Filling material

Abstract

The present invention relates to one or more sand-free cement-based caulk compositions that are highly resistant to wet wear removal. The one or more sand-free cement-based caulk compositions comprise calcium aluminate cement as a primary binder with one or more additional binder and a combination of one or more of a single anhydrite binder, metakaolin, fine limestone, coarse limestone, an acidic retarder and / or a lithium-based accelerator. The present invention relates to one or more methods of performing a wet wear test on a cured and wetted sand-free cement-based caulk composition.

Description

Technical Field

[0001] The present invention generally relates to building materials, and more particularly, to a filling material for filling spaces or joints between tiles or mosaics after installation. Background Art

[0002] During tile installation, after the tiles are adhered to a substrate (e.g., floor, wall, countertop, etc.), a grout material is typically filled into the openings or joints present between adjacent tiles. Grout is also used in various applications, including pressure grouting, embedding steel bars in masonry walls, joining sections of precast concrete, filling voids, and sealing joints. There are various tile grout compounds, such as acrylic grout, epoxy grout, and Portland grout and conventional cement-based grout. Regardless of the grout type, all grouts are expected to provide certain characteristics. These characteristics include workability, stain resistance, forming a sufficient grout fill within the space, having a uniform appearance and / or color, and being easy to clean with a minimal amount of water.

[0003] Abrasion resistance is another important characteristic of tile grout. Abrasion resistance is the ability of the surface of cured tile grout to resist wear due to scratching or friction. It depends particularly on good curing but also on other factors, including material and surface finish, aggregate hardness, mixing ratio, aggregate / paste bond, and laying and compaction. To determine abrasion resistance, a test is conducted by scratching, scrubbing, or digging into the top surface of the cured tile grout using a hard object (e.g., trowel, ordinary screwdriver, etc.). The amount of grout material scratched or scrubbed / dug out from the abrasion test provides an estimate of the potential abrasion resistance and durability of the cured grout.

[0004] Although epoxy grout has higher abrasion resistance and stain resistance compared to cement-based grout, its workability is poor or it is not easy to clean. Therefore, on-site installers generally prefer cement-based grout. Cement-based grout typically consists of a powdered mixture of cement, lime, colored pigments, and sometimes sand, which hardens when mixed with water and cured. Examples of cement-based grout include Portland cement-based grout and conventional cement-based grout. These types of grout are preferred because they provide good workability compared to non-cement-based grout (e.g., epoxy grout). Workability is an important characteristic of tile grout because it directly affects the ease of grouting and cleaning, and reduces costs due to less labor required for tile grouting work.

[0005] Cement-based caulking materials are easy to process and clean, making them continue to be the preferred grouting materials. However, when using cement-based caulking materials, over time, the caulking is prone to cracking and staining. Cement-based caulking also becomes less strong under dry conditions or over time, resulting in wear, scratching, and / or loss of caulking material due to abrasion, scratching, or friction. Therefore, property owners usually have to re-grout the bricks and tiles, which is both expensive and time-consuming. Thus, there is still a need for new and improved cement-based caulking materials, and the present invention provides a solution for this. Summary of the Invention

[0006] In view of the problems and deficiencies of the prior art, the object of the present invention is therefore to provide a sand-free caulking composition that cures sufficiently and retains moisture during and after curing to form a caulking joint that is highly resistant to wet abrasion techniques.

[0007] Another object of the present invention is to provide a caulking composition that avoids water or moisture loss before, during, and after curing.

[0008] Another object of the present invention is to provide a method for using brick and tile caulking materials when installing tiles and other bricks and tiles.

[0009] In one or more embodiments, the present invention relates to a sand-free cement-based caulking composition comprising: calcium aluminate cement present in an amount in the range of about 22-24% by weight as the main binder; one or more additional binders present in an amount in the range of about 10-14% by weight; a single anhydrite binder present in an amount in the range of about 7-9% by weight; metakaolin present in an amount in the range of about 1.5-2.5% by weight; fine limestone present in an amount in the range of about 10-20% by weight; coarse limestone present in an amount in the range of about 25-45% by weight; an acidic retarder present in an amount in the range of about 0.30-0.60% by weight; and a lithium-based accelerator present in an amount in the range of about 0.05-0.20% by weight, where the % by weight is based on the total weight of the caulking composition.

[0010] In one or more other embodiments, the present invention relates to a method for performing a wet abrasion test on a cured and wetted sand-free cement-based caulking composition.

[0011] Other objects and advantages of the present invention will be in part apparent and will in part be obvious from the specification. Brief Description of the Drawings

[0012] The features that are considered new in the present invention and the characteristic elements of the present invention are specifically set forth in the appended claims. The drawings are for illustrative purposes only and are not drawn to scale. However, the organization and method of operation of the present invention itself can be best understood by reference to the following detailed description in conjunction with the drawings, wherein:

[0013] Figure 1 is a depiction of a possible water loss area in a cured caulking joint.

[0014] Figures 2A and 2B respectively show prior art caulking joints after a wet abrasion scratch test and an excavation test are performed.

[0015] Figures 3A and 3B respectively show additional prior art caulking joints after a wet abrasion scratch test and an excavation test are performed.

[0016] Figure 4A and Figure 4B show the caulking compositions and caulking joints of the present invention after a wet abrasion scratch test and an excavation test are respectively performed.

[0017] Figure 5A and Figure 5B show other caulking compositions and caulking joints of the present invention after a wet abrasion scratch test and an excavation test are respectively performed.

[0018] Figure 6A and Figure 6B show still other caulking compositions and caulking joints of the present invention after a wet abrasion scratch test and an excavation test are respectively performed.

