Self-repairing construction waste recycled aggregate concrete and preparation method thereof
By using modified recycled coarse aggregate and biomass ash in concrete, the problems of insufficient mechanical properties and durability of self-healing recycled aggregate concrete are solved, and effective self-healing of cracks and strength improvement are achieved.
Patent Information
- Application Number
- CN202511712870.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-20
- Publication Date
- 2026-01-20
AI Technical Summary
Existing self-healing recycled aggregate concrete has insufficient mechanical properties and durability, and its crack repair effect is not good.
Self-healing recycled coarse aggregate and reinforced recycled coarse aggregate are used to replace ordinary coarse aggregate. The recycled coarse aggregate is modified by mixing calcined attapulgite clay, water glass slurry and silane coupling agent. The recycled coarse aggregate serves as a carrier for mixed microorganisms. Combined with the use of biomass ash, the compactness and interfacial adhesion of concrete are improved.
It improves the mechanical strength and durability of concrete, enables self-healing of cracks, and enhances the compressive strength and durability of concrete.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of concrete, in particular to a self-repairing construction waste recycled aggregate concrete. BACKGROUND
[0002] With the development of economy, the discharge amount of construction waste is increasing day by day, and the construction waste will seriously affect the water, air and soil on which human beings depend, so the recycling of construction waste resources has become an urgent practical problem. The recycled aggregate is obtained by crushing, washing and screening the construction waste, and some old cement mortar is attached to the surface of the recycled aggregate, and a large number of cracks exist on the surface and inside of the recycled aggregate due to the large external force in the crushing process. Compared with natural aggregate, the recycled aggregate has the disadvantages of small density, high water absorption rate and poor interfacial bonding force.
[0003] The recycled aggregate concrete is prone to cracking in the service engineering, which causes the penetration of erosive ions and reduces the durability. The microbial mineralization utilizes the function of inducing calcium carbonate deposition possessed by some mineralization microorganisms in nature, and the precipitate has good durability and is easy to adhere and cement to the surface of mortar and coarse aggregate, can effectively fill or bond the porous medium with permeability, so as to achieve the purpose of repairing the cracks of the concrete. Therefore, the recycled aggregate concrete can be repaired by the method of microbial mineralization deposition.
[0004] The existing self-repairing recycled aggregate concrete has the following problems: the mechanical properties and durability of the concrete are insufficient, and the repair effect on the cracks is poor. SUMMARY
[0005] In order to prepare a recycled aggregate concrete with good mechanical properties and durability and capable of repairing cracks, the present application provides a self-repairing construction waste recycled aggregate concrete and a preparation method thereof.
[0006] The self-repairing construction waste recycled aggregate concrete and the preparation method thereof provided by the present application adopt the following technical scheme: In a first aspect, the present application discloses a self-repairing construction waste recycled aggregate concrete, which comprises the following raw materials by weight: Cement 300-340 parts; Strengthened recycled coarse aggregate 520-600 parts; Self-repairing recycled coarse aggregate 180-300 parts; Fine aggregate 380-450 parts; Biomass ash 45-52 parts; Water reducing agent 4-7 parts; Water 140-170 parts; Nutrients 6-9 parts; The reinforced recycled coarse aggregate is prepared by mixing and modifying the recycled aggregate with calcined attapulgite, water glass slurry and silane coupling agent, and the recycled aggregate is obtained by crushing and screening the construction waste; The self-repairing recycled coarse aggregate is prepared by vacuum adsorbing mixed bacteria on the recycled coarse aggregate as a carrier, and the recycled coarse aggregate is obtained by crushing and screening the waste concrete.
[0007] By adopting the above technical scheme, the self-repairing recycled coarse aggregate and the reinforced recycled coarse aggregate are added to the concrete, the recycled coarse aggregate is wrapped by the old mortar and presents a loose and porous state, so as to be used as a carrier of mixed bacteria, meanwhile, the recycled coarse aggregate and the concrete matrix have good compatibility, can maintain the activity of the mixed bacteria, and realize the self-repairing function of the concrete on cracks; the recycled coarse aggregate is mixed and modified by calcined attapulgite, water glass slurry and silane coupling agent, the voids and cracks on the surface of the recycled coarse aggregate are filled and bonded, and the interface adhesion with the concrete is improved, the compactness of the recycled coarse aggregate is improved, and the mechanical strength of the concrete is improved.
