A MICP-fiber collaborative solidified mortar and its production process

Abstract

The present invention discloses a MICP-fiber co-cured mortar and its production process, which relates to the technical field of building materials. The production process of a MICP-fiber co-cured mortar of the present invention includes the following steps: according to the weight part ratio of mortar raw materials, the modified fiber and recycled aggregate are pre-mixed in sequence, then quartz sand, cement and silica fume are added for dry mixing, and finally water, fly ash and water reducer are added and stirred evenly to obtain the MICP-fiber co-cured mortar; the recycled aggregate is the recycled aggregate after MICP treatment; this application utilizes the synergistic effect of the modified fiber and the recycled aggregate after MICP treatment to prepare a concrete mortar with high mechanical properties, strong anti-permeability and anti-carbonization ability.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and particularly relates to a MICP-fiber co-curing mortar and its production process. Background Art

[0002] With the rapid development of the construction industry and the advancement of the urbanization process, the use of concrete materials in construction projects has a huge impact on natural resources and the environment. At the same time, when the concrete structure does not meet the functional or service life requirements, it needs to be demolished and rebuilt. Coupled with urban planning and old city renovation, the total amount of construction waste demolished each year is huge, and the construction waste generated by the construction industry has also increased unprecedentedly. Therefore, the research on the recycling and reuse of construction waste and the wide application of recycled aggregate concrete is extremely urgent. Construction waste is made into recycled aggregates through various processes for mixing recycled aggregate concrete, replacing natural aggregates for new buildings, which is of great significance for the sustainable development of resources, the environment and human society. However, compared with natural aggregates, recycled aggregates prepared from construction waste have microcracks formed due to the accumulation of mechanical damage during the production process, resulting in characteristics such as a larger porosity, high water absorption, and low strength after being damaged. The recycled aggregate concrete prepared using recycled aggregates has a decline in workability; moreover, since the surface of the recycled aggregates is attached with old cement mortar as a weak layer, it affects the bonding between the aggregates, thereby significantly reducing the mechanical properties and durability of the recycled aggregate concrete, making the mortar prepared by using recycled aggregates to replace natural aggregates have low mechanical properties, large discreteness, increased permeability, and a large chloride ion diffusion coefficient, etc., seriously affecting the performance of the configured mortar and restricting the application of recycled mortar.

[0003] Microbial Induced Calcium Carbonate Precipitation technology (MICP) utilizes the calcium carbonate induced precipitation function of some mineralizing microorganisms in nature. Through the bacterial metabolism, calcium ions and carbonate ions are combined to form calcium carbonate, and it is selectively filled or bonded on the surface of the mortar cracks to achieve the purpose of improving the pore structure of the material, strengthening weathered buildings, and repairing microcracks in concrete materials. This application uses the self-metabolism of microorganisms to generate calcium carbonate mineralization deposition on the surface of recycled construction waste, block the pores of the recycled aggregates, repair the microcracks of the recycled aggregates, reduce the water absorption of the recycled aggregates, improve the density of the recycled aggregates, improve the physical and chemical properties of the recycled aggregates, and further improve the mechanical properties and other properties of the recycled mortar. Summary of the Invention

[0004] The purpose of the present invention is to provide a MICP-fiber co-curing mortar and its production process to solve the following technical problems:

[0005] In the existing method, recycled aggregates prepared from construction waste are directly added as aggregates to mortar. The prepared mortar has characteristics such as a decrease in mechanical properties, large discreteness, increased permeability, poor carbonation resistance, poor frost resistance, and a large chloride ion diffusion coefficient.

[0006] The object of the present invention can be achieved by the following technical solutions:

[0007] A production process of MICP-fiber co-cured mortar includes the following steps:

[0008] According to the weight part ratio of mortar raw materials, recycled aggregates and modified fibers are pre-mixed, and then coarse aggregates, cement, and silica fume are added for dry mixing. Finally, water, fly ash, and water reducing agent are added and stirred evenly to obtain MICP-fiber co-cured mortar; the recycled aggregates are obtained by subjecting construction waste to MICP treatment.

[0009] The preparation method of the modified fiber composition includes the following steps:

[0010] S1: Add polypropylene fiber, maleic anhydride, benzophenone, and xylene into a reaction kettle and disperse evenly. Treat under ultraviolet light for 1 - 3 h, wash with acetone, and dry to obtain component one.