[0019] Figure 7 A graph depicting the 24-hour compressive strength measurement results of the caulking composition of the present invention.

[0020] Figure 8 A graph depicting the 28-day compressive strength measurement results of the caulking composition of the present invention.

[0021] Figure 9 A graph depicting the 28-day tensile strength measurement results of the caulking composition of the present invention.

[0022] Figure 10 A graph depicting the 28-day flexural strength measurement results of the caulking composition of the present invention.

[0023] Figure 11 A graph depicting the 28-day percentage of linear shrinkage of the caulking composition of the present invention.

[0024] Figure 12 A graph depicting the 28-day water absorption rate of the caulking composition of the present invention.

[0025] Figure 13A and Figure 13B respectively depict the graphs of the 3-day wet abrasion scratch test and the excavation test of the caulking composition of the present invention.

[0026] Figure 14 is a chart showing the components and their contents in various caulking compositions of the present invention.

[0027] Figures 15A - 15C shows an image of the wet abrasion scratch test method for a comparative test of the caulking formulation of the present invention compared to a prior art cement caulking.

[0028] Figures 16A - 16D shows Figures 15A - 15C an image of the graded wet abrasion amount of the test.

[0029] Figures 17A - 17C shows an image of the wet abrasion test for a comparative test of the caulking formulation of the present invention compared to a prior art cement caulking using a strength testing machine.

[0030] Figures 18A - 18E shows another image of the wet abrasion test for a comparative test of the caulking formulation of the present invention compared to a prior art cement caulking using a strength testing machine.

[0031] Figures 19A - 19B shows images of the comparative wet abrasion scratch test and the wet abrasion test of the caulking composition of the present invention compared to a prior art cement caulking using a strength testing machine. Detailed Description

[0032] In describing the preferred embodiments of the present invention, reference will be made herein to the Figures 1 - 19B in the accompanying drawings, in which like numbers represent like features of the present invention.

[0033] Embodiments of the present invention may include the features and / or steps described herein, as well as additional or optional ingredients, components, steps or limitations that may be understood by those skilled in the art as described herein or originally, consisting of and consisting essentially of the same. It should be understood that unless otherwise specified, all concentrations disclosed herein are weight percentages (wt%) based on the total weight of the composition or formulation prepared.

[0034] Various embodiments of the present invention provide cement-based caulking with improved and increased abrasion resistance. It has been found that in wet cement-based caulking, the water component needs to be retained in the caulking material and trapped within the filled joint in order for complete curing to occur throughout the caulking joint. However, referring to Figure 1, it has been found that water is lost by absorption into adjacent tiles or underlying substrates and / or evaporates into the air above the exposed surface of the cement grout joint. As a result, the filled grout joint cannot retain sufficient moisture to cure adequately. In addition, when the cement grout joint is wetted or comes into contact with water after curing, the grout may become "soft" and be easily scraped out of the grout joint, regardless of how much time has elapsed since the grout was installed and cured.

[0035] According to the present invention, factors affecting abrasion, including increases or decreases in abrasion, are determined by formulating a conventional cement-based grout composition and conducting abrasion tests on the cured product. The main components contained in the conventional cement-based grout composition being tested include fine sand as the main aggregate, white calcium aluminate cement, white ordinary Portland cement, and calcium sulfate, as well as other components that provide the desired properties and / or characteristics to the grout. After preparation, multiple sets of samples of cured grout joints are formed by applying the cement-based grout to the joints between adjacent 4 x 4 inch tiles to a thickness of approximately 3 / 8 inch. Each set of samples (i.e., the simulated test groups) is cured for 3 days and tested under different conditions, as described below, to determine its effect on the resulting cured state of different cement tile joints.

[0036] In a first set of cement tile grout samples, the samples were cured for 3 days and then the cement tile joints were sprayed with water at different times. For a second cement grout sample, the sample was cured for 3 days and then a wash solution containing lithium hydroxide was applied. A third set of cement tile grout samples was cured for 3 days and then sprayed after washing. A fourth set of cement tile grout samples was cured for 3 days and then the samples were immersed in water for 24 hours.

[0037] Then, the four sets of samples were subjected to a wet abrasion test and rated using a rating system in the range of 0 - 5, where a rating of "0" indicates no scratching on the sample surface and a rating of "5" indicates that the grout has been almost completely removed from the grout joint. The abrasion test on the cured grout joint was carried out using a scratching and / or excavation method. For example, referring to Figure 2A, in the third set of samples, water was applied to the cured surface and after a 5-minute waiting period, the top surface was scratched using an instrument to determine the amount of grout material removed. Figure 2B shows an excavation wet abrasion test performed on another part (or a separate set) of the third set of samples. After the wet abrasion test, the abrasion ratings for the first, second, and third sets of samples were "3" or "4", indicating that a large amount of cement grout was removed from the tile joints. The fourth set of samples that were immersed in water for 24 hours were rated "0", indicating that no cement grout was removed from the tile joints.

[0038] Based on the foregoing wet abrasion tests on the sample sets, it was concluded that water retention within the caulking compound is critical to improving wet abrasion resistance. In the first through third samples rated "3" or "4", it was found that the formed caulking joints did not retain the necessary amount of moisture / water within the composition upon curing. Referencing Figure 1 , the water / moisture is lost during and / or after curing due to absorption by the surrounding brickwork and substrate and due to evaporation at the exposed top surface. This water loss prevents the cement caulking from fully curing throughout the brick joint, resulting in a weaker brick joint that is prone to being wiped off and / or dug out. Additionally, it was found that in the sample sets tested, upon briefly applying water or moisture to the caulking joint, the major components of the caulking compound softened upon wetting as the caulking attempted to complete curing. This softness prevented the caulking from fully curing and resulted in the caulking joint being prone to being wiped off and / or dug out.