[0008] In the concrete raw materials, the self-repairing recycled coarse aggregate and the reinforced recycled coarse aggregate completely replace the coarse aggregate, and the addition of biomass ash is conducive to improving the compactness and mechanical strength of the concrete, so that the prepared concrete has the self-repairing function on cracks and improved durability on the basis of maintaining good mechanical strength.
[0009] Optionally, the reinforced recycled coarse aggregate is prepared by the following steps: S1. The construction waste is fully crushed, washed, impurity-removed and screened to obtain recycled aggregate with a particle size of 5-20mm; the attapulgite is placed at 450-500℃ for calcination for 1-1.5h, then the heating is stopped and it is naturally cooled to room temperature to obtain calcined attapulgite; the recycled aggregate and the calcined attapulgite are mixed to obtain mixed recycled aggregate; S2. The mixed recycled aggregate is placed in the prepared solution for soaking for 2-3h after being uniformly mixed according to different mass ratios of water glass, silane coupling agent and water, and then it is naturally dried after being taken out to obtain the reinforced recycled coarse aggregate.
[0010] By adopting the above technical scheme, a large amount of active silicon dioxide which can be used as a reinforcing filler is generated after the attapulgite is calcined, the silane coupling agent forms a hydrophobic film on the surface of the recycled aggregate, and the water glass hardens and precipitates silicic acid gel, so that the surface pores of the recycled aggregate are filled, the micro cracks are bonded, the surface defects of the recycled aggregate are improved, the bonding strength between the reinforced recycled coarse aggregate and the cement base is promoted, and the compressive strength of the concrete is improved.
[0011] Optionally, in step S1, the weight ratio of the recycled aggregate and the calcined palygorskite is 1:(0.4-0.6); in step S2, the mass fraction of the water glass in the prepared solution is 4%-6%, and the mass fraction of the silane coupling agent is 2%-4%.
[0012] By limiting the weight of the modified raw material, the water absorption and the crushing index of the recycled aggregate can be further controlled, so that the density and the strength of the recycled aggregate are improved by the composite modification, the interfacial bonding strength between the modified recycled aggregate and the cement is improved, and the compressive strength of the concrete is improved.
[0013] Optionally, the silane coupling agent is selected from one or more of silane coupling agent A-151, silane coupling agent KH-560, and silane coupling agent KH-550.
[0014] By using the above technical scheme, the silane coupling agent is used as a surfactant, so that the surface of the recycled aggregate changes from hydrophilic to hydrophobic, the water absorption of the recycled aggregate is reduced, the bonding performance between the recycled aggregate and the cement is improved through the reaction between the silane coupling agent and the hydroxyl groups of the cement paste, and the compatibility of the entire concrete is better.
[0015] Optionally, the self-repairing recycled coarse aggregate is prepared by the following steps: A1. The recycled coarse aggregate with a particle size of 5-10 mm is obtained by crushing and screening the waste concrete; A2. The bacteria liquid is obtained by culturing the mixed bacteria in a liquid culture medium containing sodium chloride, yeast extract powder, and tryptone, and adjusting the pH to 7.0, and the OD value of the bacteria liquid is 1.2-1.5; A3. The recycled coarse aggregate is immersed and adsorbed with the bacteria liquid under vacuum negative pressure for 20-30 min, and then dried in an oven at a constant temperature to obtain the self-repairing recycled coarse aggregate.
[0016] By using the above technical scheme, the mixed bacteria can be distributed on the surface of the recycled aggregate through vacuum adsorption, and the mixed bacteria can be protected from the alkaline environment of the concrete mortar by using the recycled aggregate as a carrier, so that the activity of the mixed bacteria can be maintained, and a good repair effect can be achieved.
[0017] Optionally, the mixed bacteria are selected from two or more of Bacillus pasteurii, Bacillus cohnii, Micrococcus halophilus, and Bacillus sphaericus.
[0018] By using the above technical scheme, the mixed bacteria are used to realize the microbial mineralization and deposition, so that the repair effect on the cracks is better, and the durability of the concrete is effectively improved.
[0019] Optionally, the biomass ash includes at least one of rice husk ash, corn straw ash, and bagasse ash.
