Hydration heat inhibitor for concrete and preparation method of hydration heat inhibitor

Abstract

The invention discloses a hydration heat inhibitor for concrete and a preparation method thereof, and belongs to the technical field of concrete admixtures. The hydration heat inhibitor for concrete is prepared from the following raw materials in parts by weight: 15 to 20 parts of modified nano cellulose, 3 to 5 parts of fluorine-containing surfactant, 8 to 12 parts of sodium gluconate, 0.5 to 1 part of ammonium pentaborate, 0.3 to 1 part of 1-hydroxyethylidene-1, 1-diphosphonic acid and 10 to 15 parts of temperature control material. According to the hydration heat inhibitor disclosed by the invention, the modified nano cellulose, the fluorine-containing surfactant and the temperature control material disodium hydrogen phosphate dodecahydrate in the hydration heat inhibitor are not simply superposed, but form a multi-level and multi-mechanism synergistic system; the fluorine-containing surfactant firstly delays the start of the reaction, after the reaction is started, the modified nanocellulose goes deep into the reaction to reduce the reaction rate, and the temperature control material absorbs and stores heat through phase change and forcefully presses the temperature rise. The hydration heat inhibitor provided by the invention can reduce the hydration heat release rate and significantly reduce the heat release under the condition of not influencing the working performance of concrete.

Description

Technical Field

[0001] This invention belongs to the field of concrete admixture technology, specifically relating to a water-based heat of hydration inhibitor for concrete and its preparation method. Background Technology

[0002] Concrete, as the most widely used building material in the world, is often used to cast various types of infrastructure, such as high-rise buildings, subways, bridges, dams, tunnels, airports, and other large-volume concrete projects. However, these projects are often plagued by cracking problems, which affects their service life. Temperature cracks are the most common, complex, and difficult-to-avoid form of cracking. Especially in the context of global warming and increasingly harsh construction environments, cracks are more likely to occur. Higher construction temperatures mean more rapid early hydration heat release, more concentrated heat, and a larger temperature difference between the inside and outside during the cooling phase. When the temperature stress exceeds the ultimate tensile strength of the concrete, temperature cracks will occur. To suppress the temperature rise caused by hydration heat, traditional techniques mainly include physical cooling methods such as using ice water mixing, pre-cooling aggregates, and adding large amounts of mineral admixtures (such as fly ash and mineral powder), as well as using chemical admixtures such as retarders and water-reducing agents to slow down the heat release process. However, these methods have certain limitations: physical cooling measures are complex to implement, costly, and have limited effectiveness; while conventional chemical admixtures can delay hydration, they are difficult to precisely control the peak temperature rise and may even affect the early strength development and long-term performance of concrete. In addition, single-mechanism control methods often cannot synergistically regulate the hydration heat release process at multiple scales.

[0003] In recent years, phase change materials (PCMs) have been explored for use in concrete temperature control, buffering temperature changes through endothermic-exothermic processes. However, common PCMs often suffer from poor compatibility with cement, easy leakage, and adverse effects on mechanical properties. Therefore, developing a hydration heat inhibitor that can synergistically suppress exothermic processes through multiple mechanisms without affecting the workability and long-term performance of concrete has become an urgent need in the industry. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a water-based heat of hydration inhibitor for concrete, which significantly suppresses heat release without affecting the workability of the concrete.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows: A water-based heat inhibitor for concrete is prepared from the following raw materials in parts by weight: 15-20 parts modified nanocellulose, 3-5 parts fluorinated surfactant, 8-12 parts sodium gluconate, 0.5-1 part ammonium pentaborate, 0.3-1 part hydroxyethylidene diphosphonic acid, and 10-15 parts temperature-controlling material.

[0006] Furthermore, the temperature-controlling material is disodium hydrogen phosphate dodecahydrate.

[0007] Furthermore, the fluorinated surfactant is one or both of sodium perfluorononenoxybenzenesulfonate and perfluorohexylethyl alcohol.

