Patent Application
20220081364
The present disclosure is directed to an admixture for cementitious compositions, cementitious compositions including the admixture composition, a method of making the admixture composition, a method of making the cementitious composition and a hardened cementitious structure prepared from the cementitious composition, including the admixture composition. The present disclosure is more particularly directed to an admixture for cementitious compositions for mitigating alkali-silica reaction, cementitious compositions including the admixture composition for mitigating alkali-silica reaction, a method of making the admixture composition for mitigating alkali-silica reaction, a method of making the cementitious composition with the admixture composition for mitigating alkali-silica reaction, and a hardened cementitious structure prepared from the cementitious composition including the admixture composition for mitigating alkali-silica reaction.
Concrete compositions are prepared from a mixture of hydraulic cement (for example, Portland cement), aggregate and water. The aggregate used to make concrete compositions typically includes a blend of fine aggregate such as sand, and coarse aggregate such as stone. Alkali-aggregate reaction (“AAR”) is a chemical reaction that occurs between the reactive components of the aggregate and the hydroxyl ions from the alkaline cement pore solution present in the concrete composition. Most of the most common alkali-aggregate reactions that occur between the aggregate and alkali hydroxide is the alkali-silica reaction (“ASR”) in which the hydroxyl ions from the alkaline cement pore solution react with reactive forms of silica from the aggregate. The result of the alkali-silica reaction is the formation of a hygroscopic alkali-silica gel that increases in volume by taking up water. As the volume of the alkali-silica gel increases it exerts an expansive pressure on the concrete resulting in cracking and ultimate failure in the hardened concrete form.
Many attempts have been made in the art to limit the expansion pressure caused by the formation of alkali-silica gels, and the overall the damaging effects of the alkali-silica reaction in hardened concrete. These attempts include the use of low alkali cement, non-reactive aggregate (for example, silica-free limestone aggregate), coated aggregates, pozzolans (for example, fly ash and silica fume), slag cement (for example, blast furnace slag), densified silica fume powder and lithium nitrate. Low alkali cement, certain types of fly ash and slag cement suffer from limited availability. Lithium nitrate suffers from uncertain availability and rapidly rising costs due to the demand for lithium for the manufacture of battery cells.
Densified silica fume is produced by treating silica fume to increase its bulk density up about 400 kg/m′ to about 720 kg/m′. Densification is usually accomplished through an air-densification process involving tumbling of the silica fume powder in a storage silo. The air-densification process is carried out by blowing compressed air from the bottom of the silo causing the silica fume particles to tumble within the silo. As the silica fume particles tumble they agglomerate together. Densified silica fume also suffers from particle agglomeration in water slurries which reduces its ability to mitigate alkali-silica reaction in concrete. Silica fume also has a higher raw material cost, and there are additional costs associated with constructing and maintaining large silos to store the densified silica fume powder.
Therefore, what is still needed in the art is an effective admixture to mitigate the effect of the alkali-silica reaction in concrete that is based on components that are readily available and cost-effective, and that are more effective in mitigating the alkali-silica reaction in concrete as compared to the proposed solutions currently known in the art.
According to a first aspect, disclosed is an alkali-silica mitigating additive for cementitious compositions comprising solid particle additives that are stabilized against particle agglomeration.
According to another aspect, disclosed is an alkali-silica mitigating additive for cementitious compositions comprising zirconia silica fume particles stabilized against particle agglomeration.
According to another aspect, disclosed is a liquid admixture composition for cementitious compositions comprising an alkali-silica reaction mitigating additive, a thickener and water, wherein said alkali-silica reaction mitigating additive is stabilized against agglomeration and the liquid admixture is stabilized against physical separation.
According to another aspect, disclosed is a liquid admixture composition for cementitious compositions comprising an alkali-silica reaction mitigating amount of zirconia silica fume, a thickener, and water, wherein said zirconia silica fume is stabilized against agglomeration and the liquid admixture is stabilized against physical separation.
According to another aspect, disclosed is a cementitious composition comprising (i) a hydraulic cementitious binder, (ii) mineral aggregate, (iii) an admixture comprising an alkali-silica reaction mitigating additive, a thickener and water, wherein said alkali-silica reaction mitigating additive is stabilized against agglomeration and the liquid admixture is stabilized against physical separation, and (iv) additional water sufficient to hydrate the hydraulic cementitious binder.
According to another aspect, disclosed is a cementitious composition comprising (i) a hydraulic cementitious binder, (ii) aggregate, (iii) an admixture composition comprising an alkali-silica reaction mitigating amount of zirconia silica fume, a thickener, wherein said zirconia silica fume is stabilized against agglomeration and the liquid admixture is stabilized against physical separation, and water and (iv) additional water sufficient to hydrate the hydraulic cementitious binder.
According to another aspect, disclosed is a method of making an admixture for cementitious compositions comprising combining together an alkali-silica reaction mitigating additive, a thickener, an activating agent for the thickener, and water to form a mixture, and activating the thickener to thicken the admixture with the thickener, wherein said alkali-silica reaction mitigating additive is stabilized against agglomeration and the liquid admixture is stabilized against physical separation.
According to another aspect, disclosed is a method of making an admixture for cementitious compositions comprising combining together an alkali-silica reaction mitigating additive, a thickener, and water to form a mixture, and adjusting the pH of the mixture with an acid neutralizing agent to activate the thickener to thicken the admixture, wherein said alkali-silica reaction mitigating additive is stabilized against agglomeration and the liquid admixture is stabilized against physical separation.
According to another aspect, disclosed is a method of making an admixture for cementitious compositions comprising combining together an alkali-silica reaction mitigating amount of zirconia silica fume, a thickener, and water to form a mixture, and adjusting the pH of the mixture with an acid neutralizing agent, wherein said zirconia silica fume is stabilized against agglomeration and the liquid admixture is stabilized against physical separation.
According to another aspect, disclosed is a method for making a cementitious composition comprising mixing together (i) a hydraulic cementitious binder, (ii) mineral aggregate, (iii) an admixture comprising an alkali-silica reaction mitigating additive, a thickener and water, wherein said alkali-silica reaction mitigating additive is stabilized against agglomeration and the liquid admixture is stabilized against physical separation, and (iv) additional water sufficient to hydrate the hydraulic cementitious binder.
According to another aspect, disclosed is a method for making a cementitious composition comprising mixing together (i) a hydraulic cementitious binder, (ii) mineral aggregate, (iii) an admixture comprising an alkali-silica reaction mitigating amount of zirconia silica fume, a thickener and water, wherein said zirconia silica fume is stabilized against agglomeration and the liquid admixture is stabilized against physical separation, and (iv) additional water sufficient to hydrate the hydraulic cementitious binder.
According to another aspect, disclosed is a method for making a cementitious form or structure comprising mixing together (i) a hydraulic cementitious binder, (ii) mineral aggregate, (iii) an admixture comprising an alkali-silica reaction mitigating additive, a thickener, and water, wherein said alkali-silica reaction mitigating additive is stabilized against agglomeration and the liquid admixture is stabilized against physical separation, and (iv) additional water sufficient to hydrate the hydraulic cementitious binder to form a cementitious mixture, placing the cementitious mixture in a suitable mold or at a selected location, and allowing the cementitious mixture to harden.
