The present invention relates in general to reinforced prefabricated compound masonry units and in particular to compound units reinforced with fiber reinforced polymer.
Structures, including residential, commercial and industrial buildings, are made from masonry using individual units laid in and bound together by mortar. The common materials of masonry construction are clay masonry such as brick and terra cotta; stone, such as marble, granite, travertine, and limestone; concrete block, including without limitation conventional concrete masonry units and autoclaved aerated concrete; glass block; stucco; and tile. Masonry is generally a highly durable form of construction. However, the materials used, the quality of the mortar and workmanship, and the pattern in which the units are assembled can significantly affect the durability of the overall masonry construction.
Concrete masonry is a commonly used building material composed of individual units whose basic composition is concrete. The units can be hollow or solid. Concrete is strong in compression and weak in tension. For cast-in-place concrete, adding embedded reinforcement provides tensile capacity. The reinforcement can include steel reinforcing bars, steel fibers, glass fibers, or plastic fiber. Reinforcement is not used in individual concrete masonry units, but masonry elements constructed of hollow units can be reinforced similar to cast-in-place concrete.
Masonry grout is similar to concrete and is poured into the hollow concrete masonry units at the building site. Care needs to be taken to properly cure the grout and achieve the required strength. Concrete, concrete masonry units, mortar, and masonry grout all contain Portland cement. Cement-based materials require a moist, controlled environment to gain strength and harden fully. The cement paste hardens over time, initially setting and becoming rigid and gaining in strength in the days and weeks following. Hydration and hardening during the first three days can be critical. Fast drying and shrinkage due to factors such as evaporation may lead to increased tensile stresses at a time when the material has not yet gained significant strength, resulting in greater shrinkage cracking. During the curing period, it is preferable to maintain conditions with a controlled temperature and humid atmosphere. Properly curing concrete leads to increased strength and lower permeability, and avoids cracking from the surface drying out prematurely. Care must also be taken to avoid freezing or overheating. Improper curing can cause scaling, reduced strength, poor abrasion resistance and cracking.
To ensure proper curing of cement-based products, it would be desired to cure them in a controlled setting rather than at the building site. This is one reason why the use of concrete masonry units (blocks) is desirable. The concrete masonry units can be partially or fully cured off site at a manufacturing facility.
The individual masonry units are transported to the building site where they are installed. To build a structure over about five feet in height, scaffolding is usually necessary to support the masons while they work. Weather can affect the progress of the masonry when laid on site as well. Individual concrete masonry units have no reinforcement. The masonry reinforcement and grout are added as and after the units are set.
Disclosed herein are embodiments of prefabricated compound masonry units and methods of producing the same. One embodiment of a prefabricated compound masonry unit comprises at least one course comprising a plurality of blocks mortared to form a layer, the at least one course having a top surface and a bottom surface each having a first side and a second side. Longitudinal tension reinforcement is provided along at least a portion of a length of the at least one course and held with bonding material.
The course of the prefabricated compound masonry unit has a joint between adjacent blocks with the longitudinal tension reinforcement spanning each joint of both the first side and the second side of one or both of the bottom surface and top surface of the at least one course. The longitudinal tension reinforcement can be fiber reinforced polymer in dowel or biscuit form. The course can have a bed extending along a length of the course with the longitudinal tension reinforcement extending along at least a portion of the length and retained in the bed with the bonding material. The course can have a bed extending along a length of the course a joint between adjacent blocks, with the longitudinal tension reinforcement spanning each joint at at least one location in the bed.
Also disclosed herein are methods of making a prefabricated compound masonry unit prior to transporting the unit to a building site. One such method comprises forming a first course from a plurality of blocks by joining adjacent blocks with mortar, running longitudinal tension reinforcement along at least a portion of a length of the first course and retaining the longitudinal tension reinforcement to the first course with a bonding material. The method can further comprise forming a channel along the first course, wherein the longitudinal tension reinforcement is run within the channel. The channel can be formed by cutting into each block or along the course or molding the channel into each block when the block is molded. The first course has a joint between adjacent blocks and the longitudinal tension reinforcement can be run only to span each joint. The first course can have a bed extending along the length and the longitudinal tension reinforcement can be run within the bed. A second course can be formed from a plurality of blocks by joining adjacent blocks with mortar. The second course can be formed with the bonding material enclosing the longitudinal tension reinforcement between the first course and second course. Any number of courses can be formed to make any size unit. The preformed compound masonry unit can then be transported to the building site.
The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:
The concept of prefabricated compound masonry units reinforced with fiber reinforced polymer (hereinafter “frp) includes individual concrete masonry units constructed as elements (walls, beams, lintels or other masonry elements) and reinforced with frp that can be transported to the building site for incorporation into a building structure. The frp provides tensile strength to the units during transportation and handling and during installation of subsequent masonry.
