Anti-crack concrete and preparation method thereof

Abstract

The invention relates to the field of concrete, and particularly discloses anti-crack concrete and a preparation method thereof. The anti-crack concrete is prepared from the following raw material components in parts by weight: 400 parts of cement; 1000 to 1100 parts of coarse aggregate; 730 to 800 parts of fine aggregate; 40 to 50 parts of modified rubber particles; 20 to 25 parts of basalt fiber; 5-6 parts of a water reducing agent; 1.3 to 1.5 parts of SAP resin; 0.015 to 0.02 part of an air entraining agent; 130 to 140 parts of water; a modifier used for preparing the modified rubber particles is sodium hydroxide and a silane coupling agent. The anti-crack concrete disclosed by the invention has good anti-crack capability, the total cracking area does not exceed 35mm < 2 > / m < 2 >, and the 28d compressive strength is not lower than 40MPa.

Description

Technical Field

[0001] This application relates to the technical field of concrete, and in particular to a crack-resistant concrete and a method for preparing the same. Background Technology

[0002] Currently, concrete, as a primary material in the construction field, plays a crucial role in building construction. With the continuous development of the construction industry, people are placing increasingly higher demands on the durability and safety of buildings, and the performance of concrete directly affects these key indicators. High-quality concrete can ensure that buildings can withstand the impact of various natural and human factors during long-term use, reduce maintenance costs, extend the service life of buildings, and contribute to the sustainable development of society. Therefore, improving the performance of concrete has become one of the key research directions in the construction field.

[0003] In traditional concrete applications, various methods have been explored to improve concrete performance, particularly in terms of strength and crack resistance. Initially, traditional concrete formulations were relied upon, but achieving a good balance between strength and crack resistance was challenging. Later, to improve the crack resistance of concrete, the industry adopted the method of incorporating modifiers, such as fibers and micro-expansion agents. These modifiers can enhance the internal structure of concrete to a certain extent, thereby improving its crack resistance. However, these methods also have some limitations. For example, the incorporation of fibers requires precise control of their proportion and dispersion uniformity; otherwise, it may affect the overall performance of the concrete. The use of micro-expansion agents requires specific construction conditions and process requirements, increasing the complexity of construction.

[0004] However, these existing methods have significant drawbacks. Traditional concrete formulations are unable to effectively resist crack formation under complex stress environments, posing a serious threat to the structural safety of buildings. While incorporating modified materials such as fibers and micro-expansion agents can improve crack resistance to some extent, the methods are costly and involve complex construction processes, increasing the cost and difficulty of building projects. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a crack-resistant concrete and a method for preparing the same.

[0006] In a first aspect, this application provides a crack-resistant concrete, wherein the raw materials used, by weight, include the following components: 400 parts cement; 1000-1100 parts coarse aggregate; 730-800 parts fine aggregate; 40-50 parts modified rubber particles; 20-25 parts basalt fiber; 5-6 parts water-reducing agent; 1.3-1.5 parts SAP resin; 0.015-0.02 parts air-entraining agent; and 130-140 parts water; wherein the modifier used to prepare the modified rubber particles is sodium hydroxide and a silane coupling agent.

[0007] Preferably, the raw materials used include the following components: 400 parts cement; 1050-1080 parts coarse aggregate; 750-780 parts fine aggregate; 45-48 parts modified rubber granules; 22-24 parts basalt fiber; 5-6 parts water-reducing agent; 1.3-1.5 parts SAP resin; 0.015-0.02 parts air-entraining agent; and 133 parts water.

[0008] By adopting the above technical solutions, this application incorporates modified rubber particles modified with sodium hydroxide and silane coupling agent into the concrete system, which can significantly improve the interfacial bonding force within the concrete and disperse stress, thereby reducing the possibility of cracking when the concrete is under stress. Basalt fiber is also added, which, by leveraging its tensile strength, acts to prevent crack formation, providing resistance before and after cracking, delaying cracking, and ensuring that the concrete specimen maintains good integrity even when damaged. Therefore, the basalt fiber in this application can compensate for the strength loss caused by the modified rubber particles and has a synergistic effect with the modified rubber particles, forming an "elastic-rigid" dual-network structure. SAP resin is also added, which can form a water-retaining zone with a diameter of approximately 100 μm, releasing 90% of its own stored water during the critical hydration period of the concrete (3-7 days), compensating for self-drying shrinkage, reducing the number of internal cracks in the concrete, and optimizing the pore structure and interfacial properties. Overall, the crack-resistant concrete prepared by blending cement, coarse aggregate, fine aggregate, modified rubber particles, basalt fiber, water-reducing agent, SAP resin, air-entraining agent, and water in this application exhibits good crack resistance, with a total crack area not exceeding 35 mm. 2 / m 2 The 28-day compressive strength is not less than 40 MPa.

