Sustained release hydration heat inhibitors, methods of making and using the same

Abstract

The present application relates to a kind of sustained-release hydration heat inhibitors and its preparation method and application, the sustained-release hydration heat inhibitor includes: starch, organic acid derivative and polymer;The weight ratio of the starch, the organic acid derivative and the polymer is 8.9~30:1.3~4.0:1.The technical problem to be solved is how to provide a kind of sustained-release hydration heat inhibitor with high cement-based material strength, high hydration heat inhibition efficiency and low dosage.The sustained-release hydration heat inhibitor, by the synergistic effect of each component of starch, organic acid derivative and polymer, has the effect of long-acting sustained-release, effectively inhibits hydration heat.By preparing starch, organic acid derivative and polymer into sustained-release hydration heat inhibitor, the method is simple, environment-friendly, and conducive to large-scale popularization and application.The sustained-release hydration heat inhibitor of the present application can effectively reduce the hydration heat of cement during cement hydration, and the dosage is low, which does not affect the later strength of cement-based material.

Description

Technical Field

[0001] This invention relates to the field of cement admixture technology, and in particular to a slow-release heat of hydration inhibitor, its preparation method, and its application. Background Technology

[0002] Cement releases a lot of heat during hydration, especially in large-volume cement-based material structures. Excessive internal temperature can lead to the accumulation of thermal stress, which in turn can cause volume deformation and structural cracking, seriously affecting the durability and safety of cement-based material structures.

[0003] Currently, hydration heat inhibitors for cement mainly include chemical retarders, phase change materials (PCMs), and mineral admixtures. Chemical retarders, such as phosphates and lignin sulfonates, reduce temperature rise by slowing down the cement hydration reaction rate, but they can easily lead to later-stage strength loss in cement-based concrete. PCMs, such as paraffin wax and fatty acid esters, absorb hydration heat through latent heat of phase change, but they suffer from problems such as leakage and poor compatibility with cement-based materials, and their effect on inhibiting temperature rise is limited. Mineral admixtures, such as fly ash and slag, reduce hydration heat by replacing part of the cement, but high dosages can affect the early strength and workability of cement-based concrete. Existing hydration heat inhibitors have low efficiency in inhibiting the hydration heat of cement-based materials, require high dosages, and lead to strength loss in cement-based materials. Furthermore, some hydration heat inhibitors have complex preparation processes and high costs, making large-scale application difficult. Summary of the Invention

[0004] The main objective of this invention is to provide a slow-release hydration heat inhibitor, its preparation method, and its application. The technical problem to be solved is how to provide a slow-release hydration heat inhibitor that results in high strength, high hydration heat inhibition efficiency, and low dosage for cement-based materials. The slow-release hydration heat inhibitor of this invention, through the synergistic effect of starch, organic acid derivatives, and polymer components, exhibits a long-lasting, slow-release effect and effectively inhibits hydration heat. The method for preparing the slow-release hydration heat inhibitor from starch, organic acid derivatives, and polymers is simple, low-cost, and environmentally friendly, facilitating large-scale application. The slow-release hydration heat inhibitor of this invention can effectively inhibit the cement hydration reaction rate during cement hydration, effectively regulate the progress and heat release of the cement hydration reaction, effectively reduce the heat of hydration, and its low dosage does not affect the later-stage strength of cement-based materials.

[0005] The objective of this invention and the technical problem it solves are achieved by the following technical solution. A sustained-release heat of hydration inhibitor according to this invention comprises:

[0006] Starch, organic acid derivatives, and polymers;

[0007] The weight ratio of the starch, the organic acid derivative, and the polymer is 8.9–30:1.3–4.0:1.

[0008] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0009] Preferably, in the aforementioned slow-release hydration heat inhibitor, the starch is selected from one or more of glutinous corn starch, tapioca starch, and wheat starch.

[0010] Preferably, in the aforementioned sustained-release heat of hydration inhibitor, the organic acid derivative is selected from one or more of citric acid, maleic anhydride, and tartaric acid.

[0011] Preferably, in the aforementioned slow-release heat of hydration inhibitor, the polymer is selected from any one of polyvinyl alcohol, polycarboxylic acid superplasticizer, and polyacrylamide.