Prefabricated compound masonry units are disclosed herein along with carriers for transporting the prefabricated compound masonry units. As used herein, a “block” is a single concrete masonry unit. As used herein, “compound” refers to the use of two or more individual blocks. A block can be clay masonry such as brick and terra cotta; stone, such as marble, granite, travertine, and limestone; concrete block, including without limitation conventional concrete masonry units and autoclaved aerated concrete; glass block; stucco; and tile. Compound masonry units can comprise a plurality of these blocks with one or more layers each of frp, epoxy or high strength mortar. Post tensioning tendons or rods incorporated into the compound masonry unit can provide added strength during handling or in the finished assembly.
The prefabricated compound masonry units are manufactured in a controlled factory setting using accepted code and practices in such a manner as to be easily transported and easily integrated into field building applications. This procedure would use craftsmen currently trained in the discipline of masonry and schooled in the new art of incorporating frp reinforcement for strategic advantages of strength. Process monitoring of the build would produce design compliance, assuring strict code conformance to achieve product quality regardless of the weather and the natural environment. The integration of one or more frp layers allows for sufficient rigidity and soundness for transportation and handling.
The prefabricated compound masonry units have many advantages over using individual units at the build site or pouring concrete at the build site. The prefabricated compound masonry units are adaptable for add-ons for last minute owner requirements. The prefabricated compound masonry units are built using the existing contingent of building trades. Use of the prefabricated compound masonry units can eliminate work stoppage due to weather conditions and lessen transportation damage and site damage of the individual units and other components. The use of prefabricated compound masonry units can also lessen occurrences of theft of product from unguarded building sites as the compound masonry units are too large to be easily transported without the proper assist and truck. The prefabricated compound masonry units limit moisture-related shrinkage issues and can be produced with consistent quality. The use of the prefabricated compound masonry units can provide “ease of building” on tight or busy sites and also provide safe, dust free construction solutions. These advantages are provided as examples and are not meant to be limiting. Those skilled in the art will recognize these advantages and more associated with the prefabricated compound masonry units and their use.
The prefabricated compound masonry units can be made to any overall shape and size desired or required by those skilled in the art so long as the units can be transported. Examples of applications for which the use of the prefabricated compound masonry units is contemplated include but are not limited to the following: columns, decorative walls, corners, floors, roofs, footings “neat” or insulated, headers for doors and windows, lintels, beams, posts, key walls, knee walls, ledges, retaining walls, wall sections, wall sections with returns and walkways.
The prefabricated compound masonry units can be built on a build base 10 as seen in
One embodiment of a prefabricated compound masonry unit is illustrated in
Longitudinal tension reinforcement 20 can be laid out on the build base 10 or base cover in an amount and configuration that is determined by the desired prefabricated compound masonry unit. Frp is used as the longitudinal tension reinforcement 20. As used herein as non-limiting examples, frp includes carbon fibers, aramid fibers, or glass fibers which are set in bonding material, which is epoxy or high strength mortar or an equivalent material. These frps can be used as the longitudinal tension reinforcement 20 because they have limited stretch, thereby providing the longitudinal reinforcement required when the prefabricated compound masonry unit 100 is lifted. Bonding material is used interchangeably with epoxy and high strength mortar and refers to the material that adheres the frp to the masonry blocks. The amount and configuration will change depending on one or more of the dimensions, weight and application of the resulting prefabricated compound masonry unit 100.
As seen in
If the longitudinal tension reinforcement 20 is in the bottom surface 16, the blocks 40 ca be laid over the epoxy 30 and frp 20 to form a base layer or first course 12 of the prefabricated compound masonry unit 100 in the desired dimensions. It is also contemplated that a first course 12 of blocks 40 will be laid and mortared on the build base 10 or base cover with the channels 25 made in the top surface of the first course 12. The epoxy 30 and frp 20 can be slid into these channels to form the first course 12 of the prefabricated compound masonry unit 100. When the base layer is complete, one or more additional layers of blocks 40 can be laid and mortared as required to achieve the final dimensions of the prefabricated compound masonry unit 100. When the number of layers is complete, additional frp 20 is incorporated into the top layer as shown in the figures. Alternatively, when all courses but one are laid and mortared, channels 25 can be provided in the surface of the next to last course within which the epoxy 30 and frp 20 is placed. When the final course is placed on top, the epoxy 30 and frp 20 will be hidden from view to provide an aesthetically finished product.
It is also contemplated that frp 20 and epoxy 30 can be used between one or more layers as required to assure the prefabricated compound masonry unit 100 has the required strength.