[0009] Preferably, the basalt fiber is graded basalt fiber with lengths of 6mm, 9mm, 12mm and 15mm respectively.

[0010] By adopting the above technical solution, this application utilizes graded basalt fibers, which can effectively enhance the strength of the concrete matrix by leveraging the synergistic effect between fiber length and spatial distribution, while minimizing damage to the elastic modulus. Overall, this significantly improves the crack resistance of the concrete.

[0011] Preferably, the weight ratio of the graded basalt fibers with lengths of 6mm, 9mm, 12mm and 15mm is (1-2):1:(1-2):2.

[0012] By adopting the above technical solution, this application controls the weight ratio of basalt fibers of different lengths, with the overall proportion of long fibers being greater than or equal to that of short fibers. This further optimizes the effect on improving concrete strength. The graded fibers exhibit good edge wall effect. Short-cut fibers achieve a good balance between optimizing mechanical properties and dispersion ability. Although long-cut fibers have a certain possibility of clumping, they can play a good role in dispersing stress and improving the bonding force of fiber-reinforced concrete. Therefore, the gradation method (fiber length selection and weight matching) of this application can maximize crack resistance and compressive strength.

[0013] Preferably, the coarse aggregate comprises continuously graded shale ceramsite with particle sizes of 5-10 mm, 10-16 mm, and 16-20 mm.

[0014] Preferably, the weight ratio of the shale ceramsite particles with particle sizes of 5-10 mm, 10-16 mm and 16-20 mm is 1:(2-3):(3-4).

[0015] Preferably, the fine aggregate comprises continuously graded manufactured sand with particle sizes of 0.15-0.3 mm, 0.3-0.6 mm and 0.6-1.18 mm.

[0016] Preferably, the weight ratio of the manufactured sand with particle sizes of 0.15-0.3 mm, 0.3-0.6 mm and 0.6-1.18 mm is (2.5-3):4:(2-2.5).

[0017] By adopting the above technical solution, this application utilizes continuously graded coarse and fine aggregates, and selects shale ceramsite and manufactured sand respectively. This reduces free water in the system, thereby reducing porosity, reducing microcracks and voids at the aggregate-slurry interface, and synergistically dispersing load stress to avoid local stress concentration. At the same time, continuous gradation can also improve fluidity, increase the efficiency of air bubble removal, and further reduce the porosity in the system. The shale ceramsite selected in this application has a porous structure that can absorb mixing water and gradually release moisture during the concrete hardening stage, forming an internal humidity compensation system. This allows for more complete cement hydration, reduces microcracks caused by drying shrinkage, and its elastic modulus and coefficient of thermal expansion are closer to those of the cement matrix. Compared with ordinary crushed stone, it can reduce interfacial stress concentration and temperature stress, and inhibit crack initiation.

[0018] Secondly, this application provides a method for preparing crack-resistant concrete, comprising the following steps: mixing the coarse aggregate, fine aggregate, modified rubber particles and basalt fiber, stirring for 2-3 minutes, then adding cement, SAP resin, water-reducing agent and air-entraining agent, stirring for 1-2 minutes, then adding water, stirring for 2-3 minutes to obtain crack-resistant concrete.

[0019] Preferably, the method for preparing the modified rubber particles includes the following steps: treating the rubber particles with sodium hydroxide, washing them, immersing the alkali-treated rubber particles in a silane coupling agent solution, wherein the amount of silane coupling agent is 1-1.5 wt% of the total amount of rubber particles, letting them stand for 20-25 hours, removing them, washing them, and drying them to obtain the modified rubber particles.