[0039] According to the present invention, it has been found that abrasion resistance is improved by retaining water within the caulking compound before, during, and after curing. Specifically, the fourth sample set was immersed in water for 24 hours after 3 days of curing, and when subjected to the wet abrasion test, it was rated "0", indicating that no cement caulking was removed from the brick joint. By adding water back into the cement caulking joint, the joint surface is resistant to scratching and digging. As another example, the fifth sample set of the above-described caulking compound was applied between bricks and allowed to cure for 3 days. Similar to the third sample set shown in FIGS. 2A - 2B, after the 3-day cure period, the sample set was sprayed with water; however, once wetted, the sample set was covered with a plastic sheet for 24 hours to trap the water and moisture therein. After 24 hours, the wet abrasion test was performed by scratching (see FIG. 3A) and by digging (see FIG. 3B). By covering the surface with plastic and allowing the water to penetrate into the caulking joint, the cement caulking was fully wetted and exhibited enhanced scratch resistance (see FIGS. 3A - 3B) compared to the third sample set not covered with plastic (see FIGS. 2A - 2B). A similar test was performed on a cement caulking brick set that had been cured for several months and was known to have failed the wet abrasion test. Once these older cured sets were wetted and covered with plastic for 24 hours, the strength and abrasion / scratch resistance of the caulking joints were improved.

[0040] According to the present invention, it has been found that a grout composition containing fine sand as the main aggregate in combination with calcium aluminate cement, ordinary Portland cement, and calcium sulfate may not cure completely due to moisture or water loss during the curing of the grout. Due to the wetting of the cured brick and tile grout joints, they are also prone to deterioration (i.e., softening). According to the present invention, it has also been found that the main component causing increased moisture loss and incomplete or defective curing is the sand used as the main aggregate in these known grout compositions. During the curing of the known ternary binder system (i.e., calcium aluminate - Portland cement - calcium sulfate), the sand causes this ternary binder system to not retain sufficient moisture, resulting in a weaker surface area of the known cured grout product (brick and tile joints). While not intending to be limiting, it is believed that the particle shape and size of the fine sand cause the grout in the filled joints to be very tight, thereby hindering the ability of the composition to absorb and retain water during and after curing.

[0041] Also in the present invention, it has been found that completely eliminating sand, especially fine sand, and replacing it with coarse limestone, as well as other modifications to its composition and amount, enables the cement grout composition of the present invention to maintain the water and / or moisture therein in order to provide cured grout joints with increased abrasion resistance (e.g., scratch resistance, gouging resistance, etc.). The cement - based grout composition of the present invention does not contain silica (no silica sand), has wet abrasion resistance (i.e., is capable of withstanding a wet abrasion test), and meets the ANSI A118.7 high - performance cement grout standard. It has been found that in the sand - free cement grout composition of the present invention, the chemical and physical properties (e.g., plasticity) of the coarse limestone provide the necessary aggregate strength similar to that of silica sand, while also achieving increased water absorption and water retention compared to the lower water absorption and water retention measurements associated with known silica - based grouts. In addition to the increased water absorption and water retention measurements, the silica - free cement - based grout of the present invention is also capable of curing fully, and the coarse limestone main aggregate tightly packs the grout joints due to its plasticity. The increased packing of the grout joints further achieves better water retention and full curing within the joints.

[0042] Referring to various embodiments, the cement - based grout of the present invention comprises one or more binder components. The first binder can be calcium aluminate cement, preferably white calcium aluminate cement, as the main binder, which is present in an amount in the range of about 22 - 24 wt% based on the total weight of the grout composition. The cement - based grout composition also comprises a cement binder present in an amount in the range of about 3 - 5 wt%. In one or more embodiments, the cement binder can include ordinary Portland cement, more preferably white ordinary Portland cement. The cement - based grout composition can also comprise a third binder, the third binder comprising calcium sulfate, preferably anhydrous calcium sulfate, which is present in an amount in the range of about 7 - 9 wt% based on the total weight of the grout composition.

[0043] The cementitious grout composition of the present invention further comprises highly reactive metakaolin (i.e., the dehydroxylated form of kaolin clay or the clay mineral kaolinite), which is present in an amount in the range of about 1.5 - 2.5 wt% based on the total weight of the grout composition. In one or more embodiments, the highly reactive metakaolin component comprises amorphous aluminosilicate. Suitable metakaolin is formed by calcining purified kaolin and is a white amorphous aluminosilicate that reacts vigorously with calcium hydroxide to form a cementitious product. It is believed that the addition of the combination of highly reactive metakaolin and a single anhydrite source helps to improve the abrasion resistance of the final grout product. That is, while not intending to be limiting, in one or more embodiments, the grout composition comprises reactive metakaolin in the absence of only anhydrous calcium sulfate binder (i.e., in the absence of a hemihydrate source (e.g., gypsum) in the grout composition).

[0044] The grout composition of the present invention further comprises one or more aggregates as filler materials. The first aggregate comprises finely crushed limestone of 325 mesh (i.e., most of the particles are 44 microns or 0.0017 inches in size). The finely crushed limestone of 325 mesh can be present in an amount in the range of about 10 - 20 wt% based on the total weight of the grout composition. The second aggregate comprises coarse limestone of 40 mesh (i.e., most of the particles are 417 microns or 0.0164 inches in size). The coarse limestone of 40 mesh is present in the grout composition in an amount in the range of about 25 - 45 wt%, preferably 35 - 45 wt%.

