Highly pervious concrete and method for its production

Abstract

The application discloses high water permeable concrete and a preparation method thereof, and belongs to the technical field of concrete. The high water permeable concrete is prepared from the following raw materials in parts by weight: 1100-1300 parts of coarse aggregate, 320-350 parts of cement, 50-70 parts of reinforcing fiber, 2-4 parts of water reducing agent, 110-120 parts of water, 48-60 parts of fly ash, 46-75 parts of compound microcapsules and 22-32 parts of cementing reinforcing agent. The high water permeable concrete has high water permeability, excellent mechanical strength and durability by the synergistic effect of the compound microcapsules of Bacillus psuedofirmus and Bacillus sphaericus and the cementing reinforcing agent. In addition, the high water permeable concrete is used to prepare water permeable pavement, and has the advantages of convenient construction, quick elimination of the water accumulation phenomenon during raining and effective play of the water permeable concrete.

Description

Technical Field

[0001] This invention belongs to the field of concrete technology, specifically relating to a highly permeable concrete and its preparation method. Background Technology

[0002] In recent years, my country has made remarkable achievements in urban construction. However, the rapid pace of urbanization has also brought significant pressure and numerous problems to cities. On the one hand, many cities have inadequate drainage systems, hindering surface water infiltration. Many parts of the city are flooded by rainwater, severely impacting people's daily lives. On the other hand, urban construction has altered many resources and the environment, disrupting normal river networks and making it even more difficult to drain surface water, leading to frequent urban flooding. Furthermore, urban land use has undergone significant changes, with large amounts of concrete and other road materials covering the urban surface, significantly reducing the permeability of the underlying surface. This has resulted in a series of urban problems such as urban flooding, land subsidence, noise pollution, and the urban heat island effect.

[0003] Permeable concrete is a new type of green and environmentally friendly concrete. It features continuous air pores and excellent air permeability and infiltration. Permeable concrete pavement can replenish groundwater, alleviate urban flooding, reduce noise, improve the urban thermal environment, and generate significant environmental and social benefits. The construction of permeable concrete pavement involves directly laying permeable mixed materials on the embankment, followed by compaction and curing. To ensure smooth rainwater infiltration, the permeable cement concrete subgrade should possess a certain degree of stability and homogeneity. Compared to conventional closed pavements, permeable pavements are open.

[0004] However, concrete still suffers from problems such as high cost, low strength, and weak durability. Therefore, it is particularly important to develop permeable concrete with high permeability, good mechanical properties, and excellent durability. Summary of the Invention

[0005] The purpose of this invention is to provide a highly permeable concrete that solves the problems of low mechanical strength and weak durability of permeable concrete.

[0006] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0007] A highly permeable concrete is prepared from the following raw materials in parts by weight: 1100-1300 parts coarse aggregate, 320-350 parts cement, 50-70 parts reinforcing fiber, 2-4 parts water-reducing agent, 110-120 parts water, 48-60 parts fly ash, 46-75 parts compound microcapsules, and 22-32 parts cementitious reinforcing agent.

[0008] Furthermore, the coarse aggregate is 5-10mm crushed stone; the reinforcing fiber is steel fiber with a length of 32mm and a width of 5mm.

[0009] Furthermore, the bonding reinforcing agent includes hydroxypropyl methylcellulose, ethylene glycol, and diacetone acrylamide, with a mass ratio of 2:1:1.

[0010] Furthermore, the preparation method of the compound microcapsules is as follows:

[0011] S1: Add sodium alginate to a beaker containing 70°C distilled water, stir until completely dissolved, cool to room temperature, add wet cells of Bacillus sarcopene and Bacillus pseudomycosis, mix well, then add peptone and inulin, mix well, let stand to remove air bubbles, and obtain encapsulating liquid;

[0012] S2: Dissolve chitosan in a 1% citric acid solution to prepare a chitosan solution, and then add calcium chloride to the chitosan solution to prepare a calcium chloride solution.

[0013] S3: Under magnetic stirring, use a 1ml syringe to dropwise add the encapsulation fluid into a calcium chloride solution containing chitosan, controlling the drip rate to 30 drops per minute;

[0014] S4: After dripping, let stand for 15 minutes to allow the curing reaction to complete. After cross-linking, filter and collect the fresh microspheres, and air dry them in a constant temperature incubator at 28℃ for 2-3 days to obtain the compound microcapsules.