[0020] By adopting the above technical solution, this application first uses sodium hydroxide to treat the rubber particles with alkali, removing the zinc stearate adhering to the surface of the rubber particles and improving the adhesion between the rubber particles and the cement paste. Then, a silane coupling agent is used to further modify the alkali-treated rubber particles. The silane coupling agent can further improve the interfacial bonding effect between the rubber particles and the cement matrix by utilizing its own hydrophilic and inorganic-philic groups, so that the final crack-resistant concrete has more stable crack resistance and compressive strength.

[0021] In summary, this application has the following beneficial technical effects: 1. The crack-resistant concrete prepared by blending cement, coarse aggregate, fine aggregate, modified rubber particles, basalt fiber, water-reducing agent, SAP resin, air-entraining agent, and water in this application has good crack resistance, with a total crack area not exceeding 35 mm. 2 / m 2 The 28-day compressive strength is not less than 40 MPa; 2. This application incorporates modified rubber particles, modified with sodium hydroxide and silane coupling agent, into the concrete system. This significantly enhances the interfacial bonding strength within the concrete, effectively dispersing stress and reducing the likelihood of cracking under load. Basalt fiber is also added, leveraging its tensile strength to inhibit crack formation. It provides resistance before and after cracking, delaying cracking and ensuring the concrete specimen maintains good integrity even after failure. Therefore, the basalt fiber compensates for the strength loss caused by the modified rubber particles, working synergistically to form an "elastic-rigid" dual-network structure. SAP resin is also added, which creates a water-retaining zone of approximately 100 μm in diameter. During the critical hydration period (3-7 days), it releases 90% of its stored water, compensating for self-drying shrinkage, reducing the number of internal cracks, and optimizing pore structure and interfacial properties. Detailed Implementation

[0022] Material source Unless otherwise specified, all raw materials used in this application are commercially available products, specifically: The cement was purchased from Anhui Huili Chemical Co., Ltd., and its grade is PO 42.5. The water-reducing agent was purchased from Jiangsu Zhaojia Building Materials Technology Co., Ltd., and the mortar water reduction rate is ≥23%. The air-entraining agent was purchased from Shandong Xiangzhao New Material Co., Ltd., and its main component is sodium dodecyl sulfate. The rubber granules were purchased from Jixi Mineral Resources in Lingshou County, with a particle size of 2-4 mm. KH560 silane coupling agent was purchased from Nanjing Ron Silicon Materials. The basalt fiber was purchased from Zhengzhou Dengdian Basalt Fiber Co., Ltd., with a density of 2.61 g / cm³. 3 Tensile strength 3200MPa, elastic modulus 91.4GPa, elongation at break 1.5%; SAP resin is a polyacrylic acid-acrylamide superabsorbent resin.

[0023] The present application will be further described in detail below with reference to preparation examples, embodiments and comparative examples.

[0024] Preparation Example 1 The method for preparing modified rubber granules includes the following steps: A 5% (w / w) NaOH solution was prepared using sodium hydroxide and water. 80 kg of washed and dried rubber granules were then immersed in the 5% NaOH solution for 24 hours. Afterward, the rubber granules were removed, rinsed with deionized water until neutral, and set aside. A 95% (v / v) ethanol solution was prepared using anhydrous ethanol and water. 800 g of KH560 silane coupling agent was dispersed in the prepared ethanol solution to obtain a 1 wt% silane coupling agent solution. The rinsed rubber granules were then immersed in the silane coupling agent solution for 25 hours. Afterward, they were removed, rinsed with deionized water until neutral, and dried to obtain modified rubber granules.

[0025] Preparation Example 2 The method for preparing modified rubber granules includes the following steps: A 5% (w / w) NaOH solution was prepared using sodium hydroxide and water. 80 kg of washed and dried rubber granules were then immersed in the 5% NaOH solution for 24 hours. Afterward, the rubber granules were removed, rinsed with deionized water until neutral, and set aside. A 95% (v / v) ethanol solution was prepared using anhydrous ethanol and water. 1.2 kg of KH560 silane coupling agent was dispersed in the prepared ethanol solution to obtain a 1 wt% silane coupling agent solution. The rinsed rubber granules were then immersed in the silane coupling agent solution for 20 hours. Afterward, they were removed, rinsed with deionized water until neutral, and dried to obtain modified rubber granules.

[0026] Comparative Preparation Example 1 A 5% NaOH solution was prepared using sodium hydroxide and water. Then, 80 kg of washed and dried rubber granules were immersed in the 5% NaOH solution for 24 hours. After that, the rubber granules were removed, rinsed with deionized water until neutral, and dried to obtain modified rubber granules.

