Patent ID: 12227454

Similar reference characters denote corresponding features consistently throughout the attached drawings.

DETAILED DESCRIPTION

Definitions

It should be understood that the drawings described above or below are for illustration purposes only. The drawings are not necessarily to scale, with emphasis generally being placed upon illustrating the principles of the present teachings. The drawings are not intended to limit the scope of the present teachings in any way.

Throughout the application, where compositions are described as having, including, or comprising specific components, or where processes are described as having, including, or comprising specific process steps, it is contemplated that compositions of the present teachings can also consist essentially of, or consist of, the recited components, and that the processes of the present teachings can also consist essentially of, or consist of, the recited process steps.

It is noted that, as used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.

In the application, where an element or component is said to be included in and/or selected from a list of recited elements or components, it should be understood that the element or component can be any one of the recited elements or components, or the element or component can be selected from a group consisting of two or more of the recited elements or components. Further, it should be understood that elements and/or features of a composition or a method described herein can be combined in a variety of ways without departing from the spirit and scope of the present teachings, whether explicit or implicit herein.

The use of the terms “include,” “includes”, “including,” “have,” “has,” or “having” should be generally understood as open-ended and non-limiting unless specifically stated otherwise.

The use of the singular herein includes the plural (and vice versa) unless specifically stated otherwise. In addition, where the use of the term “about” is before a quantitative value, the present teachings also include the specific quantitative value itself, unless specifically stated otherwise. As used herein, the term “about” refers to a ±10% variation from the nominal value unless otherwise indicated or inferred.

The term “optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances in which it does not.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the presently described subject matter pertains.

Where a range of values is provided, for example, concentration ranges, percentage ranges, or ratio ranges, it is understood that each intervening value, to the tenth of the unit of the lower limit, unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the described subject matter. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges, and such embodiments are also encompassed within the described subject matter, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the described subject matter.

Throughout the application, descriptions of various embodiments use “comprising” language. However, it will be understood by one of skill in the art, that in some specific instances, an embodiment can alternatively be described using the language “consisting essentially of” or “consisting of”.

For purposes of better understanding the present teachings and in no way limiting the scope of the teachings, unless otherwise indicated, all numbers expressing quantities, percentages or proportions, and other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained. At the very least, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

The present disclosure is directed towards a fiber reinforced concrete. As used herein, the terms ‘fiber’, ‘filament’, and ‘wire’ may be used interchangeably to indicate a slender filament used to form a reinforcing member.

Referring toFIG.1, a fiber reinforced concrete1is shown including a volume2of concrete and a plurality of discrete reinforcing members10scattered in random orientations and suspended throughout the volume2of concrete. As shown inFIGS.2A-Cand3A-C, the discrete reinforcing members10are wire meshes including a first set12of two or more parallel wires extending along their length L1in a common plane P1and a second set14of three parallel wires extending along their length L2in a common plane. As used herein, the terms “extending along their length” or “extending lengthwise” in reference to the wires of the wire mesh are used to indicate that the wires lie in a plane extending along and parallel to the longitudinal axis of the wires, as opposed to, for example, a radial or diametrical plane passing orthogonally through the wires.

The first set of wires12and second set of wires14are orthogonal to each other and constitute an entire standalone reinforcing member10, as opposed to being portions of a larger mesh. The principle behind the use of the discrete reinforcing members10being scattered throughout the volume of concrete is similar to the use of fibers in fiber reinforced concrete. Unlike rebar or large wire meshes, which are typically placed in a specific pattern or arrangement, the fibers in fiber reinforced concrete are dispersed randomly and scattered throughout a volume of concrete. Both rebar and fiber mesh reinforcement methods provide strength and ductility to the concrete, with slightly different advantages. Fibers generally are considered better in preventing small cracks in the concrete from becoming larger, similar to the effect of stitches on a wound, whereas rebar carries load after the concrete cracks, analogous to bones in the human body.

In a non-limiting embodiment, the wire meshes may be of a metallic material such as steel or polymeric material and formed by casting, as shown inFIGS.2A-C. The first set of wires12and second set of wires14extend along their respective lengths L1and L2, in a shared common plane P1. In a further non-limiting embodiment, the wire meshes are of metallic material and may be formed by welding, as shown inFIGS.3A-C, where the first set of wires12extend along their length L1in a first common plane P1and the second set of wires14extend along their length L2in a second common plane P2. The reinforcing members10may include a mesh pattern16of a total of four contiguous rectangles arranged in two rows R and two columns C.

Turning toFIG.3D, a non-limiting example of a welding process is shown to form the reinforcing member ofFIGS.3A-C. The process begins with horizontal rows of parallel wires fed by machine, upon which are pressed vertical columns of wires contacting the rows of horizontal wires and forming intersection points. A high intensity electric current is applied at the intersection points which melts a small portion of each of the horizontal and vertical wires, and forms a strong weld after cooling. The process is repeated by pressing another vertical wire against the horizontal wires and applying an electric current. After cooling, the wires are cut into a desired mesh size, e.g. 2×1, 2×2, 3×1, 3×2, or 3×3 forming a desired number of reinforcing members. While casting and welding are methods of forming the mesh using a metallic material, it is conceivable that the reinforcing members may be formed by other manufacturing methods and materials, e.g. molding using polymer reinforced glass fiber, carbon fiber, etc.