[0045] According to the present invention, the grout composition of the present invention avoids using sand, especially fine sand, as an aggregate. It has been found that when fine sand is the main aggregate in the composition, it hinders the water retention ability of the grout composition. Specifically, it is believed that due to the particle shape and size of the sand, the components within the composition are tightly packed and do not allow any water to be absorbed or retained in the voids / cavities of the grout matrix. According to the present invention, the grout composition comprises at least coarse limestone instead of fine sand to provide a sand-free, silica sand-free, and / or silicon dioxide-free grout composition. It has been found that compared with sand / silica sand, at least coarse limestone helps to absorb and retain water within the grout composition matrix due to its increased aggregate surface area. In addition, calcium carbonate in limestone absorbs and retains a larger amount of water compared with silica sand.

[0046] The composition of the present invention further comprises one or more of a redispersible powder copolymer, an accelerator, and a retarder. The redispersible powder copolymer can be used as the main polymer and is present in the composition in an amount in the range of about 1.5 - 2.5% by weight based on the total weight of the grout composition. The redispersible powder copolymer can be a water-dispersible powdered ethylene / vinyl laurate / vinyl chloride terpolymer. The accelerator is preferably a lithium-based accelerator, which is used to initiate the reaction with the main binder component or the reaction combined with the binder in the composition. The lithium-based accelerator can be in powder form and can be present in the grout composition in an amount in the range of about 0.05 - 0.20% by weight. Suitable lithium-based accelerators include lithium sulfate or lithium carbonate. The retarder can include a powdered acid (or salt derivative) for retarding the hydration / curing reaction. The retarder can be present in an amount in the range of about 0.30 - 0.60% by weight, preferably in the range of about 0.30% to 0.48% by weight in some embodiments, based on the total weight of the grout composition. Suitable powdered acidic retarders can include citric acid, tartaric acid, etc.

[0047] The grout composition of the present invention further comprises one or more rheology modifiers. The first rheology modifier can include fibers, preferably fibers 3 mm (or shorter) in length composed of cellulose, starch, glass, etc. In one or more embodiments, cellulose fibers are preferred. The fibers can be present in the grout composition in an amount in the range of about 0.25 - 0.75% by weight based on the total weight of the grout composition. The second rheology modifier can include a cellulose ether. Preferably, the second rheology modifier is a cellulose ether modifier suitable for use with cementitious materials, such as a modified hydroxypropyl methylcellulose ether, a hydroxypropyl ethylcellulose ether, or a medium-viscosity, unmodified methylhydroxyethylcellulose. The cellulose ether rheology modifier can be present in the composition in an amount in the range of about 0.05 - 0.10% by weight based on the total weight of the grout composition.

[0048] Additional components in the grout composition of the present invention can include a water reducer and a hydrophobic agent. The water reducer can include a high-range water reducer, which is present in an amount in the range of about 0.10 - 0.15% by weight based on the total weight of the grout composition. The high-range water reducer can include, for example, polycarboxylate ether, a free-flowing spray-dried powder of a modified polycarboxylate ether, melamine sulfonate, naphthalene sulfonate, lignin sulfonate, and combinations thereof. The hydrophobic agent can include a powdered dispersible hydrophobic additive, especially a hydrophobic polymer, in an amount in the range of about 0.05 - 0.20% by weight based on the total weight of the grout composition.

[0049] The grout composition of the present invention further comprises an antifoaming agent, a thickening agent, and an antimicrobial agent. The antifoaming agent may be present in an amount in the range of about 0.25 - 0.30 wt%, the thickening agent may be present in an amount in the range of about 0.01 - 0.02 wt%, and the antimicrobial agent may be present in an amount in the range of about 0.01 - 0.01 wt%, each based on the total weight of the grout composition. The antifoaming agent may be a powdered additive of hydrocarbons and polyethylene glycol on an inorganic carrier. Suitable antifoaming agents may include blends of liquid hydrocarbons and polyethylene glycol on an inorganic carrier, or powdered antifoaming agents based on fatty alcohol alkoxylates and polysiloxanes on an inorganic carrier material. The thickening agent is a viscosity / rheology modifier and may be a defatted gum-based viscosity modifier.

[0050] The various grout compositions of the present invention may further comprise an antimicrobial agent / bactericide, reinforcing fibers, and one or more colorants. For example, the grout composition of the present invention may comprise a bactericide in an amount in the range of about 0.005 - 0.02 wt% and reinforcing fibers in an amount in the range of about 0.005 - 0.02 wt%, both based on the total weight of the grout composition. The grout composition may further comprise a colorant in an amount in the range of about 0.005 - 6.0 wt% based on the total weight of the composition. Suitable colorants include iron oxide black, iron oxide yellow, iron oxide red, titanium dioxide, iron oxide blue, or chromium oxide green.

[0051] According to various embodiments, the present invention provides a high-performance cement grout having high mechanical strength (i.e., 100 - 200 MPa), high abrasion resistance, high erosion resistance, and capable of withstanding a wet abrasion test according to the ANSI A118.7 grout standard. The grout of the present invention does not contain silica and avoids using silica and / or silica sand as the main aggregate, but instead uses coarse limestone and other ingredients. It has been found that by eliminating sand and replacing it with coarse limestone, in combination with various other ingredients and their amounts (e.g., adding pozzolanic clay, increasing the Portland cement and calcium sulfate content, reducing the accelerator dosage, etc.), the grout of the present invention has multiple benefits. The benefits include, but are not limited to: providing a silica-dust-free composition that eliminates air pollutants; providing improved inter-batch color consistency; providing a whiter white grout; increasing water absorption and water retention; the plasticity of the limestone aggregate provides a tightly packed grout joint for further water retention and enables such a joint to cure fully; and providing a finished grout product that remains intact and avoids scratching when wetted.