[0015] Furthermore, in the encapsulation liquid of step S1, the mass fraction of sodium alginate is 2%; the mass fraction of wet Bacillus sarcopenia is 0.3%; the mass fraction of wet Bacillus pseudomycosis is 0.3%; the mass fraction of peptone is 3%; and the mass fraction of inulin is 1%.

[0016] Furthermore, the strain number of *Bacillus sauris* is CCTCC No. AB 2010438, purchased from the China Center for Type Culture Collection; the strain number of *Bacillus pseudomycosis* is CCTCC No. AB 2015320, purchased from the China Center for Type Culture Collection.

[0017] Furthermore, in step S2, the chitosan solution contains 0.7% chitosan by mass; and in step S2, the calcium chloride contains 4% calcium chloride by mass.

[0018] Furthermore, in step S3, the magnetic stirring speed is 300 r / min.

[0019] A method for preparing highly permeable concrete, comprising the following steps:

[0020] Mix cement, coarse aggregate, fly ash, reinforcing fiber, and binder evenly. Add 2 / 3 of the formula amount of water and stir for 3-5 minutes. Add compound microcapsules and water-reducing agent and stir for 1 minute. Add the remaining water and stir for 2-3 minutes before discharging to obtain highly permeable concrete.

[0021] The present invention uses only coarse aggregate, which effectively increases the porosity of concrete slurry and improves the permeability of concrete.

[0022] This invention's compound microcapsules contain *Bacillus salicylates* and *Bacillus pseudomycosis*. When cracks appear in concrete, air and water enter the cracks, activating dormant microorganisms. *Bacillus salicylates* and *Bacillus pseudomycosis* work synergistically to initiate metabolic activity, consuming oxygen and producing carbon dioxide. They react with calcium ions in the environment to form calcium carbonate. The deposition of calcium carbonate forms a dense calcium carbonate film, covering the crack surface and improving its mechanical properties and freeze-thaw resistance. This invention's compound microcapsules also contain peptone and inulin, nutrients essential for microbial survival, effectively ensuring the survival and reproduction of the microorganisms.

[0023] The binder enhancer of this invention possesses excellent adhesion and thickening properties. Hydroxypropyl methylcellulose, on the one hand, increases the viscosity of the paste, improves the bond between coarse aggregate and the paste, and prevents aggregate from floating and separating; on the other hand, it helps improve the fluidity of concrete, making it easier to pour. Ethylene glycol is commonly used as an antifreeze agent, improving the toughness and durability of concrete. In this invention, the binder enhancer, due to the addition of ethylene glycol, can adjust the plastic state of the concrete, indirectly enhancing the bond between aggregate and paste. Diacetone acrylamide can be used to prepare high-performance copolymer films to enhance material properties. The combination of hydroxypropyl methylcellulose, ethylene glycol, and diacetone acrylamide effectively improves the bond between the various components of concrete, prevents surface cracking, effectively improves the crack resistance of concrete, effectively improves the durability of concrete, and simultaneously improves the uniformity and stability of concrete.

[0024] Beneficial effects

[0025] This invention achieves high permeability and frost resistance in the prepared permeable concrete by rationally compounding coarse aggregate, cement, microcapsules, and binder, while also exhibiting high mechanical strength, strong durability, and excellent overall performance.

[0026] This invention utilizes highly permeable concrete to prepare permeable pavements, which are easy to construct and quickly eliminate water accumulation during rain, effectively leveraging the properties of permeable concrete. Detailed Implementation

[0027] The technical solution of the present invention will be further described below with reference to specific embodiments, but it is not limited thereto.

[0028] Example 1

[0029] A highly permeable concrete is prepared from the following raw materials in parts by weight:

[0030] 1100 parts coarse aggregate, 320 parts cement, 50 parts reinforcing fiber, 2 parts water-reducing agent, 110 parts water, 48 parts fly ash, 46 parts compound microcapsules, and 22 parts cementing and reinforcing agent.

[0031] The coarse aggregate is 5-10mm crushed stone; the reinforcing fiber is steel fiber with a length of 32mm and a width of 5mm.

[0032] The bonding reinforcing agent includes hydroxypropyl methylcellulose, ethylene glycol, and diacetone acrylamide, with a mass ratio of 2:1:1.