[0011] S2: Add component one, phosphorous acid, and xylene into a reaction kettle and disperse evenly. Heat to reflux for 0.5 - 1 h, add formaldehyde solution, and continue reflux reaction for 6 - 9 h. Wash with acetone and dry to obtain modified fibers.

[0012] As a further scheme of the present invention: In S1, the addition ratio of polypropylene fiber, 10 g of maleic anhydride, benzophenone, and xylene is 10 g: 4 - 6 g: 0.03 - 0.06 g: 50 - 100 mL.

[0013] As a further scheme of the present invention: In S2, the formaldehyde solution is 20 - 25 wt% aqueous formaldehyde solution; the addition ratio of component one, phosphorous acid, xylene, and formaldehyde solution is 10 g: 6 - 8 g: 400 - 1000 mL: 100 - 200 mL.

[0014] As a further scheme of the present invention: The specific preparation method of recycled aggregates includes the following steps:

[0015] A1: Sort and remove impurities from construction waste, perform primary crushing, magnetic separation to remove iron, secondary crushing, and grading to obtain graded aggregates.

[0016] A2: Immerse the graded aggregates in a bacterial solution for loading treatment, and then place them in a mineralization culture solution for mineral deposition treatment to obtain recycled aggregates.

[0017] As a further solution of the present invention: the graded aggregate is obtained by mixing aggregates with particle sizes of 0.15 - 0.6 mm and 0.6 - 4.75 mm at a mass ratio of 55:35 - 45.

[0018] As a further solution of the present invention: in A2, the mass ratio of the graded aggregate to the bacterial solution is 2:1 - 1.2, and the graded aggregate is soaked in the bacterial solution for 0.5 - 1 h; preparing the bacterial solution includes the following steps: mixing the Bacillus mucilaginosus bacterial powder, Bacillus kochii bacterial powder, and deionized water, and adjusting the pH to 9.5 - 10.3 to obtain the bacterial solution; the viable bacteria concentration in the bacterial solution is 1.1×10 8 - 2.4×10 8 cfu / mL; Bacillus mucilaginosus accounts for 20 - 80% of the total viable bacteria in the bacterial solution.

[0019] As a further solution of the present invention: in A2, the mass ratio of the graded aggregate to the mineralization culture solution is 1:1 - 1.2; preparing the mineralization culture solution includes the following steps: mixing 15 - 20 g of urea, 8 - 10 g of peptone, 90 - 100 g of calcium chloride, 22 - 40 g of calcium lactate, and 1000 mL of deionized water, and adjusting the pH to 8 - 9 to obtain the mineralization culture solution; the graded aggregate is soaked in the mineralization culture solution with ventilation for 7 - 14 d.

[0020] As a further solution of the present invention: the MICP - fiber co - solidified mortar includes the following raw materials in parts by weight: 660 - 750 parts by weight of cement, 150 - 400 parts by weight of silica fume, 110 - 150 parts by weight of fly ash, 620 - 700 parts by weight of coarse aggregate, 800 - 900 parts by weight of recycled aggregate, 40 - 100 parts by weight of modified fiber, 5 - 15 parts by weight of water - reducing agent, and 150 - 250 parts by weight of water.

[0021] As a further solution of the present invention: the cement is any one of P·O 42.5 grade ordinary Portland cement and P·O52.5 grade ordinary Portland cement; the coarse aggregate is limestone gravel with a particle size of 5 - 20 mm; the water - reducing agent is a polycarboxylate water - reducing agent.

[0022] As a further solution of the present invention: the fly ash is Class F Grade I.

[0023] A MICP - fiber co - solidified mortar is made by the production process of any one of the above items.

