Pre-mixed colored pervious concrete and preparation method thereof

Abstract

The application relates to the technical field of building materials, and discloses pre-mixed colored water-permeable concrete and a preparation method.The pre-mixed colored water-permeable concrete comprises the following raw materials in parts by weight: cement 420-500 parts, slag 130-180 parts, coarse aggregate 950-1120 parts, water 300-350 parts, a dyeing agent 15-20 parts, biochar 82-100 parts and plant fiber 58-70 parts.The pre-mixed colored water-permeable concrete prepared by the application has excellent water permeability, high strength, good durability, can bear heavy load and complex stress, and is green and environment-friendly.

Description

Technical Field

[0001] This application relates to the field of building materials technology, and in particular to a premixed colored permeable concrete and its preparation method. Background Technology

[0002] In recent years, with urbanization and population growth, the urban surface area has been increasing, and the natural water cycle system within cities has been damaged, leading to problems such as urban flooding, which seriously affects the quality of life of residents.

[0003] Premixed colored permeable concrete is a new type of environmentally friendly material with numerous advantages, such as high permeability and excellent landscaping effects. It can be used not only in urban construction and road paving but also in agriculture and industry. In urban construction, it can improve urban drainage and natural water circulation systems, alleviate urban flooding, and improve residents' quality of life. In agriculture, it can improve soil structure and moisture conditions, increasing crop yield and quality. In industry, it can be used in manufacturing and processing to improve production efficiency and product quality.

[0004] However, existing ready-mixed colored concrete has a porous structure, making it susceptible to pollution and erosion, with poor durability. It is easily affected by external environmental factors such as vehicle pressure and natural climate changes. At the same time, its strength is low, making it prone to cracking and damage when subjected to heavy loads and complex stresses, thus affecting its structure and performance.

[0005] Therefore, there is an urgent need to provide a permeable concrete with high strength and good durability. Summary of the Invention

[0006] In order to solve at least one of the above-mentioned technical problems and develop a permeable concrete with high strength and good durability, this application provides a premixed colored permeable concrete and a preparation method thereof.

[0007] On the one hand, the present application provides a premixed colored permeable concrete, comprising the following raw materials in parts by weight: 420-500 parts cement, 130-180 parts slag, 950-1120 parts coarse aggregate, 300-350 parts water, 15-20 parts dye, 82-100 parts biochar, and 58-70 parts plant fiber.

[0008] By adopting the above technical solution, the premixed colored permeable concrete prepared in this application has excellent permeability, high strength, good durability, can withstand heavy loads and complex stresses, is not easy to crack or break, and is green and environmentally friendly.

[0009] This application uses a specific amount of slag, which can reduce the heat of hydration of concrete and improve its durability and crack resistance. It also uses a specific amount of biochar, which has high porosity and specific surface area, to adsorb moisture, gas, and organic matter in concrete, slowing down evaporation and permeation, and improving its impermeability and durability. Secondly, the addition of biochar can reduce the specific gravity of concrete, improve its thermal insulation performance, thereby reducing energy consumption and carbon emissions, and significantly improving capillary water absorption and retention capacity. Furthermore, biochar contains a large amount of organic matter, such as humic acid, which can react with chemicals such as calcium hydroxide in concrete to form stable calcium salt and organic matter complexes, improving the strength and hardness of the concrete.

[0010] The plant fibers added in this application can increase the toughness and impact resistance of concrete, acting as a "micro-skeleton" in the concrete. They can absorb and disperse impact energy, making the concrete less prone to breakage when subjected to impact and improving its durability.

[0011] Optionally, the weight ratio of the biochar to the plant fiber is 1.3-1.5:1.

[0012] By adopting the above technical solution, this application uses a better ratio of biochar and plant fiber, and the prepared premixed colored permeable concrete has better overall performance.

[0013] Optionally, the specific surface area of ​​the biochar is 280-450 m². 2 / g.

[0014] Optionally, the average particle size of the biochar is 100-500 μm.

[0015] By adopting the above technical solution, this application uses biochar with a specific specific surface area and average particle size, which has a high surface energy, can provide better adsorption performance and better permeation performance, and can better penetrate into concrete to improve the strength and durability of concrete.