Turning toFIGS.4A-C, the fiber reinforced concrete may include reinforcing members10having a mesh pattern16including a total of two contiguous rectangles arranged in a single column C. While two rows R are shown in the embodiment ofFIGS.4A-B, a single row and two columns may be used instead. The reinforcing members10may include free ends18extending laterally outward beyond the mesh pattern16. The free ends18help with increasing the anchorage of the reinforcing members within the concrete volume. Free ends18may include straight free ends18aand/or bent free ends18b, shown inFIG.4B. Bent free ends18bmay be bent at an angle θ between 30° to 90°. While embodiments of the drawings include free ends on both the first set of wires12and second set of wires14, free ends18may be included on only one set of wires, as well as only some wires within a set of wires.

The reinforcing members10may include wires having a diameter D of between about 0.2 mm and about 3 mm. In particular, the diameter D may be between about 0.2 mm and about 2 mm. An overall length L of the reinforcing members may be about 10 mm to about 75 mm and an overall width W of the reinforcing members may be about 10 mm to about 75 mm. The wires of the reinforcing members may have a cross-section which is circular 20 or polygonal22, as shown inFIG.4C.

Turning toFIGS.5A-B, in an embodiment, free ends18may be eliminated from reinforcing members10to reduce material. This avoids the wastage of fiber material in anchorages as the anchorage to one set of parallel wires is provided by the set of orthogonal wires. Reinforcing members10may include a “center bend” about a line B1passing through a central wire member24, as shown inFIG.5A, or a “diagonal bend” about a line B2extending through diagonally opposed corners26formed in a perimeter28of the reinforcing members. In an additional embodiment, the wires may be crimped, as shown in for example, U.S. Pat. No. 2,677,955 A, herein incorporated by reference.

Turning toFIGS.6A and6B, an important advantage provided by reinforcement members10includes the resistance to cracks24in multiple directions, such as first direction d1and second direction d2. In addition, multiple wires14a,14b,14c,12a,12b,12cprovide resistance and anchorage against cracks24. InFIG.6B, transverse wires14b,12bprovide the primary anchorage of the reinforcing member10in the case where free ends are not present.

Experimental Investigation

For studying the effect of using the disclosed reinforcing members on the characteristics of concrete, standard concrete cylinders (150 mm diameter×300 mm height) were tested in compression. Locally available aggregates (fine and coarse) conforming to relevant ASTM standards (C33/C33M-2016) were used. The mix proportion of plain concrete is given in Table 1 below. Ordinary Portland cement (OPC) was used.

Fiber reinforced concrete was produced using two types of reinforcing members formed by steel wires of the same diameter (0.5 mm): (i) Straight reinforcing members of 30 mm length with hooked ends and (ii) an embodiment of the proposed reinforcing members: square wire meshes in a 2×2 mesh without free ends. Individual squares within the wire mesh were 13 mm long×13 mm wide, and thus, the total size of the mesh reinforcing members was 26 mm×26 mm. The volume of reinforcing members in concrete was 1% (i.e., 3.27% by weight). The concrete cylinders were cast of plain (having no reinforcing members) as well as the two fiber reinforced concrete types. After 28 days of curing by immersion in water, the plain and fiber reinforced concrete cylinders were tested in compression in accordance with ASTM C39/C39M-17.

TABLE 1Plain Concrete MixMaterialWeight (kg/m3)Cement (OPC)460Crushed sand380Silica sand582Coarse aggregate (Nominal798size = 10 mm)Water (water to cement184ratio = 0.40)Gli-110 (Super-plasticizer)0.65 L

The stress-strain diagrams of the three types of concrete specimens are plotted inFIG.7. As expected, the addition of steel wire reinforcing members increased the compressive strength and introduced ductility in the concrete. However, the increase in the compressive strength of concrete produced using the proposed wire mesh reinforcing members is due to (i) better distribution of the proposed reinforcing wires and (ii) less wastage of steel in end hooks. Moreover, the use of the proposed wire mesh reinforcing members substantially enhanced the ductility by significant extension of the post-peak portion of the stress-strain curve. Although the concrete produced using conventional hooked steel fibers failed by the pullout of the wires, the wire pullout was resisted in the concrete having mesh wire reinforcing members by the transverse wires and the final failure was when a full mesh was finally pulled from the specimen.

It is to be understood that the wire mesh concrete reinforcement members and methods of use thereof are not limited to the specific embodiments described above, but encompass any and all embodiments within the scope of the generic language of the following claims enabled by the embodiments described herein, or otherwise shown in the drawings or described above in terms sufficient to enable one of ordinary skill in the art to make and use the claimed subject matter.