According to another aspect, disclosed is a method for making a cementitious form or structure comprising mixing together (i) a hydraulic cementitious binder, (ii) mineral aggregate, (iii) an admixture comprising an alkali-silica reaction mitigating amount of zirconia silica fume, a thickener, and water, wherein said zirconia silica fume is stabilized against agglomeration and the liquid admixture is stabilized against physical separation, and (iv) additional water sufficient to hydrate the hydraulic cementitious binder to form a cementitious mixture, placing the cementitious mixture in a suitable mold or at a selected location, and allowing the cementitious mixture to harden.
According to another aspect, disclosed is a method of mitigating alkali-silica reaction in cementitious compositions comprising adding stabilized zirconia silica fume to a cementitious composition comprising a hydraulic cementitious binder, reactive mineral aggregate, and water, wherein said stabilized zirconia silica fume is added in amount sufficient to mitigate alkali-silica reactions.
According to another aspect, disclosed is the use of stabilized zirconia silica fume in a cementitious composition to mitigate the alkali-silica reaction.
Disclosed is a stabilized solid particle additive that is effective in mitigating the alkali-silica reaction (ASR) reaction that occurs between the hydroxyl ions from the alkaline cement pore solution and the reactive silica components of the aggregate within a cementitious composition mixture. Also disclosed is a liquid admixture for cementitious compositions that comprises the stabilized solid particulate additive that is effective in mitigating the alkali-silica reaction (ASR) reaction and where the liquid admixture is stabilized against physical separation.
The alkali-silica reaction mitigating admixture for cementitious compositions comprises a mixture of an alkali-silica reaction mitigating effective amount of an alkali-silica reaction mitigating additive, a thickener to thicken the aqueous liquid admixture and to stabilize the alkali-silica reaction mitigating additive against particle agglomeration and to stabilize the admixture against physical separation, and water.
The stabilization of the alkali-silica mitigating additive within a liquid admixture may be achieved by the thickening of an organic polymer thickener. The thickening effect of may be triggered by an activating agent for the thickener. For example, and without limitation, the thickening effect may be triggered by a change in the pH of the liquid admixture containing the additive and the organic polymer thickener. The change in pH of the liquid admixture may be achieved through the neutralization of acid groups on the organic polymer thickener. The term “neutralization” as used in this Specification means a degree of deprotonation of acid groups of the organic polymer thickener. Deprotonation of acid groups of the organic polymer thickener may be partial deprotonation where less than all of the acid groups of the organic polymer thickener are deprotonated, or full deprotonation all of the acid groups carried on the organic polymer thickener are deprotonated.
According to certain illustrative embodiments, an effective amount of an activating agent for the thickener, such as an acid neutralizing agent, is added to the mixture of alkali-silica reaction mitigating additive, thickener and water, to adjust the pH of the mixture. The adjustment of the pH of the mixture activates the thickener and results in thickening of the liquid admixture. The combination of the alkali-silica reaction mitigating additive with a thickener and acid neutralizing agent provides a liquid admixture for cementitious compositions where the alkali-silica reaction mitigating additive is dispersed within the admixture and is stabilized against agglomeration of particles. The thickener activating agent may be an agent that either decreases or increases the pH of the liquid admixture to activate the thickening of the organic polymer thickener. It should be noted that the activating agent may be capable of adjusting the pH from an acidic pH to an alkaline pH, or from an alkaline pH to an acidic pH. The activating agent may also be capable of adjusting the pH of the liquid admixture having an acidic pH from a more acid pH to a less acidic pH, or from a less acidic pH to a more acidic pH, while maintaining the pH of the liquid admixture within the acidic pH range. The activating agent may also be capable of adjusting the pH of the liquid admixture having an alkaline pH from a more alkaline pH to less alkaline pH, or from a less alkaline pH to a more alkaline pH, while maintaining the pH of the liquid admixture within the alkaline pH range.
According to certain illustrative embodiments, the acid neutralizing agent is an agent that is effective in increasing the pH of the mixture by neutralizing acid groups on the thickener present in the mixture to achieve a thickening effect. According to certain embodiments, and without limitation, an effective amount of an acid neutralizing agent is added to the mixture of alkali-silica reaction mitigating additive, thickener, and water to increase the pH of the mixture to activate the thickener. The increase in the pH of the mixture activates the thickener and results in thickening of the mixture. The combination of the alkali-silica reaction mitigating additive with a thickener and acid neutralizing agent provides a liquid admixture for cementitious compositions where the alkali-silica reaction mitigating additive is dispersed in the admixture and is stabilized against agglomeration.
For purposes of this Specification, the phrase “stabilized against agglomeration” means that the particles of the alkali-silica reaction mitigating additive agglomerate less in the presence of the activated thickener as compared to the absence of the thickener. For example, and without limitation, the particles stabilized against agglomeration may agglomerate at least about 5 percent less than particles that have not been stabilized against agglomeration. For example, and without limitation, the particles stabilized against agglomeration may agglomerate at least about 10 percent less than particles that have not been stabilized against agglomeration. For example, and without limitation, the particles stabilized against agglomeration may agglomerate at least about 25 percent less than particles that have not been stabilized against agglomeration. For example, and without limitation, the particles stabilized against agglomeration may agglomerate at least about 50 percent less than particles that have not been stabilized against agglomeration. For example, and without limitation, the particles stabilized against agglomeration may agglomerate at least about 75 percent less than particles that have not been stabilized against agglomeration. For example, and without limitation, the particles stabilized against agglomeration may agglomerate at least about 85 percent less than particles that have not been stabilized against agglomeration. For example, and without limitation, the particles stabilized against agglomeration may agglomerate at least about 95 percent less than particles that have not been stabilized against agglomeration.
For purposes of this Specification, the phrase “stabilized against physical separation” means that the liquid admixture containing particles of the alkali-silica reaction mitigating additive exhibit less physical separation of the particles of alkali-silica reaction mitigating additive from the liquid phase of the liquid admixture in the presence of the activated thickener as compared to the absence of the thickener. For example, and without limitation, the liquid admixture containing a plurality of alkali-silica reaction mitigating particles stabilized against agglomeration exhibits at least about 95 percent less physical separation of the particles of alkali-silica reaction mitigating additive from the liquid phase of the liquid admixture in the presence of the activated thickener as compared to the absence of the thickener. For example, and without limitation, the liquid admixture containing a plurality of alkali-silica reaction mitigating particles stabilized against agglomeration exhibits at least about 85 percent less physical separation of the particles of alkali-silica reaction mitigating additive from the liquid phase of the liquid admixture in the presence of the activated thickener as compared to the absence of the thickener. For example, and without limitation, the liquid admixture containing a plurality of alkali-silica reaction mitigating particles stabilized against agglomeration exhibits at least about 75 percent less physical separation of the particles of alkali-silica reaction mitigating additive from the liquid phase of the liquid admixture in the presence of the activated thickener as compared to the absence of the thickener. For example, and without limitation, the liquid admixture containing a plurality of alkali-silica reaction mitigating particles stabilized against agglomeration exhibits at least about 50 percent less physical separation of the particles of alkali-silica reaction mitigating additive from the liquid phase of the liquid admixture in the presence of the activated thickener as compared to the absence of the thickener. For example, and without limitation, the liquid admixture containing a plurality of alkali-silica reaction mitigating particles stabilized against agglomeration exhibits at least about 25 percent less physical separation of the particles of alkali-silica reaction mitigating additive from the liquid phase of the liquid admixture in the presence of the activated thickener as compared to the absence of the thickener. For example, and without limitation, the liquid admixture containing a plurality of alkali-silica reaction mitigating particles stabilized against agglomeration exhibits at least about 10 percent less physical separation of the particles of alkali-silica reaction mitigating additive from the liquid phase of the liquid admixture in the presence of the activated thickener as compared to the absence of the thickener. For example, and without limitation, the liquid admixture containing a plurality of alkali-silica reaction mitigating particles stabilized against agglomeration exhibits at least about 5 percent less physical separation of the particles of alkali-silica reaction mitigating additive from the liquid phase of the liquid admixture in the presence of the activated thickener as compared to the absence of the thickener.