[0020] By adopting the technical scheme, the nano-pore structure and micro-aggregate effect of the rice hull ash can fill the voids of the self-repairing recycled coarse aggregate, the corn straw ash and the bagasse ash have phosphates, thereby promoting the cement hydration to generate high-density gel and promoting the densification of the concrete. The compounding is beneficial to improving the mechanical strength of the concrete and reducing the adverse effects of the recycled aggregate on the concrete.
[0021] Optionally, the cement is selected as Portland cement of P.O 42.5 grade, and the fine aggregate is selected as natural river sand with a fineness modulus of 2.6-3.0.
[0022] Optionally, the nutrient substance is selected as one or more of calcium lactate and calcium formate.
[0023] By adopting the technical scheme, the nutrient substance is used to maintain the activity of the microorganism inside the concrete.
[0024] In a second aspect, the application discloses a preparation method of self-repairing construction waste recycled aggregate concrete, including the following steps: The nutrient substance, the water reducing agent and water are stirred uniformly to prepare mixed water, the reinforced recycled coarse aggregate, the self-repairing recycled coarse aggregate and the fine aggregate are stirred in a mixer for 60-100 seconds, a part of the mixed water is added and stirred for 1-2 minutes, the cement, the biomass ash and the remaining mixed water are continuously stirred for 2-3 minutes, and the self-repairing construction waste recycled aggregate concrete is obtained.
[0025] By adopting the technical scheme, the preparation method is simple, and the concrete with good mechanical strength and self-repairing performance is obtained.
[0026] In summary, the application has the following beneficial effects: The self-repairing recycled coarse aggregate and the reinforced recycled coarse aggregate are added into the concrete, the recycled coarse aggregate is wrapped by old mortar and presents a loose and porous state, thereby being able to serve as a carrier of the mixed microorganism, meanwhile, the recycled coarse aggregate and the concrete matrix have good compatibility, the activity of the mixed microorganism is maintained, and the self-repairing function of the concrete on cracks is realized; the recycled coarse aggregate is modified by mixing the calcined attapulgite, the water glass slurry and the silane coupling agent, the voids and cracks on the surface of the recycled coarse aggregate are filled and bonded, meanwhile, the interfacial adhesion with the concrete is improved, the compactness of the recycled coarse aggregate is improved, and the mechanical strength of the concrete is improved.
[0027] In the concrete raw material, the self-repairing recycled coarse aggregate and the reinforced recycled coarse aggregate completely replace the coarse aggregate, and the addition of the biomass ash is beneficial to improving the compactness and the mechanical strength of the concrete, so that the prepared concrete has the self-repairing function on cracks on the basis of maintaining good mechanical strength, and the durability is improved. DETAILED DESCRIPTION
[0028] The application will be further described in detail below with reference to the examples.
[0029] The cement is Portland cement of P.O 42.5 grade selected and purchased; The polycarboxylate high-performance water reducing agent is specifically selected and purchased from PCA-I series of Jiangsu Subote New Materials; The construction waste is obtained by sorting out branches, wood chips, glass and other organic matters from composite construction waste generated during decoration of a construction site, and includes waste concrete, brick and tile waste, lime mortar and the like. The waste concrete is obtained from waste concrete blocks removed from a construction site. The water glass is selected and purchased from Shandong Anquan Chemical Technology Co., Ltd., and has a self-concentration of 39.7%.
[0030] Preparation Example 1 The preparation method of the reinforced recycled coarse aggregate comprises the following steps: S1. The construction waste is fully crushed by an e-type crusher, and after washing and impurity removal, batch screening is performed with a diameter gradient of 20 mm, 10 mm and 5 mm, so as to screen the recycled aggregate of 5-20 mm. The attapulgite is calcined at 450℃ for 1.5h, and after stopping heating and cooling to room temperature, the calcined attapulgite is obtained. The 100 kg of recycled aggregate and 40 kg of calcined attapulgite are fully mixed to obtain the mixed recycled aggregate. S2. The water glass binder, silane coupling agent A-151 and water are mixed to obtain a mixed solution, and the mass fraction of the water glass in the mixed solution is 4%, and the mass fraction of the silane coupling agent is 2%. The mixed recycled aggregate is placed in the prepared solution for 2h, and after being taken out, it is naturally dried to obtain the reinforced recycled coarse aggregate.
