Self-healing microbial full-recycled concrete and preparation method thereof

Abstract

The invention discloses self-healing microorganism full-recycled concrete and a preparation method thereof, and belongs to the technical field of concrete materials. Modified microorganism-loaded ceramsite is adopted to load different microorganisms through a vacuum adsorption method and a soaking method; the concrete is composed of the high-alumina fly ash-slag cement, the microbe reinforced recycled fine aggregate, the microbe reinforced recycled coarse aggregate, water and the modified supported microbe ceramsite. When tiny damage is generated in the concrete, metabolism can be carried out through microorganisms attached to the recycled aggregate, then calcium carbonate is generated for damage repair, and when the concrete is greatly damaged, the modified microorganism-loaded ceramsite is damaged, and the microorganisms loaded in the ceramsite play a role to repair the concrete damage. Therefore, full-stage self-repairing of concrete damage is realized. Meanwhile, the materials adopt high-alumina fly ash, slag and recycled aggregate, so that the comprehensive utilization rate of industrial solid wastes and building solid wastes can be increased, and the environmental problems caused by the industrial solid wastes and the building solid wastes are relieved.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete materials, and in particular relates to a self-healing microbial fully regenerated concrete and a preparation method thereof. Background Art

[0002] At present, concrete is one of the most widely used building materials, and its application scope includes bridges, buildings, roads and industrial structures. As the demand for concrete in the construction industry continues to grow, construction resources such as sand and gravel aggregates and cement are becoming increasingly scarce. If construction and industrial solid waste can be recycled and recycled concrete can be produced, it will be of great significance for saving resources, protecting the environment, reducing construction costs and solving the problem of urban garbage dumping.

[0003] As a brittle material, concrete will produce cracks and local damage due to various reasons during pouring and normal use. If the concrete damage is not effectively and promptly treated, harmful ions (Cl-, Na + ) will penetrate into the concrete, causing structural deterioration, shortening the service life, and causing the concrete structure to retire early. The current mainstream concrete repair method usually uses cement mortar and other materials to compact and smooth the concrete surface or re-pour for more serious damage. This is not only time-consuming and labor-intensive, but also cannot guarantee the integrity of the repaired structure. Summary of the invention

[0004] In order to solve the deficiencies of the prior art and achieve the purpose of self-healing of concrete damage, the present invention adopts the following technical solutions:

[0005] A method for preparing self-healing microbial fully regenerated concrete comprises the following steps:

[0006] Step S101: gradually and slowly adding culture solution to the first container containing the modified microorganism-loaded porous lightweight aggregate and stirring continuously, and stopping adding after the surface of the modified microorganism-loaded porous lightweight aggregate is completely soaked by the culture solution;

[0007] Step S102: adding 1 / 3 of the weight of water into the first container containing the modified microorganism-loaded porous lightweight aggregate, and slowly adding water until the liquid in the first container completely covers the modified microorganism-loaded porous lightweight aggregate, stirring fully, and preparing the liquid into a modified microorganism-loaded porous lightweight aggregate suspension with a concentration of 5%-10%; that is, the mass of the modified microorganism-loaded porous lightweight aggregate accounts for 5%-10% of the total mass of the suspension;

[0008] Step S103: high-alumina fly ash-slag cement, microbial reinforced waste concrete recycled aggregate and 1 / 3 of water by weight are put into a second container, and a water reducer is added and stirred evenly; a water reducer is an admixture that reduces the amount of water used in a concrete mixture while maintaining the slump or fluidity of the concrete substantially unchanged, and has a dispersing effect on cement particles in the concrete mixture. The addition of the water reducer here can improve the workability of the concrete mixture under the condition of a specified water amount when mixing the concrete, that is, improve the fluidity, cohesiveness and water retention of the mixture, that is, improve the workability of the concrete mixture, and is also conducive to improving the compactness of the concrete mixture after hardening;

[0009] Step S104: slowly adding the suspension into the second container, and gradually and slowly adding the remaining water, measuring the slump of the concrete by the slump method per unit time (15min-30min), and stopping the addition when the slump of the concrete reaches 5cm-10cm, to obtain a mixed material;

[0010] Step S105: pouring the mixed material into a mold for curing and forming to obtain self-healing microbial fully regenerated concrete.

[0011] Furthermore, the microorganism is Bacillus pasteurianus, and the microorganism culture solution includes distilled water, casein peptone, urea, sodium chloride, agar powder, and soybean casein. The ratio of the microorganism culture solution is 15g casein peptone, 20g urea, 5g sodium chloride, 20g agar powder, and 5g soybean casein per 1L of distilled water, and the pH value of the microorganism culture solution is 8-10;

[0012] The preparation of the modified microbial-loaded porous lightweight aggregate comprises the following steps:

[0013] Step S201: Pour 1 / 3 of the microbial culture solution containing microorganisms into a vacuum filtration bottle, then pour in the porous fly ash regenerated ceramsite, stir with a long glass rod, then add the remaining 2 / 3 of the microbial culture solution containing microorganisms to the vacuum filtration bottle and cover all the ceramsite, filter through the vacuum filtration bottle to make the microorganisms adsorbed on the ceramsite, turn on the vacuum pump switch, start timing when the vacuum degree in the vacuum filtration bottle reaches 0.1MPa, turn off the vacuum pump after the adsorption time is 4min-5min, then open the bottle stopper after the bottle returns to normal pressure, clean the microbial culture solution remaining in the porous fly ash regenerated ceramsite, place the adsorbed ceramsite on the filter paper, vibrate the filter paper to absorb the microbial culture solution attached to the surface of the ceramsite, and place it in a ventilated place to obtain the ceramsite loaded with microorganisms;