[0052] It has been found that water aids in the full curing of the cementitious grout within the tile joints. Accordingly, the cementitious grout of the present invention has a sufficient amount of water before and during curing to enable the grout joints to fully cure and retains a sufficient amount of water after curing to provide a durable cured grout product that can withstand a wet abrasion test. Compared to prior art silica sand-based grouts, the coarse limestone within the grout of the present invention provides an increased calcium carbonate aggregate surface area for a greater and more efficient absorption and retention of water. Further, according to tests of the present invention, as described in more detail below, the grout compositions of the present invention have excellent compressive strength, flexural strength, and tensile strength compared to conventional ternary binder silica / silica sand-based grouts. Additionally, compared to conventional ternary binder silicon / silica sand-based grouts (i.e., known ternary binder systems that include calcium aluminate, portland cement, and calcium sulfate), they also have improved dry abrasion strength and linear shrinkage, remaining intact with minimal scratching.

[0053] The grout of the present invention has excellent water absorption while also being able to retain a sufficient amount of water to improve resistance to wet abrasion. Specifically, the cementitious grout of the present invention can be tightly packed into the grout joints due to the plasticity of the limestone aggregate within such compositions and has excellent resistance to wet abrasion and passes all ANSI A118.7 standards. The grout of the present invention has workability and rheology equivalent to that of sand-containing grouts but does not contain fine sand aggregate (nor a gypsum binder) and is thus an OSHA-compliant silica-free inhalable grout.

[0054] Figure 4A and Figure 4B Shows the grout composition of the present invention in a state of a fully cured grout joint. The grout compositions shown in these images include a composition containing coarse limestone as well as about 8 wt% of a snow-white filler, about 0.10 wt% of lithium carbonate, and about 0.35 wt% of citric acid, all based on the total weight of the grout composition. Both figures depict a wet abrasion test of such joints, where the initial scratch test is shown in Figure 4A and the final excavation test is shown in Figure 4B As shown, the wet abrasion test performance of the coarse limestone grout composition of the present invention is excellent compared to conventional grouts containing sand within such compositions, as shown in FIGS. 2A - 3B.

[0055] According to the present invention, it has been found that, in addition to the coarse limestone component, the various components within the caulking composition of the present invention also contribute to improving the wet abrasion testability of the resulting joints. Specifically, it has been found that the combination of a preferred amount of a lithium-based accelerator (e.g., lithium carbonate) provided at about 0.10 wt% to 0.20 wt% and a preferred amount of a powdered acidic retarder (e.g., citric acid) provided at about 0.30 wt% to 0.48 wt% shows excellent results in improving wet abrasion testability as compared to caulking agents having a larger amount (i.e., weight percentage) of such components. For example, a citric acid amount exceeding 0.60 wt% shows a decrease in wet abrasion testability.

[0056] It has also been found that including highly reactive metakaolin (i.e., kaolin) in the caulking composition of the present invention improves wet abrasion testability. Referring to the accompanying drawings, Figure 5A and Figure 5B depict the wet abrasion scratch test and the excavation test of the caulking composition of the present invention without metakaolin, respectively. In Figure 6A and Figure 6B are shown the improved wet abrasion scratch and excavation test results of the composition of the present invention containing metakaolin, respectively. It has been found that metakaolin helps to lock in moisture and achieve sufficient curing of the caulking joints. In addition to metakaolin, it has also been found that including a single source of anhydrite calcium sulfate further improves the wet abrasion testability of the caulking agent of the present invention as compared to including two sources of anhydrite and hemihydrate gypsum.

[0057] Various coarse limestone caulking compositions of the present invention were prepared and tested. Figure 14 Shown is a table of the various components within 80 prepared and tested coarse limestone caulking compositions of the present invention. It should be understood that the listed components are exemplary and that various embodiments of the present invention may include all such components or selected combinations of the listed components.

[0058] Figure 7 A graph depicting the 24-hour compressive strength measurement results of the caulking composition according to the present invention. The compressive strength is measured in PSI. The ANSI A118.7.3.5 standard is 500 PSI. The results of the 24-hour compressive strength show that all the caulking compositions of the present invention exhibit strengths far above the ANSI A118.7.3.5 standard. In Figure 7In the figure, the compressive strengths measured in PSI (from left to right) are as follows: 2810, 3170, 2800, 2780, 2840, 3070, 3140, 3010, 3350, 3070, 2700, 2670, 2990, 3030, 2740, 2900, 2880, 2810, 2960, 2940, 2950, 3240, 2800, 3030, 3120, 2820, 2950, 2910, 3180, 3160, 3140, 3220, 3280, 3430, 2990, 2980, 3020, 3000, 3140, 3200, 2690, 2700, 2870, 2840, 2630, 2670, 2720, 2890, 3020, 2890, 2790, 3380, 3240, 3170, 3160, 3010, 3110, 2550, 2810, 2440, 2800, 2640, 2270, 2570, 2640, 3150, 2990, 2900, 2880, 2860, 3070, 2710, 2950, 2990, 3150, 3010, 2900, 2990, 3020 and 3060.