[0031] Preparation Example 2 The preparation method of the reinforced recycled coarse aggregate comprises the following steps: S1. The construction waste is fully crushed by an e-type crusher, and after washing and impurity removal, batch screening is performed with a diameter gradient of 20 mm, 10 mm and 5 mm, so as to screen the recycled aggregate of 5-20 mm. The attapulgite is calcined at 500℃ for 1h, and after stopping heating and cooling to room temperature, the calcined attapulgite is obtained. The 100 kg of recycled aggregate and 60 kg of calcined attapulgite are fully mixed to obtain the mixed recycled aggregate. S2. The water glass binder, silane coupling agent KH-550 and water are mixed to obtain a mixed solution, and the mass fraction of the water glass in the mixed solution is 6%, and the mass fraction of the silane coupling agent is 4%. The mixed recycled aggregate is placed in the prepared solution for 3h, and after being taken out, it is naturally dried to obtain the reinforced recycled coarse aggregate.
[0032] Preparation Example 3 The difference between the present preparation example and preparation example 1 is that the reinforced recycled coarse aggregate is different.
[0033] The mixed recycled aggregate is no longer used in the reinforced recycled coarse aggregate, and the mixed recycled aggregate is directly replaced by the recycled aggregate.
[0034] Specifically, in step S2, the sieved recycled aggregate is directly placed in the prepared solution for soaking for 2h, and then naturally dried after being taken out to obtain the reinforced recycled coarse aggregate.
[0035] Preparation Example 4 The difference between the present preparation example and preparation example 1 is that the reinforced recycled coarse aggregate is different.
[0036] The silane coupling agent is no longer used in the reinforced recycled coarse aggregate, and an equal amount of water glass binder is used to replace the silane coupling agent.
[0037] Specifically, in step S2, the water glass binder and water are mixed to obtain a mixed solution, the mass fraction of the water glass is 6%, and the mixed recycled aggregate is placed in the prepared solution for soaking for 2h, and then naturally dried after being taken out to obtain the reinforced recycled coarse aggregate.
[0038] Preparation Example 5 The difference between the present preparation example and preparation example 1 is that the reinforced recycled coarse aggregate is different.
[0039] The water glass binder is no longer used in the reinforced recycled coarse aggregate, and an equal amount of silane coupling agent A-151 is used to replace the water glass binder.
[0040] Specifically, in step S2, the silane coupling agent A-151 and water are mixed to obtain a mixed solution, the mass fraction of the silane coupling agent is 6%, and the mixed recycled aggregate is placed in the prepared solution for soaking for 2h, and then naturally dried after being taken out to obtain the reinforced recycled coarse aggregate.
[0041] Preparation Example 6 A self-repairing recycled coarse aggregate is prepared by the following steps: A1: The waste concrete is crushed by a jaw crusher twice, washed with water, and sieved by a vibrating screen with a particle size of 10mm and 5mm to obtain recycled coarse aggregate with a particle size of 5-10mm; A2. The mixed bacteria are cultured in a liquid medium to obtain a bacterial solution, the mixed bacteria are selected from Bacillus pasteurii and Halococcus marinus, the liquid medium contains sodium chloride, yeast extract powder and tryptone, 10g of sodium chloride, 10g of tryptone and 5g of yeast extract powder are contained in each liter of solution, sodium hydroxide solution is used to adjust the pH to 7.0, and the mixed bacteria are cultured in a constant temperature shaking incubator at 33℃ and 130r / min for 2d, then centrifuged to obtain bacterial slurry, and then the bacterial slurry is resuspended with 5g / L of sterilized yeast extract solution to obtain the bacterial solution, and the OD value of the bacterial solution is 1.2; A3. The recycled coarse aggregate is impregnated with the adsorption bacterial solution under vacuum negative pressure for 20 minutes, and then dried at a constant temperature in an oven to obtain self-healing recycled coarse aggregate.