[0014] Step S202: evenly apply packaging material on the surface of the ceramsite loaded with microorganisms, and after the packaging material is solidified, a preliminary packaging ceramsite loaded with microorganisms is obtained;

[0015] Step S203: Weigh water and P.O42.5 cement in a mass ratio of 1:2, stir them thoroughly to form cement slurry, put the preliminarily encapsulated microbial-loaded ceramsite into the cement slurry, stir them thoroughly for 120 seconds, ensure that the surface of the preliminarily encapsulated microbial-loaded ceramsite is fully covered by the cement slurry, let it stand for 4 hours, and after the formed cement surface is smooth and has strength, put it into water to separate the clumped ceramsite, then fish it out, spread it flat and sprinkle water for curing, cover the surface with plastic wrap, and cure for 3 days to obtain modified microbial-loaded porous lightweight aggregate.

[0016] Furthermore, the microorganism is Bacillus coli, and the microorganism culture solution includes distilled water, creatinine, sodium chloride, sodium citrate, ammonium chloride, calcium chloride, peptone, and beef extract. The ratio of the microorganism culture solution is 2.5g creatinine, 5g sodium chloride, 5g sodium citrate, 5g ammonium chloride, 5g calcium chloride, 20g peptone, and 15g beef extract per 1L of distilled water, and the pH value of the microorganism culture solution is 7-9;

[0017] The preparation of the modified microbial-loaded porous lightweight aggregate comprises the following steps:

[0018] Step S301: add 1 / 2 of the microbial culture solution containing microorganisms into a beaker, pour in the porous fly ash regenerated ceramsite, and stir continuously with a long glass rod, then pour in the remaining 1 / 2 of the microbial culture solution containing microorganisms and completely cover all the ceramsite, soak for 18h-24h, then remove, clean the microbial culture solution remaining in the porous fly ash regenerated ceramsite, and obtain ceramsite loaded with microorganisms;

[0019] Step S302: evenly apply the encapsulation material on the surface of the ceramsite loaded with microorganisms, and wait for the encapsulation material on the surface of the ceramsite to solidify, thereby obtaining the preliminarily encapsulated ceramsite loaded with microorganisms;

[0020] Step S303: Weigh water and P.O42.5 cement in a mass ratio of 1:2, stir thoroughly to form cement slurry, put the preliminarily encapsulated microbial-loaded ceramsite into the cement slurry, stir thoroughly for 120 seconds, ensure that the surface of the preliminarily encapsulated microbial-loaded ceramsite is fully covered by the cement slurry, let it stand for 4 hours, and after the formed cement surface is smooth and has strength, put it into water to separate the clumping ceramsite, then fish it out, spread it flat and sprinkle water for curing, cover the surface with plastic wrap, and cure for 3 days to obtain modified microbial-loaded porous lightweight aggregate.

[0021] Furthermore, the microorganism culture temperature is 30° C., the bacterial solution concentration is above 10 8 cells / ml, the spore production rate is above 90%, and the bacterial solution absorbance is reduced by 50% compared with the initial state of the bacterial solution.

[0022] Furthermore, the packaging material includes microbial nutrient solution, chitosan, desulfurized gypsum and polyacrylate plasticizer, and the content thereof is: 150-200 parts of nutrient solution, 3-5 parts of chitosan, 200-300 parts of desulfurized gypsum, and 5-10 parts of polyacrylate plasticizer. Chitosan is added to the packaging material used to prepare the modified microbial-loaded porous lightweight aggregate, and its low concentration condition can inhibit the activity of microorganisms, keep them in a low energy consumption state, further improve their survival life, and improve the service life of the concrete self-healing performance.

[0023] Furthermore, the preparation of the porous fly ash regenerated ceramsite comprises the following steps:

[0024] Step S401: The incoming sludge is piled in a rainproof shed and stored in a dry place until the moisture content of the sludge reaches 75%, and then it is sealed for curing. After the incoming clay is fully dried to a dehydrated state, it is sent to a roller crusher through a box feeder and crushed into powder;

[0025] Step S402: first take the above-mentioned fly ash and sludge in a double-shaft mixer and mix them evenly, then add clay and mix them evenly, and then send them to an aging yard for 7 to 15 days;

[0026] Step S403: the aged ingredients are put into a double-shaft mixer for breaking and stirring, and then sent to a double-roll granulator to produce granular balls, which are then shaped and sieved, and the sieved particle size is 5mm-10mm;

[0027] Step S404: The granular balls that have passed the screening are sent to the double-drum plug-in rotary kiln for preheating and roasting. After the granular balls are fully expanded and the particle size reaches 5mm-20mm, the fired porous fly ash regenerated ceramsite products are dropped into a cooler for cooling, and then the porous fly ash regenerated ceramsite of different particle sizes is screened by the rotary kiln.