As non-limiting examples, the longitudinal tension reinforcement 20 can extend along at least a portion of both the first side 18 and the second side 19 of one or both of the bottom surface 16 and top surface 14 of the at least one course 12 and held with bonding material 30. The longitudinal tension reinforcement 20 can extend along substantially an entire length L of the at least one course 12. The prefabricated compound masonry unit 100 can have a plurality of courses 12 having a lowermost course and an uppermost course with the first side 18 and the second side 19 of at least one of the top surface 14 and bottom surface 16 of each of the lowermost course and the uppermost course having the channel 25 formed therein, with the longitudinal tension reinforcement 20 retained within each channel 25 with the bonding material 30.
Post-tensioning rods or bars can optionally be incorporated into the prefabricated compound masonry unit 100 as required. The need for post-tensioning rods, as well as the number of post-tensioning, will be determined by one or a combination of the dimensions, weight and application of the resulting prefabricated compound masonry unit 100, as non-limiting examples. As shown in
The epoxy 30 can be installed in the channels 25 before laying the frp 20 in the channel 25 and/or after laying the frp 20 in the channel. It is also contemplated that mortar or cement be used instead of epoxy 30 to adhere the frp 20 to the channel 25. The epoxy 30 is cured as required.
Other embodiments of the longitudinal tension reinforcement 20 are also contemplated. For example, the frp 20 can be moved into the cavity in the middle of the blocks. There the block could be cut to create a trench, or the tooling for the block molds could be amended to create a trough in which to lay the frp 20 and contain the epoxy 30 until it sets up and binds the frp in place.
Another alternative is to place the frp 20 directly in the wet mortar bed used to bind the blocks 40 together, as illustrated in
Another embodiment uses tensioned steel as the longitudinal tension reinforcement is the bottom course and frp in the top most course of the prefabricated compound masonry unit. Middle courses can incorporate with the tensioned steel or the frp as longitudinal tension reinforcement as desired or required by the application.
As shown in the figures, the longitudinal tension reinforcement 20 is in the form of a wire or rod. The longitudinal tension reinforcement can be post-tensioned or not. However, other embodiments of the longitudinal tension reinforcement 20 are contemplated. For example, the longitudinal tension reinforcement 20 can be mesh, plate or shaped frp. The shapes can include, as non-limiting examples, dowels, biscuits and other joinery known to those skilled in the art. The dowels or biscuits can be placed along joints of adjacent blocks 40 in the channels 25 if provided, in existing openings in the individual units or in apertures cut into the individual units specifically to receive the shaped frp.
The use of the longitudinal tension reinforcement as a lightweight tension member prevents cracking of the mortar joints during shipment of the prefabricated compound masonry units 100. As shown in
The layers 206, 212 of mortar mix and frp 210 can run the length of the compound masonry unit 200. It is also contemplated that at least the frp 210 only be placed in the bed 208 across the joints of individual units 202. Alternatively, the frp 210 can be laid in multiple sections in any suitable lengths that provide the requisite strength to the compound masonry unit 200.
Frp 210 can also be added to the compound unit 200 to bridge the joints between individual units 202 at the top of the course, as shown in
Another embodiment of the compound unit 200′ is shown in
The embodiment of
The layers 206, 212 of mortar mix and frp 210′ can run the length of the unit 200′. It is also contemplated that at least the frp 210′ only be placed in the bed 208 across the joints of individual units 202′. Alternatively, the frp 210′ can be laid in multiple sections in any suitable lengths that provide the requisite strength to the compound unit.
Also illustrated in
As shown in
In the embodiments disclosed herein, the compound masonry units can be compressed or post tensioned horizontally prior to applying the frp. When concrete masonry units are used other than brick, the compression reduces possible issues from mortar and unit shrinkage. The frp can be applied after compression to ensure that the proper reinforcement is provided.
In the embodiments described herein, a coating comprising poly urea can be applied to the compound masonry units prior to transporting to the build site. The poly urea provides corrosion protection and abrasion resistance and fills joints. As used herein, “poly urea” means a polymer coating that uses many different formulations of poly urea with different physical property ranges. A poly urea coating can also be used to water proof the compound masonry units as desired or required.
While the invention has been described in connection with certain embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.
This application is a continuation application of U.S. patent application Ser. No. 13/274,502 filed on Oct. 17, 2011, which claims priority to U.S. Provisional Patent Application Ser. No. 61/393,599 filed on Oct. 15, 2010 and U.S. Provisional Patent Application Ser. No. 61/439,863 filed on Feb. 5, 2011, all of which are incorporated herein in their entirety.
Number | Date | Country | |
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61439863 | Feb 2011 | US | |
61393599 | Oct 2010 | US |
Number | Date | Country | |
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Parent | 13274502 | Oct 2011 | US |
Child | 13307704 | US |