[0012] The objective of this invention and the technical problem it solves are achieved by the following technical solution. A method for preparing a sustained-release hydration heat inhibitor according to this invention includes the following steps:

[0013] S1. Add starch, inorganic acid solution or hydrolytic enzyme to water to hydrolyze and form a pregel solution;

[0014] S2. The organic acid derivative and the pregel solution are mixed and reacted to obtain a reaction mixture;

[0015] S3. The reaction mixture and the polymer are mixed and reacted to obtain a gel solution;

[0016] S4. The gel solution is fixed to obtain a sustained-release hydration heat inhibitor.

[0017] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0018] Preferably, in the aforementioned preparation method, in step S1, the concentration of the inorganic acid solution is 0.08–0.1 mol / L.

[0019] Preferably, in the aforementioned preparation method, the hydrolysis temperature in step S1 is 55–90°C.

[0020] Preferably, in the aforementioned preparation method, the reaction temperature in step S2 is 70–90°C.

[0021] Preferably, in the aforementioned preparation method, the shaping method in step S4 is freeze drying or hot pressing.

[0022] Preferably, in the aforementioned preparation method, in step S3, the reaction mixture and the polymer are mixed and kept at 40-45°C, and then a crosslinking agent is added to react and obtain a gel solution; the mixing temperature is 80-90°C.

[0023] Preferably, in the aforementioned preparation method, in step S3, the reaction mixture and the polymer are mixed and then reacted through a freeze-thaw cycle to obtain a gel solution; the mixing temperature is 80-90°C.

[0024] The objective of this invention and the technical problem it solves are achieved by the following technical solution. According to this invention, a slow-release heat of hydration inhibitor is used in cement-based materials, wherein the dosage of the slow-release heat of hydration inhibitor is 0.5-0.7% based on the total weight of the cement-based material.

[0025] By employing the above technical solution, the sustained-release hydration heat inhibitor, its preparation method, and its application proposed in this invention have at least the following advantages:

[0026] This invention proposes a slow-release hydration heat inhibitor comprising starch, an organic acid derivative, and a polymer. The organic acid derivative can react with calcium ions (Ca) in cement. 2 The polymer, through its binding with starch, directly participates in the inhibition of the hydration reaction, thereby slowing down the hydration rate of cement minerals and reducing the release of heat of hydration. It is a key active ingredient in inhibiting cement hydration. Simultaneously, the organic acid derivative can also regulate the pH value of the cement paste, further inhibiting the hydration reaction. By binding with starch, the organic acid derivative can be encapsulated, allowing for slow release during cement hydration and sustained inhibition of the hydration reaction. The polymer improves the dispersibility of the slow-release heat of hydration inhibitor in the cement paste, ensuring the uniform distribution of the active ingredient, the organic acid derivative. This enhances the mechanical strength and stability of the slow-release heat of hydration inhibitor, preventing premature decomposition in the cement paste. Furthermore, the polymer can form a composite structure with starch, optimizing the performance and stability of the slow-release heat of hydration inhibitor and further enhancing its slow-release effect. Additionally, the gel-like structure formed by starch in the cement paste increases the viscosity of the slow-release heat of hydration inhibitor, facilitating its uniform dispersion and prolonging the effect of inhibiting heat of hydration.

[0027] The present invention proposes a slow-release heat of hydration inhibitor in which the weight ratio of starch, organic acid derivative, and polymer is 8.9–30:1.3–4.0:1. This ensures the stability and long-lasting effect of the slow-release heat of hydration inhibitor, ensures that the organic acid derivative effectively inhibits the hydration reaction while avoiding excessive use of the organic acid derivative that would slow down the development of cement strength, and ensures that the polymer optimizes the performance of the slow-release heat of hydration inhibitor while avoiding excessive use of the polymer that would increase costs. This ensures that the slow-release heat of hydration inhibitor has the characteristics of long-lasting release, effective inhibition of heat of hydration, and good dispersibility, while also taking into account both economy and practicality. Starch, as the slow-release carrier, is derived from natural plants and is biodegradable, meeting green environmental protection requirements. The low dosage of polymer and organic acid derivative reduces the environmental impact.

[0028] This invention proposes a method for preparing a sustained-release heat of hydration inhibitor, which involves using starch, an organic acid derivative, and a polymer to prepare the inhibitor. First, starch, an inorganic acid solution, or a hydrolytic enzyme is added to water and hydrolyzed under stirring to form a pre-gel solution. Partial hydrolysis of the starch chains can be achieved under acidic or enzymatic catalysis, generating a pre-gel solution containing low-molecular-weight dextrin or glucose units. Second, the organic acid derivative is mixed with the pre-gel 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 sustained-release heat of hydration inhibitor is obtained through shaping. The preparation method is simple, low-cost, and environmentally friendly, facilitating large-scale application.