[0059] Figure 8 A graph depicting the 28-day compressive strength measurements of the caulking compound of the present invention. The compressive strength is measured in PSI and obtained on several different days. As depicted in the figure, the ANSI A118.7.3.5 standard is 3000 PSI. The results of the 28-day compressive strength show that all caulking compound compositions of the present invention exhibit strengths far higher than the ANSI A118.7.3.5 standard. At Figure 8In the figure, the compressive strengths measured in PSI (from left to right) are as follows: 5060, 5920, 5040, 5280, 5100, 4880, 5880, 5620, 5910, 6050, 5390, 5225, 6180, 6090, 4940, 4750, 4790, 5020, 5240, 5370, 5500, 5150, 5000, 5240, 5470, 5020, 5280, 5640, 6250, 6810, 6770, 6230, 6060, 6710, 5510, 5480, 5260, 5360, 6270, 6210, 5450, 5530, 5310, 5560, 5260, 5040, 4810, 5890, 5130, 5120, 5200, 6410, 6290, 6120, 5750, 5520, 5530, 5240, 5120, 5390, 6190, 4830, 4330, 4860, 5500, 6140, 5050, 5610, 5930, 6200, 6370, 6270, 6050, 6740, 6715, 6180, 6300, 5870, 6460 and 6180.

[0060] Figure 9 A figure depicting the 28-day tensile strength measurement results of the caulking agent of the present invention. The tensile strength is measured in PSI and obtained on several different days. As depicted in the figure, the ANSI A118.7.3.6 standard is 500 PSI. The results of the 28-day compressive strength show that most caulking agent compositions exhibit a tensile strength that meets or exceeds the ANSI A118.7.3.6 standard. In Figure 9 In the figure, the tensile strengths measured in PSI (from left to right) are as follows: 568, 509, 501, 510, 528, 554, 595, 506, 583, 519, 556, 554, 505, 541, 606, 500, 500, 520, 510, 545, 516, 510, 517, 520, 509, 529, 594, 530, 519, 541, 506, 531, 532, 498, 576, 508, 542, 516, 524, 508, 633, 528, 575, 522, 513, 530, 526, 529, 507, 588, 552, 526, 508, 494, 517, 526, 521, 566, 560, 584, 626, 543, 531, 546, 532, 599, 497, 548, 517, 687, 567, 598, 574, 503, 533, 515, 583, 492, 512 and 539.

[0061] Figure 10 A graph depicting the 28-day flexural strength measurements of the grout of the present invention. The flexural strength is measured in PSI and obtained on several different days. The ANSI A118.7.3.7 standard is 1000 PSI. The results of the 28-day flexural strength show that all the grout compositions of the present invention exhibit a flexural strength exceeding the ANSI A118.7.3.7 standard. At Figure 10 In the graph of, the tensile strengths (from left to right) measured in PSI are as follows: 1369, 1453, 1415, 1533, 1360, 1465, 1313, 1530, 1423, 1568, 1531, 1283, 1547, 1650, 1320, 1214, 1090, 1290, 1156, 1512, 1509, 1559, 1367, 1477, 1182, 1574, 1323, 1431, 1625, 1338, 1435, 1372, 1686, 1540, 1568, 1580, 1443, 1442, 1690, 1456, 1535, 1752, 1357, 1516, 1543, 1436, 1358, 1432, 1370, 1527, 1402, 1421, 1410, 1510, 1448, 1442, 1556, 1436, 1529, 1561, 1609, 1540, 1210, 1540, 1210, 1546, 1530, 1461, 1391, 1339, 1368, 1250, 1243, 1555, 1325, 1286, 1435, 1244, 1265, 1287, 1253 and 1271.

[0062] Figure 11 A graph depicting the 28-day percentage of linear shrinkage of the grout of the present invention. The linear shrinkage is obtained on several different days. As depicted in the graph, the ANSI A118.7.3.3 high standard is 0.2000%. The results of the 28-day percentage of linear shrinkage show that all the grout compositions of the present invention exhibit acceptable results lower than the ANSI A118.7.3.3 standard. At Figure 11In the figure, the linearly-shrinking percentages plotted (from left to right) are as follows: 0.1205%, 0.1425%, 0.1350%, 0.1280%, 0.1365%, 0.1365%, 0.1200%, 0.1150%, 0.1190%, 0.1540%, 0.1515%, 0.1530%, 0.1380%, 0.1465%, 0.1160%, 0.1315%, 0.1215%, 0.1175%, 0.1215%, 0.1415%, 0.1420%, 0.1520%, 0.1340%, 0.1455%, 0.1335%, 0.1315%, 0.1395%, 0.1340%, 0.1415%, 0.1595%, 0.1505%, 0.1215%, 0.1450%, 0.1380%, 0.1315%, 0.1540%, 0.1355%, 0.1480%, 0.1480%, 0.1615%, 0.1410%, 0.1390%, 0.1485%, 0.1450%, 0.1650%, 0.1550%, 0.1370%, 0.1480%, 0.1505%, 0.1565%, 0.1355%, 0.1310%, 0.1335%, 0.1215%, 0.1530%, 0.1105%, 0.1115%, 0.1575%, 0.1525%, 0.1870%, 0.1675%, 0.1480%, 0.1505%, 0.1455%, 0.1635%, 0.1670%, 0.1345%, 0.1385%, 0.1670%, 0.1885%, 0.1275%, 0.1075%, 0.1295%, 0.1050%, 0.1205%, 0.1660%, 0.1365%, 0.1260%, 0.1340% and 0.1445%.