According to certain illustrative embodiments, the alkali-silica reaction mitigating additive of the liquid admixture comprises an alkali-silica reaction mitigating amount of an amorphous silica fume. According to certain illustrative embodiments, the alkali-silica reaction mitigating additive of the liquid admixture comprises an alkali-silica reaction mitigating amount of amorphous zirconia silica fume. Zirconia silica fume is a fine amorphous particulate material prepared from zircon sand (zirconium silicate, chemical formula ZrSiO4). Zircon sand typically comprises about 67 weight percent zirconia (zirconium dioxide, chemical formula ZrO2) and about 33% silica (silicon dioxide, chemical formula SiO2). The zircon sand is subjected to a fusion process in an electric arc furnace to recover zirconium oxide (ZrO2). During the electric arc fusion process, the zirconia silica fume is separated from the zircon sand and collected as a particulate.
The chemical composition of the zirconia silica fume is greater than about 80 weight percent silica, greater than 0 to about 15 weight percent zirconia, and 0 to about 5 weight percent impurities. According to other illustrative embodiments, the chemical composition of the zirconia silica fume is greater than about 85 weight percent silica, greater than 0 to about 10 weight percent zirconia, and 0 to about 5 weight percent impurities. According to other illustrative embodiments, the chemical composition of the zirconia silica fume is greater than about 86 weight percent silica, greater than 0 to about 9 weight percent zirconia, and 0 to about 5 weight percent impurities. According to other illustrative embodiments, the chemical composition of the zirconia silica fume is greater than about 87 weight percent silica, greater than 0 to about 8 weight percent zirconia, and 0 to about 5 weight percent impurities. According to other illustrative embodiments, the chemical composition of the zirconia silica fume is greater than about 88 weight percent silica, greater than 0 to about 7 weight percent zirconia, and 0 to about 5 weight percent impurities. According to other illustrative embodiments, the chemical composition of the zirconia silica fume is greater than about 89 weight percent silica, greater than 0 to about 9 weight percent zirconia, and 0 to about 5 weight percent impurities. According to other illustrative embodiments, the chemical composition of the zirconia silica fume is greater than about 90 weight percent silica, greater than 0 to about 5 weight percent zirconia, and 0 to about 5 weight percent impurities. The amounts of silica, zirconia and impurities present is based on the total weight of the zirconia silica fume.
According to other illustrative embodiments, the chemical composition of the zirconia silica fume is (i) about 80 to about 90 weight percent silica, (ii) about 1 to about 10 weight percent, or about 2 to about 10 weight percent, or about 3 to about 10 weight percent, or about 4 to about 10 weight percent, or about 5 to about 10 weight percent, or about 6 to about 10 weight percent, or about 7 to about 10 weight percent, or about 8 to about 10 weight percent, or about 9 to about 10 weight percent zirconia, and (iii) 0 to about 5 weight percent impurities. The amounts of silica, zirconia and impurities present is based on the total weight of the zirconia silica fume.
According to other illustrative embodiments, the chemical composition of the zirconia silica fume is (i) about 85 weight percent or greater silica, (ii) about 1 to about 10 weight percent, or about 2 to about 10 weight percent, or about 3 to about 10 weight percent, or about 4 to about 10 weight percent, or about 5 to about 10 weight percent, or about 6 to about 10 weight percent, or about 7 to about 10 weight percent, or about 8 to about 10 weight percent, or about 9 to about 10 weight percent zirconia, and (iii) 0 to about 5 weight percent impurities. The amounts of silica, zirconia and impurities present is based on the total weight of the zirconia silica fume.
The impurities may be calcia (calcium oxide, chemical formula CaO), alumina (aluminum oxide, chemical formula Al2O3), iron oxide and mixtures of these impurities. According to other illustrative embodiments, the chemical composition of the zirconia silica fume is greater than about 85 weight percent silica, greater than 0 to about 10 weight percent zirconia, and 0 to about 5 weight percent impurities comprising calcia and alumina. According to other illustrative embodiments, the chemical composition of the zirconia silica fume is greater than about 85 weight percent silica, greater than 0 to about 10 weight percent zirconia, and 0 to about 4 weight percent calcia impurity, and greater than 0 to about 1 weight percent alumina impurity. According to other illustrative embodiments, the chemical composition of the zirconia silica fume is greater than about 88 weight percent silica, greater than 0 to about 9 weight percent zirconia, and 0 to about 2.5 weight percent calcia impurity and greater than 0 to about 0.5 weight percent alumina impurity. The amounts of silica, zirconia and impurities present is based on the total weight of the zirconia silica fume.
According to other illustrative embodiments, the chemical composition of the zirconia silica fume is (i) about 90 to about 99 weight percent silica, (ii) about 1 to about 10 weight percent zirconia, and (iii) less than about 0.25 weight percent calcia. The amounts of silica, zirconia and calcia present is based on the total weight of the zirconia silica fume.
According to other illustrative embodiments, the chemical composition of the zirconia silica fume is (i) about 80 to about 86 weight percent silica, (ii) about 1 to about 10 weight percent zirconia, and (iii) about 1 to about 5 weight percent calcia. The amounts of silica, zirconia and calcia present is based on the total weight of the zirconia silica fume.
According to other illustrative embodiments, the chemical composition of the zirconia silica fume is greater than about 90 weight percent silica, greater than 5 to about 10 weight percent zirconia and 0 to about 5 weight percent impurities wherein the impurities include less than 0.5 weight percent calcia According to other illustrative embodiments, the chemical composition of the zirconia silica fume is greater than about 90 weight percent silica, greater than 5 to about 10 weight percent zirconia and 0 to about 5 weight percent impurities wherein the impurities include less than 0.25 weight percent calcia. According to other illustrative embodiments, the chemical composition of the zirconia silica fume is greater than about 90 weight percent silica, greater than 5 to about 10 weight percent zirconia and 0 to about 5 weight percent impurities wherein the impurities include less than 0.125 weight percent calcia. The amounts of silica, zirconia and calcia present is based on the total weight of the zirconia silica fume.