[0008] Furthermore, the preparation method of the modified nanocellulose is as follows: (1) Acid hydrolysis pretreatment: Disperse natural plant fibers in 64wt% sulfuric acid solution, maintain the reaction temperature at 40-45℃, mechanically stir for 60-120min, after the reaction is completed, add deionized water, centrifuge the mixture at 10000rpm for 15min, discard the supernatant and collect the precipitate; (2) The cellulose after acid hydrolysis in step (1) is redispersed in deionized water to prepare a 1wt% suspension. 2,2,6,6-Tetramethylpiperidine and sodium bromide are added. The system is placed in a 4℃ water bath and sodium hypochlorite is added dropwise. During the dropwise addition, the pH value of the reaction system is controlled to be maintained between 10 and 10.5. When the pH value of the reaction system remains stable within 5 minutes and no longer decreases, the oxidation reaction has been completed. (3) The oxidized product was purified and then circulated through a high-pressure homogenizer 5 times to obtain oxidized nanocellulose gel with a solid content of 1%; (4) Dilute the gel from step (3) with deionized water to a solid content of 0.8%, adjust the pH of the suspension to 4.0-5.0, add silane coupling agent KH-550 solution, transfer the mixture to a water bath at 60-70℃, stir and react for 4-6 hours under nitrogen protection, after the reaction is completed, cool to room temperature and dry to obtain the final product modified nanocellulose.

[0009] Furthermore, in step (1), the weight ratio of natural fiber to sulfuric acid solution is 1:8.

[0010] Furthermore, in step (2), the amount of 2,2,6,6-tetramethylpiperidine added is 0.1 mmol per gram of dry fiber, the amount of sodium bromide added is 1 mmol per gram of dry fiber, and the amount of sodium hypochlorite added is 5 mmol per gram of dry fiber.

[0011] Furthermore, the purification method in step (3) is dialysis or ultrafiltration.

[0012] Furthermore, in step (4), the amount of silane coupling agent KH-550 added is 10-25% of the dry fiber weight. The silane coupling agent KH-550 solution is prepared by pre-mixing ethanol and deionized water in a volume ratio of 8:2 and then adding KH-550 and stirring magnetically for 30 minutes.

[0013] Furthermore, the amount of solvent added to the silane coupling agent KH-550 is sufficient to completely dissolve KH-550.

[0014] A method for preparing a water-based heat inhibitor for concrete includes the following steps: First, modified nanocellulose is prepared. Then, the modified nanocellulose, fluorinated surfactant, sodium gluconate, ammonium pentaborate, hydroxyethylidene diphosphonic acid and temperature control material are put into a mixer until all components are fully mixed and homogeneous. The mixture is then discharged and packaged to obtain a water-cooling heat inhibitor for concrete.

[0015] The method of using the hydration heat inhibitor of the present invention is as follows: after the hydration heat inhibitor and the gel material are mixed evenly, it is added to the concrete, and the dosage is 0.5-1.0% of the gel material.

[0016] This invention incorporates modified nanocellulose. Firstly, the numerous functional groups on the surface of nanocellulose can adsorb Ca²⁺ ions generated during the initial stage of cement hydration, acting as heterogeneous nucleation sites to induce the orderly growth of hydration products on its surface. This controlled crystallization process generates a finer, more uniform microstructure, not only delaying concentrated heat release but also improving the final mechanical properties and durability of concrete. Secondly, the modification with the silane coupling agent KH-550 introduces hydrophobic organic segments, improving the compatibility of nanocellulose with the cement matrix. Simultaneously, its improved dispersibility reduces water consumption to some extent, indirectly lowering the heat of hydration. Modified nanocellulose effectively increases the viscosity of the paste, locking in moisture, preventing bleeding and segregation, significantly reducing plastic shrinkage in concrete, avoiding early cracking, and forming the first line of defense against cracking caused by heat of hydration. The network structure formed by modified nanocellulose physically hinders the contact between water and cement particles, delaying the hydration process to some extent, helping to smooth the hydration heat release peak, and producing a synergistic effect with other retarding components.

[0017] The fluorinated surfactant added in this invention significantly reduces the surface tension of the solution, lowering the surface tension of water to an extremely low level. This allows it to more effectively wet cement particles and form an extremely thin hydrophobic film on the surface of the cement particles. This film directly hinders the contact between water and cement particles, significantly delaying the onset of the hydration reaction. Furthermore, as a highly efficient surfactant, it introduces microbubbles, which act as "micro-buffer units" in the concrete. These bubbles can accommodate the water and paste that expand due to the heat of hydration, releasing internal pressure and reducing damage to the microstructure of the concrete. Simultaneously, the introduction of these bubbles also improves the slump retention and workability of fresh concrete.

