Low-heat high-strength cementitious material, method for preparing same, and use thereof

Abstract

The present application relates to a low-heat high-strength cementing material and a preparation method and application thereof, and the low-heat high-strength cementing material comprises, in percentage by weight: low-heat cement 72.5-79%, fly ash 9-11%, mineral powder 5-9%, silica fume 1-5%, and a hydration heat inhibitor 1.1-2.8%, wherein the hydration heat inhibitor comprises starch, a polymer and an organic acid derivative. The technical problem to be solved is how to provide a cementing material with low hydration heat and high strength, and the low-heat high-strength cementing material is prepared by the combined action of low-heat cement, mineral admixtures (fly ash, mineral powder and silica fume) and a hydration heat inhibitor, so as to significantly reduce the hydration heat of the cementing material and ensure high compressive strength and good durability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cement concrete, in particular to a low-heat high-strength cementitious material and a preparation method and application thereof. BACKGROUND

[0002] Traditional Portland cement generates a large amount of heat during the hydration process. For large volume concrete structures, such as dams, bridges, high-rise building foundations, etc., the internal temperature rise generates thermal stress, which may cause cracking of the large volume concrete structure, affecting the stability and service life of the concrete.

[0003] Low-heat cement can reduce the temperature gradient inside the concrete, thereby reducing thermal stress and temperature cracks. Common low-heat cement is mixed with a large amount of mineral admixtures, such as slag, fly ash and pozzolanic ash, etc. By adjusting the composition and content of the mineral admixtures, the generation of hydration heat is reduced.

[0004] However, the existing low-heat cement still has the problem of high hydration heat in the concrete applied in special scenarios such as large volume concrete, high temperature environment concrete, ultra-high performance concrete, etc., which easily causes structural cracking. In addition, although the addition of mineral admixtures in the prior art can reduce the hydration heat, the reduction is limited, and it may also lead to insufficient early strength of the concrete, affecting the construction progress. Therefore, how to reduce the hydration heat while maintaining high concrete strength needs to be solved. SUMMARY

[0005] The main purpose of the present application is to provide a low-heat high-strength cementitious material and a preparation method and application thereof. The technical problem to be solved is to provide a cementitious material with low hydration heat and high strength. The low-heat high-strength cementitious material significantly reduces the hydration heat of the cementitious material through the combined action of low-heat cement, mineral admixtures (fly ash, mineral powder and silica fume) and a hydration heat inhibitor, and ensures high compressive strength and good durability.

[0006] The purpose of the present application and the solution to its technical problems are realized by adopting the following technical solutions. According to the low-heat high-strength cementitious material proposed in the present application, by weight percentage, it comprises:

[0007] low-heat cement 72.5-79%, fly ash 9-11%, mineral powder 5-9%, silica fume 1-5% and hydration heat inhibitor 1.1-2.8%;

[0008] The hydration heat inhibitor comprises starch, polymer and organic acid derivative.

[0009] The purpose of the present application and the solution to its technical problems can also be further realized by adopting the following technical measures.

[0010] Preferably, the low-heat high-strength cementitious material as described above, the weight ratio of the starch, the organic acid derivative and the polymer is 1:2.7-6:1.7-3.5.

[0011] Preferably, the low-heat high-strength cementitious material as described above, the starch is selected from one or more of waxy corn starch, tapioca starch and wheat starch.

[0012] Preferably, the low-heat high-strength cementitious material as described above, the organic acid derivative is selected from one or more of citric acid, maleic anhydride and tartaric acid.

[0013] Preferably, the low-heat high-strength cementitious material as described above, the polymer is selected from any one of polyvinyl alcohol, polycarboxylic acid superplasticizer and polyacrylamide.

[0014] The purposes and technical problems of the present application are also achieved by the following technical solutions. According to the present application, a preparation method of a low-heat high-strength cementitious material is provided, which comprises the following steps:

[0015] (1) mixing and stirring 72.5-79 wt% of low-heat cement, 9-11 wt% of fly ash, 5-9 wt% of mineral powder and 1-5 wt% of silica fume uniformly to obtain a pre-cementitious material;

[0016] (2) mixing and stirring 1.1-2.8 wt% of a hydration heat inhibitor and the pre-cementitious material uniformly to obtain a low-heat high-strength cementitious material; the hydration heat inhibitor comprises a starch, a polymer and an organic acid derivative.

