FIELD OF INVENTION
The present invention relates a method of applying pressure with a spike roller onto an exposed surface of a concrete to incorporate fibers below the exposed surface. The present invention also relates to a method of incorporating a liquid polymer into a concrete by applying pressure onto a layer of liquid polymer placed on the exposed surface using a spike roller. Applying pressure with a spike roller can also provide a texture onto the exposed surface of the concrete. The present invention further relates to a novel spike roller.
DESCRIPTION OF RELATED ART
Concrete is used in constructing building, bridges, and roads. Concrete is often prepared as a ready mix at a central site and transported using a truck to a location where a wet concrete mix is then placed in a form. However, for larger construction projects, such transportation becomes costly and the quality of concrete could vary significantly, depending upon the weather and the distance between the central site and the project site where placement occurs. Alternatively, concrete may be prepared on location, the project site, using a portable concrete plant. However, existing portable concrete plants do not have sufficient temperature control mechanisms to deliver uniform quality concrete products, especially for ultra-high performance concrete.
Ultral-high performance concrete (UHPC) is a fiber-reinforced, portland cement-based product that provides advanced performance over traditional concrete, including excellent mechanical performance and resistance against environmental degradation. In FHWA Publication No. FHWA-HRT-19-011, the Federal Highway Administration (FHWA) defines UHPC as follows:
- UHPC is a cementitious composite material composed of an optimized gradation of granular constituents, a water-to-cementitious materials ratio less than 0.25, and a high percentage of discontinuous internal fiber reinforcement. In general, the mechanical properties of UHPC include compressive strength greater than 21.7 ksi (150 MPa) and sustained post-cracking tensile strength greater than 0.72 ksi (5 MPa). UHPC has a discontinuous pore structure that reduces liquid ingress, significantly enhancing durability compared to conventional concrete.
As an alternative to steel with properties more advanced than traditional concrete, UHPC technology is gaining credibility as the building material of the future. UHPC has been used in bridge structures in the U.S. from the early 2000s. Today, UHPC is gaining interest among transportation agencies especially as a joint fill material to connect precast structural systems. In addition to a structural material, UHPC can also be used as an architectural material. Due to UHPC's ductile behavior and decrease in the use of non-prestressed steel reinforcement, precast producers can achieve complex shapes that are durable and cost effective, with the resulting product requiring little or no maintenance.
Possible uses of UHPC in highway and bridges include constructing new highways and bridges out of UHPC or another self-leveling concrete, providing an overlay of UHPC, or another self-leveling concrete, on top of existing structures, as well as repairing joints in bridges and highways utilizing UHPC or a self-leveling concrete.
Challenges associated with utilizing self-leveling concrete, such as UHPC, in such highway and bridge applications include providing a roughened transportation surface while minimizing project cycle time to reduce highway or road closings and reducing the creation dust hazards onsite. A roughened surface is desirable to achieve minimize slippage and to reduce wear surface area of the road surface.
Current method for providing a roughened surface is by grinding down over-filled concrete. This traditional method creates unwanted dust from the grinding and takes time and resources. An alternative method currently available is brushing the wet concrete surface.
A yet further challenge with using self-leveling concrete, such as UHPC, is the lack of a controlled delivery system, where a polymer additive such as a surface finishing agent, is needed to treat an exposed surface of UHPC. Incorporating such additive into the concrete mix prior to placement is cost prohibitive when such additive is only needed on the exposed surface of the concrete, and may interfere with the chemistry of the concrete mix. As a result, no surface finishing agent is currently used with UHPC.
SUMMARY OF THE INVENTION
The present invention is directed to a method of incorporating a liquid polymer into a concrete comprising:
- pouring a fluid concrete mixture into a cavity, thereby providing the concrete having at least one exposed surface,
- applying a liquid polymer onto the exposed surface, thereby providing a liquid polymer layer onto the exposed surface;
- rolling said layer of liquid polymer on the exposed surface with a spike roller having a plurality of extended spikes, wherein the rolling is applied with sufficient pressure to enable said extended spikes to pierce the exposed surface, thereby incorporating said liquid polymer into the concrete.
The present invention is also directed to a method of providing a textured surface onto a concrete comprising:
- pouring a fluid concrete mixture into a cavity, thereby providing the concrete having at least one exposed surface,
- rolling said exposed surface with a spike roller having a plurality of extended spikes, wherein the rolling is applied with sufficient pressure to enable said extended spikes to pierce the exposed surface, thereby creating a textured surface on the exposed surface, said textures surface having a texture that is a negative counterpart of the spike roller.
The present invention is additionally directed to a method of laying down fibers below an exposed surface of a concrete, the method comprising:
- providing a fluid concrete mixture, wherein said fluid concrete mixture includes a liquid component and at least one fiber selected from a metallic fiber and a polymeric fiber;
- pouring the fluid concrete mixture into a cavity, thereby providing the concrete having at least one exposed surface, said at least one exposed surface comprising exposed ends of said at least one fiber,
- rolling said exposed surface with a spike roller having a plurality of extended spikes, wherein the rolling is applied with sufficient pressure to enable said extended spikes to pierce the exposed surface, thereby laying down said exposed ends of the at least one fiber to below the exposed surface.
