Additive suitable for improving toughness of concrete at high temperature

Abstract

The invention belongs to the technical field of concrete preparation, and particularly relates to an additive suitable for improving the toughness of concrete at high temperature. According to the invention, calcite, flint clay and aluminum powder are mixed, and fine particles can fill pores in the concrete, so that the compactness of the concrete is improved, the shrinkage of the concrete is counteracted, and the toughness of the concrete is further improved; a network structure among the deoxidized rubber powder, the steel fiber and the styrene-acrylic emulsion can absorb and dissipate more energy, so that the impact resistance and toughness of the concrete are improved. Therefore, the additive prepared by specifically combining the raw materials can still improve the toughness of the concrete and prevent the concrete from cracking even in a high-temperature environment, so that the concrete meets the requirements of structural forms such as tensile strength and bending resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of concrete preparation, and particularly relates to an additive suitable for improving the toughness of concrete at high temperatures. Background Art

[0002] Concrete is a composite material prepared by mixing cement, water, sand (fine aggregate), stone (coarse aggregate), and additives and admixtures added when necessary in a certain proportion, and obtained through stirring, forming, and curing. It plays a wide and crucial role in fields such as construction, infrastructure construction, industrial and civil engineering.

[0003] Toughness refers to the ability of concrete to absorb energy and deform under stress without immediate failure. When the toughness of concrete is poor, it is prone to cracking under the action of external forces (such as loads, temperature changes, shrinkage, etc.), which not only affects the aesthetics of the structure but may even affect the normal use of the structure.

[0004] There are reports on additives for improving the toughness of concrete in the prior art. For example, in Chinese Patent CN107857503A, a concrete additive is prepared by mixing raw materials such as fly ash, silica powder, polypropylene fiber, zeolite powder, calcium lignosulfonate powder, acrylic emulsion, sulfuric acid, water, propanediamine phosphate, polysulfone resin, acrylate rubber, 4-dimethylaminopyridine, poly[(2-epoxyethyl)-1,2-cyclohexanediol] 2-ethyl-2-(hydroxymethyl)-1,3-propanediol ether, etc. Although it can improve the toughness of concrete to a certain extent, the preparation process is relatively cumbersome and not suitable for high-temperature environments. Summary of the Invention

[0005] The purpose of the present invention is to provide an additive suitable for improving the toughness of concrete at high temperatures, with a simple preparation process, which is not only suitable for high-temperature environments but also can improve the toughness of concrete.

[0006] The present invention provides an additive suitable for improving the toughness of concrete at high temperatures. In terms of mass parts, the additive comprises the following raw materials: 50 - 60 parts of calcite, 15 - 20 parts of pyrophyllite, 1 - 2 parts of aluminum powder, 13 - 16 parts of deoxidized rubber powder, 10 - 12 parts of styrene-acrylic emulsion, and 5 - 6 parts of steel fiber.

[0007] Preferably, the preparation method of the deoxidized rubber powder comprises:

[0008] Disperse the rubber powder in a sodium hypochlorite solution, and successively carry out ultrasonic stirring and drying to obtain the deoxidized rubber powder.

[0009] Preferably, the mass ratio of the rubber powder to the sodium hypochlorite solution is 0.6 - 0.8:1;

[0010] The mass concentration of the sodium hypochlorite solution is 1.5%-2.5%.

[0011] Preferably, the parameters of the ultrasonic stirring include: the temperature is 35-38°C, the time is 3-4 h, the power is 800-900 w, and the stirring speed is 1200-1300 rpm;

[0012] The temperature of the drying is 75-85°C.

[0013] The present invention provides a preparation method of the additive described in the above technical solution, including the following steps:

[0014] Mix calcite powder, pyrophyllite powder and aluminum powder, and then carry out calcination, cooling and grinding in sequence to obtain a mixed powder;

[0015] Mix and stir deoxidized rubber powder and steel fibers to obtain a stirred product;

[0016] Mix the mixed powder, the stirred product and styrene-acrylic emulsion evenly and dry them to obtain an additive.