[0017] The purposes and technical problems of the present application can also be further achieved by the following technical measures.

[0018] Preferably, the preparation method as described above, the preparation method of the hydration heat inhibitor comprises the following steps:

[0019] S1. adding a starch, an inorganic acid solution or a hydrolytic enzyme into water to hydrolyze and form a pre-gel solution;

[0020] S2. mixing an organic acid derivative and the pre-gel solution to react and obtain a reaction mixture;

[0021] S3. mixing the reaction mixture and a polymer to react and obtain a gel solution;

[0022] S4. shaping the gel solution to obtain a hydration heat inhibitor.

[0023] The purposes and technical problems of the present application are also solved by the following technical solutions. The low hydration heat cement concrete according to the present application comprises low heat high strength cementitious material, sand, gravel and water, wherein the low heat high strength cementitious material is the low heat high strength cementitious material as described above.

[0024] Preferably, the low hydration heat cement concrete as described above has a water to low heat high strength cementitious material weight ratio of 0.35 to 0.40.

[0025] The purposes and technical problems of the present application are also solved by the following technical solutions. The low hydration heat cement concrete according to the present application is used in mass concrete structures or high temperature resistant concrete structures or ultra high performance concrete structures.

[0026] By the above technical solutions, the low heat high strength cementitious material, the preparation method and the application thereof according to the present application have at least the following advantages:

[0027] The low heat high strength cementitious material according to the present application comprises low heat cement 72.5 to 79%, fly ash 9 to 11%, mineral powder 5 to 9%, silica fume 1 to 5% and hydration heat inhibitor 1.1 to 2.8%, wherein the hydration heat inhibitor comprises starch, organic acid derivative and polymer. The low heat high strength cementitious material is prepared by the combined action of low heat cement, mineral admixture (fly ash, mineral powder and silica fume) and hydration heat inhibitor to significantly reduce the hydration heat and ensure high compressive strength and good durability. The low heat cement 72.5 to 79% is the main component of the low heat high strength cementitious material, which can reduce the hydration heat by reducing the content of tricalcium aluminate and increasing the content of dicalcium silicate. The fly ash 9 to 11% and the mineral powder 5 to 9% as the mineral admixture can effectively reduce the hydration rate and hydration heat of the low heat high strength cementitious material and increase the later strength of the low heat high strength cementitious material. The silica fume 1 to 5% as the micro-filler can fill the pores in the low heat high strength cementitious material, further improve the density and strength of the low heat high strength cementitious material and improve the microstructure of the low heat high strength cementitious material. The hydration heat inhibitor comprises starch, polymer and organic acid derivative, which can delay the hydration reaction rate of the low heat high strength cementitious material by the synergistic effect of the components of starch, organic acid derivative and polymer, and has the effects of long-acting slow release and effective inhibition of hydration heat.

[0028] The low-heat high-strength cementitious material in the low-heat cement concrete provided by the application comprises a hydration heat inhibitor, and the hydration heat inhibitor comprises starch, a polymer and an organic acid derivative; the starch in the hydration heat inhibitor interacts with the surface of cement particles through its molecular chain, adsorbs and inhibits the dissolution of tricalcium silicate, delays the cement hydration reaction, reduces the early hydration heat release peak; the organic acid derivative in the hydration heat inhibitor delays the formation of ettringite, inhibits the nucleation of hydrated calcium silicate, interferes with the nucleation and growth of the hydration product, slows down the cement hydration reaction rate; the polymer in the hydration heat inhibitor reacts with the cement hydration product through the functional groups on its molecular chain in the cement hydration, further regulates the progress and heat release of the cement hydration reaction. Meanwhile, the three components of the hydration heat inhibitor can interact with each other; the starch can wrap the organic acid derivative, so that the organic acid derivative is slowly released in the cement hydration process, continuously inhibits the hydration reaction and reduces the hydration heat release; the starch and the polymer ensure the uniform distribution of the organic acid derivative in the low-heat high-strength cementitious material through the slow-release and dispersion effect, so as to slow down the hydration reaction rate.