[0018] This invention incorporates disodium hydrogen phosphate dodecahydrate, a temperature-controlling material that effectively absorbs heat without causing pollution. When the internal temperature of the concrete rises, this material undergoes a multi-step dehydration reaction, absorbing a large amount of latent heat of phase change, thereby inhibiting a rapid temperature rise. When the internal temperature of the concrete begins to decrease later, the material recrystallizes and releases its stored latent heat, thus slowing down the cooling of the concrete.

[0019] Beneficial effects The hydration heat inhibitor of this invention has a good effect on inhibiting cement hydration, reducing the hydration heat release rate, and significantly reducing the heat release.

[0020] The modified nanocellulose, fluorinated surfactant, and temperature-controlling material in the hydration heat inhibitor of this invention are not simply superimposed, but constitute a multi-level, multi-mechanism synergistic system. The fluorinated surfactant first delays the start of the reaction. After the reaction begins, the modified nanocellulose penetrates deep into the interior to reduce the reaction rate. The temperature-controlling material absorbs and stores heat through phase change, strongly suppressing the temperature rise, thereby significantly reducing the hydration heat of large-volume concrete. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to specific embodiments, but it is not limited thereto.

[0022] Example 1 A water-based heat inhibitor for concrete comprises the following raw materials in parts by weight: 15 parts modified nanocellulose, 3 parts fluorinated surfactant, 8 parts sodium gluconate, 0.5 parts ammonium pentaborate, 0.3 parts hydroxyethylidene diphosphonic acid, and 10 parts temperature-controlling material.

[0023] The temperature-controlling material is disodium hydrogen phosphate dodecahydrate.

[0024] The fluorinated surfactant is sodium perfluorononenoxybenzenesulfonate.

[0025] The method for preparing the modified nanocellulose is as follows: (1) Acid hydrolysis pretreatment: Disperse natural plant fibers in 64wt% sulfuric acid solution, keep the reaction temperature at 40℃, mechanically stir for 80min, after the reaction is completed, add deionized water, centrifuge the mixture at 10000rpm for 15min, discard the supernatant and collect the precipitate; (2) The cellulose after acid hydrolysis in step (1) is redispersed in deionized water to prepare a 1wt% suspension. 2,2,6,6-Tetramethylpiperidine and sodium bromide are added. The system is placed in a 4℃ water bath and sodium hypochlorite is added dropwise. During the dropwise addition, the pH value of the reaction system is controlled to be maintained between 10 and 10.5. When the pH value of the reaction system remains stable within 5 minutes and no longer decreases, the oxidation reaction has been completed. (3) The oxidized product was purified by 5 cycles of high-pressure homogenization to obtain oxidized nanocellulose gel with a solid content of 1%; (4) Dilute the gel from step (3) with deionized water to a solid content of 0.8%, adjust the pH of the suspension to 4.0, add silane coupling agent KH-550 solution, transfer the mixture to a water bath at 60°C, stir and react for 4 hours under nitrogen protection, after the reaction is completed, cool to room temperature and dry to obtain the final product modified nanocellulose.

[0026] In step (1), the weight ratio of natural fiber to sulfuric acid solution is 1:8.

[0027] In step (2), the amount of 2,2,6,6-tetramethylpiperidine added is 0.1 mmol per gram of dry fiber, the amount of sodium bromide added is 1 mmol per gram of dry fiber, and the amount of sodium hypochlorite added is 5 mmol per gram of dry fiber.

[0028] In step (4), the amount of silane coupling agent KH-550 added is 10% of the dry fiber weight. The silane coupling agent KH-550 solution is prepared by pre-mixing ethanol and deionized water in a volume ratio of 8:2 and then adding KH-550 and stirring magnetically for 30 minutes.

[0029] A method for preparing a water-based heat inhibitor for concrete includes the following steps: First, modified nanocellulose is prepared. Then, the modified nanocellulose, fluorinated surfactant, sodium gluconate, ammonium pentaborate, hydroxyethylidene diphosphonic acid and temperature control material are put into a mixer until all components are fully mixed and homogeneous. The mixture is then discharged and packaged to obtain a water-cooling heat inhibitor for concrete.

[0030] Example 2 A water-based heat inhibitor for concrete is prepared from the following raw materials in parts by weight: 17 parts modified nanocellulose, 4 parts fluorinated surfactant, 10 parts sodium gluconate, 0.8 parts ammonium pentaborate, 0.6 parts hydroxyethylidene diphosphonic acid, and 13 parts temperature-controlling material.