The particles of zirconia silica fume may exhibit a certain granularity, narrow particle size distribution and a large surface area. The particles of zirconia silica fume exhibit a particle size distribution (d50) of 10 μm or less. The particles of zirconia silica fume exhibit a particle size distribution (d50) of 6 μm, or 5 μm, or 4 μm, or 3 μm, or 2 μm, or 1 μm. A particle size distribution d50 of no greater than 6 μm is optimal for particle dispersion within an aqueous slurry admixture for mitigation of the alkali-silica reaction. The particles of zirconia silica fume may exhibit a BET surface area in the range of about 1 to about 30 m2/g, about 10 to about 30 m2/g, about 10 to about 25 m2/g, about 15 to about 25 m2/g, about 10 to about 15 m2/g, about 1 to about 20 m2/g, about 5 to about 20 m2/g, about 10 to about 20 m2/g, about 12 to about 20 m2/g, or about 15 to about 20 m2/g. Particularly useful zirconia silica fume particles have a measured BET surface area in the range of about 12 to about 20 m2/g. The crystalline structure of the particles of zirconia silica fume may me monoclinic, tetragonal or cubic.
Without limitation, and only by way of illustration, suitable zirconia silica fume for use in the present admixture composition, cementitious composition and methods are commercially available from Henan Superior Abrasives Import and Export Co., Ltd. (Zhengzhou, Henan, China), Luoyang Ruowen Trading Co., Ltd. (Hongshan Township, Xigong District, Luoyang Henan, China), Saint-Gobain Research (China) Co., Ltd. (Min Hang Development Zone, Shanghai, China), TAM Ceramics, LLC (Niagara Falls, N.Y., USA), and Washington Mills Tonawanda, Inc. (Tonawanda, N.Y., USA).
According to certain embodiments, the particles of zirconia silica fume are stabilized within the aqueous liquid slurry admixture through a combination of a thickener and pH adjustment with the pH altering agent. According to certain embodiments, the particles of zirconia silica fume are stabilized within the aqueous liquid slurry admixture through a combination of a thickener and pH adjustment with the pH increasing agent. The thickeners for the solid particles of zirconia silica fume comprise organic polymer thickeners. Suitable organic polymer thickeners for the admixture composition may include cross-linked acrylic polymer thickeners, alkali soluble emulsion polymer thickeners and associative polymer thickeners.
Without limitation, and only by way of illustration, suitable commercially available cross-linked acrylic polymers include CARBOPOL ETD-2691, CARBOPOL EZ-2 and CARBOPOL EZ-5 commercially available from The Lubrizol Corporation (Cleveland, Ohio, USA). These cross-linked poly(acrylic) acid polymers thicken through absorption of water following activation by pH neutralization. CARBOPOL ETD-2619, CARBOPOL EZ-2 and CARBOPOL EZ-5 are cross-linked poly(acrylic acid) polymers that are easily dispersed in aqueous systems, and provide solution thickening upon neutralization (ie, an increase in pH) and shear-thinning rheology properties to enable dispensing or pumping of finished products.
Without limitation, and only by way of illustration, suitable commercially available alkali soluble emulsion polymer thickeners include ACRYSOL ASE-60 and ACRYSOL ASE-1000 commercially available from The Dow Chemical Company (Midland, Mich., USA). These thickeners are copolymers of an acid and an ester. According to certain embodiments, these organic thickeners are copolymers of methacrylic acid and alkyl acrylate ester. According to yet further embodiments, these organic thickeners are copolymers of methacrylic acid and ethyl acrylate ester. The copolymer may have a 50:50 ratio of methacrylic acid to ethyl acrylate ester. The methacrylic acid is soluble in water, while the ethyl acrylate ester is insoluble in water. These alkali-soluble/swellable emulsion polymers are generally insoluble at low pH and soluble at high pH. At low pH these emulsion thickeners are not soluble in water and do not impart any thickening to the admixture composition. Upon pH neutralization these alkali-soluble polymer emulsions become soluble and clear, and thickening of the admixture composition occurs. Both ACRYSOL ASE-60 and ACRYSOL ASE-1000 are supplied as a low viscosity, low pH aqueous emulsions. The thickening of the admixture composition is triggered by a change from low pH to high pH (ie, pH-triggered thickeners). The alkali-soluble emulsion polymer thickeners may be activated (ie, “triggered”) at about pH 8. Both ACRYSOL ASE-60 and ACRYSOL ASE-1000 are non-cellulosic, acid-containing cross-linked acrylic emulsion polymers. Upon acid neutralization with a base, the emulsion thickeners impart thickening to the admixture composition through swelling of the emulsion particles.
Associative thickeners are polymers that are modified to contain hydrophobic groups. The associative thickeners impart thickening through both pH-activated (ie, pH-triggered) water absorption and through association of hydrophobic groups. The hydrophobic groups of the associative thickeners interact with each other and with other components in the admixture composition to create a three-dimensional polymer network within the admixture composition. The three-dimensional network restricts the motion of components within the admixture which results in thickening. Without limitation, and only by way of illustration, suitable commercially available associative polymer thickeners include CARBOPOL ETD 2623, CARBOPOL EZ-3 and CARBOPOL EZ-4 commercially available from The Lubrizol Corporation (Cleveland, Ohio, USA) and ACRYSOL TT-615 commercially available from The Dow Chemical Company (Midland, Mich., USA).
For illustrative embodiments of the admixture that include an alkali-activated thickener, an acid neutralizing agent is added to the mixture of the alkali-silica reaction mitigating additive and the polymeric thickener to raise the pH of the admixture to a pH where the thickening action of the thickener of the liquid admixture begins, starts, or otherwise commences. The acid neutralizing agent is any alkali or base substance or combination of substances that react with an acid or acid group(s) to neutralize it. These agent usually alkali metal oxides, alkaline earth metal oxides, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, alkaline earth metal hydroxides, alkali metal hydrogen carbonates, alkaline earth metal hydrogen carbonates, ammonium hydroxide and amines. According to certain illustrative embodiments, the acid neutralizing agent comprises one or more alkaline earth hydroxides. According to certain illustrative embodiments, the alkaline metal hydroxide comprises calcium hydroxide or magnesium hydroxide. According to certain illustrative embodiments, the acid neutralizing agent comprises one or more alkali metal hydroxides. According to certain illustrative embodiments, the alkali metal hydroxide comprises sodium hydroxide or potassium hydroxide.
According to other illustrative embodiments, the admixture composition contains the alkali-silica reaction mitigating additive, the polymeric thickener and water, and has an initial pH which is sufficient to achieve activation of the polymer thickener and thickening of the liquid admixture without the addition of a pH adjusting agent. The initial pH of the liquid admixture may be acidic or alkaline, and the organic polymer thickener is activated at this initial ad pH.