[0029] The above description is only a summary of the technical scheme of the application, in order to more clearly understand the technical means of the application, and the content of the description can be implemented. The following will be described in detail with the preferred embodiments of the application. DETAILED DESCRIPTION

[0030] In order to further illustrate the technical means and effects adopted by the application to achieve the predetermined application purpose, the following will be described in detail with the specific implementation, structure, characteristics and effects of a low-heat high-strength cementitious material, a preparation method thereof and application thereof according to the preferred embodiments of the application.

[0031] The low-heat high-strength cementitious material comprises, in percentage by weight, 72.5-79% of low-heat cement, 9-11% of fly ash, 5-9% of mineral powder, 1-5% of silica fume and 1.1-2.8% of hydration heat inhibitor. The hydration heat inhibitor comprises starch, polymer and organic acid derivative. The low-heat high-strength cementitious material comprises 72.5-79% of low-heat cement, 9-11% of fly ash, 5-9% of mineral powder, 1-5% of silica fume and 1.1-2.8% of hydration heat inhibitor. The low-heat cement 72.5-79% is the main component of the low-heat high-strength cementitious material, which can reduce the hydration heat by reducing the content of tricalcium aluminate and increasing the content of dicalcium silicate. The fly ash 9-11% and the mineral powder 5-9% can effectively reduce the hydration rate and hydration heat of the low-heat high-strength cementitious material and improve the later strength of the low-heat high-strength cementitious material. The silica fume 1-5% can fill the pores in the low-heat high-strength cementitious material, further improve the density and strength of the low-heat high-strength cementitious material, and improve the microstructure of the low-heat high-strength cementitious material. The hydration heat inhibitor comprises starch, polymer and organic acid derivative, which can delay the cement hydration reaction rate in the low-heat high-strength cementitious material by the synergistic effect of the components of starch, organic acid derivative and polymer, has the effects of long-acting release and effective inhibition of hydration heat. The low-heat high-strength cementitious material can balance the low hydration heat and high strength by the synergistic effect of 72.5-79% of low-heat cement, 9-11% of fly ash, 5-9% of mineral powder, 1-5% of silica fume and 1.1-2.8% of hydration heat inhibitor (starch, polymer and organic acid derivative).

[0032] According to the present application, the weight ratio of starch, organic acid derivative and polymer in the hydration heat inhibitor is 1:2.7-6:1.7-3.5, which can ensure the stability and long-acting of the hydration heat inhibitor, can ensure that the organic acid derivative effectively inhibits the hydration reaction, while avoiding the slow strength development of the low-heat high-strength cementitious material caused by excessive use, can ensure that the polymer optimizes the performance of the inhibitor, while avoiding the cost increase caused by excessive use, ensures that the inhibitor has the characteristics of long-acting release, effective inhibition of hydration heat and good dispersibility, and at the same time, the economy and practicability are taken into account. The organic acid derivative is selected from one or more of citric acid, maleic anhydride and tartaric acid, which can combine with calcium ions in cement to delay the hydration reaction rate and is the key active ingredient for inhibiting the hydration reaction. The starch is selected from one or more of waxy corn starch, cassava starch and wheat starch, which can wrap the organic acid derivative, slowly release the active ingredient, prolong the hydration heat inhibition effect, and the starch is derived from natural plants and has degradability, which meets the green and environmental protection requirements. The polymer is selected from any one of polyvinyl alcohol, polycarboxylic acid superplasticizer and polyacrylamide, which can improve the dispersibility and mechanical strength of the hydration heat inhibitor.

[0033] According to one embodiment of the present invention, the fly ash is Grade I fly ash, which has high activity and low carbon content, and can better improve the workability and durability of low-heat high-strength cementitious materials.

[0034] According to one embodiment of the present invention, the mineral powder is S95 grade mineral powder, which has high activity and fineness, and can improve the strength and durability of low-heat high-strength cementitious materials.

[0035] According to one embodiment of the present invention, the silica fume is undisturbed silica fume, which can better fill the pores in low-heat, high-strength cementitious materials, thereby improving density and strength.