[0016] Optionally, the plant fiber is one or more of coconut fiber, flax fiber, or palm fiber.

[0017] Optionally, the plant fiber is any two of coconut fiber, flax fiber, or palm fiber, and the weight ratio of any two plant fibers is 1:1.

[0018] Optionally, the plant fiber is coconut fiber, flax fiber, and palm fiber, and the weight ratio of the coconut fiber, the flax fiber, and the palm fiber is 0.3-0.5:0.2-0.6:0.3-0.5.

[0019] By adopting the above technical solution, this application uses a plant fiber system prepared by a specific ratio of coconut fiber, flax fiber and palm fiber, which has good toughness and impact resistance, can enhance the crack resistance and fatigue resistance of concrete, and the addition of these plant fibers can also provide a certain thermal insulation effect for concrete, improving its durability and stability.

[0020] Optionally, the plant fiber is a modified plant fiber, and the raw materials of the modified plant fiber include plant fiber, polyolefin and initiator in a weight ratio of 1:0.8-1.5:0.1-0.15.

[0021] By adopting the above technical solution, this application introduces flexible segments into plant fibers to prepare modified plant fibers, which improves the flexibility of plant fibers and their compatibility with concrete components. The modified plant fibers can be better dispersed in concrete and form a more uniform structure. At the same time, the introduction of flexible segments can also effectively alleviate the stress concentration inside the concrete, improve the toughness and impact resistance of the concrete, and also have good durability and stability.

[0022] Optionally, the biochar is one of coconut shell charcoal, bamboo charcoal, or rice straw charcoal.

[0023] By adopting the above technical solution, the premixed colored permeable concrete prepared in this application has excellent strength, durability and stability.

[0024] On the other hand, this application provides a method for preparing premixed colored permeable concrete, comprising the following steps:

[0025] S1. After mixing cement and slag, add coarse aggregate and continue mixing to prepare mixture A;

[0026] S2. Mix biochar and plant fiber together to prepare mixture B;

[0027] S3. Mix the mixture A, water and dye together, then add the mixture B and mix again to prepare premixed colored permeable concrete.

[0028] By adopting the above technical solution, the preparation method of the premixed colored permeable concrete of this application is simple, easy to implement, and low in cost, which can meet the needs of large-scale production; moreover, the prepared premixed colored permeable concrete has excellent strength, durability and stability.

[0029] In summary, the present invention has at least one of the following beneficial technical effects:

[0030] 1. The premixed colored permeable concrete prepared in this application has excellent permeability, high strength, good durability, can withstand heavy loads and complex stresses, and is also green and environmentally friendly;

[0031] 2. This application uses a specific amount of biochar, which has high porosity and specific surface area. It can adsorb moisture, gas, organic matter, etc. in concrete, slow down evaporation and permeation in concrete, and improve the impermeability and durability of concrete. Secondly, the incorporation of biochar can reduce the specific gravity of concrete, improve the thermal insulation performance of concrete, thereby reducing the energy consumption and carbon emissions of concrete, and significantly improve capillary water absorption and water retention capacity. In addition, biochar contains a large amount of organic matter, such as humic acid, which can react with chemical substances such as calcium hydroxide in concrete to form a stable calcium salt and organic matter complex, thereby improving the strength and hardness of concrete.

[0032] 3. The plant fibers added in this application can increase the toughness and impact resistance of concrete, and play the role of "micro-skeleton" in concrete. They can absorb and disperse impact energy, making concrete less prone to breakage when subjected to impact and improving its durability.

[0033] 4. The preparation method of the premixed colored permeable concrete of this application is simple, easy to implement, and low in cost, which can meet the needs of large-scale production. Detailed Implementation

[0034] The present application will be further described in detail below with reference to the embodiments.

[0035] This application designs a premixed colored permeable concrete, comprising the following raw materials in parts by weight: 420-500 parts cement, 130-180 parts slag, 950-1120 parts coarse aggregate, 300-350 parts water, 15-20 parts dye, 82-100 parts biochar, and 58-70 parts plant fiber.