[0031] The temperature-controlling material is disodium hydrogen phosphate dodecahydrate.

[0032] The fluorinated surfactant is perfluorohexylethyl alcohol.

[0033] The method for preparing the modified nanocellulose is as follows: (1) Acid hydrolysis pretreatment: Disperse natural plant fibers in 64wt% sulfuric acid solution, maintain the reaction temperature at 45℃, mechanically stir for 60min, after the reaction is completed, add deionized water, centrifuge the mixture at 10000rpm for 15min, discard the supernatant and collect the precipitate; (2) The cellulose after acid hydrolysis in step (1) is redispersed in deionized water to prepare a 1wt% suspension. 2,2,6,6-Tetramethylpiperidine and sodium bromide are added. The system is placed in a 4℃ water bath and sodium hypochlorite is added dropwise. During the dropwise addition, the pH value of the reaction system is controlled to be maintained between 10 and 10.5. When the pH value of the reaction system remains stable within 5 minutes and no longer decreases, the oxidation reaction has been completed. (3) The oxidized product was purified by 5 cycles of high-pressure homogenization to obtain oxidized nanocellulose gel with a solid content of 1%; (4) Dilute the gel from step (3) with deionized water to a solid content of 0.8%, adjust the pH of the suspension to 4.5, add silane coupling agent KH-550 solution, transfer the mixture to a water bath at 65°C, stir and react for 5 hours under nitrogen protection, after the reaction is completed, cool to room temperature and dry to obtain the final product modified nanocellulose.

[0034] In step (1), the weight ratio of natural fiber to sulfuric acid solution is 1:8.

[0035] In step (2), the amount of 2,2,6,6-tetramethylpiperidine added is 0.1 mmol per gram of dry fiber, the amount of sodium bromide added is 1 mmol per gram of dry fiber, and the amount of sodium hypochlorite added is 5 mmol per gram of dry fiber.

[0036] In step (4), the amount of silane coupling agent KH-550 added is 15% of the dry fiber weight. The silane coupling agent KH-550 solution is prepared by pre-mixing ethanol and deionized water in a volume ratio of 8:2 and then adding KH-550 and stirring magnetically for 30 minutes.

[0037] A method for preparing a water-based heat inhibitor for concrete includes the following steps: First, modified nanocellulose is prepared. Then, the modified nanocellulose, fluorinated surfactant, sodium gluconate, ammonium pentaborate, hydroxyethylidene diphosphonic acid and temperature control material are put into a mixer until all components are fully mixed and homogeneous. The mixture is then discharged and packaged to obtain a water-cooling heat inhibitor for concrete.

[0038] Example 3 A water-based heat inhibitor for concrete is prepared from the following raw materials in parts by weight: 20 parts modified nanocellulose, 5 parts fluorinated surfactant, 12 parts sodium gluconate, 1 part ammonium pentaborate, 1 part hydroxyethylidene diphosphonic acid, and 15 parts temperature-controlling material.

[0039] The temperature-controlling material is disodium hydrogen phosphate dodecahydrate.

[0040] The fluorinated surfactant is sodium perfluorononenoxybenzenesulfonate.

[0041] The method for preparing the modified nanocellulose is as follows: (1) Acid hydrolysis pretreatment: Disperse natural plant fibers in 64wt% sulfuric acid solution, maintain the reaction temperature at 45℃, mechanically stir for 120min, after the reaction is completed, add deionized water, centrifuge the mixture at 10000rpm for 15min, discard the supernatant and collect the precipitate; (2) The cellulose after acid hydrolysis in step (1) is redispersed in deionized water to prepare a 1wt% suspension. 2,2,6,6-Tetramethylpiperidine and sodium bromide are added. The system is placed in a 4℃ water bath and sodium hypochlorite is added dropwise. During the dropwise addition, the pH value of the reaction system is controlled to be maintained between 10 and 10.5. When the pH value of the reaction system remains stable within 5 minutes and no longer decreases, the oxidation reaction has been completed. (3) The oxidized product was purified by 5 cycles of high-pressure homogenization to obtain oxidized nanocellulose gel with a solid content of 1%; (4) Dilute the gel from step (3) with deionized water to a solid content of 0.8%, adjust the pH of the suspension to 5.0, add silane coupling agent KH-550 solution, transfer the mixture to a water bath at 70°C, stir and react for 6 hours under nitrogen protection, after the reaction is completed, cool to room temperature and dry to obtain the final product modified nanocellulose.