[0036] A second aspect of this invention provides a method for preparing a low-heat, high-strength cementitious material, comprising the following steps:

[0037] (1) Mix 72.5-79 wt% low-heat cement, 9-11 wt% fly ash, 5-9 wt% mineral powder and 1-5 wt% silica fume and stir evenly to obtain a pre-cemented material;

[0038] (2) Mix 1.1 to 2.8 wt% of the heat of hydration inhibitor and the pregel material and stir evenly to obtain a low-heat, high-strength gel material; the heat of hydration inhibitor contains starch, polymer and organic acid derivatives.

[0039] The preparation method of the present invention first mixes and stirs low-heat cement, fly ash, mineral powder and silica fume to obtain a pre-cementing material, and then mixes and stirs it with a heat of hydration inhibitor (starch, polymer and organic acid derivative) to obtain a low-heat high-strength cementitious material. The preparation method is simple and the process can be directly integrated into the subsequent preparation process of low-heat cement concrete without additional equipment, and has high industrial application value.

[0040] According to the present invention, the preparation method of the hydration heat inhibitor includes the following steps:

[0041] S1. Add starch, inorganic acid solution or hydrolytic enzyme to water to hydrolyze and form a pregel solution;

[0042] S2. The organic acid derivative and the pregel solution are mixed and reacted to obtain a reaction mixture;

[0043] S3. The reaction mixture and the polymer are mixed and reacted to obtain a gel solution;

[0044] S4. The gel solution is fixed to obtain a hydration heat inhibitor.

[0045] First, starch, an inorganic acid solution, or a hydrolytic enzyme is added to water and hydrolyzed under stirring to form a pregel solution. The inorganic acid solution or hydrolytic enzyme catalyzes partial hydrolysis of the starch chains, generating a pregel solution containing low-molecular-weight dextrin or glucose units. Second, an organic acid derivative is mixed with the pregel solution, reacting to form a reaction mixture with starch-organic acid covalent bonds. The carboxylic acid groups of the organic acid derivative condense with the starch hydroxyl groups. Third, the polymer and the reaction mixture are stirred and mixed, reacting to form a gel solution with a cross-linked network structure. Finally, a stable hydration heat inhibitor is obtained through shaping. The preparation method is simple, low-cost, and environmentally friendly, facilitating large-scale application.

[0046] According to one embodiment of the present invention, in the preparation method of the hydration heat inhibitor, in step S3, the reaction mixture and the polymer are mixed at 80-90°C, kept at 40-45°C for 10-30 minutes, and then a crosslinking agent is added to react and obtain a gel solution with a crosslinked network structure. The crosslinking agent can be selected by those skilled in the art as needed, and the present invention does not impose any particular limitation; for example, it can be glutaraldehyde or a redox initiation system.

[0047] According to one embodiment of the present invention, in the preparation method of the hydration heat inhibitor, in step S3, the reaction mixture and the polymer are mixed at 80-90°C, and then a gel solution with a cross-linked network structure is obtained by a freeze-thaw cycle reaction.

[0048] According to one embodiment of the present invention, in the preparation method of the heat of hydration inhibitor, in step S4, the shaping method is freeze-drying or hot-pressing. This results in a heat of hydration inhibitor with more stable performance.

[0049] A third aspect of this invention provides a low-heat-of-hydration cement concrete, comprising a low-heat-of-high-strength cementitious material, sand, gravel, and water, wherein the low-heat-of-high-strength cementitious material is as described above. Sand and gravel serve as aggregates, and water serves as a reaction medium, together with the low-heat-of-high-strength cementitious material to form the low-heat-of-hydration cement concrete.