[0024] The beneficial effects of the present invention:

[0025] (1) First, the construction waste is sorted to remove impurities, subjected to primary crushing, magnetic separation to remove iron, secondary crushing, and grading to obtain graded aggregate. After the graded aggregate is soaked in the bacterial solution for loading treatment, it is then placed in a mineralization culture solution for mineral deposition treatment to obtain recycled aggregate. In this application, the microbial mineralization deposition technology utilizes respiration (Bacillus mucilaginosus, Bacillus cohnii) to produce CO3 2+ , and Ca 2+ in the concrete and CO3 2+ react at the surface of microbial cells with the microorganism as the nucleation site to form insoluble CaCO3 crystals. The calcium carbonate crystals prepared inside and in the cracks of the recycled aggregate have good compatibility and interfacial strength with the cement-based material, and good durability. Then, using polypropylene fiber as the base material, through maleic anhydride modification and phosphorous acid modification, a modified polypropylene fiber with carboxyl groups and phosphoric acid groups on the molecular weight branches is obtained, that is, the modified fiber. The grafted phosphonic acid groups and carboxylic acid groups on the molecular chain of the modified fiber prepared in this application have more negative charges and stronger Ca 2+ complexation, form ionic bonds with Ca 2+ in calcium carbonate, and the phosphoric acid groups can effectively reduce the competitive adsorption of SO4 2- .

[0026] In this application, the modified fiber and the recycled aggregate are blended and then added to the mortar. The recycled aggregate includes aggregate, bacterial solution, nutrient salts, etc. as a liquid with strong fluidity. Under the action of the modified fiber, it has the advantages of strong infiltration performance and high interfacial bonding strength with other substances in the cement mortar. When the concrete is formed, the spores of aerobic alkaliphilic bacteria and the corresponding nutrients are incorporated. When the concrete cracks, external substances such as oxygen and moisture penetrate, and the dormant spores are activated and germinated to restore their metabolic functions, continuously inducing calcium carbonate deposition, thereby repairing the concrete cracks and preventing harmful substances from entering the interior of the concrete to corrode the steel bars. When the cracks are repaired and closed, new spore dormant bodies can be generated inside, waiting for the start of the next repair. During the preparation and subsequent use of the mortar, the modified fiber utilizes the carboxyl groups and phosphoric acid groups on the branches to capture Ca 2+ in the mortar and induce the role of local mineralization. Adding the modified fiber in this application can not only reduce the length of plastic cracks, but also has an obvious effect on refining cracks. Specific Embodiments

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0028] Example 1 The specific preparation method of recycled aggregate includes the following steps:

[0029] A1: Sort and remove impurities from construction waste, perform primary crushing, magnetic separation to remove iron, secondary crushing, and grading to obtain graded aggregate. Mix aggregates with particle sizes of 0.15 - 0.6 mm and 0.6 - 4.75 mm in a mass ratio of 55:45;

[0030] A2: Prepare the bacterial solution: Mix Bacillus mucilaginosus powder, Bacillus kochii powder, and deionized water, then add sodium hydroxide to adjust the pH to 10 to obtain the bacterial solution. The viable bacteria concentration in the bacterial solution is 2.4×10 8 cfu / mL; Bacillus mucilaginosus accounts for 50% of the total viable bacteria in the bacterial solution;

[0031] A3: Immerse the graded aggregate in the bacterial solution (the mass ratio of graded aggregate to bacterial solution is 2:1.2), and perform a load treatment under a vacuum condition of 0.6 Mpa for 0.5 h;

[0032] A4: Prepare the mineralization culture medium: Mix 20 g of urea, 10 g of peptone, 100 g of calcium chloride, 40 g of calcium lactate, and 1000 mL of deionized water, then add sodium hydroxide to adjust the pH to 9 to obtain the mineralization culture medium;

[0033] A5: Place the graded aggregate after the load treatment in the mineralization culture medium (the mass ratio of graded aggregate to mineralization culture medium is 1:1.2), and soak for 14 d under ventilation conditions for mineral deposition treatment to obtain recycled aggregate.

[0034] Example 2 The preparation method of the modified fiber composition includes the following steps:

[0035] S1: Add 10 g of polypropylene fiber (diameter 15 um, tensile strength 400 MPa, elastic modulus 12 GPa, length 30 mm), 4 g of maleic anhydride, 0.03 g of benzophenone, and 50 mL of xylene into the reaction kettle and disperse evenly. Perform ultraviolet light irradiation treatment for 1 h under an ultraviolet light intensity of 150 w / m 2 and wash with acetone and dry to obtain Component 1;

[0036] S2: Add 10 g of Component 1, 6 g of phosphorous acid, and 400 mL of xylene into the reaction kettle and disperse evenly. Heat to reflux for 0.5 h, add 100 mL of 20 wt% formaldehyde aqueous solution, and continue reflux reaction for 6 h. Wash with acetone and dry to obtain the modified fiber.