[0033] The preparation method of the compound microcapsules is as follows:

[0034] S1: Add sodium alginate to a beaker containing 70°C distilled water, stir until completely dissolved, cool to room temperature, add wet cells of Bacillus sarcopene and Bacillus pseudomycosis, mix well, then add peptone and inulin, mix well, let stand to remove air bubbles, and obtain encapsulating liquid;

[0035] S2: Dissolve chitosan in a 1% citric acid solution to prepare a chitosan solution, and then add calcium chloride to the chitosan solution to prepare a calcium chloride solution.

[0036] S3: Under magnetic stirring, use a 1ml syringe to dropwise add the encapsulation fluid into a calcium chloride solution containing chitosan, controlling the drip rate to 30 drops per minute;

[0037] S4: After dripping, let stand for 15 minutes to allow the curing reaction to complete. After cross-linking, filter and collect the fresh microspheres, and air dry them in a constant temperature incubator at 28℃ for 2-3 days to obtain the compound microcapsules.

[0038] In the encapsulation fluid of step S1, the mass fraction of sodium alginate is 2%; the mass fraction of wet Bacillus sarcopenia is 0.3%; the mass fraction of wet Bacillus pseudomycosis is 0.3%; the mass fraction of peptone is 3%; and the mass fraction of inulin is 1%.

[0039] The strain of *Bacillus sarcopenia*, numbered CCTCC No. AB 2010438, was purchased from the China Center for Type Culture Collection; the strain of *Bacillus pseudomycosis*, numbered CCTCC No. AB 2015320, was also purchased from the China Center for Type Culture Collection.

[0040] In step S2, the mass fraction of chitosan is 0.7%; the mass fraction of calcium chloride is 4%.

[0041] In step S3, the magnetic stirring speed is 300 r / min.

[0042] A method for preparing highly permeable concrete, comprising the following steps:

[0043] Mix cement, coarse aggregate, fly ash, reinforcing fiber, and binder evenly. Add 2 / 3 of the formula amount of water and stir for 3-5 minutes. Add compound microcapsules and water-reducing agent and stir for 1 minute. Add the remaining water and stir for 2-3 minutes before discharging to obtain highly permeable concrete.

[0044] Example 2

[0045] A highly permeable concrete is prepared from the following raw materials in parts by weight:

[0046] 1200 parts coarse aggregate, 330 parts cement, 60 parts reinforcing fiber, 3 parts water-reducing agent, 115 parts water, 54 parts fly ash, 60 parts compound microcapsules, and 25 parts cementing and reinforcing agent.

[0047] The coarse aggregate is 5-10mm crushed stone; the reinforcing fiber is steel fiber with a length of 32mm and a width of 5mm.

[0048] The bonding reinforcing agent includes hydroxypropyl methylcellulose, ethylene glycol, and diacetone acrylamide, with a mass ratio of 2:1:1.

[0049] The preparation method of the compound microcapsules is as follows:

[0050] S1: Add sodium alginate to a beaker containing 70°C distilled water, stir until completely dissolved, cool to room temperature, add wet cells of Bacillus sarcopene and Bacillus pseudomycosis, mix well, then add peptone and inulin, mix well, let stand to remove air bubbles, and obtain encapsulating liquid;

[0051] S2: Dissolve chitosan in a 1% citric acid solution to prepare a chitosan solution, and then add calcium chloride to the chitosan solution to prepare a calcium chloride solution.

[0052] S3: Under magnetic stirring, use a 1ml syringe to dropwise add the encapsulation fluid into a calcium chloride solution containing chitosan, controlling the drip rate to 30 drops per minute;

[0053] S4: After dripping, let stand for 15 minutes to allow the curing reaction to complete. After cross-linking, filter and collect the fresh microspheres, and air dry them in a constant temperature incubator at 28℃ for 2-3 days to obtain the compound microcapsules.

[0054] The encapsulation liquid in step S1 contains 2% sodium alginate by mass; the encapsulation liquid in step S1 contains 0.3% wet Bacillus sarcopeniae cells and 0.3% wet Bacillus pseudomycosis cells; the encapsulation liquid in step S1 contains 3% peptone by mass and 1% inulin by mass.

[0055] The strain of *Bacillus sarcopenia*, numbered CCTCC No. AB 2010438, was purchased from the China Center for Type Culture Collection; the strain of *Bacillus pseudomycosis*, numbered CCTCC No. AB 2015320, was also purchased from the China Center for Type Culture Collection.

[0056] In step S2, the mass fraction of chitosan is 0.7%; in step S2, the mass fraction of calcium chloride is 4%.

[0057] In step S3, the magnetic stirring speed is 300 r / min.