[0050] The low-heat, high-strength cementitious material in low-heat cement concrete of this invention includes a hydration heat inhibitor. The hydration heat inhibitor comprises starch, a polymer, and an organic acid derivative. The starch in the hydration heat inhibitor interacts with the surface of cement particles through its molecular chains, adsorbing and inhibiting the dissolution of tricalcium silicate, thus delaying the cement hydration reaction and reducing the early hydration exothermic peak. The organic acid derivative in the hydration heat inhibitor delays the formation of ettringite, inhibits the nucleation of hydrated calcium silicate, interferes with the nucleation and growth of hydration products, and slows down the cement hydration reaction rate. The polymer in the hydration heat inhibitor reacts with cement hydration products through the functional groups on its molecular chains during cement hydration, further regulating the process of the cement hydration reaction and heat release. Simultaneously, the three components of the hydration heat inhibitor interact with each other. Starch can encapsulate the organic acid derivative, causing it to be slowly released during cement hydration, continuously inhibiting the hydration reaction and reducing the heat release. The starch and polymer, through slow release and dispersion, ensure that the organic acid derivative is uniformly distributed in the low-heat, high-strength cementitious material, avoiding excessively rapid or slow local reactions.

[0051] According to the present invention, the weight ratio of water to the low-heat, high-strength cementitious material is 0.35 to 0.40. Maintaining a water-cement ratio of 0.35 to 0.40 ensures that the low-heat cement concrete exhibits high strength and durability.

[0052] The fourth aspect of this invention proposes the application of low-heat hydration cement concrete as described above in large-volume concrete structures, high-temperature resistant concrete structures, or ultra-high-performance concrete structures.

[0053] The application of low-heat cement concrete, which includes low-heat, high-strength cementitious materials, in large-volume concrete structures, high-temperature resistant concrete structures, or ultra-high-performance concrete structures can achieve a balance between low heat of hydration and high strength. It can reduce heat of hydration without affecting strength development and has great potential for industrial applications.

[0054] The present invention will be further described below with reference to specific embodiments, but this should not be construed as a limitation on the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention still fall within the scope of protection of the present invention.

[0055] Unless otherwise specified, all materials and reagents mentioned below are commercially available products well known to those skilled in the art; unless otherwise specified, all methods described are methods known in the art. Unless otherwise defined, the technical or scientific terms used should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0056] The low-heat cement used in the following examples is commercially available low-heat silicate cement, the fly ash is grade I fly ash, the mineral powder is grade S95 mineral powder, and the silica fume is unprocessed silica fume.

[0057] Example 1

[0058] This invention is used to illustrate the preparation of low-heat, high-strength cementitious materials and the preparation of low-heat cement concrete.

[0059] (1) Preparation of low-heat high-strength cementitious materials

[0060] Mix 790g of low-heat cement, 110g of fly ash, 60g of mineral powder, and 30g of silica fume and stir evenly to obtain a pre-cementing material. Then add 18g of hydration heat inhibitor (starch, polymer, and organic acid derivative) to the pre-cementing material, mix and stir evenly to obtain a low-heat high-strength cementitious material.

[0061] (2) Preparation of low-heat cement concrete

[0062] Mix 8% water, 21% sand, 50% gravel and 21% of the low-heat high-strength cementitious material prepared in (1) and stir evenly. The weight ratio of water to low-heat high-strength cementitious material is 0.38, and low-heat cement concrete is obtained.

[0063] Example 2

[0064] This invention is used to illustrate the preparation of low-heat, high-strength cementitious materials and low-heat cement concrete.

[0065] (1) Preparation of low-heat high-strength cementitious materials

[0066] 790g of low-heat cement, 110g of fly ash, 50g of mineral powder, and 40g of silica fume were mixed and stirred evenly to obtain a pre-cementing material. Then, 22g of a hydration heat inhibitor was added to the pre-cementing material and mixed evenly to obtain a low-heat high-strength cementitious material. The preparation process of the hydration heat inhibitor was as follows: 3g of cassava starch was added to 200mL of deionized water and stirred at 90℃ for 1h. Then, 0.08mol / L sulfuric acid solution was added, and hydrolysis was carried out for 1.5h. At 75℃, 12g of maleic anhydride was added to the starch solution, and the reaction was carried out for 2.5h. 7g of polyacrylamide was added, and the mixture was stirred and mixed at 80℃ for 1.5h. The temperature was lowered to 40℃, and a redox initiation system was added to carry out a cross-linking reaction for 1.5h. The product was then shaped using hot pressing to obtain the hydration heat inhibitor.