[0028] Furthermore, the microbial enhanced waste concrete recycled aggregate includes microbial enhanced recycled fine aggregate and microbial enhanced recycled coarse aggregate, the average particle size of the microbial enhanced recycled fine aggregate is 1mm-3mm; the particle size of the microbial enhanced recycled coarse aggregate is 5mm-20mm; the microbial enhanced recycled fine aggregate and the microbial enhanced recycled coarse aggregate are obtained by crushing, screening, washing and drying construction solid waste to obtain ordinary recycled fine aggregate and ordinary recycled coarse aggregate, and then infiltrating with microbial culture solution, and the treatment method is as follows:

[0029] Ordinary recycled fine aggregate and ordinary recycled coarse aggregate are respectively placed in two culture solutions containing microorganisms for soaking. When the microorganism is Bacillus pasteurianus, the soaking time of ordinary recycled fine aggregate is 4h-8h, and the soaking time of ordinary recycled coarse aggregate is 24h-48h; when the microorganism is Bacillus coxii, the soaking time of ordinary recycled fine aggregate is 2h-4h, and the soaking time of ordinary recycled coarse aggregate is 12h-24h. After being fished out, they are naturally dried, left to stand and sprayed with microbial culture solution for curing for 3 days.

[0030] The recycled aggregate is immersed in a culture solution containing microorganisms for infiltration treatment. Through the metabolic function of the microorganisms, calcium carbonate is generated to repair the initial damage inside the recycled aggregate, making its structure denser.

[0031] When concrete is slightly disturbed, small damage may occur inside it first, but the expanded clay will not break. At this time, the microorganisms attached to the recycled aggregate can metabolize and repair the small damage. When the damage increases, causing the expanded clay to break and the microorganisms inside it to flow out, the concentration of microorganisms inside the concrete increases, which can quickly repair the damage and ultimately achieve self-healing of the concrete throughout the entire process to meet engineering needs.

[0032] A self-healing microbial fully recycled concrete comprises fly ash-slag cement, microbial reinforced waste concrete recycled aggregate, water and modified microbial loaded porous lightweight aggregate, wherein the fly ash-slag cement is 400-600 parts by weight of aluminum fly ash-slag cement, the microbial reinforced waste concrete recycled aggregate is 1400-2000 parts by weight, the water is 300-500 parts by weight, and the modified microbial loaded porous lightweight aggregate is 20-40 parts by weight.

[0033] Furthermore, the aluminum fly ash-slag cement is high-aluminum fly ash-slag cement, comprising high-aluminum fly ash, slag, and calcium peroxide, wherein the mass ratio of high-aluminum fly ash to slag is 2:1, calcium peroxide accounts for 1%-3% of the total mass of the high-aluminum fly ash-slag cement, and the Al2O3 content in the high-aluminum fly ash is 35%-40%;

[0034] The modified microbial-loaded porous lightweight aggregate comprises porous fly ash regenerated ceramsite, microorganisms, microbial culture solution, packaging materials and a cement thin layer, wherein the raw materials used in the porous fly ash regenerated ceramsite include fly ash, sludge and clay in a mass ratio of 7:2:1, and the particle size of the porous fly ash regenerated ceramsite is 5mm-20mm, and the density is 300kg / m 3 -500kg / m 3 , mass adsorption rate is 300%-400%, water absorption rate is 10%-15%;

[0035] The microorganisms in the recycled aggregate of the microbial reinforced waste concrete are Bacillus pasteurianus, which is a urease bacteria and can hydrolyze urea into CO3 through the urease produced by its own metabolism. 2- and NH4 + ,CO3 2- The Ca in the concrete 2+ Combined to form CaCO3 precipitate.

[0036] The use of high-alumina fly ash-slag cement can further adjust the alkaline environment in the concrete to a pH value suitable for the survival of microorganisms through the alkali neutralization reaction of the large amount of Al2O3 contained in the high-alumina fly ash, thereby promoting the mineralization of microorganisms. Adding calcium peroxide to the cement can not only serve as a calcium source to promote the production of calcium carbonate together with microorganisms, but also release a large amount of oxygen, providing a good oxygen environment for the survival of microorganisms and ensuring that the microorganisms can survive normally.

[0037] Furthermore, the microorganism in the microbial enhanced waste concrete recycled aggregate is Bacillus coli, which is an aerobic bacterium that can convert organic carbon into inorganic carbon. In the metabolic process, it converts organic acid carbon into calcium carbonate and releases carbon dioxide, which continuously generates CO3 in an alkaline environment. 2- And further with the Ca in the concrete 2+ Combined to form CaCO3 precipitate.

[0038] The advantages and beneficial effects of the present invention are:

[0039] The microbial fully regenerated concrete of the present invention can generate CaCO3 to fill the damaged part through microbial mineralization after the structure or component is damaged, thereby achieving a self-healing effect; at the same time, through the microbial mineralization deposition, the strength of the initial weak positions such as the internal interface transition zone, gaps and cracks of the concrete is further enhanced, thereby reducing internal defects, reducing pore water content, enhancing frost resistance, and improving the density of the concrete, enhancing the concrete's resistance to chloride ion corrosion and carbonization, and comprehensively improving the durability of the concrete; the high-aluminum fly ash-slag cement used in the present invention can not only improve the utilization rate of industrial waste, but also a large amount of Al2O3 in the high-aluminum fly ash can react with OH in the concrete -The reaction lowers the pH value and increases the survival rate of microorganisms. By adding CaO2, a calcium source is provided for microbial mineralization, thereby increasing the damage repair rate. Using desulfurized gypsum as the base material for packaging material can improve the utilization rate of industrial solid waste, and can also appropriately lower the pH value of the microbial growth environment, so that the microorganisms remain in a suitable growth environment. Adding chitosan to the packaging material can inhibit the rapid growth of microorganisms, thereby ensuring that the microorganisms can survive longer in a closed environment. The use of microbial-enhanced recycled coarse aggregate and microbial-enhanced recycled fine aggregate as aggregates can not only improve the strength of recycled aggregates, but also ensure self-repair of concrete damage throughout the entire process, and then promote the recycling of construction solid waste, thereby improving resource utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a flow chart of a method for preparing self-healing microbial fully regenerated concrete in the present invention.

[0041] Figure 2 It is a curve diagram showing the effect of chitosan concentration on microbial survival in the present invention.

[0042] Figure 3 This is a curve diagram showing the influence of the high-aluminum fly ash dosage on the maximum repair width of microorganisms in the present invention.

[0043] Figure 4 It is a curve diagram showing the influence of the content of high-aluminum fly ash on the thickness of the microbial restoration layer in the present invention. DETAILED DESCRIPTION

[0044] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0045] The present invention introduces microorganisms into concrete to generate calcium carbonate or promote CO3 2- The formation of calcium carbonate crystals can then repair concrete damage and enable the concrete to achieve self-healing function. This "self-healing" function is to gradually generate calcium carbonate crystals from the damaged surface inside the concrete, and its bonding degree is stronger than that of artificially filled repair materials. In addition, this "self-healing" function can also repair the concrete in time when any minor damage that is difficult to observe manually occurs, so that the concrete is always in the best condition, and secondary damage caused by human factors can be avoided during the "self-healing" process. Therefore, it is urgent to explore concrete that has environmental effects and can achieve self-healing.

[0046] like Figure 1 As shown, a method for preparing self-healing microbial fully regenerated concrete comprises the following steps:

[0047] Step 1: Place the modified microorganism-loaded porous lightweight aggregate in a mixer, gradually and slowly add the culture solution therein while stirring continuously until the surface of the modified microorganism-loaded porous lightweight aggregate is completely soaked, and then stop adding;

[0048] Step 2: Add 1 / 3 of water into a mixer containing the modified microorganism-loaded porous lightweight aggregate, and slowly add water until the water completely covers the modified microorganism-loaded porous lightweight aggregate, and stir thoroughly to prepare a modified microorganism-loaded porous lightweight aggregate suspension with a concentration of 5%-10%;

[0049] Step 3: Put the high-alumina fly ash-slag cement, microbial enhanced waste concrete recycled aggregate and 1 / 3 of the water by weight into another mixer, and add a water reducing agent to mix evenly;

[0050] Step 4: Slowly add the suspension prepared in step 1 to the mixer in step 2, and then gradually and slowly add the remaining water. The slump of the concrete is measured by the slump method every 15min-30min on site until the slump of the concrete reaches 5cm-10cm. Stop adding;

[0051] Step 5: Finally, pour the mixed material into a mold for curing and forming to obtain self-healing microbial fully regenerated concrete.

[0052] The self-healing microbial fully recycled concrete prepared according to the method is composed of high-aluminum fly ash-slag cement, microbial-reinforced waste concrete recycled aggregate, water and modified loaded microbial porous lightweight aggregate, and the weight proportions of the raw materials are: 400-600 parts of high-aluminum fly ash-slag cement, 1400-2000 parts of microbial-reinforced waste concrete recycled aggregate, 300-500 parts of water, and 20-40 parts of modified loaded microbial porous lightweight aggregate.

[0053] High-alumina fly ash-slag cement is composed of high-alumina fly ash, slag and calcium peroxide, wherein the mass ratio of high-alumina fly ash to slag is 2:1, calcium peroxide accounts for 1%-3% of the total mass of high-alumina fly ash-slag cement, and the Al2O3 content in high-alumina fly ash is 35%-40%.

[0054] The modified microbial-loaded porous lightweight aggregate is composed of porous fly ash recycled ceramsite, microorganisms, microbial culture solution, packaging materials and a cement thin layer. The porous fly ash recycled ceramsite uses fly ash, sludge and clay as raw materials, and the mass fraction ratio is 7:2:1; the particle size of the porous fly ash recycled ceramsite is 5mm-20mm, and the density is 300kg / m 3 -500kg / m 3 , the mass adsorption rate is 300%-400%, and the water absorption rate is 10%-15%.

[0055] The microorganism is Bacillus pasteurianus or Bacillus coli. Bacillus pasteurianus is a urease-producing bacterium that can hydrolyze urea into CO3 through the urease produced by its own metabolism. 2- and NH4 + , and then CO3 2- Ca in the surrounding medium 2+ Combined to form CaCO3 precipitation; Bacillus coli is an aerobic bacterium that can convert organic carbon into inorganic carbon. During the metabolism process, it can convert organic acid carbon into calcium carbonate and release carbon dioxide. Carbon dioxide continuously generates CO3 in an alkaline environment 2- And further with Ca in concrete 2+ Combined to form CaCO3 precipitate.