[0017] Preferably, the parameters of the calcination include: the temperature is 1100-1150°C, and the time is 50-55 min;

[0018] The mixed powder is the undersize of a 40-50 mesh sieve.

[0019] Preferably, the temperature of the drying is 100-120°C.

[0020] Preferably, the water content of the additive is ≤3%.

[0021] The present invention provides the application of the additive described in the above technical solution in enhancing the toughness of concrete in a high-temperature environment and / or preparing a product for enhancing the toughness of concrete applicable to a high-temperature environment.

[0022] The present invention provides a method for enhancing the toughness of concrete applicable to high temperatures, including the following steps:

[0023] Prepare concrete by using the additive described in the above technical solution;

[0024] The dosage of the additive is 10%-15% of the total weight of the concrete raw materials.

[0025] Beneficial effects:

[0026] The present invention provides an additive suitable for improving the toughness of concrete at high temperatures. In parts by mass, the additive comprises the following raw materials: 50-60 parts of calcite, 15-20 parts of fireclay, 1-2 parts of aluminum powder, 13-16 parts of deoxidized rubber powder, 10-12 parts of styrene-acrylic emulsion, and 5-6 parts of steel fiber. By mixing calcite, fireclay, and aluminum powder, the fine particles can fill the pores inside the concrete, improve the density of the concrete, offset the shrinkage of the concrete, and thus improve the toughness of the concrete; the network structure among the deoxidized rubber powder, steel fiber, and styrene-acrylic emulsion can absorb and dissipate more energy, improving the impact resistance and toughness. Therefore, after the above raw materials are specifically combined, the additive prepared therefrom can be applied to high-temperature environments and can improve the toughness of concrete.

[0027] Based on the above technical advantages, the present invention also provides the application of the additive described in the above technical solution in improving the toughness of concrete in a high-temperature environment and preparing a product for improving the toughness of concrete suitable for a high-temperature environment. By adding the additive to the concrete in a specific proportion, the toughness of the concrete can be greatly improved. Specific Embodiments

[0028] In the present invention, unless otherwise specified, the raw materials, methods, and equipment used are all conventional selections.

[0029] To further illustrate the present invention, the following describes in detail the solution provided by the present invention in combination with embodiments, but they cannot be construed as limiting the protection scope of the present invention.

[0030] Example 1

[0031] A method for preparing a high-temperature resistant and tough concrete, the steps are as follows:

[0032] (1) Additive raw materials:

[0033] In parts by mass, the additive comprises the following raw materials: 50 parts of calcite, 15 parts of fireclay, 2 parts of aluminum powder, 13 parts of deoxidized rubber powder, 11 parts of styrene-acrylic emulsion, and 5 parts of steel fiber;

[0034] Among them, the preparation method of the deoxidized rubber powder is:

[0035] According to the mass ratio of 0.6:1 (i.e., rubber powder: sodium hypochlorite solution), the rubber powder is dispersed in a sodium hypochlorite solution with a mass concentration of 1.5%, and ultrasonic stirring is carried out at 35°C, 900w, and 1300rpm for 4h, and then suction filtration and washing are carried out in sequence, and the washed rubber powder is dried at 80°C to obtain the deoxidized rubber powder.

[0036] (2) Preparation of the additive

[0037] Calcite and fireclay are respectively ground and then passed through a 40-mesh sieve to obtain calcite powder and fireclay powder;

[0038] After mixing the calcite powder, fireclay powder and aluminum powder, they are calcined at 1100 - 1150 °C for 50 min, with a heating rate of 8 - 10 °C / min during this period, and then cooled in the furnace. The cooled mixture is ground and passed through a 40-mesh sieve to obtain a mixed powder;

[0039] The deoxidized rubber powder and steel fibers are mixed and stirred evenly, and then left standing for 10 min to obtain a stirred material; and the mixed powder and styrene-acrylic emulsion are successively added to the stirred material and mixed evenly. Then, the mixture is dried at 120 °C to obtain an additive with a water content of 2%.

[0040] (3) Preparation of concrete

[0041] By mass, the concrete comprises the following raw materials: 80 parts of cement, 16 parts of sand, 12 parts of gravel, 30 parts of water, and 20 parts of the additive in step (2).