[0067] (2) Preparation of low-heat cement concrete

[0068] Mix 8% water, 21% sand, 50% gravel and 21% of the low-heat high-strength cementitious material prepared in (1) and stir evenly. The weight ratio of water to low-heat high-strength cementitious material is 0.38, and low-heat cement concrete is obtained.

[0069] Example 3

[0070] This invention is used to illustrate the preparation of low-heat, high-strength cementitious materials and the preparation of low-heat cement concrete.

[0071] (1) Preparation of low-heat high-strength cementitious materials

[0072] 790g of low-heat cement, 90g of fly ash, 80g of mineral powder, and 20g of silica fume were mixed and stirred evenly to obtain a pre-cementing material. Then, 15.5g of a hydration heat inhibitor was added to the pre-cementing material and mixed evenly to obtain a low-heat high-strength cementitious material. The preparation process of the hydration heat inhibitor was as follows: 2.5g of wheat starch was added to 200mL of deionized water and stirred at 90℃ for 1h. Then, 0.08mol / L sulfuric acid solution was added, and hydrolysis was carried out for 1.5h. At 75℃, 8g of tartaric acid was added to the starch solution, and the reaction was carried out for 2.5h. 5g of polyvinyl alcohol was added, and the mixture was stirred and mixed at 80℃ for 1.5h. The temperature was lowered to 40℃, and glutaraldehyde, a crosslinking agent, was added for a crosslinking reaction for 1.5h. The product was then shaped using hot pressing to obtain the hydration heat inhibitor.

[0073] (2) Preparation of low-heat cement concrete

[0074] 7% water, 23% sand, 50% gravel and 20% of the low-heat high-strength cementitious material prepared in (1) were mixed and stirred evenly. The weight ratio of water to low-heat high-strength cementitious material was 0.35, resulting in low-hydration heat cement concrete.

[0075] Example 4

[0076] This invention is used to illustrate the preparation of low-heat, high-strength cementitious materials and the preparation of low-heat cement concrete.

[0077] (1) Preparation of low-heat high-strength cementitious materials

[0078] 790g of low-heat cement, 100g of fly ash, 70g of mineral powder, and 30g of silica fume were mixed and stirred evenly to obtain a pre-cementing material. Then, 18g of a hydration heat inhibitor was added to the pre-cementing material and mixed evenly to obtain a low-heat high-strength cementitious material. The preparation process of the hydration heat inhibitor was as follows: 2.0g of glutinous corn starch was added to 200mL of deionized water and stirred at 90℃ for 1h. Then, 0.08mol / L sulfuric acid solution was added, and hydrolysis was carried out for 1.5h. At 75℃, 10g of citric acid was added to the starch solution, and the reaction was carried out for 2.5h. 6g of polyvinyl alcohol was added, and the mixture was stirred and mixed at 80℃ for 1.5h. The temperature was lowered to 40℃, and glutaraldehyde, a crosslinking agent, was added for a crosslinking reaction for 1.5h. The product was then shaped using hot pressing to obtain the hydration heat inhibitor.

[0079] (2) Preparation of low-heat cement concrete

[0080] Mix 8% water, 22% sand, 50% gravel and 20% of the low-heat high-strength cementitious material prepared in (1) and stir evenly. The weight ratio of water to low-heat high-strength cementitious material is 0.40 to obtain low-hydration heat cement concrete.

[0081] Example 5

[0082] This invention is used to illustrate the preparation of low-heat, high-strength cementitious materials and the preparation of low-heat cement concrete.

[0083] (1) Preparation of low-heat high-strength cementitious materials

[0084] 790g of low-heat cement, 110g of fly ash, 60g of mineral powder, and 40g of silica fume were mixed and stirred evenly to obtain a pre-cementing material. Then, 22g of a hydration heat inhibitor was added to the pre-cementing material and mixed evenly to obtain a low-heat high-strength cementitious material. The preparation process of the hydration heat inhibitor was as follows: 3.0g of cassava starch was added to 200mL of deionized water and stirred at 90℃ for 1h. Then, 0.08mol / L sulfuric acid solution was added, and hydrolysis was carried out for 1.5h. At 75℃, 12g of tartaric acid was added to the starch solution, and the reaction was carried out for 2.5h. 7g of polycarboxylate superplasticizer was added, and the mixture was stirred and mixed at 80℃ for 1.5h. The temperature was lowered to 40℃, and glutaraldehyde, a crosslinking agent, was added for a crosslinking reaction for 1.5h. The product was then freeze-dried to obtain the hydration heat inhibitor.