[0037] Example 3 The preparation method of the modified fiber composition includes the following steps:

[0038] S1: Add 10 g of polypropylene fibers (diameter 15 μm, tensile strength 400 MPa, elastic modulus 12 GPa, length 30 mm), 5 g of maleic anhydride, 0.05 g of benzophenone, and 70 mL of xylene into a reaction kettle and disperse them evenly. Under an ultraviolet light intensity of 150 w / m 2 carry out ultraviolet light treatment for 2 h, wash with acetone, and dry to obtain Component 1;

[0039] S2: Add 10 g of Component 1, 7 g of phosphorous acid, and 700 mL of xylene into a reaction kettle and disperse them evenly. Heat up to reflux for 0.5 h, add 150 mL of 20 wt% formaldehyde aqueous solution, and continue reflux reaction for 7 h. Wash with acetone and dry to obtain the modified fibers.

[0040] The preparation method of the modified fiber composition in Example 4 includes the following steps:

[0041] S1: Add 10 g of polypropylene fibers (diameter 15 μm, tensile strength 400 MPa, elastic modulus 12 GPa, length 30 mm), 6 g of maleic anhydride, 0.06 g of benzophenone, and 100 mL of xylene into a reaction kettle and disperse them evenly. Under an ultraviolet light intensity of 150 w / m 2 carry out ultraviolet light treatment for 3 h, wash with acetone, and dry to obtain Component 1;

[0042] S2: Add 10 g of Component 1, 8 g of phosphorous acid, and 1000 mL of xylene into a reaction kettle and disperse them evenly. Heat up to reflux for 1 h, add 200 mL of 20 wt% formaldehyde aqueous solution, and continue reflux reaction for 9 h. Wash with acetone and dry to obtain the modified fibers.

[0043] Example 5 The production process of a MICP-fiber co-cured mortar includes the following steps:

[0044] Pre-mix 900 parts by weight of the recycled aggregate prepared in Example 1 and 60 parts by weight of the modified fibers prepared in Example 2. Then continue to add 700 parts by weight of limestone gravel with a particle size of 5 - 20 mm, 750 parts by weight of P·O 42.5 grade ordinary Portland cement, and 300 parts by weight of silica fume (loss on ignition 4.5%, specific surface area 2.2×10 4 m 2 / kg, activity index 120%, silicon dioxide 95%, water demand ratio 109%) for dry mixing. Finally, add 250 parts by weight of water, 150 parts by weight of Class F Grade I fly ash, and 15 parts by weight of polycarboxylate superplasticizer (KLB-E polycarboxylate high-performance superplasticizer produced by Chongqing Kangloubao Building Materials Co., Ltd.) and stir evenly to obtain the MICP-fiber co-cured mortar; the recycled aggregate is obtained by subjecting construction waste to MICP treatment.

[0045] Example 6 The production process of a MICP-fiber co-cured mortar includes the following steps:

[0046] Pre-mix 900 parts by weight of the recycled aggregate prepared in Example 1 and 60 parts by weight of the modified fiber prepared in Example 3. Then continue to add 700 parts by weight of limestone gravel with a particle size of 5 - 20 mm, 750 parts by weight of P·O 42.5 grade ordinary Portland cement, and 300 parts by weight of silica fume (loss on ignition 4.5%, specific surface area 2.2×10 4 m 2 / kg, activity index 120%, silica 95%, water demand ratio 109%) for dry mixing. Finally, add 250 parts by weight of water, 150 parts by weight of class F grade I fly ash, and 15 parts by weight of polycarboxylate superplasticizer (KLB-E polycarboxylate high-performance superplasticizer produced by Chongqing Kangloubao Building Materials Co., Ltd.) and stir evenly to obtain MICP-fiber co-cured mortar; the recycled aggregate is obtained by subjecting construction waste to MICP treatment.