According to other illustrative embodiments, the initial pH of the liquid admixture comprising the alkali-silica reaction mitigating additive, thickener and water is acidic and the pH must be adjusted to an alkaline pH to activate the thickening effect of the thickener. According to certain illustrative embodiments, the admixture composition containing the alkali-silica reaction mitigating additive, the polymeric thickener and water may have an initial pH as low as about 4. According to certain illustrative embodiments, the admixture composition containing the alkali-silica reaction mitigating additive, the polymeric thickener and water may have an initial pH in the range of about 4 to about 7. According to certain illustrative embodiments, the acid neutralizing agent is added to the mixture of the alkali-silica reaction mitigating additive, the polymeric thickener and water in an amount sufficient to increase the initial pH of the mixture of the mixture to activate the polymer thickener. According to certain illustrative embodiments, the acid neutralizing agent is added to the mixture of the alkali-silica reaction mitigating additive, the polymeric thickener and water in an amount sufficient to increase the initial pH of the mixture of about 4 to about 7, to a more alkaline in the range of about 8 to about 13. According to certain illustrative embodiments, the acid neutralizing agent is added to the mixture of the alkali-silica reaction mitigating additive, the polymeric thickener and water in an amount sufficient to increase the initial pH of the mixture of about 4 to about 7, to a more alkaline pH in the range of about 8 to about 12. According to certain illustrative embodiments, the acid neutralizing agent is added to the mixture of the alkali-silica reaction mitigating additive, the polymeric thickener and water in an amount sufficient to increase the initial pH of the mixture of about 4 to about 7, to a more alkaline pH in the range of about 9 to about 12. According to certain illustrative embodiments, the acid neutralizing agent is added to the mixture of the alkali-silica reaction mitigating additive, the polymeric thickener and water in an amount sufficient to increase the initial of the mixture of about 4 to about 7, to a more alkaline pH in the range of about 9 to about 11. According to certain illustrative embodiments, the acid neutralizing agent is added to the mixture of the alkali-silica reaction mitigating additive, the polymeric thickener and water in an amount sufficient to increase the initial pH of the mixture of about 4 to about 7, to a more alkaline pH in the range of about 9 to about 10. It should be noted that some polymeric thickeners can be activated by an activating agent, such as an acid neutralizing agent, at a pH slightly above 5.
The admixture composition of the present disclosure comprises from about 20 to about 80 weight percent of the alkali-silica reaction mitigating additive, from about 0.1 to about 5 weight percent of the thickener for the alkali-silica mitigating additive, from about 14 to about 80 weight percent water, and from about 0.05 to about 0.5 of the thickener activating agent, such as an acid neutralizing agent.
According to other embodiments, the alkali-silica reaction mitigating additive may comprise metakaolin particles that have been stabilized. Without limitation, and only by way of illustration, metakaolin pozzolanic particles are commercially available from BASF Corporation (Charlotte, N.C., USA).
Disclosed is a method of making an ASR-mitigating admixture for cementitious compositions. The method of making the admixture comprises combining together an alkali-silica reaction mitigating additive, such as zirconia silica fume, a thickener for the alkali-silica reaction mitigating additive, and water to form an aqueous mixture. The method may involve dispersing the particulate zirconia silica fume in a suitable amount of water to form an aqueous dispersion. The organic polymer thickener is added to the dispersion of zirconia silica fume, and the pH of the mixture is adjusted by the addition of an acid neutralizing agent. According to further illustrative embodiments, the method involves increasing the pH of the aqueous mixture with an acid neutralizing agent.
A cementitious composition comprising the disclosed admixture is further disclosed. The cementitious composition comprises a hydraulic cementitious binder, one or more mineral aggregates, the alkali-silica reaction mitigating admixture and a sufficient amount of water to hydrate the hydraulic binder of the cementitious composition.
As used herein, the term cement refers to any hydraulic cement. Hydraulic cements are materials that set and harden in the presence of water. Suitable non-limiting examples of hydraulic cements include Portland cement, masonry cement, alumina cement, refractory cement, magnesia cements, such as a magnesium phosphate cement, a magnesium potassium phosphate cement, calcium aluminate cement, calcium sulfoaluminate cement, calcium sulfate hemi-hydrate cement, oil well cement, ground granulated blast furnace slag, natural cement, hydraulic hydrated lime, and mixtures thereof. Portland cement, as used in the trade, means a hydraulic cement produced by pulverizing clinker, comprising of hydraulic calcium silicates, calcium aluminates, and calcium ferroaluminates, with one or more of the forms of calcium sulfate as an interground addition. Portland cements according to ASTM C150 are classified as types I, II, III, IV, or V.
The cementitious composition may also include any cement admixture or additive including set accelerators, set retarders, air entraining agents, air detraining agents, corrosion inhibitors, dispersants, pigments, plasticizers, super plasticizers, wetting agents, water repellants, fibers, dampproofing agent, gas formers, permeability reducers, pumping aids, fungicidal admixtures, germicidal admixtures, insecticidal admixtures, bonding admixtures, strength enhancing agents, shrinkage reducing agents, aggregates, pozzolans, and mixtures thereof.
The term dispersant as used throughout this specification includes, among others, polycarboxylate dispersants. Polycarboxylate dispersants refer to dispersants having a carbon backbone with pendant side chains, wherein at least a portion of the side chains are attached to the backbone through a carboxyl group, an ether group, an amide group or an imide group. The term dispersant is also meant to include those chemicals that also function as a plasticizer, water reducers, high range water reducers, fluidizer, antiflocculating agent, or superplasticizer for cementitious compositions. Without limitation, and only by way of illustration, suitable dispersants include polycarboxylates (including polycarboxylate ethers), lignosulfonates (calcium lignosulfonates, sodium lignosulfonates and the like), salts of sulfonated naphthalene sulfonate condensates, salts of sulfonated melamine sulfonate condensates, beta naphthalene sulfonates, sulfonated melamine formaldehyde condensates, naphthalene sulfonate formaldehyde condensate resins, polyaspartates, oligomeric dispersants and mixtures thereof.
The term air entrainer includes any chemical that will entrain air in cementitious compositions. Air entrainers can also reduce the surface tension of a composition at low concentration. Air-entraining admixtures are used to purposely entrain microscopic air bubbles into concrete. Air-entrainment dramatically improves the durability of concrete exposed to moisture during cycles of freezing and thawing. In addition, entrained air greatly improves a concrete's resistance to surface scaling caused by chemical deicers. Air entrainment also increases the workability of fresh concrete while eliminating or reducing segregation and bleeding. Without limitation, and only by way of illustration, suitable air entrainers include salts of wood resin, certain synthetic detergents, salts of sulfonated lignin, salts of petroleum acids, salts of proteinaceous material, fatty and resinous acids and their salts, alkylbenzene sulfonates, salts of sulfonated hydrocarbons and mixtures thereof.
Set retarder admixtures are used to retard, delay, or slow the rate of setting of concrete. Set retarders can be added to the concrete mix upon initial batching or sometime after the hydration process has begun. Set retarders are used to offset the accelerating effect of hot weather on the setting of concrete, or delay the initial set of concrete or grout when difficult conditions of placement occur, or problems of delivery to the job site, or to allow time for special finishing processes or to aid in the reclamation of concrete left over at the end of the work day. Without limitation, and only by way of illustration, suitable set retarders include lignosulfonates, hydroxylated carboxylic acids, lignin, borax, gluconic, tartaric and other organic acids and their corresponding salts, phosphonates, certain carbohydrates and mixtures thereof may be used as a set retarder.
Air detrainers are used to decrease the air content in the mixture of concrete. Without limitation, and only by way of illustration, suitable air detrainers include tributyl phosphate, dibutyl phthalate, octyl alcohol, water-insoluble esters of carbonic and boric acid, silicones and mixtures thereof.