[0085] (2) Preparation of low-heat cement concrete

[0086] Mix 8% water, 20% sand, 50% gravel and 22% of the low-heat high-strength cementitious material prepared in (1) and stir evenly. The weight ratio of water to low-heat high-strength cementitious material is 0.36, and low-heat cement concrete is obtained.

[0087] Example 6

[0088] This invention is used to illustrate the preparation of low-heat, high-strength cementitious materials and the preparation of low-heat cement concrete.

[0089] (1) Preparation of low-heat high-strength cementitious materials

[0090] 790g of low-heat cement, 90g of fly ash, 80g of mineral powder, and 20g of silica fume were mixed and stirred evenly to obtain a pre-cementing material. Then, 15.5g of a hydration heat inhibitor was added to the pre-cementing material and mixed evenly to obtain a low-heat high-strength cementitious material. The preparation process of the hydration heat inhibitor was as follows: 2.5g of wheat starch was added to 200mL of deionized water and stirred at 90℃ for 1h. Then, 0.08mol / L sulfuric acid solution was added, and hydrolysis was carried out for 1.5h. At 75℃, 8g of maleic anhydride was added to the starch solution, and the reaction was carried out for 2.5h. 5g of polyacrylamide was added, and the mixture was stirred and mixed at 80℃ for 1.5h. The temperature was lowered to 40℃, and glutaraldehyde, a crosslinking agent, was added for a crosslinking reaction for 1.5h. The product was then freeze-dried to obtain the hydration heat inhibitor.

[0091] (2) Preparation of low-heat cement concrete

[0092] Mix 8% water, 21% sand, 50% gravel and 21% of the low-heat high-strength cementitious material prepared in (1) and stir evenly. The weight ratio of water to low-heat high-strength cementitious material is 0.38, and low-heat cement concrete is obtained.

[0093] Example 7

[0094] This invention is used to illustrate the preparation of low-heat, high-strength cementitious materials and the preparation of low-heat cement concrete.

[0095] (1) Preparation of low-heat high-strength cementitious materials

[0096] 790g of low-heat cement, 100g of fly ash, 60g of mineral powder, and 30g of silica fume were mixed and stirred evenly to obtain a pre-cementing material. Then, 18g of a hydration heat inhibitor was added to the pre-cementing material and mixed evenly to obtain a low-heat high-strength cementitious material. The preparation process of the hydration heat inhibitor was as follows: 2.0g of glutinous corn starch was added to 200mL of deionized water and stirred at 90℃ for 1h. Then, 0.08mol / L sulfuric acid solution was added, and hydrolysis was carried out for 1.5h. At 75℃, 10g of tartaric acid was added to the starch solution, and the reaction was carried out for 2.5h. 6g of polycarboxylate superplasticizer was added, and the mixture was stirred and mixed at 80℃ for 1.5h. The temperature was lowered to 40℃, and glutaraldehyde, a crosslinking agent, was added for a crosslinking reaction for 1.5h. The product was then freeze-dried to obtain the hydration heat inhibitor.

[0097] (2) Preparation of low-heat cement concrete

[0098] Mix 8% water, 21% sand, 50% gravel and 21% of the low-heat high-strength cementitious material prepared in (1) and stir evenly. The weight ratio of water to low-heat high-strength cementitious material is 0.38, and low-heat cement concrete is obtained.

[0099] Comparative Example 1

[0100] Comparative Example 1 is ordinary silicate cement concrete.

[0101] Comparative Example 2

[0102] This is used to illustrate the preparation of low-heat, high-strength cementitious materials and the preparation of cement concrete.

[0103] (1) Preparation of low-heat high-strength cementitious materials

[0104] Mix 790g of low-heat cement, 100g of fly ash, 60g of mineral powder, and 30g of silica fume and stir evenly to obtain a pre-cementing material. Then add 8g of hydration heat inhibitor (starch, polymer, and organic acid derivative) to the pre-cementing material, mix and stir evenly to obtain a low-heat high-strength cementitious material.