[0042] In step (1), the weight ratio of natural fiber to sulfuric acid solution is 1:8.

[0043] In step (2), the amount of 2,2,6,6-tetramethylpiperidine added is 0.1 mmol per gram of dry fiber, the amount of sodium bromide added is 1 mmol per gram of dry fiber, and the amount of sodium hypochlorite added is 5 mmol per gram of dry fiber.

[0044] In step (4), the amount of silane coupling agent KH-550 added is 10-25% of the dry fiber weight. The silane coupling agent KH-550 solution is prepared by pre-mixing ethanol and deionized water in a volume ratio of 8:2 and then adding KH-550 and stirring magnetically for 30 minutes.

[0045] A method for preparing a water-based heat inhibitor for concrete includes the following steps: First, modified nanocellulose is prepared. Then, the modified nanocellulose, fluorinated surfactant, sodium gluconate, ammonium pentaborate, hydroxyethylidene diphosphonic acid and temperature control material are put into a mixer until all components are fully mixed and homogeneous. The mixture is then discharged and packaged to obtain a water-cooling heat inhibitor for concrete.

[0046] Comparative Example 1 A water-based heat inhibitor for concrete is prepared from the following raw materials in parts by weight: 15 parts cellulose, 3 parts fluorinated surfactant, 8 parts sodium gluconate, 0.5 parts ammonium pentaborate, 0.3 parts hydroxyethylidene diphosphonic acid, and 10 parts temperature-controlling material.

[0047] The temperature-controlling material is disodium hydrogen phosphate dodecahydrate.

[0048] The fluorinated surfactant is sodium perfluorononenoxybenzenesulfonate.

[0049] A method for preparing a water-based heat inhibitor for concrete includes the following steps: First, modified nanocellulose is prepared. Nanocellulose, fluorinated surfactant, sodium gluconate, ammonium pentaborate, hydroxyethylidene diphosphonic acid and temperature control material are put into a mixer until all components are fully mixed and uniform. The mixture is then discharged and packaged to obtain a water-cooling heat inhibitor for concrete.

[0050] Compared with Example 1, this comparative example is identical to Example 1 except that the cellulose is not modified. All other raw materials and steps are the same as in Example 1.

[0051] Comparative Example 2 A water-based heat inhibitor for concrete is prepared from the following raw materials in parts by weight: 15 parts modified nanocellulose, 3 parts surfactant, 8 parts sodium gluconate, 0.5 parts ammonium pentaborate, 0.3 parts hydroxyethylidene diphosphonic acid, and 10 parts temperature-controlling material.

[0052] The temperature-controlling material is disodium hydrogen phosphate dodecahydrate.

[0053] The surfactant is sodium dodecylbenzenesulfonate.

[0054] The method for preparing the modified nanocellulose is as follows: (1) Acid hydrolysis pretreatment: Disperse natural plant fibers in 64wt% sulfuric acid solution, keep the reaction temperature at 40℃, mechanically stir for 80min, after the reaction is completed, add deionized water, centrifuge the mixture at 10000rpm for 15min, discard the supernatant and collect the precipitate; (2) The cellulose after acid hydrolysis in step (1) is redispersed in deionized water to prepare a 1wt% suspension. 2,2,6,6-Tetramethylpiperidine and sodium bromide are added. The system is placed in a 4℃ water bath and sodium hypochlorite is added dropwise. During the dropwise addition, the pH value of the reaction system is controlled to be maintained between 10 and 10.5. When the pH value of the reaction system remains stable within 5 minutes and no longer decreases, the oxidation reaction has been completed. (3) The oxidized product was purified by 5 cycles of high-pressure homogenization to obtain oxidized nanocellulose gel with a solid content of 1%; (4) Dilute the gel from step (3) with deionized water to a solid content of 0.8%, adjust the pH of the suspension to 4.0, add silane coupling agent KH-550 solution, transfer the mixture to a water bath at 60°C, stir and react for 4 hours under nitrogen protection, after the reaction is completed, cool to room temperature and dry to obtain the final product modified nanocellulose.

[0055] In step (1), the weight ratio of natural fiber to sulfuric acid solution is 1:8.

[0056] In step (2), the amount of 2,2,6,6-tetramethylpiperidine added is 0.1 mmol per gram of dry fiber, the amount of sodium bromide added is 1 mmol per gram of dry fiber, and the amount of sodium hypochlorite added is 5 mmol per gram of dry fiber.