[0063] Figure 12 The figure depicts the 28-day water absorption rate of the caulking compound of the present invention. The percentage of water absorption was obtained on several different days. As depicted in the figure, the ANSI A118.7.3.4 high standard is 5.00%. The results of the 28-day water absorption percentage show that all caulking compound compositions of the present invention exhibit acceptable results lower than the ANSI A118.7.3.4 standard. At Figure 12In the figures, the percentage of water absorption plotted (from left to right) is as follows: 3.07%, 3.18%, 3.29%, 3.00%, 3.13%, 3.17%, 3.47%, 3.40%, 3.36%, 2.34%, 2.29%, 2.32%, 3.60%, 3.57%, 3.01%, 3.77%, 3.59%, 3.66%, 3.82%, 3.32%, 2.64%, 2.09%, 3.21%, 3.21%, 2.94%, 3.10%, 3.28%, 2.98%, 3.10%, 3.00%, 3.18%, 3.37%, 3.33%, 3.38%, 3.14%, 3.32%, 3.30%, 3.12%, 3.11%, 3.33%, 2.99%, 3.03%, 2.91%, 2.97%, 3.03%, 3.09%, 3.67%, 3.48%, 3.62%, 3.49%, 3.54%, 3.37%, 3.09%, 3.11%, 3.42%, 3.79%, 3.60%, 3.39%, 2.35%, 3.82%, 2.88%, 2.81%, 3.90%, 3.23%, 2.87%, 3.08%, 3.21%, 3.64%, 3.79%, 3.02%, 3.39%, 3.22%, 3.54%, 3.03%, 3.32%, 3.58%, 3.89%, 3.85%, 3.78% and 3.69%.

[0064] Figure 13A and 13B Figures depicting the 3-day wet abrasion test of the caulking compound of the present invention. Figure 13A depict the 3-day wet abrasion scratch test of the caulking compound of the present invention, while Figure 13B depict the 3-day wet abrasion excavation test of the caulking compound of the present invention. Similarly, the ratings are based on a grading system in the range of 0 - 5, where a rating of "0" indicates no scratches on the sample surface, and a rating of "5" indicates that the caulking compound has been almost completely removed from the caulking joint. These figures depict the scratch and excavation wet abrasion test ratings of currently known caulking compound compositions (i.e., scratch is 1.0 and excavation is 2.5). Also shown in these figures are the current industry standard ratings (according to test method WI9.1.81), with an acceptable scratch resistance rating of 1.5 and an acceptable excavation resistance rating of 3.5. Referring to Figure 13A , all 80 tested caulking compound samples of the present invention exhibited a rating of 0.0 (zero), indicating no scratches in such caulking joints. Figure 13B shows that among the 80 tested caulking compounds of the present invention, only 4 exhibited excavation, with each caulking compound having a rating of only 0.5. Thus, all tested samples demonstrated excellent scratch and excavation resistance to the wet abrasion test.

[0065] Additional tests were conducted on one or more grout formulations of the present invention and compared with conventional grout materials. In this case, a wet abrasion test was conducted on a cement grout, including a wet abrasion scratch test and a wet abrasion test using a strength testing machine to determine the strength (e.g., softness or hardness) of such grout after curing and exposure to moisture / water. Refer to Figures 15A - 15C , a grout formulation of the present invention and a comparative prior art cement grout were prepared and tested against each other. In this case, the prior art cement grout was prepared and mixed according to the recommended mixing instructions. A preferred sand - free cement - based grout composition of the present invention was prepared. The prior art grout and the sand - free cement - based grout composition of the present invention were applied to test areas, which included 4'x4' tiles that were separated from each other by 1 / 4” grout joints / gaps and adhered to a cement backer board using a cement adhesive or the thinnest adhesive. The tested grouts were applied or deposited into different 1 / 4” grout joints / gaps and then washed.

[0066] After allowing the test areas to cure for 7 days, a wet abrasion scratch test was conducted on each cured prior art cement grout and the grout of the present invention. As Figure 15A shown, each grout to be subjected to the wet abrasion test was measured and a 2 - inch - long space was marked on it, and then 1 g (1 ml) of water was applied to the marked place along the pre - measured grout joint, as Figure 15B shown. The applied water was left on the grout joint for 5 minutes. Refer to Figure 15C , after 5 minutes, a scratch test was conducted. The tester's hand was placed on the mock - up test area, and the tip of a plastic spoon was used to scratch the grout surface 5 times in a smooth and forceful motion while leaving the water in place to ensure that the abrasion test of the grout was carried out in a wet state.

[0067] The wet abrasion scratch test was graded based on the amount of abrasion / grout removal, ranging from 0 to 5. Grade 0 indicates that no traces (or almost no scratches) were observed on the surface. Refer to Figure 16A , Grade 1 indicates slight traces on the surface and almost no grout removal. As Figure 16B shown, Grade 2 shows that the scratch left obvious chisel marks on the grout surface. Refer to Figure 16C , Grade 3 indicates that the scratch left larger marks on the surface and some grout was removed from the joint. Grade 4 shows that in Figure 16D , it indicates that the scratch left significant grooves on the joint surface and a large amount of grout was removed from the joint. Grade 5 means that almost all of the grout was easily removed from the grout joint.

[0068] Wet abrasion tests were also performed using an intensity testing machine to determine the strength of the sealant applied and cured in the wet state. As described above, a prior art cement sealant and the sealant of the present invention were prepared and applied to a test area paved with bricks and tiles. However, in the wet abrasion strength test, the applied sealant was cured for 24 hours, or more preferably 3 days. The wet abrasion test using the intensity testing machine determines the ability of the cementitious sealant to withstand / resist abrasion when exposed to water / moisture.