[0042] Example 2

[0043] A preparation method of a high-temperature resistant and tough concrete, the steps are as follows:

[0044] (1) Additive raw materials:

[0045] By mass, the additive comprises the following raw materials: 55 parts of calcite, 15 parts of fireclay, 1.5 parts of aluminum powder, 13 parts of deoxidized rubber powder, 11 parts of styrene-acrylic emulsion, and 5 parts of steel fibers;

[0046] Among them, the preparation method of the deoxidized rubber powder is:

[0047] According to the mass ratio of 0.8:1 (i.e., rubber powder: sodium hypochlorite solution), the rubber powder is dispersed in a sodium hypochlorite solution with a mass concentration of 1.5%, and ultrasonically stirred at 35 °C, 900 w, and 1300 rpm for 4 h. Then, suction filtration and washing are carried out successively, and the washed rubber powder is dried at 80 °C to obtain the deoxidized rubber powder.

[0048] (2) Preparation of the additive

[0049] Calcite and fireclay are respectively ground and then passed through a 40-mesh sieve to obtain calcite powder and fireclay powder;

[0050] After mixing the calcite powder, fireclay powder and aluminum powder, they are calcined at 1100 - 1150 °C for 50 min, with a heating rate of 8 - 10 °C / min during this period, and then cooled in the furnace. The cooled mixture is ground and passed through a 40-mesh sieve to obtain a mixed powder;

[0051] Mix the deoxidized rubber powder and steel fibers evenly, then let it stand for 10 minutes to obtain a stirred mixture; then add the mixed powder and styrene-acrylic emulsion to the stirred mixture in sequence and mix evenly. Then, dry the mixture at 120°C to obtain an additive with a water content of 2%.

[0052] (3) Prepare concrete

[0053] By mass, the concrete comprises the following raw materials: 80 parts of cement, 16 parts of sand, 12 parts of gravel, 30 parts of water, and 20 parts of the additive in step (2).

[0054] Example 3

[0055] A preparation method of a high-temperature resistant and high-toughness concrete, the steps are as follows:

[0056] (1) Additive raw materials:

[0057] By mass, the additive comprises the following raw materials: 50 parts of calcite, 15 parts of fireclay, 2 parts of aluminum powder, 13 parts of deoxidized rubber powder, 11 parts of styrene-acrylic emulsion, and 5 parts of steel fibers;

[0058] Among them, the preparation method of the deoxidized rubber powder is as follows:

[0059] Disperse the rubber powder in a sodium hypochlorite solution with a mass concentration of 1.5% according to a mass ratio of 0.6:1 (i.e., rubber powder: sodium hypochlorite solution), carry out ultrasonic stirring at 35°C, 900 w, and 1300 rpm for 4 h, then carry out suction filtration and washing in sequence, and dry the washed rubber powder at 80°C to obtain the deoxidized rubber powder.

[0060] (2) Prepare the additive

[0061] Grind calcite and fireclay respectively and pass through a 40-mesh sieve to obtain calcite powder and fireclay powder;

[0062] Mix the calcite powder, fireclay powder and aluminum powder, then calcine at 1100 - 1150°C for 55 min, with a heating rate of 8 - 10°C / min during the period, and cool with the furnace. Grind the cooled mixture and pass through a 40-mesh sieve to obtain a mixed powder;

[0063] Mix the deoxidized rubber powder and steel fibers evenly, then let it stand for 10 minutes to obtain a stirred mixture; then add the mixed powder and styrene-acrylic emulsion to the stirred mixture in sequence and mix evenly. Then, dry the mixture at 120°C to obtain an additive with a water content of 3%.

[0064] (3) Prepare concrete

[0065] By mass fraction, the concrete comprises the following raw materials: 80 parts of cement, 16 parts of sand, 12 parts of crushed stone, 30 parts of water, and 23 parts of the additive in step (2).