[0029] This invention proposes the application of a slow-release hydration heat inhibitor in cement-based materials. During cement hydration, organic acid derivatives react with cement minerals, slowing down the hydration rate and reducing the release of hydration heat. Starch encapsulates the organic acid derivatives, allowing them to be slowly released during cement hydration, continuously inhibiting the hydration reaction. Polymers improve dispersibility and enhance structural stability, ensuring the uniformity and persistence of the slow-release process. Through the slow-release and dispersing effects of starch and polymers, the organic acid derivatives are ensured to be uniformly distributed in the cement paste, avoiding excessively rapid or slow local reactions. Through the synergistic effect of these three components, the slow-release hydration heat inhibitor of this invention can effectively reduce the hydration heat of cement, making it suitable for large-volume cement-based material engineering and effectively preventing cracks in large-volume cement-based materials caused by temperature stress. In particular, based on the total weight of the cement-based material, the dosage of the slow-release hydration heat inhibitor is low, only 0.5% to 0.7% of the total weight of the cement-based material, resulting in a reduction of the peak hydration heat release of the cement-based material by more than 40%.

[0030] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Detailed Implementation

[0031] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description, in conjunction with preferred embodiments, describes the specific implementation, structure, features and effects of a sustained-release hydration heat inhibitor, its preparation method and application, based on the present invention.

[0032] The first aspect of this invention proposes a slow-release heat of hydration inhibitor, comprising starch, an organic acid derivative, and a polymer. The starch is selected from one or more of glutinous corn starch, tapioca starch, and wheat starch. Starch is derived from natural plants and is biodegradable and environmentally friendly. As a slow-release carrier, starch can encapsulate active ingredients such as the organic acid derivative and release them slowly during cement hydration. Furthermore, the gel-like structure formed in the cement paste increases the viscosity of the slow-release heat of hydration inhibitor, facilitating its uniform dispersion in the cement paste and thus prolonging the effect of inhibiting heat of hydration. The organic acid derivative is selected from one or more of citric acid, maleic anhydride, and tartaric acid, and can react with calcium ions (Ca) in cement. 2 The organic acid derivative directly participates in the inhibition of the hydration reaction, slowing down the hydration rate of cement minerals and thus reducing the release of heat of hydration. It can also regulate the pH of the cement paste, further influencing the hydration reaction. Through binding with starch, the organic acid derivative can be slowly released, continuously inhibiting the hydration reaction, making it a key active ingredient in inhibiting cement hydration. The polymer is selected from any one of polyvinyl alcohol, polycarboxylic acid superplasticizer, and polyacrylamide. It can improve the dispersibility of the slow-release hydration heat inhibitor in the cement paste, ensuring uniform distribution of the active ingredient (organic acid derivative). It can improve the mechanical strength and stability of the slow-release hydration heat inhibitor, preventing premature decomposition in the cement paste. Furthermore, it can form a complex structure with starch, optimizing the performance and stability of the slow-release hydration heat inhibitor and further enhancing its slow-release effect.

[0033] The slow-release heat of hydration inhibitor proposed in this invention ensures its stability and long-lasting effect by controlling the weight ratio of starch, organic acid derivatives, and polymer within the range of 8.9–30:1.3–4.0:1. This ensures the effective inhibition of hydration reactions by the organic acid derivatives, while avoiding excessive use that would slow down cement strength development. It also ensures the polymer optimizes the performance of the slow-release heat of hydration inhibitor, while avoiding excessive use that would increase costs. This results in a slow-release heat of hydration inhibitor with long-lasting effect, effective inhibition of heat of hydration, and good dispersibility, while also considering economic efficiency and practicality. The starch, derived from natural plants, is biodegradable and meets green environmental protection requirements. The low usage of polymers and organic acid derivatives reduces environmental impact.

[0034] A second aspect of this invention provides a method for preparing a sustained-release hydration heat inhibitor, comprising the following steps:

[0035] First, starch, an inorganic acid solution, or a hydrolytic enzyme is added to water and hydrolyzed under stirring to form a pregel solution. Partial hydrolysis of the starch chains can be achieved under acidic or enzymatic catalysis, 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 to form a gel solution with a cross-linked network structure. Finally, a stable sustained-release hydration heat inhibitor is obtained through shaping. The preparation method is simple, low-cost, and environmentally friendly, facilitating large-scale application.