[0056] The culture temperature of the above two strains was 30°C, the concentration of the bacterial solution was 108 cells / ml or above, the spore production rate was 90% or above, and the absorbance of the bacterial solution was reduced by 50% compared with the initial state of the bacterial solution.

[0057] When the microorganism is Bacillus pasteurianus, the microorganism culture solution is composed of distilled water, casein peptone, urea, sodium chloride, agar powder, and soybean casein. The ratio of the microorganism culture solution is 15g casein peptone, 20g urea, 5g sodium chloride, 20g agar powder, and 5g soybean casein per 1L of distilled water, and the pH value of the microorganism culture solution is 8-10.

[0058] When the microorganisms loaded on the modified microorganism-loaded porous lightweight aggregate are Bacillus pasteurianus, the preparation method thereof is as follows:

[0059] Step 1: First, pour 1 / 3 of the culture solution containing microorganisms into a vacuum filtration bottle, then pour in the porous fly ash regenerated ceramsite, stir with a long glass rod, and add the remaining 2 / 3 of the culture solution containing microorganisms to the vacuum filtration bottle and cover all the ceramsite, turn on the vacuum pump switch, and start timing when the vacuum degree in the vacuum filtration bottle reaches 0.1MPa. After the adsorption time is 4min-5min, turn off the vacuum pump, open the bottle stopper after the bottle returns to normal pressure, place the adsorbed ceramsite on the filter paper, vibrate the filter paper to absorb the culture solution attached to the surface of the ceramsite, and place it in a ventilated place to obtain ceramsite loaded with microorganisms;

[0060] Step 2: evenly apply the encapsulation material on the surface of the ceramsite loaded with microorganisms, and wait for the encapsulation material on the surface of the ceramsite to solidify and obtain the preliminarily encapsulated ceramsite loaded with microorganisms;

[0061] Step 3: Weigh water and P.O42.5 cement in a mass ratio of 1:2, stir thoroughly to form cement slurry, put the preliminarily encapsulated microbial-loaded ceramsite into the cement slurry, stir thoroughly for 120 seconds to ensure that the surface of the preliminarily encapsulated microbial-loaded ceramsite is fully covered by the cement slurry, let it stand for 4 hours, and when the cement surface is smooth and strong, put it into water to separate the clumping particles, then fish it out, spread it flat and sprinkle water for curing, cover the surface with plastic wrap, and cure for 3 days to make modified microbial-loaded porous lightweight aggregate.

[0062] When the microorganism is Bacillus coli, the microorganism culture solution is composed of distilled water, creatinine, sodium chloride, sodium citrate, ammonium chloride, calcium chloride, peptone and beef extract. The ratio of the microorganism culture solution is 2.5g creatinine, 5g sodium chloride, 5g sodium citrate, 5g ammonium chloride, 5g calcium chloride, 20g peptone and 15g beef extract per 1L of distilled water, and the pH value of the microorganism culture solution is 7-9.

[0063] When the microorganisms loaded on the modified microbial-loaded porous lightweight aggregate are Bacillus coli, the preparation method thereof is as follows:

[0064] Step 1: Take 1 / 2 of the culture solution containing microorganisms, add it all to a beaker, pour in the porous fly ash regenerated ceramsite, and stir it continuously with a long glass rod, then pour in the remaining 1 / 2 of the culture solution containing microorganisms until all the ceramsite is completely covered, soak for 18h-24h, remove and wipe off the surface culture solution to obtain ceramsite loaded with microorganisms;

[0065] Step 2: evenly apply the encapsulation material on the surface of the ceramsite loaded with microorganisms, and wait for the encapsulation material on the surface of the ceramsite to solidify and obtain the preliminarily encapsulated ceramsite loaded with microorganisms;

[0066] Step 3: Weigh water and P.O42.5 cement in a mass ratio of 1:2, stir thoroughly to form cement slurry, put the preliminarily encapsulated microbial-loaded ceramsite into the cement slurry, stir thoroughly for 120 seconds to ensure that the surface of the preliminarily encapsulated microbial-loaded ceramsite is fully covered by the cement slurry, let it stand for 4 hours, and when the cement surface is smooth and strong, put it into water to separate the clumping particles, then fish it out, spread it flat and sprinkle water for curing, cover the surface with plastic wrap, and cure for 3 days to make modified microbial-loaded porous lightweight aggregate.

[0067] The packaging material consists of microbial nutrient solution, chitosan, desulfurized gypsum and polyacrylate plasticizer, and its content is: 150-200 parts of nutrient solution, 3-5 parts of chitosan, 200-300 parts of desulfurized gypsum and 5-10 parts of polyacrylate plasticizer.

[0068] Microbial enhanced waste concrete recycled aggregate is divided into microbial enhanced recycled fine aggregate and microbial enhanced recycled coarse aggregate. The average particle size of microbial enhanced recycled fine aggregate is 1mm-3mm; the particle size of microbial enhanced recycled coarse aggregate is 5mm-20mm; microbial enhanced recycled fine aggregate and microbial enhanced recycled coarse aggregate are obtained by crushing, screening, washing and drying construction solid waste to obtain ordinary recycled fine aggregate and ordinary recycled coarse aggregate, and then infiltrating with microbial culture solution.