[0066] Comparative Example 1

[0067] A preparation method of a high-temperature resistant and tough concrete, the steps are as follows:

[0068] (1) Additive raw materials:

[0069] By mass fraction, the additive comprises the following raw materials: 50 parts of calcite, 15 parts of pyrophyllite, 2 parts of aluminum powder, 13 parts of rubber powder, 11 parts of styrene-acrylic emulsion, and 5 parts of steel fiber;

[0070] (2) Prepare the additive

[0071] Calcite and pyrophyllite are respectively ground and passed through a 40-mesh sieve to obtain calcite powder and pyrophyllite powder;

[0072] After mixing the calcite powder, pyrophyllite powder and aluminum powder, calcine at 1100 - 1150 °C for 50 min, with a heating rate of 8 - 10 °C / min during the period, and cool with the furnace. Grind the cooled mixture and pass through a 40-mesh sieve to obtain a mixed powder;

[0073] Mix the rubber powder and steel fiber evenly and let stand for 10 min to obtain a stirred material; and add the mixed powder and styrene-acrylic emulsion to the stirred material in sequence and mix evenly. Then dry the mixture at 120 °C to obtain an additive with a water content of 2%.

[0074] (3) Prepare the concrete

[0075] By mass fraction, the concrete comprises the following raw materials: 80 parts of cement, 16 parts of sand, 12 parts of crushed stone, 30 parts of water, and 20 parts of the additive in step (2).

[0076] Comparative Example 2

[0077] A preparation method of a high-temperature resistant and tough concrete, the steps are as follows:

[0078] (1) Additive raw materials:

[0079] By mass fraction, the additive comprises the following raw materials: 70 parts of calcite, 15 parts of pyrophyllite, 2 parts of aluminum powder, 13 parts of deoxidized rubber powder, 11 parts of styrene-acrylic emulsion, and 10 parts of steel fiber;

[0080] Among them, the preparation method of the deoxidized rubber powder is as follows:

[0081] Disperse rubber powder in sodium hypochlorite solution with a mass concentration of 1.5% according to the mass ratio of 0.6:1 (i.e., rubber powder: sodium hypochlorite solution), and perform ultrasonic stirring at 35°C, 900w, and 1300rpm for 4h. Then, perform suction filtration and washing in sequence, and dry the washed rubber powder at 80°C to obtain deoxidized rubber powder.

[0082] (2) Preparation of additives

[0083] Grind calcite and fireclay respectively and pass through a 40-mesh sieve to obtain calcite powder and fireclay powder;

[0084] Mix the calcite powder, fireclay powder and aluminum powder, and calcine at 1100 - 1150°C for 50min. During this period, the heating rate is 8 - 10°C / min, and cool with the furnace. Grind the cooled mixture and pass through a 40-mesh sieve to obtain a mixed powder;

[0085] Mix the deoxidized rubber powder and steel fibers evenly and let stand for 10min to obtain a stirred material; and add the mixed powder and styrene-acrylic emulsion to the stirred material in sequence and mix evenly. Then, dry the mixture at 120°C to obtain an additive with a water content of 2%.

[0086] (3) Preparation of concrete

[0087] By mass, the concrete includes the following raw materials: 80 parts of cement, 16 parts of sand, 12 parts of gravel, 30 parts of water, and 20 parts of the additive in step (2).

[0088] Comparative Example 3

[0089] A preparation method of a high-temperature resistant and tough concrete, the steps are as follows:

[0090] (1) Additive raw materials:

[0091] By mass, the additive includes the following raw materials: 50 parts of dolomite, 15 parts of fireclay, 2 parts of aluminum powder, 13 parts of deoxidized rubber powder, 11 parts of styrene-acrylic emulsion, and 5 parts of steel fiber;

[0092] Among them, the preparation method of the deoxidized rubber powder is:

[0093] Disperse rubber powder in sodium hypochlorite solution with a mass concentration of 1.5% according to the mass ratio of 0.6:1 (i.e., rubber powder: sodium hypochlorite solution), and perform ultrasonic stirring at 35°C, 900w, and 1300rpm for 4h. Then, perform suction filtration and washing in sequence, and dry the washed rubber powder at 80°C to obtain deoxidized rubber powder.