[0047] Example 7 A production process of MICP-fiber co-cured mortar, comprising the following steps:

[0048] Pre-mix 900 parts by weight of the recycled aggregate prepared in Example 1 and 60 parts by weight of the modified fiber prepared in Example 4. Then continue to add 700 parts by weight of limestone gravel with a particle size of 5 - 20 mm, 750 parts by weight of P·O 42.5 grade ordinary Portland cement, and 300 parts by weight of silica fume (loss on ignition 4.5%, specific surface area 2.2×10 4 m 2 / kg, activity index 120%, silica 9%, water demand ratio 109%) for dry mixing. Finally, add 250 parts by weight of water, 150 parts by weight of class F grade I fly ash, and 15 parts by weight of polycarboxylate superplasticizer (KLB-E polycarboxylate high-performance superplasticizer produced by Chongqing Kangloubao Building Materials Co., Ltd.) and stir evenly to obtain MICP-fiber co-cured mortar; the recycled aggregate is obtained by subjecting construction waste to MICP treatment.

[0049] Comparative Example 1 The specific preparation method of recycled aggregate comprises the following steps:

[0050] A1: Sort and remove impurities, primary crushing, magnetic separation for iron removal, secondary crushing, and grading of construction waste to obtain graded aggregate, and mix aggregates with particle sizes of 0.15 - 0.6 mm and 0.6 - 4.75 mm with a mass ratio of 55:45;

[0051] A2: Prepare the bacterial solution: Mix the bacterial powder of Bacillus mucilaginosus, the bacterial powder of Bacillus kochii, and deionized water, and then add sodium hydroxide to adjust the pH to 10 to obtain the bacterial solution; the viable bacteria concentration in the bacterial solution is 2.4×10 8 cfu / mL; Bacillus mucilaginosus accounts for 50% of the total viable bacteria in the bacterial solution;

[0052] A3: Soak the graded aggregate in the bacterial solution (the mass ratio of the graded aggregate to the bacterial solution is 2:1.2), and perform a loading treatment under a vacuum condition of 0.6 Mpa for 0.5 h to obtain recycled aggregate.

[0053] The preparation method of the modified fiber composition in Comparative Example 2 includes the following steps:

[0054] S1: Add 10 g of polypropylene fiber (diameter 15 um, tensile strength 400 MPa, elastic modulus 12 GPa, length 30 mm), 5 g of maleic anhydride, 0.05 g of benzophenone, and 70 mL of xylene into the reaction kettle and disperse evenly. Under an ultraviolet light intensity of 150 w / m 2 carry out ultraviolet light treatment for 2 h, wash with acetone, and dry to obtain modified fiber.

[0055] A production process of MICP-fiber co-cured mortar in Comparative Example 4 includes the following steps:

[0056] Pre-mix 900 parts by weight of the recycled aggregate prepared in Example 1 and 60 parts by weight of the modified fiber prepared in Comparative Example 2, and then continue to add 700 parts by weight of limestone gravel with a particle size of 5 - 20 mm, 750 parts by weight of P·O 42.5 grade ordinary portland cement, and 300 parts by weight of silica fume (loss on ignition 4.5%, specific surface area 2.2×10 4 m 2 / kg, activity index 120%, silica 95%, water demand ratio 109%) for dry mixing. Finally, add 250 parts by weight of water, 150 parts by weight of class F grade I fly ash, and 15 parts by weight of polycarboxylate superplasticizer (KLB-E polycarboxylate high-performance superplasticizer produced by Chongqing Kangloubao Building Materials Co., Ltd.) and stir evenly to obtain MICP-fiber co-cured mortar; the recycled aggregate is obtained by MICP treatment of construction waste.

[0057] A production process of MICP-fiber co-cured mortar in Comparative Example 5 includes the following steps:

[0058] Pre-mix 900 parts by weight of the recycled aggregate prepared in Comparative Example 1 and 60 parts by weight of the modified fiber prepared in Example 3, and then continue to add 700 parts by weight of limestone gravel with a particle size of 5 - 20 mm, 750 parts by weight of P·O 42.5 grade ordinary portland cement, and 300 parts by weight of silica fume (loss on ignition 4.5%, specific surface area 2.2×10 4 m 2( / kg, activity index 120%, silica 95%, water demand ratio 109%) for dry mixing, and finally 250 parts by weight of water, 150 parts by weight of Class F Grade I fly ash, and 15 parts by weight of polycarboxylate superplasticizer (KLB-E polycarboxylate high-performance superplasticizer produced by Chongqing Kangloubao Building Materials Co., Ltd.) were added and stirred evenly to obtain MICP-fiber co-cured mortar; the recycled aggregate was obtained by MICP treatment of construction waste.

