoam block  21 .  
         [0038]     According to an embodiment of the present invention the styrofoam block  21  is placed on the concrete foundation pad  23 . Foam filled castings  27  are affixed to the top  31  and sides of the structure. Wiring  33  may be used to affix the foam castings  27  to the styrofoam block  21 , as shown in  FIG. 6 . In one embodiment one or more castings are wired into through the anchor hole  25  as well to anchor the castings  27  to the structure and give them durability. Concrete is then poured through the anchor hole and over the top of the styrofoam block  21 , thereby anchoring the styrofoam block  21  to the concrete pad  23 . The upper casting  31  is then placed over the styrofoam block  21  and the seams between the castings  27  are cemented together with cement  28 .  
         [0039]      FIG. 7  shows the same construction but incorporating rebar armature  35 . Although this may be structurally desirable in some situations, one of the advantages of this method of construction is that the complications of rebar can be avoided. Typically the use of rebar in construction requires that the structure be engineered, then inspected and approved by a building inspector in several steps that require a pause in construction.  
         [0040]     In contrast, in the present invention a structurally strong and fully waterproof concrete structure can be assembled with a relatively low level of skill in a matter of hours, and without the need for rebar.  FIG. 8  is a cutaway schematic view of the side of a fountain built as an embodiment of the present invention. The fountain includes a water pump  39  and a riser pipe  41  that through which water  42  is pumped over the upper casting  31  into a basin  43 , such as a swimming pool.  
         [0041]     It will be appreciated that the invention has been described hereabove with reference to certain examples or embodiments as shown in the drawings. Various additions, deletions, changes and alterations may be made to the above-described embodiments and examples without departing from the intended spirit and scope of this invention. Accordingly, it is intended that all such additions, deletions, changes and alterations be included within the scope of the following claims. Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.