[0036] According to one embodiment of the present invention, starch, an inorganic acid solution, or a hydrolytic enzyme is added to water and hydrolyzed under stirring to form a pregel solution, generating a pregel solution containing low molecular weight dextrin or glucose units. Catalysis with an inorganic acid solution at a concentration of 0.08–0.1 mol / L or enzyme catalysis can further effectively promote the partial hydrolysis of starch chains at 55–90°C to form a pregel solution. Mixing an organic acid derivative with the starch pregel solution forms a reaction mixture with starch-organic acid covalent bonds. At 70–90°C, the condensation of the carboxylic acid groups of the organic acid derivative with the starch hydroxyl groups can be further effectively promoted, while maintaining the fluidity of the reaction mixture. Stirring and mixing the polymer and the reaction mixture forms a gel solution with a cross-linked network structure. Mixing at 80–90°C further improves the diffusion ability of the polymer chains. Finally, a stable sustained-release heat of hydration inhibitor is obtained through shaping. Furthermore, a more stable sustained-release heat of hydration inhibitor can be obtained through freeze-drying or hot-press molding.

[0037] According to the present invention, 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.

[0038] According to the present invention, the inorganic acid solution can be selected by those skilled in the art as needed, for example, it can be a hydrochloric acid solution with a concentration of 0.1 mol / L, a sulfuric acid solution with a concentration of 0.08 mol / L, etc.

[0039] According to the present invention, when mixing organic acid derivatives and starch pregel solutions, N,N-dimethylpropanolamine can also be used as a solvent to enhance the compatibility between organic acid derivatives and starch pregel solutions.

[0040] According to the present invention, the polymer and the reaction mixture are stirred and mixed at 80-90°C and then kept at 40-45°C for 10-30 minutes to provide the optimal reaction temperature for the subsequent addition of the crosslinking agent. Then, the crosslinking agent is added and reacted to obtain a gel solution.

[0041] According to the present invention, the reaction mixture and the polymer are stirred and mixed at 80-90°C and then reacted by a freeze-thaw cycle to obtain a gel solution.

[0042] According to the present invention, before the gel solution is set, it can be post-modified as needed, and micro-control can be achieved by sol-gel method. Finally, it is set by freeze drying or hot pressing.

[0043] It should be noted that the freeze-drying conditions described in this invention can be selected by those skilled in the art as needed. For example, they can be: pre-freezing: maintaining at -60℃ for 4–6 hours; first drying: -35℃ to -25℃, vacuum degree 10–30 Pa, 24–36 hours; second drying: 25℃–30℃, vacuum degree 5–15 Pa, 8–12 hours. Therefore, the sustained-release heat of hydration inhibitor prepared by freeze-drying has a porosity of over 92% and a specific surface area of ​​not less than 17.3 m². 2 / g, which has the effect of effectively inhibiting the heat of hydration.

[0044] It should be noted that the hot pressing conditions described in this invention can be selected by those skilled in the art as needed. For example, they can be: preheating: 60°C for 30 minutes; pressurizing: 10-15 MPa for 1-2 hours; cooling: natural cooling to room temperature. Thus, the sustained-release heat of hydration inhibitor prepared by hot pressing has a structural density increased by more than 30% and a compressive strength increased by more than 25%, effectively suppressing heat of hydration and exhibiting high strength.

[0045] This invention proposes a method for preparing a slow-release hydration heat inhibitor. The inhibitor is prepared from starch, organic acid derivatives, and polymers. This slow-release hydration heat inhibitor effectively suppresses the cement hydration reaction rate during cement hydration, effectively regulates the process and heat release of the cement hydration reaction, and effectively reduces the heat of hydration. This slow-release hydration heat inhibitor features long-lasting slow release, effective inhibition of hydration heat, and good dispersibility, while also being economical and practical.

[0046] A third aspect of the present invention provides the application of a slow-release heat of hydration inhibitor in cement-based materials, wherein the dosage of the slow-release heat of hydration inhibitor is 0.5-0.7% based on the total weight of the cement-based materials.