[0058] A method for preparing highly permeable concrete, comprising the following steps:

[0059] Mix cement, coarse aggregate, fly ash, reinforcing fiber, and binder evenly. Add 2 / 3 of the formula amount of water and stir for 3-5 minutes. Add compound microcapsules and water-reducing agent and stir for 1 minute. Add the remaining water and stir for 2-3 minutes before discharging to obtain highly permeable concrete.

[0060] Example 3

[0061] A highly permeable concrete is prepared from the following raw materials in parts by weight:

[0062] 1300 parts coarse aggregate, 350 parts cement, 70 parts reinforcing fiber, 4 parts water-reducing agent, 120 parts water, 60 parts fly ash, 75 parts compound microcapsules, and 32 parts cementing and reinforcing agent.

[0063] The coarse aggregate is 5-10mm crushed stone; the reinforcing fiber is steel fiber with a length of 32mm and a width of 5mm.

[0064] The bonding reinforcing agent includes hydroxypropyl methylcellulose, ethylene glycol, and diacetone acrylamide, with a mass ratio of 2:1:1.

[0065] The preparation method of the compound microcapsules is as follows:

[0066] S1: Add sodium alginate to a beaker containing 70°C distilled water, stir until completely dissolved, cool to room temperature, add wet cells of Bacillus sarcopene and Bacillus pseudomycosis, mix well, then add peptone and inulin, mix well, let stand to remove air bubbles, and obtain encapsulating liquid;

[0067] S2: Dissolve chitosan in a 1% citric acid solution to prepare a chitosan solution, and then add calcium chloride to the chitosan solution to prepare a calcium chloride solution.

[0068] S3: Under magnetic stirring, use a 1ml syringe to dropwise add the encapsulation fluid into a calcium chloride solution containing chitosan, controlling the drip rate to 30 drops per minute;

[0069] S4: After dripping, let stand for 15 minutes to allow the curing reaction to complete. After cross-linking, filter and collect the fresh microspheres, and air dry them in a constant temperature incubator at 28℃ for 2-3 days to obtain the compound microcapsules.

[0070] The mass fraction of sodium alginate in the encapsulation fluid of step S1 is 2%; the mass fraction of wet Bacillus sarcopenia is 0.3%; the mass fraction of wet Bacillus pseudomycosis is 0.3%; the mass fraction of peptone is 3%; and the mass fraction of inulin is 1%.

[0071] The strain of *Bacillus sarcopenia*, numbered CCTCC No. AB 2010438, was purchased from the China Center for Type Culture Collection; the strain of *Bacillus pseudomycosis*, numbered CCTCC No. AB 2015320, was also purchased from the China Center for Type Culture Collection.

[0072] In step S2, the mass fraction of chitosan is 0.7%; the mass fraction of calcium chloride is 4%.

[0073] In step S3, the magnetic stirring speed is 300 r / min.

[0074] A method for preparing highly permeable concrete, comprising the following steps:

[0075] Mix cement, coarse aggregate, fly ash, reinforcing fiber, and binder evenly. Add 2 / 3 of the formula amount of water and stir for 3-5 minutes. Add compound microcapsules and water-reducing agent and stir for 1 minute. Add the remaining water and stir for 2-3 minutes before discharging to obtain highly permeable concrete.

[0076] Comparative Example 1

[0077] A highly permeable concrete is prepared from the following raw materials in parts by weight:

[0078] 1300 parts coarse aggregate, 350 parts cement, 70 parts reinforcing fiber, 4 parts water-reducing agent, 120 parts water, 60 parts fly ash, 75 parts compound microcapsules, and 32 parts cementing and reinforcing agent.

[0079] The coarse aggregate is 5-10mm crushed stone; the reinforcing fiber is steel fiber with a length of 32mm and a width of 5mm.

[0080] The bonding reinforcing agent includes hydroxypropyl methylcellulose, ethylene glycol, and diacetone acrylamide, with a mass ratio of 2:1:1.

[0081] The preparation method of the compound microcapsules is as follows:

[0082] S1: Add sodium alginate to a beaker containing 70°C distilled water, stir until completely dissolved, cool to room temperature, add wet Bacillus salsa cells and mix well, then add peptone and inulin, mix well, let stand to remove air bubbles, and obtain encapsulating liquid;

[0083] S2: Dissolve chitosan in a 1% citric acid solution to prepare a chitosan solution, and then add calcium chloride to the chitosan solution to prepare a calcium chloride solution.