Bonding agents may be added to Portland cement compositions to increase the bond strength between old and new concrete. Without limitation, and only by way of illustration, suitable bonding agents include organic materials such as rubber, polyvinyl chloride, polyvinyl acetate, acrylics, styrene butadiene copolymers, other powdered polymers and mixtures thereof.
Corrosion inhibitors may be included in the cementitious compositions to protect embedded reinforcing steel from corrosion. The high alkaline nature of the concrete causes a passive and non-corroding protective oxide film to form on the steel. However, carbonation or the presence of chloride ions from deicers or seawater can destroy or penetrate the film and result in corrosion. Corrosion-inhibiting admixtures chemically mitigate this corrosion reaction. Without limitation, and only by way of illustration, suitable corrosion inhibitors include calcium nitrite, sodium nitrite, sodium benzoate, certain phosphates or fluorosilicates, fluoroaluminates, amines, and mixtures thereof.
Dampproofing agents may be included in the cementitious compositions reduce the permeability of concrete that have low cement contents, high water-cement ratios, or a deficiency of fines in the aggregate. The dampproofing agents retard moisture penetration into dry concrete. Without limitation, and only by way of illustrative, dampproofing agent include certain soaps, stearates, petroleum products and mixtures thereof.
Gas formers, or gas-forming agents, may be included in cementitious compositions to cause a slight expansion prior to hardening. The amount of expansion is dependent upon the amount of gas-forming material used and the temperature of the fresh cementitious mixture. Without limitation, and only by way of illustration, suitable gas-forming agent include aluminum powder, resin soap, vegetable or animal glue, saponin or hydrolyzed protein and mixtures thereof.
Reinforcing fibers may be distributed throughout an unhardened concrete mixture. Upon hardening of the mixture, this concrete is referred to as fiber-reinforced concrete. The cementitious mixture may include inorganic fibers, organic fibers, and blends of these types of fibers. Without limitation and only by way of illustration, suitable reinforcing fibers that may be included in the zirconium fibers, metal fibers, metal alloy fibers (eg, steel fibers), fiberglass, polyethylene, polypropylene, fibers nylon fibers, polyester fibers, rayon fibers, high-strength aramid fibers and mixtures thereof.
Fungicidal, germicidal, and insecticidal admixtures may be included in the cementitious compositions to control bacterial and fungal growth on or in the hardened cementitious structure.
The admixture composition of the present disclosure comprises from about 20 to about 80 weight percent of the alkali-silica reaction mitigating additive, from about 0.1 to about 5 weight percent of the thickener for the alkali-silica mitigating additive, from about 14 to about 80 weight percent water, from about 0.05 to about 0.5 of the acid neutralizing agent, and from about 0.1 to about 5 of a dispersant for cementitious compositions. The dispersant for cementitious compositions may comprise a polycarboxylate dispersant. According to certain illustrative embodiments, the dispersant for cementitious compositions comprises a polycarboxylate ether dispersant.
The amount of the liquid admixture to be added to the cementitious compositions should be sufficient to provide a dosage amount of the alkali-silica reaction mitigating additive, such as, for example, stabilized zirconia silica fume, in the range of greater than 0 to about 10 percent by weight of cement, or in the range of greater than 1 to about 10 percent by weight of cement, or in the range of greater than 2 to about 10 percent by weight of cement, or in the range of greater than 3 to about 10 percent by weight of cement, or in the range of greater than 4 to about 10 percent by weight of cement, or in the range of greater than 5 to about 10 percent by weight of cement, or in the range of greater than 6 to about 10 percent by weight of cement, or in the range of greater than 7 to about 10 percent by weight of cement, or in the range of greater than 8 to about 10 percent by weight of cement, or in the range of greater than 9 to about 10 percent by weight of cement.
Further disclosed is a method for making a cementitious composition. The method of making the cementitious composition comprises mixing together a hydraulic cementitious binder, one or more mineral aggregates, an admixture comprising an alkali-silica reaction mitigating additive, a thickener and water, and further water in a sufficient amount to hydrate the hydraulic cementitious binder in the composition.
According to certain embodiments, the method of making the cementitious composition comprises mixing together a hydraulic cementitious binder, one or more mineral aggregates, an admixture comprising an alkali-silica reaction mitigating additive comprising a zirconia silica fume, a thickener and water, and further water in a sufficient amount to hydrate the hydraulic cementitious binder in the composition.
According to certain embodiments, the method of making the cementitious composition comprises mixing together a hydraulic cementitious binder, a fine aggregate comprising silica sand, a coarse aggregate comprising crushed stone, an admixture comprising an alkali-silica reaction mitigating additive comprising zirconia silica fume, a thickener for the zirconia silica fume and water, and further water in a sufficient amount to hydrate the hydraulic cementitious binder in the composition.
According to certain illustrative embodiments, the method of making the cementitious composition comprises mixing together a hydraulic cementitious binder, one or more mineral aggregates, an admixture comprising an alkali-silica reaction mitigating additive, a thickener and water, further water in a sufficient amount to hydrate the hydraulic cementitious binder in the composition, and one or more additional admixtures.
Also disclosed is a method for making a hardened cementitious form or structure. The method comprises mixing together (i) a hydraulic cementitious binder, (ii) one or more mineral aggregates, (iii) an admixture comprising an alkali-silica reaction mitigating additive, a thickener, and a water, and (iv) further water to hydrate the hydraulic cementitious binder to form a cementitious mixture. The cementitious mixture is then placed at a selected location and to cure or harden to form a hardened cementitious structure.
It should be understood that when a range of values is described in the present disclosure, it is intended that any and every value within the range, including the end points, is to be considered as having been disclosed. For example, the amount of a component in “a range of from about 1 to about 100” is to be read as indicating each and every possible amount of that component between 1 and 100. It is to be understood that the inventors appreciate and understand that any and all amounts of components within the range of amounts of components are to be considered to have been specified, and that the inventors have possession of the entire range and all the values within the range.
In the present disclosure, the term “about” used in connection with a value is inclusive of the stated value and has the meaning dictated by the context. For example, the term “about” includes at least the degree of error associated with the measurement of the particular value. One of ordinary skill in the art would understand the term “about” is used herein to mean that an amount of “about” of a recited value results the desired degree of effectiveness in the compositions and/or methods of the present disclosure. One of ordinary skill in the art would further understand that the metes and bounds of the term “about” with respect to the value of a percentage, amount or quantity of any component in an embodiment can be determined by varying the value, determining the effectiveness of the compositions for each value, and determining the range of values that produce compositions with the desired degree of effectiveness in accordance with the present disclosure. The term “about” is further used to reflect the possibility that a composition may contain trace components of other materials that do not alter the effectiveness of the composition.
The following examples are set forth merely to further illustrate the coating compositions and methods of making the ASR-mitigating admixture, cementitious compositions and method of the making the admixture and cementitious composition. The illustrative examples should not be construed as limiting the admixture composition, the cementitious composition incorporating the admixture composition, or the methods of making or using the admixture composition in any manner.