[0059] Comparative Example 6 A production process of MICP-fiber co-cured mortar, comprising the following steps:

[0060] 900 parts by weight of the recycled aggregate prepared in Example 1, 700 parts by weight of limestone gravel with a particle size of 5-20 mm, 750 parts by weight of P·O 42.5 ordinary Portland cement, and 300 parts by weight of silica fume (loss on ignition 4.5%, specific surface area 2.2×10 4 m 2 / kg, activity index 120%, silica 95%, water demand ratio 109%) for dry mixing, and finally 250 parts by weight of water, 150 parts by weight of Class F Grade I fly ash, and 15 parts by weight of polycarboxylate superplasticizer (KLB-E polycarboxylate high-performance superplasticizer produced by Chongqing Kangloubao Building Materials Co., Ltd.) were added and stirred evenly to obtain MICP-fiber co-cured mortar; the recycled aggregate was obtained by MICP treatment of construction waste.

[0061] Performance testing

[0062] (1) Compressive strength: According to GB / T 17671-1999 "Test Method for Strength of Cement Mortar", specimens of the mortar prepared in Examples 5-7 and Comparative Examples 3-5 were prepared and cured for 28 d. When the test blocks were placed, the sides were facing up and the centers coincided with the center of the pressure plate of the hydraulic press. A directional loading mode was adopted, the flexural load was controlled at 50 N / s, and the compressive load was 2.4 kN / s until the specimen was damaged, and the compressive strength Ra and flexural strength Rb were calculated:

[0063] Ra = F / A

[0064] In the formula, Ra - compressive strength, MPa; F - maximum load at specimen failure, N; A - area of the compressed part, mm;

[0065] Rb = 3PL / (2bh 2 )

[0066] In the formula, Rb - flexural strength, MPa; P - ultimate load at specimen failure, N; L - distance between support cylinders, mm; b - width of the specimen cross-section, mm; h - height of the specimen cross-section, mm; the test results are shown in Table 1;

[0067] (2) Capillary water absorption rate: Tested according to the "RILEM 25 PEM Ⅱ-6 Standard". The specimen with high bond energy was placed in an oven at 50°C until the weight change was less than 0.1%. Then the specimen was completely immersed in tap water, and the weight change of the specimen was recorded at fixed time intervals (wipe the surface of the specimen with a towel until there is no obvious water before weighing) and the water absorption rate was calculated. The test results are shown in Table 1;

[0068] Table 1: Statistical table of performance test data for Examples 5-7 and Comparative Examples 3-5

[0069]

[0070] As can be seen from Table 1, the recycled aggregate treated by MICP and the modified fiber prepared in this application act synergistically and are added to the mortar. The prepared mortar has excellent mechanical properties, as well as low water absorption rate and low discreteness performance.

[0071] (3) Chloride ion erosion resistance test: Tested according to the rapid chloride ion diffusion coefficient method (RCM) in the "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete" GB / T 50082-2009, and the chloride ion diffusion coefficient was calculated according to the following formula:

[0072]

[0073] In the formula, D RCM - Unsteady chloride ion diffusion coefficient of concrete, m 2 / s; T - Average value of the initial temperature and final temperature of the anode solution, °C; L - Thickness of the specimen, mm; U - Test voltage, V; X d - Average value of chloride ion penetration depth, mm; t - Test duration of the specimen, h; The test results are shown in Table 2;

[0074] Table 2: Statistical table of chloride ion erosion resistance performance data for Examples 5-7 and Comparative Examples 3-5

[0075]

[0076] As can be seen from Table 2, the recycled aggregate treated by MICP and the modified fiber prepared in this application act synergistically and are added to the mortar, effectively improving the chloride ion penetration resistance of the mortar.

[0077] The above has described a specific embodiment of the present invention in detail, but the content described is only the preferred embodiment of the present invention and cannot be considered as limiting the scope of implementation of the present invention. Any equivalent changes and improvements made within the scope of the application of the present invention should still fall within the scope covered by the patent of the present invention.