[0027] Comparative Preparation Example 2 A 95% (v / v) ethanol solution was prepared using anhydrous ethanol and water. Then, 800g of KH560 silane coupling agent was dispersed in the prepared ethanol solution to obtain a 1wt% (w / w) silane coupling agent solution. Subsequently, 80kg of washed and dried rubber particles were immersed in the silane coupling agent solution for 25 hours. After that, the particles were removed, rinsed with deionized water until neutral, and dried to obtain modified rubber particles.

[0028] Example 1 A method for preparing crack-resistant concrete includes the following steps: Coarse aggregate, fine aggregate, modified rubber particles prepared in Preparation Example 1 and basalt fiber were mixed together and stirred for 3 minutes. Cement, SAP resin, water-reducing agent and air-entraining agent were added and stirred for 2 minutes. Water was added and stirred for 2 minutes to obtain crack-resistant concrete. The specific dosage is shown in Table 1. The basalt fiber consists of basalt fibers with lengths of 6 mm, 9 mm, 12 mm and 15 mm, in a weight ratio of 1:1:2:2; the coarse aggregate consists of shale ceramsite with particle sizes of 5-10 mm, 10-16 mm and 16-20 mm, in a weight ratio of 1:3:3. The fine aggregate includes manufactured sand with particle sizes of 0.15-0.3 mm, 0.3-0.6 mm and 0.6-1.18 mm, in a weight ratio of 3:4:2.

[0029] Example 2 A method for preparing crack-resistant concrete includes the following steps: Coarse aggregate, fine aggregate, modified rubber particles prepared in Example 2, and basalt fiber were mixed together. After stirring for 2 minutes, cement, SAP resin, water-reducing agent, and air-entraining agent were added. After stirring for 1 minute, water was added and stirred for 3 minutes to obtain crack-resistant concrete. The specific dosages are shown in Table 1. The basalt fiber includes basalt fibers with lengths of 6mm, 9mm, 12mm and 15mm, in a weight ratio of 2:1:1:2; the coarse aggregate includes shale ceramsite with particle sizes of 5-10mm, 10-16mm and 16-20mm, in a weight ratio of 1:2:4. The fine aggregate includes manufactured sand with particle sizes of 0.15-0.3 mm, 0.3-0.6 mm and 0.6-1.18 mm, in a weight ratio of 2.5:4:2.5.

[0030] Table 1. Amounts of substances used in Examples 1-2 (kg) Examples 3-4 A method for preparing crack-resistant concrete differs from Example 1 in that the amounts of each substance are different, as shown in Table 2, while the rest are the same as in Example 1.

[0031] Table 2. Amounts of substances used in Examples 3-4 (kg) substance Example 3 Example 4 cement 400 400 Coarse aggregate (shale ceramsite) 1050 1080 Fine aggregate (manufactured sand) 780 750 Modified rubber granules 45 48 Basalt fiber 24 22 Water reducing agent 5 6 SAP resin 1.5 1.3 Entraining agent 0.015 0.02 water 133 133 Example 5 A method for preparing crack-resistant concrete differs from Example 1 in that: the basalt fiber includes basalt fibers with lengths of 9 mm and 15 mm, with a weight ratio of 1:2, while the rest are the same as in Example 1.

[0032] Example 6 A method for preparing crack-resistant concrete differs from Example 1 in that: the basalt fiber includes basalt fibers with lengths of 6 mm and 12 mm, with a weight ratio of 1:2, while the rest are the same as in Example 1.

[0033] Example 7 A method for preparing crack-resistant concrete differs from Example 1 in that: 5-10mm, 10-16mm, and 16-20mm shale ceramsite are all replaced with coal gangue according to the same gradation and weight ratio design, while the rest is the same as in Example 1.

[0034] Example 8 A method for preparing crack-resistant concrete differs from Example 1 in that: 5-10mm, 10-16mm and 16-20mm shale ceramsite are all replaced with iron tailings ceramsite according to the same gradation and weight ratio design, while the rest is the same as in Example 1.

[0035] Comparative Example 1 The difference from Example 1 is that all the modified rubber particles prepared in Preparation Example 1 were replaced with the modified rubber particles prepared in Comparative Preparation Example 1, while the rest were the same as in Example 1.