[0057] In step (4), the amount of silane coupling agent KH-550 added is 10% of the dry fiber weight. The silane coupling agent KH-550 solution is prepared by pre-mixing ethanol and deionized water in a volume ratio of 8:2 and then adding KH-550 and stirring magnetically for 30 minutes.

[0058] A method for preparing a water-based heat inhibitor for concrete includes the following steps: First, modified nanocellulose is prepared. Then, the modified nanocellulose, surfactant, sodium gluconate, ammonium pentaborate, hydroxyethylidene diphosphonic acid, and temperature control material are put into a mixer until all components are fully mixed and homogeneous. The mixture is then discharged and packaged to obtain a water-cooling heat inhibitor for concrete.

[0059] Compared with Example 1, this comparative example is identical to Example 1 except that the surfactant is changed to sodium dodecylbenzenesulfonate.

[0060] Comparative Example 3 A water-based heat inhibitor for concrete is prepared from the following raw materials in parts by weight: 15 parts modified nanocellulose, 3 parts fluorinated surfactant, 8 parts sodium gluconate, 0.5 parts ammonium pentaborate, and 0.3 parts hydroxyethylidene diphosphonic acid.

[0061] The fluorinated surfactant is sodium perfluorononenoxybenzenesulfonate.

[0062] The method for preparing the modified nanocellulose is as follows: (1) Acid hydrolysis pretreatment: Disperse natural plant fibers in 64wt% sulfuric acid solution, keep the reaction temperature at 40℃, mechanically stir for 80min, after the reaction is completed, add deionized water, centrifuge the mixture at 10000rpm for 15min, discard the supernatant and collect the precipitate; (2) The cellulose after acid hydrolysis in step (1) is redispersed in deionized water to prepare a 1wt% suspension. 2,2,6,6-Tetramethylpiperidine and sodium bromide are added. The system is placed in a 4℃ water bath and sodium hypochlorite is added dropwise. During the dropwise addition, the pH value of the reaction system is controlled to be maintained between 10 and 10.5. When the pH value of the reaction system remains stable within 5 minutes and no longer decreases, the oxidation reaction has been completed. (3) The oxidized product was purified by 5 cycles of high-pressure homogenization to obtain oxidized nanocellulose gel with a solid content of 1%; (4) Dilute the gel from step (3) with deionized water to a solid content of 0.8%, adjust the pH of the suspension to 4.0, add silane coupling agent KH-550 solution, transfer the mixture to a water bath at 60°C, stir and react for 4 hours under nitrogen protection, after the reaction is completed, cool to room temperature and dry to obtain the final product modified nanocellulose.

[0063] In step (1), the weight ratio of natural fiber to sulfuric acid solution is 1:8.

[0064] In step (2), the amount of 2,2,6,6-tetramethylpiperidine added is 0.1 mmol per gram of dry fiber, the amount of sodium bromide added is 1 mmol per gram of dry fiber, and the amount of sodium hypochlorite added is 5 mmol per gram of dry fiber.

[0065] In step (4), the amount of silane coupling agent KH-550 added is 10% of the dry fiber weight. The silane coupling agent KH-550 solution is prepared by pre-mixing ethanol and deionized water in a volume ratio of 8:2 and then adding KH-550 and stirring magnetically for 30 minutes.

[0066] A method for preparing a water-based heat inhibitor for concrete includes the following steps: First, modified nanocellulose is prepared. Then, the modified nanocellulose, fluorinated surfactant, sodium gluconate, ammonium pentaborate, and hydroxyethylidene diphosphonic acid are added into a mixer until all components are fully mixed and homogeneous. The mixture is then discharged and packaged to obtain a water-cooling heat inhibitor for concrete.

[0067] Compared with Example 1, this comparative example is identical to Example 1 except that no temperature control material is added. All other raw materials and steps are the same as in Example 1.

[0068] Performance testing Hydration heat inhibitors from Examples 1-3 and Comparative Examples 1-3 were added to concrete at a dosage of 1% of the mass of the gel material. The concrete mix proportions are shown in Table 1, with no hydration heat inhibitors added as the baseline (blank control). The test results of the relevant performances are shown in Table 2, according to the relevant provisions in JCT 2608-2020 "Inhibitors for Hydration Temperature Rise in Concrete".