[0069] The processing method of recycled aggregate is as follows: ordinary recycled fine aggregate and ordinary recycled coarse aggregate are respectively placed in two culture solutions containing microorganisms for soaking. When the microorganism is Bacillus pasteurianus, the soaking time of ordinary recycled fine aggregate is 4h-8h, and the soaking time of ordinary recycled coarse aggregate is 24h-48h; when the microorganism is Bacillus coxii, the soaking time of ordinary recycled fine aggregate is 2h-4h, and the soaking time of ordinary recycled coarse aggregate is 12h-24h. After being fished out, they are naturally dried, left to stand and sprayed with microbial culture solution for curing for 3 days.

[0070] The preparation method of porous fly ash regenerated ceramsite is as follows:

[0071] Step 1: The incoming sludge is piled in a rainproof shed and stored in a dry place until the sludge moisture content reaches 75%, then it is sealed for curing. The incoming clay is fully dried to a dehydrated state and then fed into a roller crusher through a box feeder to be crushed into powder;

[0072] Step 2: Take the above-mentioned fly ash and sludge and send them into a double-shaft mixer to mix them evenly, then put the clay into the double-shaft mixer, mix them evenly, and then send them to the aging yard for 7-15 days;

[0073] Step 3: The aged ingredients are put into a double-shaft mixer for breaking and stirring, and then sent to a double-roll granulator to produce granular balls, which are shaped and sieved to a particle size of 5mm-10mm;

[0074] Step 4: Send the qualified granular balls to the double-drum plug-in rotary kiln for preheating and roasting. After the granular balls are fully expanded and the particle size reaches 5mm-20mm, the fired porous fly ash regenerated ceramsite products are dropped into the cooler for cooling, and then screened into finished products of different particle sizes by rotary screening.

[0075] The present invention encapsulates the microbial strains with mineralization in porous ceramsite and uses them in concrete. When the concrete is damaged to different degrees, the damaged parts of the concrete and even the internal minor damage can be repaired in time by the mineralization of the microorganisms, so as to ensure that the concrete structure can be used normally. At the same time, by using high-aluminum fly ash-slag cement, the alkaline environment in the concrete can be further adjusted to a pH value suitable for the survival of microorganisms through the large amount of Al2O3 contained in the high-aluminum fly ash. The pH value, thereby promoting the microorganisms to exert their mineralization, and adding calcium peroxide to the cement can not only promote the production of calcium carbonate together with the microorganisms as a calcium source, but also release a large amount of oxygen, provide a good oxygen environment for the survival of microorganisms, and ensure that the microorganisms can survive normally; at the same time, chitosan is added to the encapsulation material used to prepare the modified microbial-loaded porous lightweight aggregate, and the activity of the microorganisms can be inhibited under low concentration conditions, so that the microorganisms can maintain a low energy consumption state, further improve their survival life, and improve the service life of the concrete self-healing performance. In addition, the present invention soaks the regenerated aggregate in a culture solution containing microorganisms for infiltration treatment, and generates calcium carbonate through the metabolic function of the microorganisms to repair the initial damage inside the regenerated aggregate, making its structure more compact. When the concrete is slightly disturbed, small damage may occur inside it first, but it does not damage the ceramsite. At this time, the microorganisms attached to the regenerated aggregate can metabolize and repair the small damage; when the damage increases, causing the ceramsite to break and the microorganisms loaded inside to flow out, the concentration of microorganisms inside the concrete increases, and the damage can be quickly repaired, and finally the whole process of concrete self-healing is achieved to meet the needs of the project.

[0076] Embodiment 1:

[0077] A self-healing microbial fully recycled concrete is made from the following raw materials in parts by mass: 400 parts of high-aluminum fly ash-slag cement, 500 parts of water, 30 parts of modified loaded microbial porous lightweight aggregate, and 1500 parts of microbially reinforced waste concrete recycled aggregate; wherein the microbially reinforced waste concrete recycled aggregate is divided into microbially reinforced fine aggregate and microbially reinforced coarse aggregate, with 500 parts of microbially reinforced recycled fine aggregate and 1000 parts of microbially reinforced recycled coarse aggregate; in the high-aluminum fly ash-slag cement, the amount of calcium peroxide added accounts for 1% of the cement mass.

[0078] Among them, microbial enhanced recycled fine aggregate and microbial enhanced recycled coarse aggregate are obtained by crushing, screening, washing and drying construction solid waste to obtain ordinary recycled fine aggregate and ordinary recycled coarse aggregate, and then soaked in microbial culture solution; among them, the average particle size of microbial enhanced recycled fine aggregate is 1mm-3mm; the particle size of microbial enhanced recycled coarse aggregate is 5mm-20mm; the modified loaded microbial porous lightweight aggregate is composed of porous fly ash recycled ceramsite, microorganisms, microbial culture solution, packaging materials and cement thin layer. Among them, the raw materials of porous fly ash recycled ceramsite are fly ash, sludge and clay, and the mass fraction ratio is 7:2:1; the particle size of porous fly ash recycled ceramsite is 5mm-20mm, and the density is 300kg / m 3 -500kg / m 3 , the mass adsorption rate is 300%-400%, and the water absorption rate is 10%-15%.