[0042] Preparation Example 7 A self-healing recycled coarse aggregate is prepared through the following steps: A1: The waste concrete is crushed twice by a jaw crusher, washed with water, and screened with vibrating screens with particle sizes of 10mm and 5mm to obtain recycled coarse aggregate with a particle size of 5-10mm. A2. The mixed bacteria were cultured in a liquid culture medium to obtain a bacterial solution. The mixed bacteria were Bacillus coccidioides, Bacillus cereus, and Bacillus spheroidae. The liquid culture medium contained sodium chloride, yeast extract, and tryptone. Each liter of solution contained 10g of sodium chloride, 10g of tryptone, and 5g of yeast extract. The pH was adjusted to 7.0 using sodium hydroxide solution. After culturing in a constant temperature shaking incubator at 33℃ and 130r / min for 2 days, the bacterial solution was centrifuged to obtain bacterial sludge. The bacterial sludge was then resuspended in a 5g / L sterile yeast extract solution to obtain a bacterial solution. The OD value of the bacterial solution was 1.5. A3. The recycled coarse aggregate is impregnated with the adsorption bacterial solution under vacuum negative pressure for 30 minutes, and then dried at a constant temperature in an oven to obtain self-healing recycled coarse aggregate. Example
[0043] Example 1 Self-healing construction waste recycled aggregate concrete, comprising the following raw materials: 300 kg of cement; 520 kg of reinforced recycled coarse aggregate prepared in Example 1; 180 kg of self-healing regenerated coarse aggregate was prepared in Example 6; 380 kg of fine aggregate, made from natural river sand with a fineness of 2.6 mesh; 45 kg of biomass ash, specifically rice husk ash; 4 kg of water-reducing agent, specifically a polycarboxylate-based high-efficiency water-reducing agent; 140 kg of water; 6 kg of nutrients, specifically calcium lactate.
[0044] Self-healing recycled aggregate concrete from construction waste is prepared through the following steps: Nutrients, water-reducing agents, and water are mixed evenly to make mixing water. Reinforced recycled coarse aggregate, self-healing recycled coarse aggregate, and fine aggregate are mixed in a mixer for 60 seconds. A portion of the mixing water is added and mixed for 1 minute. Then, cement, biomass ash, and the remaining mixing water are added and mixed for another 2 minutes to obtain self-healing construction waste recycled aggregate concrete.
[0045] Example 2 Self-healing construction waste recycled aggregate concrete, comprising the following raw materials: Cement 340 kg; reinforced recycled coarse aggregate prepared in Preparation Example 1 600 kg; Self-repairing recycled coarse aggregate prepared in Preparation Example 6 300 kg; Fine aggregate 450 kg, natural river sand with fineness modulus of 2.6 is selected; Biomass ash 52 kg, rice husk ash is specifically selected; Water reducing agent 7 kg, polycarboxylate high efficiency water reducing agent is specifically selected; Water 170 kg; nutrient 9 kg, calcium lactate is specifically selected.
[0046] The self-repairing construction waste recycled aggregate concrete is prepared by the following steps: The nutrient, the water reducing agent and the water are stirred uniformly to prepare mixing water, the reinforced recycled coarse aggregate, the self-repairing recycled coarse aggregate and the fine aggregate are stirred in a mixer for 100 s, a part of the mixing water is added and stirred for 2 min, the cement, the biomass ash and the remaining mixing water are continuously stirred for 3 min to obtain the self-repairing construction waste recycled aggregate concrete.
[0047] Example 3 The self-repairing construction waste recycled aggregate concrete comprises the following raw materials: Cement 320 kg; reinforced recycled coarse aggregate prepared in Preparation Example 1 580 kg; Self-repairing recycled coarse aggregate prepared in Preparation Example 6 240 kg; Fine aggregate 410 kg, natural river sand with fineness modulus of 2.8 is selected; Biomass ash 48 kg, rice husk ash is specifically selected; Water reducing agent 5 kg, polycarboxylate high efficiency water reducing agent is specifically selected; Water 150 kg; nutrient 8 kg, calcium formate is specifically selected.
[0048] The self-repairing construction waste recycled aggregate concrete is prepared by the following steps: The nutrient, the water reducing agent and the water are stirred uniformly to prepare mixing water, the reinforced recycled coarse aggregate, the self-repairing recycled coarse aggregate and the fine aggregate are stirred in a mixer for 80 s, a part of the mixing water is added and stirred for 1 min, the cement, the biomass ash and the remaining mixing water are continuously stirred for 3 min to obtain the self-repairing construction waste recycled aggregate concrete.