[0036] Comparative Example 2 The difference from Example 1 is that all the modified rubber particles prepared in Preparation Example 1 were replaced with the modified rubber particles prepared in Comparative Preparation Example 2, while the rest were the same as in Example 1.

[0037] Comparative Example 3 The difference from Example 1 is that SAP resin is removed, while everything else is the same as in Example 1.

[0038] Performance testing 1. The early-age crack resistance of concrete was tested according to GB / T 50082-2024 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete". The concrete specimen size was 800mm × 600mm × 100mm. Two identical specimens were set up for each example or comparative example. The test results were expressed as the calculated total crack area per unit area (mm²). 2 / m 2 ) to represent; 2. The mechanical strength of concrete was tested in accordance with GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Ordinary Concrete". The concrete specimen size was 150mm×150mm×150mm. Three identical specimens were set up for each example or comparative example. The test results were expressed as the calculated 28-day compressive strength (MPa).

[0039] Table 3 Performance Test Table Group <![CDATA[Total cracking area (mm 2 / m 2 )]]> 28-day compressive strength (MPa) Example 1 31.4 46.5 Example 2 31.1 46.9 Example 3 30.0 47.5 Example 4 30.4 47.2 Example 5 32.9 45.2 Example 6 33.4 44.3 Example 7 34.6 41.3 Example 8 34.2 40.2 Comparative Example 1 34.5 44.4 Comparative Example 2 36.8 42.9 Comparative Example 3 33.7 45.7 Data Analysis: As can be seen from Table 3, the total crack area in Examples 1-4 of this application is as low as 30.0-31.4 mm. 2 / m 2 The 28-day compressive strength was 46.5-47.5 MPa, proving that the modified rubber particles modified with sodium hydroxide and silane coupling agent added to the concrete system can significantly improve the interfacial bonding force of the concrete, thereby dispersing stress and reducing the possibility of cracking under stress. Basalt fiber was also added, which, by exerting its tensile strength, can prevent crack formation, providing resistance before and after cracking, delaying cracking, and ensuring that the concrete specimen maintains good integrity when damaged. Therefore, the basalt fiber in this application can compensate for the strength loss caused by the modified rubber particles and has a synergistic effect with the modified rubber particles to form an "elastic-rigid" dual network structure. SAP resin was also added, which can form a water storage area with a diameter of about 100 μm. During the critical hydration period of concrete (3-7 days), 90% of its own stored water is released to compensate for self-drying shrinkage, reduce the number of internal cracks in the concrete, and optimize the pore structure and interfacial performance. Overall, the crack-resistant concrete prepared by this application using a blend of cement, coarse aggregate, fine aggregate, modified rubber particles, basalt fiber, water-reducing agent, SAP resin, air-entraining agent and water has good crack resistance.

[0040] The total crack area in Examples 5-6 increased significantly, while the 28-day compressive strength decreased, demonstrating that the graded basalt fibers used in this application exhibit a good synergistic effect between fiber length and spatial distribution, effectively improving the strength of the concrete matrix with minimal damage to the elastic modulus. Overall, this significantly enhances the crack resistance of concrete. By controlling the weight ratio of basalt fibers of different lengths, with the overall proportion of long fibers being greater than or equal to that of short fibers, the effect on improving concrete strength can be further optimized. The graded fibers exhibit a good edge-wall effect, and the short-cut fibers achieve a good balance between optimizing mechanical properties and dispersion capabilities. Although the long-cut fibers have a certain possibility of clumping, they can effectively disperse stress and enhance the bonding force of fiber-reinforced concrete. Therefore, the gradation method (fiber length selection and weight matching) of this application can maximize crack resistance and compressive strength.

[0041] The total crack area in Examples 7-8 increased significantly, and the 28-day compressive strength decreased, proving that this application utilizes continuously graded coarse and fine aggregates, and selects shale ceramsite and manufactured sand respectively. This reduces free water in the system, thereby reducing porosity, reducing microcracks and voids at the aggregate-slurry interface, and synergistically dispersing load stress to avoid local stress concentration. At the same time, continuous gradation can also improve fluidity, increase the efficiency of air bubble removal, and further reduce the porosity in the system. The shale ceramsite selected in this application has a porous structure that can absorb mixing water and gradually release moisture during the concrete hardening stage, forming an internal humidity compensation system. This allows for more complete cement hydration, reduces microcracks caused by drying shrinkage, and its elastic modulus and coefficient of thermal expansion are closer to those of the cement matrix. Compared with ordinary crushed stone, it can reduce interfacial stress concentration and temperature stress, and inhibit crack initiation.