[0079] The preparation method of porous fly ash regenerated ceramsite is as follows:

[0080] Step 1: The incoming sludge is piled in a rainproof shed and stored in a dry place until the sludge moisture content reaches 75%, then it is sealed for curing. The incoming clay is fully dried to a dehydrated state and then fed into a roller crusher through a box feeder to be crushed into powder;

[0081] Step 2: Take the above-mentioned fly ash and sludge and send them into a double-shaft mixer to mix them evenly, then put the clay into the double-shaft mixer, mix them evenly, and then send them to the aging yard for 7-15 days;

[0082] Step 3: The aged ingredients are put into a double-shaft mixer for breaking and stirring, and then sent to a double-roll granulator to produce granular balls, which are shaped and sieved to a particle size of 5mm-10mm;

[0083] Step 4: Send the qualified granular balls to the double-drum plug-in rotary kiln for preheating and roasting. After the granular balls are fully expanded and the particle size reaches 5mm-20mm, the fired porous fly ash regenerated ceramsite products are dropped into the cooler for cooling, and then screened into finished products of different particle sizes by rotary screening.

[0084] The microorganisms loaded on the modified microbial-loaded porous lightweight aggregate are Bacillus pasteurianus, and the preparation method thereof is as follows:

[0085] Step 1: Prepare the culture medium. The ratio of the culture medium is to add 15g casein peptone, 20g urea, 5g sodium chloride, 20g agar powder, and 5g soybean casein to every 1L of distilled water, and the pH value of the microbial culture medium is 8-10;

[0086] Step 2: First, pour 1 / 3 of the culture solution containing microorganisms into a vacuum filtration bottle, then pour in the porous fly ash regenerated ceramsite, stir with a long glass rod, and add the remaining 2 / 3 of the culture solution containing microorganisms to the vacuum filtration bottle and cover all the ceramsite, turn on the vacuum pump switch, and start timing when the vacuum degree in the vacuum filtration bottle reaches 0.1MPa. After the adsorption time is 5 minutes, turn off the vacuum pump, open the bottle stopper after the bottle returns to normal pressure, place the adsorbed ceramsite on the filter paper, vibrate the filter paper to absorb the culture solution attached to the surface of the ceramsite, and place it in a ventilated place to obtain ceramsite loaded with microorganisms;

[0087] Step 3: Prepare packaging materials. The packaging materials are composed of nutrient solution, chitosan, desulfurized gypsum and polyacrylate plasticizer, and the content is: 150 parts of nutrient solution, 3 parts of chitosan, 200 parts of desulfurized gypsum, and 5 parts of polyacrylate plasticizer;

[0088] Step 4: evenly apply the encapsulation material on the surface of the ceramsite loaded with microorganisms, wait for the encapsulation material on the surface of the ceramsite to solidify, and obtain the preliminarily encapsulated ceramsite loaded with microorganisms;

[0089] Step 5: Weigh water and P.O42.5 cement in a mass ratio of 1:2, stir thoroughly to form cement slurry, put the preliminarily encapsulated microbial-loaded ceramsite into the cement slurry, stir thoroughly for 120 seconds to ensure that the surface of the preliminarily encapsulated microbial-loaded ceramsite is fully covered by the cement slurry, let it stand for 4 hours, and when the cement surface is smooth and strong, put it into water to separate the clumping particles, then fish it out, spread it flat and sprinkle water for curing, cover the surface with plastic wrap, and cure for 3 days to make modified microbial-loaded porous lightweight aggregate.

[0090] The preparation method of bio-enhanced waste concrete recycled aggregate is as follows:

[0091] Bio-enhanced waste concrete recycled aggregate is divided into microbial enhanced recycled fine aggregate and microbial enhanced recycled coarse aggregate. The microbial enhanced recycled fine aggregate and the microbial enhanced recycled coarse aggregate are obtained by crushing, screening, cleaning and drying the construction solid waste to obtain ordinary recycled fine aggregate and ordinary recycled coarse aggregate. Then the ordinary recycled fine aggregate and the ordinary recycled coarse aggregate are respectively placed in two culture solutions containing microorganisms for immersion. The immersion time of ordinary recycled fine aggregate is 4 hours, and the immersion time of ordinary recycled coarse aggregate is 24 hours. After being fished out, they are naturally dried and left to stand and sprayed with culture solution for curing for 3 days.

[0092] The preparation method of the self-healing microbial fully regenerated concrete is as follows:

[0093] Step 1: Place the modified microorganism-loaded porous lightweight aggregate in a mixer, gradually and slowly add the culture solution therein while stirring continuously until the surface of the modified microorganism-loaded porous lightweight aggregate is completely soaked, and then stop adding;

[0094] Step 2: Add 1 / 3 of water into a mixer containing the modified microorganism-loaded porous lightweight aggregate, and slowly add water until the water completely covers the modified microorganism-loaded porous lightweight aggregate, and stir thoroughly to prepare a modified microorganism-loaded porous lightweight aggregate suspension with a concentration of 5%-10%;

[0095] Step 3: Put the high-alumina fly ash-slag cement, microbial enhanced recycled fine aggregate, microbial enhanced recycled coarse aggregate and 1 / 3 of the weight of water into another mixer, and add a water reducing agent to mix evenly;

[0096] Step 4: Slowly add the suspension prepared in step 1 to the mixer in step 2, and then gradually and slowly add the remaining water. The slump of the concrete is measured by the slump method every 15min-30min on site until the slump of the concrete reaches 5cm-10cm. Stop adding;

[0097] Step 5: Finally, pour the mixed material into a mold for curing and forming to obtain self-healing microbial fully regenerated concrete.