[0069] Table 1 Concrete mix proportions (kg / m³) 3 ) Table 2 Performance Test Results As shown in Table 2, the hydration heat inhibitor of the present invention can effectively reduce the peak hydration heat release of concrete. Compared with the reference cement, the reduction rate of the hydration peak value in the examples can reach more than 50%, with the highest reduction rate of hydration peak value in Example 1 reaching 58.43%. Similarly, the concrete samples of Examples 1-3 of the present invention also significantly reduced the 24-hour heat release compared with the reference cement. However, in Comparative Examples 1-3 with altered composition of the hydration heat inhibitor of the present invention, the synergistic effect of modified nanocellulose, temperature-controlling materials, and fluorinated surfactants disappeared, resulting in a significant reduction in the hydration heat inhibition effect and a significant increase in the peak heat release and the amount of heat released.

[0070] It should be noted that the above embodiments are merely some preferred embodiments of the present invention, and not all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

Claims

1. A water-based heat inhibitor for concrete, characterized in that, The raw materials include the following components by weight: modified nanocellulose 15-20 parts, fluorine-containing surfactant 3-5 parts, sodium gluconate 8-12 parts, ammonium pentaborate 0.5-1 part, hydroxyethylidene diphosphonic acid 0.3-1 part, and temperature control material 10-15 parts.

2. The hydraulic heat inhibitor for concrete according to claim 1, characterized by, The temperature control material is dodecahydrate sodium phosphate.

3. The hydraulic heat inhibitor for concrete according to claim 1, characterized by, The fluorine-containing surfactant is one or both of sodium perfluoro noneneoxy benzene sulfonate and perfluoro hexyl ethyl alcohol.

4. The hydraulic heat inhibitor for concrete according to claim 1, wherein The preparation method of the modified nanocellulose is as follows: (1) acid hydrolysis pretreatment: disperse natural plant dry fibers in a 64wt% sulfuric acid solution, keep the reaction temperature at 40-45℃, mechanically stir for 60-120min, after the reaction is completed, add deionized water, centrifuge the mixture at 10000rpm for 15min, discard the supernatant, and collect the precipitate; (2) disperse the cellulose after acid hydrolysis in step (1) in deionized water to prepare a 1wt% suspension, add 2,2,6,6-tetramethylpiperidine and sodium bromide, place the system in a 4℃ water bath, and drop sodium hypochlorite, control the pH value of the reaction system to be maintained at 10-10.5 during the dropping process, and the pH value of the reaction system is stable within 5min and does not decrease any more, which means that the oxidation reaction is complete; (3) purify the product after oxidation, and then treat it by a high-pressure homogenizer for 5 cycles to obtain an oxidized nanocellulose gel, which has a solid content of 1%; (4) dilute the gel in step (3) with deionized water to a solid content of 0.8%, adjust the pH value of the suspension to 4.0-5.0, add a silane coupling agent KH-550 solution, transfer the mixed system to a 60-70℃ water bath, stir under nitrogen protection for 4-6h, cool to room temperature after the reaction is completed, and dry to obtain the final product, modified nanocellulose.

5. The hydraulic heat inhibitor for concrete according to claim 4, characterized by In step (1), the weight ratio of dry fibers to sulfuric acid solution is 1:

8.

6. The hydraulic heat inhibitor for concrete according to claim 4, wherein In step (2), the addition amount of 2,2,6,6-tetramethylpiperidine is 0.1mmol per gram of dry fibers, the addition amount of sodium bromide is 1mmol per gram of dry fibers, and the addition amount of sodium hypochlorite is 5mmol per gram of dry fibers.

7. The hydraulic heat inhibitor for concrete according to claim 4, wherein In step (4), the addition amount of silane coupling agent KH-550 is 10-25% of the weight of dry fibers, and the silane coupling agent KH-550 solution is prepared by mixing ethanol and deionized water in a volume ratio of 8:2 in advance and then adding KH-550, and magnetically stirring for 30min.

8. A method for producing the hydration heat inhibitor for concrete according to claims 1 to 7, characterized by, The method comprises the following steps: First, prepare modified nanocellulose, and then put the modified nanocellulose, fluorine-containing surfactant, sodium gluconate, ammonium pentaborate, hydroxyethylidene diphosphonic acid, and temperature control material into a mixer, until all components are fully mixed and uniform, discharge, package, and the concrete hydration heat inhibitor is obtained.

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