[0094] (2) Preparation of additives

[0095] Dolomite and pyrophyllite are respectively ground and then passed through a 40-mesh sieve to obtain dolomite powder and pyrophyllite powder;

[0096] After mixing the dolomite powder, pyrophyllite powder and aluminum powder, they are calcined at 1100 - 1150 °C for 50 min. During this period, the heating rate is 8 - 10 °C / min, and they are cooled with the furnace. The cooled mixture is ground and passed through a 40-mesh sieve to obtain a mixed powder;

[0097] The deoxidized rubber powder and steel fibers are mixed and stirred evenly, and then left standing for 10 min to obtain a stirred material; and the mixed powder and styrene-acrylic emulsion are sequentially added to the stirred material and mixed evenly. Then, at 120 °C, the mixture is dried to obtain an additive with a water content of 2%.

[0098] (3) Preparation of concrete

[0099] By mass, the concrete includes the following raw materials: 80 parts of cement, 16 parts of sand, 12 parts of gravel, 30 parts of water, and 20 parts of the additive in step (2).

[0100] Comparative Example 4

[0101] A preparation method of a high-temperature resistant and tough concrete, the steps are as follows:

[0102] (1) Additive raw materials:

[0103] By mass, the additive includes the following raw materials: 50 parts of calcite, 15 parts of pyrophyllite, 2 parts of aluminum powder, 13 parts of deoxidized rubber powder, 11 parts of styrene-acrylic emulsion, and 5 parts of cellulose fiber;

[0104] Among them, the preparation method of the deoxidized rubber powder is as follows:

[0105] According to the mass ratio of 0.6:1 (i.e., rubber powder: sodium hypochlorite solution), the rubber powder is dispersed in a sodium hypochlorite solution with a mass concentration of 1.5%, and ultrasonic stirring is carried out at 35 °C, 900 w, and 1300 rpm for 4 h. Then, suction filtration and washing are carried out in sequence, and at 80 °C, the washed rubber powder is dried to obtain the deoxidized rubber powder.

[0106] (2) Preparation of additive

[0107] Calcite and pyrophyllite are respectively ground and then passed through a 40-mesh sieve to obtain calcite powder and pyrophyllite powder;

[0108] After mixing the calcite powder, pyrophyllite powder and aluminum powder, they are calcined at 1100 - 1150 °C for 50 min. During this period, the heating rate is 8 - 10 °C / min, and they are cooled with the furnace. The cooled mixture is ground and passed through a 40-mesh sieve to obtain a mixed powder;

[0109] Mix the deoxidized rubber powder and cellulose fiber evenly by stirring, and then let it stand for 10 minutes to obtain a stirred mixture; then add the mixed powder and styrene-acrylic emulsion to the stirred mixture in sequence and mix evenly. Then, dry the mixture at 120 °C to obtain an additive with a water content of 2%.

[0110] (3) Prepare concrete

[0111] By mass, the concrete comprises the following raw materials: 80 parts of cement, 16 parts of sand, 12 parts of crushed stone, 30 parts of water, and 20 parts of the additive in step (2).

[0112] Comparative Example 5

[0113] A preparation method of a high-temperature resistant and tough concrete, the steps are as follows:

[0114] (1) Additive raw materials:

[0115] By mass, the additive comprises the following raw materials: 50 parts of calcite, 15 parts of pyrophyllite, 2 parts of aluminum powder, 13 parts of deoxidized rubber powder, 11 parts of styrene-acrylic emulsion, and 5 parts of steel fiber;

[0116] Among them, the preparation method of the deoxidized rubber powder is as follows:

[0117] Disperse the rubber powder in a sodium hypochlorite solution with a mass concentration of 1.5% according to a mass ratio of 0.6:1 (i.e., rubber powder: sodium hypochlorite solution), and carry out ultrasonic stirring at 35 °C, 900 w, and 1300 rpm for 4 h. Then, carry out suction filtration and washing in sequence, and dry the washed rubber powder at 80 °C to obtain the deoxidized rubber powder.