The present invention is further directed to a spike roller having a plurality of protruding spikes extending from a center core, at least one of said spikes having a tapered end with at least one profile surface that meets at a center point opposite the center core.
BRIEF DISCRIPTION OF THE DRAWINGS
FIG. 1 shows a side perspective of a preferred embodiment incorporating a polymer layer into the exposed surface of a concrete.
FIG. 1A shows a top perspective of the tapered end of a spike on the spike roller shown in FIG. 1.
FIG. 1B shows a side perspective of the tapered end of a spike of the spike roller shown in FIG. 1.
FIG. 2 shows a side perspective of a preferred embodiment of the method for laying down exposed ends of fibers in concrete.
FIG. 3 shows a textured concrete surface made with a preferred embodiment of the spike roller of the present invention.
FIG. 4 provides a closeup side perspective of a spike roller of the present invention.
FIG. 5 shows an elevated perspective of a spike roller of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a method of incorporating a layer of liquid polymer into an exposed concrete surface by rolling the layer of liquid polymer on the exposed surface with a spike roller having a plurality of extended spikes, wherein the rolling is applied with sufficient pressure to enable the extended spikes to penetrate the exposed surface, thereby incorporating the liquid polymer into the formed concrete. A preferred embodiment is shown in FIG. 1, a fluid concrete mixture is placed through traditional methods to provide a concrete 100 in a cavity (not shown) with an exposed surface 110. A cavity can be a concrete form (or mold) or a crack or a joint between existing concrete. A layer of fluid polymer 120 is provided on top of the exposed surface 110 through traditional means, such as, for example using a spray nozzle. To incorporate the layer of fluid polymer 120 into the exposed surface 110, the method of the present invention uses a spike roller 200 having a plurality of spikes 220 extending from a center core 210. Preferably, each of the plurality of spikes 220 has a tapered end 230 that meets at a point 235 opposite of the center core 210. More preferably, as shown in FIGS. 1A and 1B, the tapered end 230 includes a number of grooves pointing downward to convey the polymer from the layer of fluid polymer 120 into the exposed surface 110. As the spike roller 200 is rolled across the layer of fluid polymer 120, an amount of pressure is applied on the spike roller 200 to enable the point 235 of the tapered end 230 to penetrate the layer of fluid polymer 120 and the exposed surface 110 as shown in 235.
The presentation invention also relates to a method of laying down exposed fiber components contained in concrete below an exposed surface of a concrete by rolling the exposed surface with a spike roller having a plurality of extended spikes, wherein the rolling is applied with sufficient pressure to enable said extended spikes to pierce the exposed surface, thereby laying down said exposed ends of the at least one fiber to below the exposed surface. As shown in FIG. 2, in a preferred embodiment, a fluid concrete mixture containing a plurality of fibers is placed through traditional methods to provide a concrete 100 with an exposed surface 110. The fibers can be either polymeric fibers or metallic fibers, or a combination of both. Inevitably, some of the fibers 130 will have an exposed end 132 sticking up from the exposed surface 110. In accordance to the present invention, a spike roller 300 having a plurality of spikes 320 extending from a center core 300 is used to lay down the exposed end of the fibers 132 beneath the exposed surface 110 of the concrete. The inventive method accomplishes this by rolling the spike roller 300 across the exposed surface 110 with sufficient pressure to have the spikes 320 penetrate the exposed surface 110 as shown in 325. In a further preferred embodiment the spikes 320 have a tapered end 330 that meet at a point 335 opposite the center core 310. In an even further embodiment, the distance between the point 335 of two adjacent spikes 320 is wide enough to allow the exposed end 132 of fibers to go between such adjacent spikes, as shown in 325. In a preferred embodiment, the profile of the tapered end 330 is an isosceles triangle with a base. The deepest that the spikes 320 will penetrate the exposed surface 110, if used correctly, is by not going beyond the base of the isosceles triangle or widest part of the triangle. Laying down the fibers in accordance to the present invention also release air bubbles from the concrete.
The present invention also relates to a method of providing a textured surface onto a concrete comprising rolling an exposed surface of the concrete with a spike roller having a plurality of extended spikes, wherein the rolling is applied with sufficient pressure to enable the extended spikes to penetrate the exposed surface, thereby creating a textured surface on the exposed surface, said textures surface having a texture that is a negative counterpart of the spike roller, as shown in FIG. 3.
The present invention additionally relates to a spike roller having a plurality of protruding spikes extending from a center core, at least one of said spikes having a tapered end with at least one profile surface that meets at a center point opposite the center core. As shown in FIG. 4, a preferred embodiment of the spike roller 400 of the invention is made of polymer resin with a center core 410 and a multitude of spikes 420 having a tapered end 430 that meet at a point 440 opposite the center core. As shown in FIG. 5, in a further preferred embodiment the spike roller 500 includes a number of spike plates 505, each with a plurality of spikes 520 extending from a center core 510 and a tapered end 530 opposite the center core. Each of the spike plates 505 are secured together at the center core 510. In a preferred embodiment, a handle (not shown) may be attached to the center core 510 in such a way that the axis of the handle is perpendicular to the axis 515 of the center core 510. In a further preferred embodiment, such a handle is attached in a way a equal number of spike plates 505 is disposed on both sides of the handle.
Patent Application
20210054582