[0036] The present application discloses a method for preparing premixed colored permeable concrete, comprising the following steps:

[0037] S1. After mixing cement and slag, add coarse aggregate and continue mixing to prepare mixture A;

[0038] S2. Mix biochar and plant fiber together to prepare mixture B;

[0039] S3. Mix the mixture A, water and dye together, then add the mixture B and mix again to prepare premixed colored permeable concrete. Specific Implementation

[0041] The raw materials used in this application are as follows. Unless otherwise specified, all raw materials used in this application are commercially available:

[0042] Cement: CAS No. 1327-39-5;

[0043] Slag: Its chemical composition includes 85-95% SiO2;

[0044] Coarse aggregate: 6-9mm single-grade limestone crushed stone;

[0045] Water: Selected from tap water;

[0046] Staining agent: Selected from iron oxide yellow, CAS number, 51274-00-1;

[0047] Polyolefin: Shanghai Jufu New Material Technology Co., Ltd., Model: PP AW864;

[0048] Coconut fiber: 10-15mm in length and 8-10μm in diameter;

[0049] Flax fiber: 10-15mm in length and 8-10μm in diameter;

[0050] Palm fiber: 10-15mm in length and 8-10μm in diameter;

[0051] Initiator: Selected from methyl ethyl ketone peroxide, CAS No. 1338-23-4;

[0052] Coconut shell charcoal: 95% purity;

[0053] Bamboo charcoal: 95% purity;

[0054] Rice straw charcoal: 95% purity.

[0055] Testing items and methods:

[0056] Compressive strength and flexural strength (MPa): tested according to GB / T50081-2019 Standard for Test Methods of Physical and Mechanical Properties of Concrete;

[0057] Freeze-thaw cycle resistance: Tested according to GB / T 50082-2009 "Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete".

[0058] Examples 1-3

[0059] The specific raw material dosages for a premixed colored permeable concrete in Examples 1-3 are shown in Table 1.

[0060] Table 1

[0061]

[0062]

[0063] The biochar was selected from rice straw charcoal, with a specific surface area of ​​280 m². 2 / g, with an average particle size of 100μm, and the plant fiber is selected from coconut fiber.

[0064] The preparation methods of premixed colored permeable concrete in Examples 1-3 include the following steps:

[0065] S1. After mixing cement and slag, add coarse aggregate and continue mixing to prepare mixture A;

[0066] S2. Mix biochar and plant fiber together to prepare mixture B;

[0067] S3. Mix mixture A, water and dye, then add mixture B and mix to prepare premixed colored permeable concrete.

[0068] Comparative Example 1

[0069] Based on Example 2, except that an equal amount of plant fiber was used to replace biochar, the other components and preparation methods were the same as in Example 2.

[0070] Comparative Example 2

[0071] Based on Example 2, except that an equal amount of biochar was used to replace plant fiber, the other components and preparation methods were the same as in Example 2.

[0072] Comparative Example 3

[0073] Based on Example 2, except for the different preparation method, the other components are the same as in Example 2. The specific preparation method is as follows: S1, take cement, slag and coarse aggregate, mix and stir to prepare mixture A;

[0074] S2. Add biochar and plant fiber to mixture A, mix and stir to prepare mixture B;

[0075] S3. Mix mixture A, mixture B, water and dye to prepare premixed colored permeable concrete.

[0076] The performance of the premixed colored permeable concrete prepared in Examples 1-3 and Comparative Examples 1-3 was tested, and the test results are shown in Table 2.

[0077] Table 2

[0078]

[0079] As can be seen from Examples 1-3, Comparative Examples 1-3 and Table 2, the premixed colored permeable concrete prepared in this application has excellent comprehensive performance, with a 28-day compressive strength of 50.5-52.7 MPa, a 28-day flexural strength of 4.9-5.2 MPa, and a freeze-thaw cycle resistance of 195-205, indicating high strength and good durability.

[0080] As can be seen from Comparative Examples 1-2, Example 2 and Table 2, the premixed colored permeable concrete prepared by adding only biochar or only plant fiber has poor comprehensive performance. However, the premixed colored permeable concrete prepared by adding both biochar and plant fiber has excellent strength and durability. The inventors speculate that the biochar and plant fiber compound system can comprehensively improve the comprehensive performance of concrete.