[0105] (2) Preparation of cement concrete

[0106] 8% water, 21% sand, 50% gravel and 21% of the low-heat high-strength cementitious material prepared in (1) were mixed and stirred evenly. The weight ratio of water to low-heat high-strength cementitious material was 0.38, and cement concrete was obtained.

[0107] The cement concrete obtained in Examples 1-7 and Comparative Examples 1-2 were subjected to hydration heat and compressive strength tests, as shown in Table 1. The 7-day hydration heat reduction peak refers to the hydration heat reduction peak calculated on the 7th day of hydration heat release, by comparing the hydration heat curves of the low hydration heat cement concrete prepared in this invention with those of the ordinary silicate cement concrete in Comparative Example 1.

[0108] Table 1 shows the peak reduction in compressive strength and 7-day heat of hydration for Examples 1-7 and Comparative Examples 1-2.

[0109]

[0110]

[0111] As can be seen from the data of the above embodiments and comparative examples, the low-heat high-strength cementitious material of the present invention has high hydration heat inhibition efficiency and does not affect the strength development of concrete. The hydration heat at 7 days is reduced by at least 50% compared with ordinary silicate cement concrete, and the compressive strength at 28 days exceeds 60MPa. Furthermore, the preparation process of the low-heat high-strength cementitious material of the present invention is simple, the cost is low, and it is environmentally friendly, and it has the potential for large-scale promotion and application.

[0112] The technical features in the claims and / or specification of this invention can be combined, and the combination is not limited to the combinations obtained through reference in the claims. Technical solutions obtained by combining the claims and / or technical features are also within the scope of protection of this invention.

[0113] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A low-heat, high-strength cementitious material, characterized in that, On a weight percentage basis, it includes: Low-heat cement 72.5-79%, fly ash 9-11%, mineral powder 5-9%, silica fume 1-5%, and hydration heat inhibitor 1.1-2.8%; The hydration heat inhibitor comprises starch, a polymer, and an organic acid derivative; the organic acid derivative is selected from one or more of citric acid, maleic anhydride, and tartaric acid; the polymer is selected from any one of polyvinyl alcohol, polycarboxylic acid superplasticizer, and polyacrylamide; the weight ratio of starch, the organic acid derivative, and the polymer is 1:2.7~6:1.7~3.

5.

2. The low-heat, high-strength cementitious material according to claim 1, characterized in that, The starch is selected from one or more of glutinous corn starch, tapioca starch, and wheat starch.

3. A method for preparing a low-heat, high-strength cementitious material according to claim 1 or 2, characterized in that, It includes the following steps: (1) Mix 72.5~79wt% of low-heat cement, 9~11wt% of fly ash, 5~9wt% of mineral powder and 1~5wt% of silica fume and stir evenly to obtain pre-cemented material; (2) Mix 1.1~2.8wt% of the heat of hydration inhibitor and the pregel material and stir evenly to obtain a low-heat, high-strength gel material; the heat of hydration inhibitor contains starch, polymer and organic acid derivatives.

4. The preparation method according to claim 3, characterized in that, The preparation method of the hydration heat inhibitor includes the following steps: S1. Add starch, inorganic acid solution or hydrolytic enzyme to water to hydrolyze and form a pregel solution; S2. The organic acid derivative and the pregel solution are mixed and reacted to obtain a reaction mixture; S3. The reaction mixture and the polymer are mixed and reacted to obtain a gel solution; S4. The gel solution is fixed to obtain a hydration heat inhibitor.

5. A low-heat cement concrete, comprising low-heat, high-strength cementitious materials, sand, aggregate, and water, characterized in that, The low-heat high-strength cementitious material is the low-heat high-strength cementitious material as described in claim 1 or 2.

6. The cement concrete according to claim 5, characterized in that, The weight ratio of water to the low-heat, high-strength cementitious material is 0.35 to 0.

40.

7. The application of the low heat of hydration cement concrete as described in claim 5 in large-volume concrete structures, high-temperature resistant concrete structures, or ultra-high performance concrete structures.

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