[0047] The application of the slow-release hydration heat inhibitor prepared by this invention in cement-based materials demonstrates that the starch in the slow-release hydration heat inhibitor, through its molecular chain interaction with the surface of cement particles, adsorbs and inhibits the dissolution of tricalcium silicate, thus delaying the cement hydration reaction and reducing the early hydration exothermic peak. The organic acid derivative in the slow-release hydration heat inhibitor, by delaying 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 slow-release hydration heat inhibitor reacts with cement hydration products through the functional groups on its molecular chain during cement hydration, further regulating the process of the cement hydration reaction and heat release. Simultaneously, the three components of the slow-release hydration heat inhibitor interact with each other. The starch can encapsulate the organic acid derivative, allowing it to be slowly released during cement hydration, continuously inhibiting the hydration reaction and reducing the heat release of hydration. The starch and polymer, through slow release and dispersion, ensure the uniform distribution of the organic acid derivative in the cement paste, avoiding excessively rapid or slow local reactions.

[0048] Therefore, when the slow-release heat of hydration inhibitor prepared by this invention is applied to cement-based materials, the dosage of the slow-release heat of hydration inhibitor is 0.5-0.7% based on the total weight of the cement-based material, and the peak value of the heat of hydration of the cement-based material is reduced by more than 40%.

[0049] 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.

[0050] 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.

[0051] Example

[0052] Examples 1-7 illustrate how the addition of the slow-release heat of hydration inhibitor of the present invention reduces the peak value of the heat of hydration in cement paste and the 28-day compressive strength of cement mortar test blocks.

[0053] The reduction in the peak value of the maximum heat release rate of hydration was used as the criterion for judging the performance of the slow-release heat of hydration inhibitor of this invention. Under the same conditions, the greater the reduction in the peak value of the heat release rate, the better the performance of the slow-release heat of hydration inhibitor in inhibiting cement hydration. The test method was performed in accordance with Chapter 6, Isothermal Conductivity Calorimetry, of GB / T 12959-2024 "Method for Determination of Heat of Hydration of Cement".

[0054] In the embodiments of the present invention, 42.5 ordinary Portland cement is used, and the mix proportion and preparation of the cement mortar test blocks and the test method for compressive strength are performed in accordance with GB / T50081-2002 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete".

[0055] Example 1

[0056] 100g of glutinous corn starch was added to 1000mL of water, stirred at 55℃, and 0.1mol / L hydrochloric acid solution was slowly added dropwise. The hydrolysis reaction was carried out for 1 hour, and the starch was partially hydrolyzed to form a pregel solution. 15g of citric acid was added to the pregel solution, and the reaction was carried out at 90℃ for 2 hours to obtain a reaction mixture. After the reaction was completed, 5g of polycarboxylate superplasticizer was added, and the mixture was stirred and mixed at 90℃ for 1 hour. Then, the temperature was lowered to 45℃, and an appropriate amount of glutaraldehyde was added and reacted for 1 hour. The gel solution was then freeze-dried to obtain a hydration heat inhibitor.

[0057] The prepared inhibitor was added to cement at a dosage of 0.6%, and the test was conducted according to the experimental method. The results showed that the peak value of the maximum exothermic hydration rate was reduced by 66.0%, and the 28-day compressive strength reached 53.1 MPa.

[0058] Example 2

[0059] 120g of cassava starch was added to 1200mL of water, stirred at 90℃, and 0.08mol / L sulfuric acid solution was slowly added dropwise. The hydrolysis reaction was carried out for 1.5h, and the starch was partially hydrolyzed to form a pregel solution. 20g of maleic anhydride was added to the pregel solution, and the reaction was carried out at 70℃ for 2.5h to obtain a reaction mixture. After the reaction was completed, 8g of polyacrylamide was added, and the mixture was stirred and mixed at 80℃ for 1.5h. Then the temperature was lowered to 40℃, and a redox initiation system was added and reacted for 1.5h. The gel solution was then fixed by hot pressing to obtain a hydration heat inhibitor.

[0060] The inhibitor was added to cement at a dosage of 0.7%, and tests were conducted according to the experimental method. The results showed that the peak value of the maximum exothermic hydration rate was reduced by 68.6%, and the 28-day compressive strength reached 51.5 MPa.