[0081] As can be seen from Comparative Example 3, Example 2 and Table 2, the present application adopts a specific method for preparing premixed colored permeable concrete, which results in more uniform dispersion of raw material components and superior overall performance of the prepared concrete.

[0082] Examples 4-5

[0083] Based on Example 2, except for the different weight ratio of biochar and plant fiber, the other components and preparation methods are the same as in Example 2.

[0084] Example 4

[0085] The total weight of biochar and plant fiber is 145 kg, and the weight ratio of biochar to plant fiber is 1.4:1.

[0086] Example 5

[0087] The total weight of biochar and plant fiber is 145 kg, and the weight ratio of biochar to plant fiber is 1.5:1.

[0088] Examples 6-7

[0089] Based on Example 4, except for the type of biochar, the other components and preparation methods are the same as in Example 4.

[0090] Example 6

[0091] Biochar is made from bamboo and wood.

[0092] Example 7

[0093] The biochar is made from coconut shells.

[0094] Examples 8-9

[0095] Based on Example 7, except for the specific surface area and average particle size of the biochar, the other components and preparation methods are the same as in Example 7.

[0096] Example 8

[0097] Biochar has a specific surface area of ​​350 m². 2 / g, with an average particle size of 300μm.

[0098] Example 9

[0099] The specific surface area of ​​biochar is 450 m².2 / g, with an average particle size of 500μm.

[0100] The performance of the premixed colored permeable concrete prepared in Examples 4-9 was tested, and the test results are shown in Table 3.

[0101] Table 3

[0102]

[0103] As can be seen from Examples 4-5, 2 and Table 3, the premixed colored permeable concrete prepared by this application using a better ratio of biochar and plant fiber has superior overall performance.

[0104] As can be seen from Examples 6-7, 4 and Table 3, compared with rice straw charcoal and bamboo charcoal, the premixed colored permeable concrete prepared by coconut shell charcoal selected in this application has better comprehensive performance. The inventors speculate that although rice straw charcoal, bamboo charcoal and coconut shell charcoal are all porous materials, coconut shell charcoal has a more obvious effect on improving the pore structure and interface performance of the prepared concrete.

[0105] As can be seen from Examples 7-9 and Table 3, the biochar selected in this application has a better specific surface area and average particle size, which has higher surface energy, can provide better adsorption performance, and better permeation performance, and can better penetrate into concrete to improve the strength and durability of concrete.

[0106] Examples 10-15

[0107] Based on Example 8, except that the weight of the plant fiber is 63 kg and the plant fiber is different, the other components and preparation methods are the same as in Example 8.

[0108] Example 10

[0109] The plant fiber is flax fiber.

[0110] Example 11

[0111] The plant fiber is palm fiber.

[0112] Example 12

[0113] The plant fibers are coconut fiber and flax fiber, with a weight ratio of 1:1.

[0114] Example 13

[0115] The plant fibers are coconut fiber and palm fiber, with a weight ratio of 1:1.

[0116] Example 14

[0117] The plant fibers are flax and palm fibers, with a weight ratio of 1:1.

[0118] Example 15

[0119] The plant fibers are coconut fiber, flax fiber and palm fiber, with a weight ratio of 1:1:1.

[0120] Examples 16-17

[0121] Based on Example 15, except that the weight of plant fiber remains the same and the weight ratio of coconut fiber, flax fiber and palm fiber is different, the other components and preparation methods are the same as in Example 15.

[0122] Example 16

[0123] The weight ratio of coconut fiber, flax fiber, and palm fiber is 0.3:0.2:0.3.

[0124] Example 17

[0125] The weight ratio of coconut fiber, flax fiber, and palm fiber is 0.5:0.6:0.5.

[0126] Examples 18-20

[0127] Based on Example 15, except that the plant fiber is modified plant fiber and the raw materials of the modified plant fiber include plant fiber, polyolefin and initiator, the other components and preparation methods are the same as in Example 15;

[0128] The initiator is methyl ethyl ketone peroxide;

[0129] Preparation method of modified plant fiber: Take plant fiber, add 0.1 mol / L sodium hydroxide solution and stir for 40 min. Take out the plant fiber, clean and dry it. Then add polyolefin and initiator and react at 85℃ for 2 h to obtain modified plant fiber. The amount of sodium hydroxide solution is 1.2 times the amount of plant fiber.