[0084] S3: Under magnetic stirring, use a 1ml syringe to dropwise add the encapsulation fluid into a calcium chloride solution containing chitosan, controlling the drip rate to 30 drops per minute;

[0085] S4: After dripping, let stand for 15 minutes to allow the curing reaction to complete. After cross-linking, filter and collect the fresh microspheres, and air dry them in a constant temperature incubator at 28℃ for 2-3 days to obtain the compound microcapsules.

[0086] The encapsulation fluid in step S1 contains 2% sodium alginate by mass; 0.6% wet Bacillus saprophyticus cells by mass; 3% peptone by mass; and 1% inulin by mass.

[0087] The strain of *Bacillus sauris* was numbered CCTCC No. AB 2010438 and was purchased from the China Center for Type Culture Collection.

[0088] In step S2, the mass fraction of chitosan is 0.7%; the mass fraction of calcium chloride is 4%.

[0089] In step S3, the magnetic stirring speed is 300 r / min.

[0090] A method for preparing highly permeable concrete, comprising the following steps:

[0091] Mix cement, coarse aggregate, fly ash, reinforcing fiber, and binder evenly. Add 2 / 3 of the formula amount of water and stir for 3-5 minutes. Add compound microcapsules and water-reducing agent and stir for 1 minute. Add the remaining water and stir for 2-3 minutes before discharging to obtain highly permeable concrete.

[0092] Compared with Example 3, this comparative example is identical to Example 3 except that only Bacillus sarcopene is added to the microcapsules. The source materials and steps are the same as in Example 3.

[0093] Comparative Example 2

[0094] A highly permeable concrete is prepared from the following raw materials in parts by weight:

[0095] 1300 parts coarse aggregate, 350 parts cement, 70 parts reinforcing fiber, 4 parts water-reducing agent, 120 parts water, 60 parts fly ash, 75 parts compound microcapsules, and 32 parts cementing and reinforcing agent.

[0096] The coarse aggregate is 5-10mm crushed stone; the reinforcing fiber is steel fiber with a length of 32mm and a width of 5mm.

[0097] The bonding reinforcing agent includes hydroxypropyl methylcellulose, ethylene glycol, and diacetone acrylamide, with a mass ratio of 2:1:1.

[0098] The preparation method of the compound microcapsules is as follows:

[0099] S1: Add sodium alginate to a beaker containing 70°C distilled water, stir until completely dissolved, cool to room temperature, add wet Bacillus pseudomycosis cells and mix well, then add peptone and inulin, mix well, let stand to remove air bubbles, and obtain encapsulating liquid;

[0100] S2: Dissolve chitosan in a 1% citric acid solution to prepare a chitosan solution, and then add calcium chloride to the chitosan solution to prepare a calcium chloride solution.

[0101] S3: Under magnetic stirring, use a 1ml syringe to dropwise add the encapsulation fluid into a calcium chloride solution containing chitosan, controlling the drip rate to 30 drops per minute;

[0102] S4: After dripping, let stand for 15 minutes to allow the curing reaction to complete. After cross-linking, filter and collect the fresh microspheres, and air dry them in a constant temperature incubator at 28℃ for 2-3 days to obtain the compound microcapsules.

[0103] The mass fraction of sodium alginate in the encapsulation fluid of step S1 is 2%; the mass fraction of wet Bacillus pseudomycosis cells is 0.6%; the mass fraction of peptone is 3%; and the mass fraction of inulin is 1%.

[0104] The strain of *Pseudomonas aeruginosa* was identified as CCTCC No. AB 2015320 and was purchased from the China Center for Type Culture Collection.

[0105] In step S2, the mass fraction of chitosan is 0.7%; the mass fraction of calcium chloride is 4%.

[0106] In step S3, the magnetic stirring speed is 300 r / min.

[0107] A method for preparing highly permeable concrete, comprising the following steps:

[0108] Mix cement, coarse aggregate, fly ash, reinforcing fiber, and binder evenly. Add 2 / 3 of the formula amount of water and stir for 3-5 minutes. Add compound microcapsules and water-reducing agent and stir for 1 minute. Add the remaining water and stir for 2-3 minutes before discharging to obtain highly permeable concrete.

[0109] Compared with Example 3, this comparative example is identical to Example 3 except that only Bacillus pseudomycosis is added to the microcapsules.