[0061] Example 3

[0062] 80g of wheat starch was added to 800mL of water, stirred at 80℃, and an enzyme catalyst was added. The hydrolysis reaction was carried out for 50min, and the wheat starch was partially hydrolyzed to form a pregel solution. 12g of tartaric acid was added to the pregel solution, and the reaction was carried out at 85℃ for 1.5h to obtain a reaction mixture. After the reaction was completed, 6g of polyvinyl alcohol was added, and the mixture was stirred and mixed at 88℃ for 1h. Crosslinking was carried out through a freeze-thaw cycle. Finally, the gel solution was post-modified using the sol-gel method for micro-control, and then freeze-dried to obtain a hydration heat inhibitor.

[0063] When the inhibitor was added to cement at a dosage of 0.5%, tests showed that the peak hydration heat release rate was reduced by 46.1%, and the 28-day compressive strength reached 55.8 MPa.

[0064] Example 4

[0065] 150g of glutinous corn starch was added to 1500mL of deionized water, stirred at 85℃, and 0.1mol / L hydrochloric acid solution was slowly added dropwise. The hydrolysis reaction was carried out for 1 hour, and the glutinous corn starch was partially hydrolyzed to form a pregel solution. 18g of tartaric acid was added to the pregel solution, and the reaction was carried out at 85℃ for 2 hours. After the reaction was completed, 7g of polyvinyl alcohol was added, and the mixture was stirred and mixed at 90℃ for 1 hour. Then, the temperature was lowered to 50℃, and an appropriate amount of glutaraldehyde was added and reacted for 1 hour. The gel solution was then freeze-dried to obtain a hydration heat inhibitor.

[0066] The prepared inhibitor was added to cement at a dosage of 0.6%, and the test was conducted according to the experimental method. The results showed that the peak value of the maximum exothermic hydration rate was reduced by 55.2%, and the 28-day compressive strength reached 54.2 MPa.

[0067] Example 5

[0068] 130g of cassava starch was added to 1300mL of deionized water, stirred at 90℃, and 0.08mol / L sulfuric acid solution was slowly added dropwise. The hydrolysis reaction was carried out for 1.5h, and the cassava starch was partially hydrolyzed to form a pregel solution. 16g of citric acid was added to the pregel solution, and the reaction was carried out at 80℃ for 2h. After the reaction was completed, 9g of polyacrylamide was added, and the mixture was stirred and mixed at 85℃ for 1.5h. Then, the temperature was lowered to 40℃, and a redox initiation system was added to initiate the reaction for 1.5h. The gel solution was then freeze-dried to obtain a hydration heat inhibitor.

[0069] When the inhibitor was added to cement at a dosage of 0.7%, the test results showed that the peak value of the maximum heat release rate of hydration was reduced by 62.7%, and the 28-day compressive strength reached 53.1 MPa.

[0070] Example 6

[0071] 110g of wheat starch was added to 1100mL of deionized water, stirred at 90℃, and an enzyme catalyst was added. The hydrolysis reaction was carried out for 50min, and the starch was partially hydrolyzed to form a pregel solution. 14g of maleic anhydride was added to the pregel solution, and the reaction was carried out at 88℃ for 1.5h. After the reaction was completed, 6g of polycarboxylate superplasticizer was added, and the mixture was stirred and mixed at 88℃ for 1h. Then, the temperature was lowered to 45℃, and an appropriate amount of glutaraldehyde was added and reacted for 1h. The gel solution was then post-modified using the sol-gel method for micro-control, and finally freeze-dried to obtain a hydration heat inhibitor.

[0072] When the inhibitor was added to cement at a dosage of 0.6%, tests showed that the peak value of the maximum heat release rate of hydration was reduced by 65.0%, and the 28-day compressive strength reached 54.7 MPa.

[0073] Example 7

[0074] 140g of glutinous corn starch was added to 1400mL of deionized water, stirred at 90℃, and 0.08mol / L hydrochloric acid solution was slowly added dropwise. The hydrolysis reaction lasted for 1 hour, resulting in partial hydrolysis of the starch to form a pre-gel solution. 8g of citric acid and 8g of tartaric acid were added to the pre-gel solution, and the reaction was carried out at 85℃ for 2 hours. After the reaction was complete, 8g of polyvinyl alcohol was added, and the mixture was stirred and mixed at 90℃ for 1 hour. Crosslinking was performed through a freeze-thaw cycle. The gel solution underwent post-modification treatment using a sol-gel method for micro-control, and finally, freeze-drying was performed to obtain a hydration heat inhibitor. The slurry pH was 4.2. The release rate of organic acids was controlled by slow-release starch to avoid a sudden drop in pH that could disrupt the coagulation process.