[0130] Example 18

[0131] The weight ratio of plant fiber, polyolefin and initiator is 1:0.8:0.1.

[0132] Example 19

[0133] The weight ratio of plant fiber, polyolefin and initiator is 1:1.2:0.12.

[0134] Example 20

[0135] The weight ratio of plant fiber, polyolefin and initiator is 1:1.5:0.15.

[0136] The performance of the premixed colored permeable concrete prepared in Examples 10-20 was tested, and the test results are shown in Table 4.

[0137] Table 4

[0138]

[0139]

[0140] As can be seen from Examples 10-11, 8 and Table 4, the strength of the premixed colored permeable concrete prepared with coconut fiber in this application is better than that of the premixed colored permeable concrete prepared with flax fiber or palm fiber, and the freeze-thaw resistance of the premixed colored permeable concrete prepared with flax fiber is better than that of the premixed colored permeable concrete prepared with coconut fiber or palm fiber.

[0141] As can be seen from Examples 11-15 and Table 4, the premixed colored permeable concrete prepared by using plant fibers prepared by combining coconut fiber, flax fiber and palm fiber in this application has better overall performance.

[0142] As can be seen from Examples 15-17 and Table 4, the premixed colored permeable concrete prepared by selecting a better ratio of coconut fiber, flax fiber and palm fiber in this application has better overall performance. The inventors speculate that the plant fiber system prepared by using a specific ratio of coconut fiber, flax fiber and palm fiber has better toughness and impact resistance, which can enhance the crack resistance and fatigue resistance of concrete. In addition, the addition of these plant fibers can also provide a certain thermal insulation effect for concrete, and improve its durability and stability.

[0143] As can be seen from Examples 15, 18-20 and Table 4, the premixed colored permeable concrete prepared using modified plant fibers in this application exhibits superior overall performance. The inventors speculate that by introducing flexible segments into the plant fibers to prepare modified plant fibers, the flexibility of the plant fibers and their compatibility with concrete components are improved. The modified plant fibers can be better dispersed in the concrete and form a more uniform structure. At the same time, the introduction of flexible segments can effectively alleviate stress concentration within the concrete, improve the toughness and impact resistance of the concrete, and also have good durability and stability.

[0144] The above are all 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 principles of this application should be covered within the scope of protection of this application.

Claims

1. A premixed colored permeable concrete, characterized in that, The raw materials include the following parts by weight: 420-500 parts cement, 130-180 parts slag, 950-1120 parts coarse aggregate, 300-350 parts water, 15-20 parts dye, 82-100 parts biochar, and 58-70 parts modified plant fiber. The modified plant fiber raw materials include plant fiber, polyolefin and initiator in a weight ratio of 1:0.8-1.5:0.1-0.15; The modified plant fiber comprises coconut fiber, flax fiber, and palm fiber, wherein the weight ratio of coconut fiber, flax fiber, and palm fiber is 0.3-0.5:0.2-0.6:0.3-0.

5. The weight ratio of the biochar to the plant fiber is 1.3-1.5:

1.

2. The premixed colored permeable concrete according to claim 1, characterized in that, The specific surface area of ​​the biochar is 280-450 m². 2 / g.

3. The premixed colored permeable concrete according to claim 1, characterized in that, The average particle size of the biochar is 100-500 μm.

4. The premixed colored permeable concrete according to claim 1, characterized in that, The biochar is one of coconut shell charcoal, bamboo charcoal, or rice straw charcoal.

5. A method for preparing premixed colored permeable concrete according to any one of claims 1-4, characterized in that, Includes the following steps: S1. After mixing cement and slag, add coarse aggregate and continue mixing to prepare mixture A; S2. Mix biochar and modified plant fiber together to prepare mixture B; S3. Mix the mixture A, water and dye together, then add the mixture B and mix again to obtain the premixed colored permeable concrete.

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