[0118] (2) Prepare the additive

[0119] Grind calcite and pyrophyllite respectively and pass through a 40-mesh sieve to obtain calcite powder and pyrophyllite powder;

[0120] Mix the calcite powder, pyrophyllite powder, aluminum powder, deoxidized rubber powder, steel fiber, and styrene-acrylic emulsion evenly, and then dry the mixture at 120 °C to obtain an additive with a water content of 2%.

[0121] (3) Prepare concrete

[0122] By mass, the concrete comprises the following raw materials: 80 parts of cement, 16 parts of sand, 12 parts of crushed stone, 30 parts of water, and 20 parts of the additive in step (2).

[0123] Comparative Example 6

[0124] A preparation method of a high-temperature resistant and tough concrete, the steps are as follows:

[0125] (1) Additive raw materials:

[0126] On a mass fraction basis, the additive comprises the following raw materials: 50 parts of calcite, 15 parts of pyrophyllite, 2 parts of aluminum powder, 13 parts of deoxidized rubber powder, 11 parts of styrene-acrylic emulsion, and 5 parts of steel fiber;

[0127] Among them, the preparation method of the deoxidized rubber powder is as follows:

[0128] Disperse the rubber powder in a sodium hypochlorite solution with a mass concentration of 1.5% according to a mass ratio of 0.6:1 (i.e., rubber powder: sodium hypochlorite solution), carry out ultrasonic stirring at 35 °C, 900 w, and 1300 rpm for 4 h, then carry out suction filtration and washing in sequence, and dry the washed rubber powder at 80 °C to obtain the deoxidized rubber powder.

[0129] (2) Prepare the additive

[0130] Grind calcite and pyrophyllite respectively and then pass through a 40-mesh sieve to obtain calcite powder and pyrophyllite powder;

[0131] Mix the calcite powder, pyrophyllite powder and aluminum powder, then calcine at 1100 - 1150 °C for 50 min, with a heating rate of 8 - 10 °C / min during this period, and cool with the furnace. Grind the cooled mixture and pass through a 40-mesh sieve to obtain a mixed powder;

[0132] Mix the deoxidized rubber powder, steel fiber, mixed powder and styrene-acrylic emulsion evenly, and then dry the mixture at 120 °C to obtain an additive with a water content of 2%.

[0133] (3) Prepare the concrete

[0134] On a mass fraction basis, the concrete comprises the following raw materials: 80 parts of cement, 16 parts of sand, 12 parts of gravel, 30 parts of water, and 40 parts of the additive in step (2).

[0135] Comparative Example 7

[0136] The preparation method of the concrete comprises the following steps:

[0137] On a mass fraction basis, the concrete comprises the following raw materials: 80 parts of cement, 16 parts of sand, 12 parts of gravel, and 30 parts of water.

[0138] Application Example 1

[0139] For the concretes prepared in Examples 1-3 and Comparative Examples 1-7, 12 cubes with a side length of 150 mm were prepared for each type of concrete. After standard curing for 28 days, they were taken out and naturally dried, and the cubes were respectively placed in an environment of 25°C, 200°C, 500°C, and 800°C for isothermal treatment for 3 h (3 parallel repeated cubes were set at each temperature). After cooling to room temperature, the average flexural strength of each treatment was measured, and the results are shown in Table 1.

[0140] Table 1 Average flexural strength in different treatments (unit: Mpa)

[0141] Processing 25℃ 200℃ 500℃ 800℃ Example 1 8.5 6.6 5.1 2.5 Example 2 8.4 6.5 5.1 2.1 Example 3 8.3 6.5 5.0 2.3 Comparative Example 1 6.5 5.2 3.8 0.9 Comparative Example 2 7.3 5.3 3.3 0.8 Comparative Example 3 7.8 5.1 3.6 0.7 Comparative Example 4 7.5 5.8 4.5 1.1 Comparative Example 5 7.1 5.5 4.1 0.9 Comparative Example 6 6.5 4.9 3.2 1.2 Comparative Example 7 6.2 5.0 3.0 0.6

[0142] Combined with the data in Table 1, it can be seen that after preparing concrete with the additives obtained in Examples 1-3, after being treated at 800°C for 3 hours, the highest flexural strength still remained at 2.1 - 2.5 Mpa; while for the concretes prepared by the methods in Comparative Examples 1-7, after high-temperature treatment, the flexural strength decreased significantly. Thus, it can be seen that omitting the additives prepared in the present invention in concrete, or adding the additives obtained by changing raw materials or parameters to concrete, is not conducive to maintaining high flexural strength of concrete.