[0110] Comparative Example 3

[0111] A highly permeable concrete is prepared from the following raw materials in parts by weight:

[0112] 1300 parts coarse aggregate, 350 parts cement, 70 parts reinforcing fiber, 4 parts water-reducing agent, 120 parts water, 60 parts fly ash, 75 parts compound microcapsules, and 32 parts cementing and reinforcing agent.

[0113] The coarse aggregate is 5-10mm crushed stone; the reinforcing fiber is steel fiber with a length of 32mm and a width of 5mm.

[0114] The bonding reinforcing agent includes hydroxypropyl methylcellulose and diacetone acrylamide, with a mass ratio of 2:1.

[0115] The preparation method of the compound microcapsules is as follows:

[0116] S1: Add sodium alginate to a beaker containing 70°C distilled water, stir until completely dissolved, cool to room temperature, add wet cells of Bacillus sarcopene and Bacillus pseudomycosis, mix well, then add peptone and inulin, mix well, let stand to remove air bubbles, and obtain encapsulating liquid;

[0117] S2: Dissolve chitosan in a 1% citric acid solution to prepare a chitosan solution, and then add calcium chloride to the chitosan solution to prepare a calcium chloride solution.

[0118] S3: Under magnetic stirring, use a 1ml syringe to dropwise add the encapsulation fluid into a calcium chloride solution containing chitosan, controlling the drip rate to 30 drops per minute;

[0119] S4: After dripping, let stand for 15 minutes to allow the curing reaction to complete. After cross-linking, filter and collect the fresh microspheres, and air dry them in a constant temperature incubator at 28℃ for 2-3 days to obtain the compound microcapsules.

[0120] The mass fraction of sodium alginate in the encapsulation fluid of step S1 is 2%; the mass fraction of wet Bacillus sarcopenia is 0.3%; the mass fraction of wet Bacillus pseudomycosis is 0.3%; the mass fraction of peptone is 3%; and the mass fraction of inulin is 1%.

[0121] The strain of *Bacillus sarcopenia*, numbered CCTCC No. AB 2010438, was purchased from the China Center for Type Culture Collection; the strain of *Bacillus pseudomycosis*, numbered CCTCC No. AB 2015320, was also purchased from the China Center for Type Culture Collection.

[0122] In step S2, the mass fraction of chitosan is 0.7%; the mass fraction of calcium chloride is 4%.

[0123] In step S3, the magnetic stirring speed is 300 r / min.

[0124] A method for preparing highly permeable concrete, comprising the following steps:

[0125] Mix cement, coarse aggregate, fly ash, reinforcing fiber, and binder evenly. Add 2 / 3 of the formula amount of water and stir for 3-5 minutes. Add compound microcapsules and water-reducing agent and stir for 1 minute. Add the remaining water and stir for 2-3 minutes before discharging to obtain highly permeable concrete.

[0126] Compared with Example 3, this comparative example is identical to Example 3 except that diethanol is not added to the bonding reinforcing agent.

[0127] Comparative Example 4

[0128] A highly permeable concrete is prepared from the following raw materials in parts by weight:

[0129] 1300 parts coarse aggregate, 350 parts cement, 70 parts reinforcing fiber, 4 parts water-reducing agent, 120 parts water, 60 parts fly ash, 75 parts compound microcapsules, and 32 parts cementing and reinforcing agent.

[0130] The coarse aggregate is 5-10mm crushed stone; the reinforcing fiber is steel fiber with a length of 32mm and a width of 5mm.

[0131] The bonding reinforcing agent includes hydroxypropyl methylcellulose and ethylene glycol, with a mass ratio of 2:1.

[0132] The preparation method of the compound microcapsules is as follows:

[0133] S1: Add sodium alginate to a beaker containing 70°C distilled water, stir until completely dissolved, cool to room temperature, add wet cells of Bacillus sarcopene and Bacillus pseudomycosis, mix well, then add peptone and inulin, mix well, let stand to remove air bubbles, and obtain encapsulating liquid;

[0134] S2: Dissolve chitosan in a 1% citric acid solution to prepare a chitosan solution, and then add calcium chloride to the chitosan solution to prepare a calcium chloride solution.

[0135] S3: Under magnetic stirring, use a 1ml syringe to dropwise add the encapsulation fluid into a calcium chloride solution containing chitosan, controlling the drip rate to 30 drops per minute;

[0136] S4: After dripping, let stand for 15 minutes to allow the curing reaction to complete. After cross-linking, filter and collect the fresh microspheres, and air dry them in a constant temperature incubator at 28℃ for 2-3 days to obtain the compound microcapsules.