[0042] The total crack area of ​​Comparative Examples 1-2 increased significantly, and the 28-day compressive strength decreased, proving that this application first used sodium hydroxide to treat the rubber particles with alkali, removing the zinc stearate adhering to the surface of the rubber particles and improving the adhesion between the rubber particles and the cement paste. Subsequently, a silane coupling agent was used to further modify the alkali-treated rubber particles. The silane coupling agent can further improve the interfacial adhesion between the rubber particles and the cement matrix by utilizing its own hydrophilic and inorganic groups, so that the final crack-resistant concrete has more stable crack resistance and compressive strength.

[0043] The total crack area of ​​Comparative Example 3 increased significantly, and the 28-day compressive strength decreased, proving that the SAP resin of this application can form a water storage area with a diameter of about 100 μm, release 90% of its own stored water during the critical hydration period of concrete (3-7 days), compensate for self-drying shrinkage, reduce the number of internal cracks in concrete, and optimize pore structure and interface performance.

[0044] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A crack-resistant concrete, characterized in that, The raw materials used, by weight, include the following components: 400 parts cement; 1000-1100 parts coarse aggregate; Fine aggregate 730-800 parts; modified rubber granules 40-50 parts; Basalt fiber 20-25 parts; water-reducing agent 5-6 parts; SAP resin 1.3-1.5 parts; air-entraining agent 0.015-0.02 parts; water 130-140 parts; the modifier used to prepare the modified rubber particles is sodium hydroxide and silane coupling agent.

2. The crack-resistant concrete according to claim 1, characterized in that, The raw materials used include the following components: 400 parts cement; 1050-1080 parts coarse aggregate; 750-780 parts fine aggregate; 45-48 parts modified rubber granules; 22-24 parts basalt fiber; 5-6 parts water-reducing agent; 1.3-1.5 parts SAP resin; 0.015-0.02 parts air-entraining agent; and 133 parts water.

3. The crack-resistant concrete according to claim 1, characterized in that, The basalt fibers are graded basalt fibers with lengths of 6mm, 9mm, 12mm and 15mm respectively.

4. The crack-resistant concrete according to claim 3, characterized in that, The weight ratio of the graded basalt fibers with lengths of 6 mm, 9 mm, 12 mm and 15 mm is (1-2):1:(1-2):

2.

5. The crack-resistant concrete according to claim 1, characterized in that, The coarse aggregate includes continuously graded shale ceramsite with particle sizes of 5-10 mm, 10-16 mm, and 16-20 mm.

6. The crack-resistant concrete according to claim 5, characterized in that, The weight ratio of the shale ceramsite particles with particle sizes of 5-10 mm, 10-16 mm and 16-20 mm is 1:(2-3):(3-4).

7. The crack-resistant concrete according to claim 1, characterized in that, The fine aggregate includes continuously graded manufactured sand with particle sizes of 0.15-0.3 mm, 0.3-0.6 mm and 0.6-1.18 mm.

8. The crack-resistant concrete according to claim 7, characterized in that, The weight ratio of the manufactured sand with particle sizes of 0.15-0.3 mm, 0.3-0.6 mm and 0.6-1.18 mm is (2.5-3):4:(2-2.5).

9. A method for preparing crack-resistant concrete according to any one of claims 1-8, characterized in that, Includes the following steps: The coarse aggregate, fine aggregate, modified rubber particles and basalt fiber are mixed together and stirred for 2-3 minutes. Then, cement, SAP resin, water-reducing agent and air-entraining agent are added and stirred for 1-2 minutes. Then, water is added and stirred for 2-3 minutes to obtain crack-resistant concrete.

10. A method for preparing crack-resistant concrete according to claim 9, characterized in that, The method for preparing the modified rubber particles includes the following steps: Rubber particles are treated with sodium hydroxide, washed, and then immersed in a silane coupling agent solution. The amount of silane coupling agent is 1-1.5 wt% of the total amount of rubber particles. After standing for 20-25 hours, the particles are removed, washed, and dried to obtain modified rubber particles.

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