[0143] Application Example 2

[0144] Using the method in Application Example 1, the concretes prepared in Examples 1-3 and Comparative Examples 1-7 were treated, and the average compressive strength of each treatment was measured, and the results are shown in Table 2.

[0145] Table 2 Average compressive strength in different treatments (unit: Mpa)

[0146]

[0147]

[0148] From the data in Table 2, it can be seen that after preparing concrete by the methods in Examples 1-3, after being treated at 800°C for 3 hours, the compressive strength was above 40.5 Mpa; while for the concretes prepared by the methods in Comparative Examples 1-7, after the same treatment, the highest compressive strength was only 34.2 Mpa.

[0149] To sum up, after the specific combination of calcite, fireclay, aluminum powder, deoxidized rubber powder, styrene-acrylic emulsion, and steel fiber, the raw materials can synergistically exert their effects. Even in a high-temperature environment, it can still improve the toughness of concrete, prevent cracks from occurring in concrete, and make it meet the requirements of tensile, flexural and other structural forms. Therefore, the additive prepared in the present invention can improve the toughness of concrete, and thus is beneficial to increasing the service life of concrete.

[0150] Although the above embodiments have described the present invention in detail, they are only a part of the embodiments of the present invention, rather than all embodiments. People can also obtain other embodiments based on this embodiment without creative efforts, and these embodiments all fall within the protection scope of the present invention.

Claims

1. An additive applicable to enhancing the toughness of concrete at high temperatures, characterized in that, By mass parts, the additive comprises the following raw materials: 50 - 60 parts of calcite, 15 - 20 parts of pyrophyllite, 1 - 2 parts of aluminum powder, 13 - 16 parts of deoxidized rubber powder, 10 - 12 parts of styrene-acrylic emulsion, and 5 - 6 parts of steel fiber.

2. The additive according to claim 1, wherein The preparation method of the deoxidized rubber powder comprises: Dispersing the rubber powder in a sodium hypochlorite solution, and successively performing ultrasonic stirring and drying to obtain the deoxidized rubber powder.

3. The additive according to claim 2, characterized in that, The mass ratio of the rubber powder to the sodium hypochlorite solution is 0.6 - 0.8:1; The mass concentration of the sodium hypochlorite solution is 1.5% - 2.5%.

4. The additive according to claim 2, wherein The parameters of the ultrasonic stirring include: temperature of 35 - 38 °C, time of 3 - 4 h, power of 800 - 900 w, and stirring speed of 1200 - 1300 rpm; The drying temperature is 75 - 85 °C.

5. The preparation method of the additive according to any one of claims 1-4, characterized in that, Comprises the following steps: Mixing calcite powder, pyrophyllite powder and aluminum powder, and successively performing calcination, cooling and grinding to obtain a mixed powder; Mixing and stirring the deoxidized rubber powder and steel fiber to obtain a stirred material; Mixing the mixed powder, the stirred material and the styrene-acrylic emulsion evenly and drying to obtain the additive.

6. The preparation method according to claim 5, characterized in that, The parameters of the calcination include: temperature of 1100 - 1150 °C, time of 50 - 55 min; The mixed powder is the undersize material passing through a 40 - 50 mesh sieve.

7. The preparation method according to claim 5, characterized in that, The drying temperature is 100 - 120 °C.

8. The preparation method according to claim 5, wherein The moisture content of the additive is ≤ 3%.

9. Use of the additive according to any one of claims 1 - 4 in enhancing the toughness of concrete in a high-temperature environment and / or preparing a product for enhancing the toughness of concrete applicable to a high-temperature environment.

10. A method for improving the toughness of concrete applicable to high temperatures, characterized in that, Comprises the following steps: Preparing concrete by using the additive according to any one of claims 1 - 4; The dosage of the additive is 10% - 15% of the total weight of the concrete raw materials.

Images