Claims

1. A production process for MICP-fiber synergistically cured mortar, characterized in that: The steps include: According to the weight ratio of the mortar raw materials, the recycled aggregate and modified fiber are pre-mixed, and then coarse aggregate, cement, and silica fume are added and dry-mixed. Finally, water, fly ash, and a water reducer are added and stirred evenly to obtain MICP-fiber synergistically cured mortar; the recycled aggregate is obtained by MICP treatment of construction waste; the coarse aggregate is limestone crushed stone with a particle size of 5-20 mm; The preparation method of the modified fiber comprises the following steps: S1: Add polypropylene fiber, maleic anhydride, benzophenone, and xylene into a reaction kettle and disperse them evenly. Treat with ultraviolet light for 1-3 hours, wash with acetone, and dry to obtain component 1. S2: Add component 1, phosphorous acid and xylene into a reaction kettle and disperse them evenly. Heat and reflux for 0.5-1h. Add formaldehyde solution and continue reflux reaction for 6-9h. Wash with acetone and dry to obtain modified fiber.

2. The production process of a MICP-fiber collaborative curing mortar according to claim 1, characterized in that: The addition ratio of polypropylene fiber, maleic anhydride, benzophenone, and xylene in S1 is 10 g: 4-6 g: 0.03-0.06 g: 50-100 mL.

3. The production process of a MICP-fiber synergistic curing mortar according to claim 1, characterized in that: The formaldehyde solution in S2 is a 20-25wt% formaldehyde aqueous solution; the addition ratio of component 1, phosphorous acid, xylene, and formaldehyde solution is 10g:6-8g:400-1000mL:100-200mL.

4. The production process of a MICP-fiber collaborative curing mortar according to claim 1, characterized in that: The specific preparation method of the recycled aggregate comprises the following steps: A1: Construction waste is sorted and removed, crushed once, magnetically separated for iron removal, crushed twice, and graded to obtain graded aggregates. A2: After the graded aggregate is immersed in bacterial solution for loading treatment, it is placed in mineralization culture medium for mineral deposition treatment to obtain recycled aggregate.

5. The production process of a MICP-fiber collaborative curing mortar according to claim 4, characterized in that: The graded aggregate is obtained by mixing aggregates with a particle size of 0.15-0.6 mm and aggregates with a particle size of 0.6-4.75 mm in a mass ratio of 55:35-45.

6. The production process of a MICP-fiber collaborative curing mortar according to claim 4, characterized in that: The mass ratio of A2 medium-graded aggregate to bacterial solution is 2:1-1.2, and the graded aggregate is soaked in the bacterial solution for 0.5-1h. The bacterial solution is prepared by mixing Bacillus subtilis powder, Bacillus cohnii powder, and deionized water, and adjusting the pH to 9.5-10.3 to obtain a bacterial solution; the concentration of live bacteria in the bacterial solution is 1.1×10 8 -2.4×10 8 cfu / mL; Bacillus subtilis accounts for 20-80% of the total viable bacteria in the bacterial solution.

7. The production process of a MICP-fiber collaborative curing mortar according to claim 4, characterized in that: The mass ratio of A2 medium-graded aggregate to mineralization culture medium is 1:1-1.2; the preparation of the mineralization culture medium includes the following steps: mixing 15-20g of urea, 8-10g of peptone, 90-100g of calcium chloride, 22-40g of calcium lactate, and 1000mL of deionized water, and adjusting the pH to 8-9 to obtain the mineralization culture medium; and soaking the graded aggregate in the mineralization culture medium with ventilation for 7-14 days.

8. The production process of a MICP-fiber collaborative curing mortar according to claim 1, characterized in that: The MICP-fiber synergistically cured mortar includes the following raw materials in parts by weight: 660-750 parts by weight of cement, 150-400 parts by weight of silica fume, 110-150 parts by weight of fly ash, 620-700 parts by weight of coarse aggregate, 800-900 parts by weight of recycled aggregate, 40-100 parts by weight of modified fiber, 5-15 parts by weight of water reducer, and 150-250 parts by weight of water.

9. The production process of a MICP-fiber collaborative curing mortar according to claim 1, characterized in that: The cement is any one of P·O 42.5 grade ordinary Portland cement and P·O 52.5 grade ordinary Portland cement; and the water reducer is a polycarboxylate water reducer.

10. A MICP-fiber synergistic curing mortar, characterized in that: The mortar is made by the production process of the MICP-fiber collaborative curing mortar according to any one of claims 1 to 9.

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