[0075] The prepared inhibitor was added to cement at a dosage of 0.5%, and the test was conducted according to the experimental method. The results showed that the peak value of the maximum exothermic hydration rate was reduced by 52.3%, and the 28-day compressive strength reached 51.5 MPa.

[0076] Blank example

[0077] The blank example is the baseline group, without the addition of the slow-release heat of hydration inhibitor of the present invention.

[0078] Comparative Example 1

[0079] 100g of glutinous corn starch was added to 1000mL of water, stirred at 55℃, and 0.1mol / L hydrochloric acid solution was slowly added dropwise. The hydrolysis reaction was carried out for 1 hour to form a pre-gel solution. The pre-gel solution was cooled to 45℃ and freeze-dried to obtain the inhibitor.

[0080] The prepared inhibitor was added to cement at a dosage of 0.6%, and the test was conducted according to the experimental method. The results showed that the peak value of the maximum exothermic hydration rate was reduced by 40.2%, and the 28-day compressive strength reached 48.4 MPa.

[0081] Comparative Example 2

[0082] Dissolve 15g of citric acid in 1000mL of water to obtain a mixture. Cool to 45℃. Freeze-dry to fix the shape, and obtain the inhibitor.

[0083] The prepared inhibitor was added to cement at a dosage of 0.6%, and the test was conducted according to the experimental method. The results showed that the peak value of the maximum exothermic hydration rate was reduced by 33.5%, and the 28-day compressive strength reached 50.5 MPa.

[0084] Comparative Example 3

[0085] Add 5g of polycarboxylate superplasticizer to 1000mL of water and stir for 1 hour. Freeze-dry to set the mixture and obtain the inhibitor.

[0086] The prepared inhibitor was added to cement at a dosage of 0.6%, and the test was conducted according to the experimental method. The results showed that the peak value of the maximum exothermic hydration rate was reduced by 43.2%, and the 28-day compressive strength reached 47.3 MPa.

[0087] Table 1 shows the test data for the comparative and example cases.

[0088]

[0089] As can be seen from the data of the above embodiments and comparative examples, when the slow-release heat of hydration inhibitor of the present invention is applied in cement-based materials, the dosage of the slow-release heat of hydration inhibitor is 0.5-0.7% based on the total weight of the cement-based materials. The peak value of the heat of hydration of the cement-based materials is reduced by more than 40%, and its 28-day compressive strength increases normally, meeting engineering requirements and complying with relevant standards.

[0090] Therefore, the slow-release heat of hydration inhibitor of the present invention has high efficiency in inhibiting the heat of hydration of cement-based materials, low dosage, and does not affect the later strength of cement-based materials. At the same time, the preparation process of the slow-release heat of hydration inhibitor of the present invention is simple, low in cost, and environmentally friendly, and has the potential for large-scale promotion and application.

[0091] 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.

[0092] 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 sustained-release hydration heat inhibitor, characterized in that, It includes: Starch, organic acid derivatives, and polymers; The weight ratio of the starch, the organic acid derivative, and the polymer is 8.9~30:1.3~4.0:1; 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.

2. The inhibitor 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 sustained-release hydration heat inhibitor according to claim 1 or 2, characterized in that, It 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 sustained-release hydration heat inhibitor.

4. The preparation method according to claim 3, characterized in that, In step S1, the concentration of the inorganic acid solution is 0.08~0.1 mol / L; the hydrolysis temperature is 55~90℃.

5. The preparation method according to claim 3, characterized in that, In step S2, the reaction temperature is 70~90℃; In step S4, the shaping method is freeze drying or hot pressing.

6. The preparation method according to claim 3, characterized in that, In step S3, the reaction mixture and the polymer are mixed and kept at 40~45°C, and then a crosslinking agent is added to react and obtain a gel solution; the mixing temperature is 80~90°C.

7. The preparation method according to claim 3, characterized in that, In step S3, the reaction mixture and the polymer are mixed and then reacted through a freeze-thaw cycle to obtain a gel solution; the mixing temperature is 80~90℃.

8. The application of a slow-release heat of hydration inhibitor according to claim 1 or 2 in cement-based materials, characterized in that, Based on the total weight of the cement-based materials, the dosage of the slow-release heat of hydration inhibitor is 0.5~0.7%.

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