[0069] Reference Figure 17A , after allowing the sealant joint to cure for 3 days, a 3” (3 inches) space on the sealant joint was measured with a ruler and 3 points were marked on the bricks and tiles, which were spaced 0.75" apart along the line. Reference Figure 17B and Figure 17C , at the 0.75" points of each mark drawn on the bricks and tiles, an intensity testing machine guide (as Figure 17C shown) was used as a micrometer to determine the initial depth, and a total of 3 measurements were made for each sealant joint. Each marked sealant section was wetted by applying 1 g (1 ml) of water along the pre-measured sealant joint, and then the water was left on the sealant joint for 5 minutes. As Figure 18A and Figure 18B shown, a base intensity testing machine was prepared by ensuring that the 3D printed plastic tip was fixed to the sharp edge of the testing machine.

[0070] Reference Figure 18C and Figure 18D , after the water had been left on the sealant joint for 5 minutes, any excess water remaining in or on the sealant joint was removed or wiped off. Using the intensity testing machine guide, the base intensity testing machine was used at the required or pre-selected tension (e.g., for cementitious sealants, the middle position is preferred), and pressure was applied on the intensity testing machine such that the base of the tester was flush with the intensity testing machine guide (as Figure 18D shown). Once the pressure was applied, using a smooth and forceful motion, the intensity testing machine was reciprocated along the line spaced 3" apart, achieving 5 complete rotations (one rotation includes one reciprocation). Reference Figure 12 E, the wet abrasion test using the intensity testing machine was graded by placing the intensity testing machine guide along the sealant joint and using a micrometer to measure the depth of each position / point previously taken along the sealant joint before abrasion (see Figure 18E ). The average difference of all 3 measurement values was determined as the wet abrasion measurement value.

[0071] Using Figures 15A to 18EThe wet abrasion test method is used to test various caulking agents known in the art and compare them with the sand-free cement-based caulking agent compositions according to one or more embodiments of the present invention. As shown in the figure, compared with the conventional caulking agent compositions known in the art, the sand-free cement-based caulking agent compositions of the present invention exhibit excellent performance in wet abrasion excavation, scratching, and strength tests.

[0072] Although the present invention has been specifically described in connection with specific preferred embodiments, it will be apparent that many alternatives, modifications, and variations will be clear to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims will cover any such alternatives, modifications, and variations as long as they fall within the true scope and spirit of the present invention.

[0073] The present invention has thus been described, and what is claimed is set forth in the claims.

Claims

1. A sand-free cement-based grout composition, comprising: Calcium aluminate cement present in an amount in the range of about 22 - 24% by weight as the main binder; One or more additional binders present in an amount in the range of about 10 - 14% by weight; A single anhydrite binder present in an amount in the range of about 7 - 9% by weight; Metakaolin present in an amount in the range of about 1.5 - 2.5% by weight; Fine limestone present in an amount in the range of about 10 - 20% by weight; Coarse limestone present in an amount in the range of about 25 - 45% by weight; An acidic retarder present in an amount in the range of about 0.30 - 0.60% by weight; A lithium-based accelerator present in an amount in the range of about 0.05 - 0.20% by weight; And wherein the % by weight is based on the total weight of the grout composition.

2. The grout according to claim 1, wherein the calcium aluminate cement comprises white calcium aluminate cement.

3. The grout according to claim 1, wherein the single anhydrite binder comprises anhydrous calcium sulfate binder.

4. The grout according to claim 1, the grout further comprising Portland cement binder present in an amount in the range of about 3 - 5% by weight.

5. The grout according to claim 4, wherein the Portland cement comprises white ordinary Portland cement.

6. The grout according to claim 1, wherein the fine limestone comprises finely crushed limestone of 325 mesh.

7. The grout according to claim 1, wherein the coarse limestone comprises coarse limestone of 40 mesh.

8. The grout according to claim 1, wherein the acidic retarder comprises citric acid or tartaric acid.

9. The grout according to claim 1, wherein the lithium-based accelerator comprises lithium carbonate or lithium sulfate.

10. The grout according to claim 1, wherein the metakaolin comprises highly reactive amorphous aluminosilicate.

11. The grout according to claim 1, the grout further comprising a water-dispersible powder present in an amount in the range of about 1.5 - 2.5% by weight.

12. The grout according to claim 1, the grout further comprising a hydrophobic polymer present in an amount in the range of about 0.05 - 0.20% by weight.

13. The grout according to claim 1, the grout further comprising a first rheology modifier present in an amount in the range of about 0.05 - 0.10% by weight, the first rheology modifier comprising cellulose ether.

14. The grout according to claim 13, the grout further comprising a second rheology modifier present in an amount in the range of about 0.25 - 0.75% by weight, the second rheology modifier comprising fibers with a length of 3 mm or shorter.

15. The grout according to claim 1, the grout further comprising an antifoaming agent present in an amount in the range of about 0.25 - 0.30% by weight.

16. The grout according to claim 1, the grout further comprising a water reducer present in an amount in the range of about 0.10 - 0.15% by weight, the water reducer comprising a high-range water reducer.

17. The caulking compound according to claim 1, wherein the caulking compound further comprises a thickener present in an amount in the range of about 0.01 - 0.02% by weight, and the thickener comprises gellan gum.

18. The caulking compound according to claim 1, wherein the caulking compound further comprises a biocide present in an amount in the range of about 0.01 - 0.02% by weight.

19. The caulking compound according to claim 1, wherein the caulking compound further comprises reinforcing fibers present in an amount in the range of about 0.01 - 0.02% by weight.

20. The caulking compound according to claim 1, wherein the caulking compound further comprises a colorant present in an amount in the range of about 0.005 - 6.0% by weight.

21. A cured caulking joint, the cured caulking joint comprising the caulking compound composition according to claim 1, and the cured caulking joint remaining intact when subjected to wet abrasion scratching and excavation.

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