The effect of the disclosed admixture to mitigate the alkali-silica reaction was evaluated in accordance with ASTM C1260-14 (Aug. 1, 2014 Edition), “Standard Test Method for Potential Alkali Reactivity of Aggregates (Mortar-Bar Method).” Mortar bars were prepared using Portland cement, borosilicate aggregate, water and the presently disclosed alkali-silica reaction mitigation admixture. The Portland cement used to prepare the mortar bars was selected to have an alkali content that has a negligible effect on expansion. Twenty-five weight percent (25 wt. %) of borosilicate aggregate was used as the pessimum amount of aggregate for the study. Samples of mortar compositions were placed into suitable molds for preparing the mortar bar specimens. The molds were maintained in a molding environment having a temperature in the range of 20° C. to about 27.5° C. and a relative humidity of not less than 50% for a period of about 24 hours. The mortar bar specimen were removed from the molds and placed in storage containers. The storage containers were immersed with tap water having a temperature of 23° C.±2° C. The storage containers were sealed and placed in an over or water bath at 80° C.±2° C. for a period of 24 hours. The samples were removed from the storage containers and dried with a towel. The zero reading of teach mortar bar specimen is measured and recorded. The mortar bar specimens are then placed into a container and immersed in 1N NaOH. The container is sealed and placed into an over or water bath at 80° C.±2° C. Subsequent readings of the mortar bar specimens are taken periodically for 14 days. The difference between the subsequent readings and the zero readings represent the expansion of the mortar bar specimens during a given time period.
A study was carried out to design a suitable mortar bar mix for mortar bar expansion testing. The effect of the inclusion of 20-100 weight percent of coarse borosilicate aggregate, based on the total dry weight of the coarse and fine aggregate in the mix, on expansion of mortar bars resulting from alkali-silica reaction was evaluated. Potential mortar bar mixtures are set forth in Table 1 below.
Mortar bars were prepared and tested for expansion as a result of the alkali-silica reaction in accordance with ASTM C1260-14 for a period of 14 days. Expansion readings were taken at 0, 3, 5, 7, 10, 12 and 14 days. The results of the mortar mix design study are shown in
A study was carried out to measure the effect of the inclusion of LiNO3 as an alkali-silica reaction mitigation additive on the expansion of mortar bars. The mortar bar mixtures evaluated are set forth in Table 2 below.
Mortar bars were prepared and tested for expansion as a result of the alkali-silica reaction in accordance with ASTM C1260-14 for a period of 14 days. Expansion readings were taken at 0, 2, 5, 7, 10, 12 and 14 days. The results of the mortar mix design study are shown in
A study was carried out to measure the effect of the inclusion of Al(NO3)3 as an alkali-silica reaction mitigation additive on the expansion of mortar bars. The mortar bar mixtures evaluated are set forth in Table 3 below.
Mortar bars were prepared and tested for expansion as a result of the alkali-silica reaction in accordance with ASTM C1260-14 for a period of 14 days. Expansion readings were taken at 0, 3, 5, 7 10, 12 and 14 days. The results of the mortar mix design study are shown in
A study was carried out to measure the effect of the inclusion of Ca(NO3)2 as an alkali-silica reaction mitigation additive on the expansion of mortar bars. The mortar bar mixtures evaluated are set forth in Table 4 below.
Mortar bars were prepared and tested for expansion as a result of the alkali-silica reaction in accordance with ASTM C1260-14 for a period of 14 days. Expansion readings were taken at 0, 3, 5, 7 10, 12 and 14 days. The results of the mortar mix design study are shown in
A study was carried out to measure the effect of the inclusion of Ca(NO2)2 as an alkali-silica reaction mitigation additive on the expansion of mortar bars. The mortar bar mixtures evaluated are set forth in Table 5 below.
Mortar bars were prepared and tested for expansion as a result of the alkali-silica reaction in accordance with ASTM C1260-14 for a period of 14 days. Expansion readings were taken at 0, 2, 5, 7, 9, 12 and 14 days. The results of the mortar mix design study are shown in
A study was carried out to measure the effect of the inclusion of a colloidal silica sol as an alkali-silica reaction mitigation additive on the expansion of mortar bars. The colloidal silica sol used was comprised of 30 weight percent pure silica (SiO2) (16 percent by volume) and 70 weight percent water (84 percent by volume). The density of the colloidal silica sol was 1.2 g/cm3 and the pH was about 10. The average particle diameter size of the pure silica particles was 7 nm. The mortar bar mixtures evaluated are set forth in Table 6 below.
Mortar bars were prepared and tested for expansion as a result of the alkali-silica reaction in accordance with ASTM C1260-14 for a period of 14 days. Expansion readings were taken at 0, 2, 5, 7, 10, 12 and 14 days. The results of the mortar mix design study are shown in
Mortar bars were prepared and tested for expansion as a result of the alkali-silica reaction in accordance with ASTM C1260-14 for a period of 14 days. Expansion readings were taken at 0, 2, 5, 7, 9, 12 and 14 days.
A study was carried out to measure the effect of the inclusion of an admixture comprising a stabilized zirconia silica fume slurry as an alkali-silica reaction mitigation admixture on the expansion of mortar bars. The admixture was thickened with an alkali-soluble polyacrylate thickener and pH adjustment with 50% NaOH. The composition of the stabilized zirconia silica fume slurry admixture is set forth in Table 8 below.
The mortar bar mixtures of Table 9 were prepared using the ASR mitigating admixture of Table 8.
Mortar bars were prepared and tested for expansion as a result of the alkali-silica reaction in accordance with ASTM C1260-14 for a period of 14 days. Expansion readings were taken at 0, 2, 5, 7, 9, 12 and 14 days.
A study was carried out to measure the effect of the inclusion of an admixture comprising a stabilized zirconia silica fume slurry as an alkali-silica reaction mitigation admixture on the expansion of mortar bars. The admixture was thickened with an alkali-soluble polyacrylate thickener and pH adjustment with 50% NaOH. The composition of the stabilized zirconia silica fume slurry admixture is set forth in Table 10 below.
The mortar bar mixtures of Table 11 were prepared using the ASR mitigating admixture of Table 10.
Mortar bars were prepared and tested for expansion as a result of the alkali-silica reaction in accordance with ASTM C1260-14 for a period of 14 days. Expansion readings were taken at 0, 3, 5, 7, 9, 12 and 14 days. The results of the study are shown in
A study was carried out to compare the effect of agglomerated densified silica fume and an aqueous admixture slurry of stabilized zirconia silica fume on expansion of mortar bars resulting from the alkali-silica reaction.
A stabilized zirconia silica fume slurry as an alkali-silica reaction mitigation admixture was prepared in accordance with the composition of Table 12 below. The zirconia silica fume used in the admixture composition was obtained from Washington Mills. The admixture was thickened with an alkali-soluble polyacrylate thickener and pH adjustment with 50% NaOH.
The mortar bar mixtures of Table 12 were prepared using the ASR mitigating admixture of Table 13.
A stabilized zirconia silica fume slurry as an alkali-silica reaction mitigation admixture was prepared in accordance with the composition of Table 14 below. The zirconia silica fume used in the admixture composition was obtained from Washington Mills. The admixture was thickened with an alkali-soluble polyacrylate thickener and pH adjustment with 50% NaOH.