[0137] The mass fraction of sodium alginate in the encapsulation fluid of step S1 is 2%; the mass fraction of wet Bacillus sarcopenia is 0.3%; the mass fraction of wet Bacillus pseudomycosis is 0.3%; the mass fraction of peptone is 3%; and the mass fraction of inulin is 1%.

[0138] The strain of *Bacillus sarcopenia*, numbered CCTCC No. AB 2010438, was purchased from the China Center for Type Culture Collection; the strain of *Bacillus pseudomycosis*, numbered CCTCC No. AB 2015320, was also purchased from the China Center for Type Culture Collection.

[0139] In step S2, the mass fraction of chitosan is 0.7%; the mass fraction of calcium chloride is 4%.

[0140] In step S3, the magnetic stirring speed is 300 r / min.

[0141] A method for preparing highly permeable concrete, comprising the following steps:

[0142] Mix cement, coarse aggregate, fly ash, reinforcing fiber, and binder evenly. Add 2 / 3 of the formula amount of water and stir for 3-5 minutes. Add compound microcapsules and water-reducing agent and stir for 1 minute. Add the remaining water and stir for 2-3 minutes before discharging to obtain highly permeable concrete.

[0143] Compared with Example 3, this comparative example is identical to Example 3 except that diacetone acrylamide is not added to the bonding reinforcing agent.

[0144] Comparative Example 5

[0145] A highly permeable concrete is prepared from the following raw materials in parts by weight:

[0146] 1300 parts coarse aggregate, 350 parts cement, 70 parts reinforcing fiber, 4 parts water-reducing agent, 120 parts water, 60 parts fly ash, 75 parts compound microcapsules, and 32 parts cementing and reinforcing agent.

[0147] The coarse aggregate is 5-10mm crushed stone; the reinforcing fiber is steel fiber with a length of 32mm and a width of 5mm.

[0148] The bonding and reinforcing agent is hydroxypropyl methylcellulose.

[0149] The preparation method of the compound microcapsules is as follows:

[0150] S1: Add sodium alginate to a beaker containing 70°C distilled water, stir until completely dissolved, cool to room temperature, add wet cells of Bacillus sarcopene and Bacillus pseudomycosis, mix well, then add peptone and inulin, mix well, let stand to remove air bubbles, and obtain encapsulating liquid;

[0151] S2: Dissolve chitosan in a 1% citric acid solution to prepare a chitosan solution, and then add calcium chloride to the chitosan solution to prepare a calcium chloride solution.

[0152] S3: Under magnetic stirring, use a 1ml syringe to dropwise add the encapsulation fluid into a calcium chloride solution containing chitosan, controlling the drip rate to 30 drops per minute;

[0153] S4: After dripping, let stand for 15 minutes to allow the curing reaction to complete. After cross-linking, filter and collect the fresh microspheres, and air dry them in a constant temperature incubator at 28℃ for 2-3 days to obtain the compound microcapsules.

[0154] The mass fraction of sodium alginate in the encapsulation fluid of step S1 is 2%; the mass fraction of wet Bacillus sarcopenia is 0.3%; the mass fraction of wet Bacillus pseudomycosis is 0.3%; the mass fraction of peptone is 3%; and the mass fraction of inulin is 1%.

[0155] The strain of *Bacillus sarcopenia*, numbered CCTCC No. AB 2010438, was purchased from the China Center for Type Culture Collection; the strain of *Bacillus pseudomycosis*, numbered CCTCC No. AB 2015320, was also purchased from the China Center for Type Culture Collection.

[0156] In step S2, the mass fraction of chitosan is 0.7%; the mass fraction of calcium chloride is 4%.

[0157] In step S3, the magnetic stirring speed is 300 r / min.

[0158] A method for preparing highly permeable concrete, comprising the following steps:

[0159] Mix cement, coarse aggregate, fly ash, reinforcing fiber, and binder evenly. Add 2 / 3 of the formula amount of water and stir for 3-5 minutes. Add compound microcapsules and water-reducing agent and stir for 1 minute. Add the remaining water and stir for 2-3 minutes before discharging to obtain highly permeable concrete.

[0160] Compared with Example 3, this comparative example is identical to Example 3 except that only hydroxypropyl methylcellulose is added as the bonding reinforcing agent.