[0049] Example 4 The difference between the present example and Example 1 is that the reinforced recycled coarse aggregate and the self-repairing recycled coarse aggregate in the concrete raw materials are different.
[0050] The reinforced recycled coarse aggregate in the present example is the reinforced recycled coarse aggregate prepared in Preparation Example 2; The self-repairing recycled coarse aggregate in the embodiment is used to prepare the self-repairing recycled coarse aggregate prepared in Preparation Example 7.
[0051] Example 5 The difference between the embodiment and Example 1 is that the biomass ash in the concrete raw material is different.
[0052] In the embodiment, the biomass ash is selected to be a mixture of rice husk ash and corn straw ash, specifically 30 kg of rice husk ash and 15 kg of corn straw ash.
[0053] Example 6 The difference between the embodiment and Example 1 is that the biomass ash in the concrete raw material is different.
[0054] In the embodiment, the biomass ash is selected to be a mixture of rice husk ash and corn straw ash, specifically 30 kg of rice husk ash and 15 kg of corn straw ash.
[0055] Comparative Example Comparative Example 1 The difference between the comparative example and Example 1 is that the reinforced recycled coarse aggregate in the concrete raw material is different.
[0056] In the comparative example, the reinforced recycled coarse aggregate is selected to be the reinforced recycled coarse aggregate prepared in Preparation Example 3.
[0057] Comparative Example 2 The difference between the comparative example and Example 1 is that the reinforced recycled coarse aggregate in the concrete raw material is different.
[0058] In the comparative example, the reinforced recycled coarse aggregate is selected to be the reinforced recycled coarse aggregate prepared in Preparation Example 4.
[0059] Comparative Example 3 The difference between the comparative example and Example 1 is that the reinforced recycled coarse aggregate in the concrete raw material is different.
[0060] In the comparative example, the reinforced recycled coarse aggregate is selected to be the reinforced recycled coarse aggregate prepared in Preparation Example 5.
[0061] Comparative Example 4 The difference between the comparative example and Example 1 is that the self-repairing recycled coarse aggregate in the concrete raw material is different.
[0062] In the comparative example, the self-repairing recycled coarse aggregate is selected to be ceramsite instead of recycled coarse aggregate as a carrier for mixed bacteria, and the ceramsite is immersed and adsorbed with bacterial solution under vacuum negative pressure.
[0063] Performance Test The concrete of each example and comparative example was cast into a test piece, demolded after standing for 48 h, and precracked after curing for 7 d under the condition of 85% RH and 22℃. The precracking was carried out on the concrete test piece as the object of investigation, and the compressive strength of the example and comparative example was tested by a universal pressure testing machine according to the standard GB / T 50081-2002 "Standard for Testing Methods of Mechanical Properties of Ordinary Concrete", the method being to adjust the press machine to load at a rate of 0.04 mm / min, while observing the side crack development by a crack observation instrument, and measuring and recording the crack width developed on the four sides of each test piece after compression, when the side of the test piece appeared 0.3-0.5 mm crack, the loading was stopped and unloaded after holding for 90 s, and after removal, 3 cracks with crack width of 0.3-0.5 mm were selected in each test piece and marked; then the test piece was watered and cured, and the repair performance was determined by a crack observation instrument and an electronic scanning microscope.
[0064] According to the above table, it can be seen that in the present application, by adding self-repairing recycled coarse aggregate in the concrete raw materials, the microorganisms are adsorbed by the recycled coarse aggregate as a carrier, so that the concrete with self-repairing function is prepared, and the compatibility of the recycled coarse aggregate and the cement mortar is good, which can better maintain the activity of the microorganisms. By adding the reinforced recycled coarse aggregate, after compounding the calcined attapulgite and the recycled aggregate, mixing and modifying by water glass and silane coupling agent, the filling and bonding of the surface pores of the recycled coarse aggregate are realized, avoiding the adverse effect of the recycled coarse aggregate on the mechanical strength of the concrete; by compounding with biomass ash, cement and other components, the mechanical properties of the concrete are improved.
[0065] The specific embodiment is only an explanation of the present application, and is not a limitation of the present application, and those skilled in the art can make modifications to the specific embodiment without creative contribution after reading the present specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.