The mortar bar mixtures of Table 15 were prepared using the ASR mitigating admixture of Table 14.
A stabilized zirconia silica fume slurry as an alkali-silica reaction mitigation admixture was prepared in accordance with the composition of Table 16 below. The zirconia silica fume used in the admixture composition was obtained from TAM Ceramics LLC. The admixture was thickened with an alkali-soluble polyacrylate thickener and pH adjustment with 50% NaOH.
The mortar bar mixtures of Table 17 were prepared using the ASR mitigating admixture of Table 16.
A stabilized zirconia silica fume slurry as an alkali-silica reaction mitigation admixture was prepared in accordance with the composition of Table 18 below. The zirconia silica fume used in the admixture composition was obtained from TAM Ceramics LLC. The admixture was thickened with an alkali-soluble polyacrylate thickener and pH adjustment with 50% NaOH.
The mortar bar mixtures of Table 19 were prepared using the ASR mitigating admixture of Table 18.
A stabilized zirconia silica fume slurry as an alkali-silica reaction mitigation admixture was prepared in accordance with the composition of Table 20 below. The zirconia silica fume used in the admixture composition was obtained from TAM Ceramics LLC. The admixture was thickened with an alkali-soluble polyacrylate thickener and pH adjustment with 50% NaOH.
The mortar bar mixtures of Table 21 were prepared using the ASR mitigating admixture of Table 20.
A stabilized zirconia silica fume slurry as an alkali-silica reaction mitigation admixture was prepared in accordance with the composition of Table 22 below. The zirconia silica fume used in the admixture composition was obtained from Saint-Gobain. The admixture was thickened with an alkali-soluble polyacrylate thickener and pH adjustment with 50% NaOH.
The mortar bar mixtures of Table 23 were prepared using the ASR mitigating admixture of Table 22.
A stabilized zirconia silica fume slurry as an alkali-silica reaction mitigation admixture was prepared in accordance with the composition of Table 24 below. The zirconia silica fume used in the admixture composition was obtained from Ruowen. The admixture was thickened with an alkali-soluble polyacrylate thickener and pH adjustment with 50% NaOH.
The mortar bar mixtures of Table 24 were prepared using the ASR mitigating admixture of Table 25.
A study was carried out to investigate the effect of the inclusion of a polycarboxylate ether dispersant within an alkaline admixture comprising a stabilized zirconia silica fume particles as an alkali-silica reaction mitigation admixture. The admixture was thickened with an alkali-soluble polyacrylate thickener and pH adjustment with 10% NaOH. The compositions of the stabilized zirconia silica fume slurry admixture with and without a polycarboxylate ether dispersant are set forth in Tables 26A and 26B below.
The viscosities of the liquid admixtures of Tables 26A and 26B were measured using a Brookfield Viscometer with a rotating #64 spindle. The results of the viscosity measurements are set forth in Table 27 below:
The admixture of Table 26A includes 20.6% by volume of the zirconia silica fume and 77.4% by volume of water. The admixture of Table 26B includes 49.6% by volume zirconia silica fume and 46% by volume water. The results shown in Table 27 indicate that the inclusion of 2.2% by volume of a polycarboxylate ether dispersant in the admixture of Table 26B allows inclusion of over two times the amount of zirconia silica fume in the same volume while still maintaining a flowable and workable admixture that can be easily dispensed into a cementitious composition.
A further study was carried out to investigate the effect of different species of zirconia silica fume particles on the viscosity of the alkali-silica reaction mitigation admixture. The admixture was thickened with an alkali-soluble polyacrylate thickener and pH adjustment with 50% NaOH. The compositions of the stabilized zirconia silica fume slurry admixtures are set forth in Tables 28A and 28B below. The zirconia silica fume of the admixture of Table 28A was obtained from TAM Ceramics, LLC. The zirconia silica fume of the admixture of Table 28B was obtained from Saint-Gobain Research (China) Co., Ltd.
The viscosities of the liquid admixtures of Tables 28A and 28B were measured using a Brookfield Viscometer with a rotating #64 spindle. The results of the viscosity measurements are set forth in Table 29 below:
The admixture of Table 28A includes 20.6% by volume of the zirconia silica fume from TAM Ceramics and 77.4% by volume of water. The admixture of Table 28B includes 33.3% by volume zirconia silica fume from Saint-Gobain and 65% by volume water. The results shown in Table 29 indicate that the use of zirconia silica fume obtained from Saint-Gobain results in an admixture viscosity that is more than 50% less at 100, 50 and 20 RPM the admixture prepared with zirconia silica fume obtained from TAM Ceramics, LLC.
A further study was carried out to investigate the effect of different species of monoclinic zirconia silica fume particles on the viscosity of the alkali-silica reaction mitigation admixture. The admixture was thickened with an alkali-soluble polyacrylate thickener and pH adjustment with 50% NaOH. The compositions of the stabilized zirconia silica fume slurry admixtures are set forth in Tables 30A and 30B below. The zirconia silica fume of the admixture of Table 30A was obtained from Saint-Gobain Research (China) Co., Ltd. The zirconia silica fume of the admixture of Table 30B was obtained from Henan Superior Abrasives Import and Export Co., Ltd.
The viscosities of the liquid admixtures of Tables 30A and 30B were measured using a Brookfield Viscometer with a rotating #64 spindle. The results of the viscosity measurements are set forth in Table 31 below:
The results shown in Table 31 indicate that the use of monoclinic zirconia silica fume obtained from Saint-Gobain and Henan Superior results admixtures that exhibit similar admixture viscosities.
Mortar bars were prepared using a liquid admixture comprising zirconia silica fume particles obtained from Henan Superior and were stabilized against agglomeration. The dosage amounts of the admixture for the study were 0% (control), 2%, 4%, 6%, 8% and 10% by cement weight (% cwt) The mortar bars were tested for expansion as a result of the alkali-silica reaction in accordance with ASTM C1260-14 for a period of 14 days. Expansion readings were taken at 0, 2, 5, 7, 9, 12 and 14 days. The results of the study are shown in
A stabilized alkali-silica reaction mitigation admixture was prepared utilizing MetaMax metakaolin from BASF Corporation as the alkali-silica reaction mitigating particle additive in accordance with the composition of Table 32 below. The admixture was thickened with an alkali-soluble polyacrylate thickener and pH adjustment with 50% NaOH.
Mortar bars were prepared using a liquid admixture of Table 32. The dosage amounts of the admixture for the study were 0% (control), 2%, 4%, 6%, 8% and 10% by cement weight (% cwt). The mortar bars were tested for expansion as a result of the alkali-silica reaction in accordance with ASTM C1260-14 for a period of 14 days. Expansion readings were taken at 0, 2, 5, 7, 9 and 14 days. The results of the study are shown in
While the admixture composition, cementitious composition including the admixture composition, and methods of making the admixture and cementitious compositions have been described in connection with various illustrative embodiments, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiments for performing the same function disclosed herein without deviating therefrom. The illustrative embodiments described above are not necessarily in the alternative, as various embodiments may be combined to provide the desired characteristics. Therefore, the disclosure should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2020/013092 | 1/10/2020 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62790533 | Jan 2019 | US |