[0161] Performance testing

[0162] The highly permeable concretes prepared in Examples 1-3 and Comparative Examples 1-5 were cured for 28 days. The porosity and permeability coefficient of the permeable concrete were tested according to CJJ / T135-2009 "Technical Specification for Permeable Cement Concrete Pavement"; the compressive strength of the permeable concrete was tested according to GB / T50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete"; and the frost resistance of the permeable concrete was tested according to GB / T50082-2009 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete". The results are shown in Table 1.

[0163] Table 1. Performance test results of permeable concrete

[0164]

[0165]

[0166] As shown in Table 1, compared with Example 3, the compressive strength loss rate of Comparative Examples 1 and 2, under the condition of changing the bacterial agent composition, was significantly increased. This indicates that the effect is weakened if either of the two bacterial agents in the microcapsules of the present invention is missing. It also shows that the two bacterial agents of the present invention synergistically deposit calcium carbonate to form a dense calcium carbonate film, covering the crack surface and improving its mechanical properties and freeze-thaw resistance. From Example 3 and Comparative Examples 3-5, it can be seen that the cementitious reinforcing agent has a significant impact on various aspects of the performance of permeable concrete. In summary, the highly permeable concrete prepared by the present invention has good permeability, good freeze-thaw resistance, and good mechanical properties, which can meet the requirements for the use of permeable concrete.

[0167] 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 highly permeable concrete, characterized in that, The raw materials include the following parts by weight: 1100-1300 parts coarse aggregate, 320-350 parts cement, 50-70 parts reinforcing fiber, 2-4 parts water-reducing agent, 110-120 parts water, 48-60 parts fly ash, 46-75 parts compound microcapsules, and 22-32 parts cementing and reinforcing agent. The bonding reinforcing agent includes hydroxypropyl methylcellulose, ethylene glycol, and diacetone acrylamide, with a mass ratio of 2:1:

1.

2. The highly permeable concrete according to claim 1, characterized in that, The coarse aggregate is 5-10mm crushed stone; the reinforcing fiber is steel fiber with a length of 32mm and a width of 5mm.

3. The highly permeable concrete according to claim 1, characterized in that, The preparation method of the compound microcapsules is as follows: S1: Add sodium alginate to a beaker containing 70°C distilled water, stir until completely dissolved, cool to room temperature, add wet cells of Bacillus sarcopene and Bacillus pseudomycosis, mix well, then add peptone and inulin, mix well, let stand to remove air bubbles, and obtain encapsulating liquid; S2: Dissolve chitosan in a 1% citric acid solution to prepare a chitosan solution, and then add calcium chloride to the chitosan solution to prepare a calcium chloride solution. S3: Under magnetic stirring, use a 1ml syringe to dropwise add the encapsulation fluid into a calcium chloride solution containing chitosan, controlling the drip rate to 30 drops per minute; S4: After dripping, let stand for 15 minutes to allow the curing reaction to complete. After cross-linking, filter and collect the fresh microspheres, and air dry them in a constant temperature incubator at 28℃ for 2-3 days to obtain the compound microcapsules.

4. The highly permeable concrete according to claim 3, characterized in that, In the encapsulation fluid of step S1, the mass fraction of sodium alginate is 2%; the mass fraction of wet Bacillus sarcopenia is 0.3%; the mass fraction of wet Bacillus pseudomycosis is 0.3%; the mass fraction of peptone is 3%; and the mass fraction of inulin is 1%.

5. The highly permeable concrete according to claim 3, characterized in that, The strain of *Bacillus sarcopenia* was CCTCC No. AB 2010438 and was purchased from the China Center for Type Culture Collection; the strain of *Bacillus pseudomycosis* was CCTCC No. AB 2015320 and was purchased from the China Center for Type Culture Collection.

6. The highly permeable concrete according to claim 3, characterized in that, In step S2, the chitosan solution contains 0.7% chitosan by mass; the calcium chloride solution contains 4% calcium chloride by mass.

7. The highly permeable concrete according to claim 3, characterized in that, In step S3, the magnetic stirring speed is 300 r / min.

8. A method for preparing highly permeable concrete according to any one of claims 1-7, characterized in that, The high permeability concrete is prepared by the following steps: mix cement, coarse aggregate, fly ash, reinforcing fiber and cementitious agent for 3-5 minutes, add 2 / 3 of the formula amount of water and stir for 2-3 minutes, add compound microcapsules and water-reducing agent and stir for 1 minute, then add the remaining water, stir for 2-3 minutes and discharge to obtain the high permeability concrete.

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