Claims
1. A self-healing construction and demolition waste recycled aggregate concrete, characterized by, The raw materials include the following weight parts: Cement 300-340 parts; Reinforced recycled coarse aggregate 520-600 parts; Self-repairing recycled coarse aggregate 180-300 parts; Fine aggregate 380-450 parts; Biomass ash 45-52 parts; Water reducing agent 4-7 parts; Water 140-170 parts; Nutrients 6-9 parts; The reinforced recycled coarse aggregate is prepared by mixing and modifying the recycled aggregate with calcined attapulgite, water glass slurry and silane coupling agent, and the recycled aggregate is obtained by crushing and screening the construction waste; The self-repairing recycled coarse aggregate is prepared by vacuum adsorbing mixed bacteria on the recycled coarse aggregate as a carrier, and the recycled coarse aggregate is obtained by crushing and screening the waste concrete.
2. The self-healing construction and demolition waste recycled aggregate concrete according to claim 1, characterized in that, The reinforced recycled coarse aggregate is prepared by the following steps: S1. The construction waste is fully crushed, washed, impurity-removed and screened to obtain recycled aggregate with a particle size of 5-20 mm; the attapulgite is calcined at 450-500 DEG C for 1-1.5 h, then the heating is stopped and it is naturally cooled to room temperature to obtain calcined attapulgite; the recycled aggregate and the calcined attapulgite are mixed to obtain mixed recycled aggregate; S2. The mixed recycled aggregate is soaked in the prepared solution for 2-3 h after being uniformly mixed with water glass, silane coupling agent and water in different mass ratios, and then it is naturally dried after being taken out to obtain the reinforced recycled coarse aggregate.
3. The self-healing construction and demolition waste recycled aggregate concrete according to claim 2, characterized in that: In step S1, the weight ratio of the recycled aggregate to the calcined attapulgite is 1:(0.4-0.6); in step S2, the mass fraction of the water glass in the prepared solution is 4%-6%, and the mass fraction of the silane coupling agent is 2%-4%.
4. The self-healing construction and demolition waste recycled aggregate concrete according to claim 2, characterized in that: The silane coupling agent is selected from one or more of silane coupling agent A-151, silane coupling agent KH-560 and silane coupling agent KH-550.
5. The self-healing construction and demolition waste recycled aggregate concrete according to claim 1, wherein, The self-repairing recycled coarse aggregate is prepared by the following steps: A1. The waste concrete is crushed and screened to obtain recycled coarse aggregate with a particle size of 5-10 mm; A2. The mixed bacteria are cultured in a liquid medium to obtain a bacterial solution, the liquid medium contains sodium chloride, yeast extract powder and tryptone, the pH is adjusted to 7.0, and the OD value of the bacterial solution is 1.2-1.5; A3. The recycled coarse aggregate is immersed and adsorbed with the bacterial solution under vacuum negative pressure for 20-30 min, and then it is dried in an oven at a constant temperature to obtain the self-repairing recycled coarse aggregate.
6. The self-healing construction and demolition waste recycled aggregate concrete according to claim 5, characterized in that: The mixed bacteria are selected from two or more of Bacillus pasteurii, Bacillus cohnii, Micrococcus marinus and Bacillus sphaericus.
7. The self-healing construction and demolition waste recycled aggregate concrete according to claim 1, characterized in that: The biomass ash includes at least one of rice husk ash and corn stalk ash, and bagasse ash.
8. The self-healing construction and demolition waste recycled aggregate concrete according to claim 1, characterized in that: The cement is selected from P.O 42.5 grade Portland cement, and the fine aggregate is selected from natural river sand with a fineness modulus of 2.6-3.
0.
9. The self-healing construction and demolition waste recycled aggregate concrete according to claim 1, characterized in that: The nutrients are selected from one or more of calcium lactate and calcium formate.
10. A method of producing a self-healing construction waste recycled aggregate concrete according to any one of claims 1 to 9, characterized in that, The method comprises the following steps: The nutrients, water reducing agent and water are uniformly stirred to prepare mixed water, the reinforced recycled coarse aggregate, self-repairing recycled coarse aggregate and fine aggregate are stirred in a mixer for 60-100 s, a part of the mixed water is added and stirred for 1-2 min, the cement, biomass ash and the remaining mixed water are further added and stirred for 2-3 min to obtain the self-repairing construction waste recycled aggregate concrete.