[0098] like Figure 2 As shown in the figure, the self-healing microbial fully regenerated concrete prepared in this embodiment is tested and determined to have an OD of 1.5 mg / L-2.5 mg / L when the chitosan concentration is 1.5 mg / L-2.5 mg / L. 600 When the chitosan concentration in the control group was 0, the OD 600 Reached 0.71, does not meet OD 600 The chitosan concentration reaches 0.8-1.2, so the survival time of microorganisms in concrete can be increased, which is conducive to the self-healing of concrete. Figure 3-4 As shown in the figure, high-aluminum fly ash has a great influence on the self-repairing performance of microbially enhanced all-in-vivo concrete. When the addition amount is less than 20%, the repair ability of the microbially enhanced recycled concrete specimen is reduced compared with that of the microbially enhanced recycled concrete specimen without high-aluminum fly ash. The reason is that the Al2O3 content is low, the alkali neutralization ability is limited, and the pH value inside the specimen is high. When the addition amount is 60%-80% (the content of high-aluminum fly ash in high-aluminum fly ash-slag cement), the repair effect is the best, the maximum crack repair width is 0.2mm, and the repair layer thickness is 145μm. At this time, the alkali neutralization ability of Al2O3 plays a significant role. When the addition amount is greater than 80%, the improvement effect is no longer obvious. At this time, the change in pH value has little effect on microorganisms. Therefore, the chitosan concentration and high-aluminum fly ash addition amount selected in this example can greatly improve the self-healing ability of concrete and improve the durability of concrete.

[0099] Embodiment 2:

[0100] Different from Example 1, in the present example, when preparing the modified microbial-loaded porous lightweight aggregate, 200 parts of culture solution, 5 parts of chitosan, 300 parts of desulfurized gypsum, and 10 parts of polyacrylate plasticizer are used in step 3, and the rest is the same as in Example 1.

[0101] Embodiment 3:

[0102] A self-healing microbial fully recycled concrete is made from the following raw materials in parts by mass: 600 parts of high-aluminum fly ash-slag cement, 30 parts of modified loaded microbial porous lightweight aggregate, 500 parts of water, and 1900 parts of microbially reinforced waste concrete recycled aggregate; wherein the microbially reinforced waste concrete recycled aggregate is divided into microbially reinforced fine aggregate and microbially reinforced coarse aggregate, with 700 parts of microbially reinforced recycled fine aggregate and 1200 parts of microbially reinforced recycled coarse aggregate; in the high-aluminum fly ash-slag cement, the amount of calcium peroxide added accounts for 2% of the cement mass.

[0103] Among them, microbial enhanced recycled fine aggregate and microbial enhanced recycled coarse aggregate are obtained by crushing, screening, washing and drying construction solid waste to obtain ordinary recycled fine aggregate and ordinary recycled coarse aggregate, and then soaked in microbial culture solution; among them, the average particle size of microbial enhanced recycled fine aggregate is 1mm-3mm; the particle size of microbial enhanced recycled coarse aggregate is 5mm-20mm; the modified loaded microbial porous lightweight aggregate is composed of porous fly ash recycled ceramsite, microorganisms, microbial culture solution, packaging materials and cement thin layer. Among them, the raw materials of porous fly ash recycled ceramsite are fly ash, sludge and clay, and the mass fraction ratio is 7:2:1; the particle size of porous fly ash recycled ceramsite is 10mm-20mm, and the density is 300kg / m 3 -500kg / m 3 , the mass adsorption rate is about 300%-400%, and the water absorption rate is 10%-15%.

[0104] The preparation method of porous fly ash regenerated ceramsite is as follows:

[0105] Step 1: The incoming sludge is piled in a rainproof shed and stored in a dry place until the sludge moisture content reaches 75%, then it is sealed for curing. The incoming clay is fully dried to a dehydrated state and then fed into a roller crusher through a box feeder to be crushed into powder;

[0106] Step 2: Take the above-mentioned fly ash and sludge and send them into a double-shaft mixer to mix them evenly, then put the clay into the double-shaft mixer, mix them evenly, and then send them to the aging yard for 7-15 days;

[0107] Step 3: The aged ingredients are put into a double-shaft mixer for breaking and stirring, and then sent to a double-roll granulator to produce granular balls, which are shaped and sieved to a particle size of 5mm-10mm;

[0108] Step 4: Send the qualified granular balls to the double-drum plug-in rotary kiln for preheating and roasting. After the granular balls are fully expanded and the particle size reaches 5mm-20mm, the fired porous fly ash regenerated ceramsite products are dropped into the cooler for cooling, and then screened into finished products of different particle sizes by rotary screening.

[0109] The microorganisms loaded on the modified microbial-loaded porous lightweight aggregate are Bacillus cohnii, and the preparation method thereof is as follows:

[0110] Step 1: Prepare the culture medium. The ratio of the culture medium is to add 2.5g creatinine, 5g sodium chloride, 5g sodium citrate, 5g ammonium chloride, 5g calcium chloride, 20g peptone, and 15g beef extract to every 1L of distilled water, and the pH value of the microbial culture medium is 7-9;

[0111] Step 2: Take 1 / 2 of the culture solution containing microorganisms, add it all to a beaker, pour in the porous fly ash regenerated ceramsite, and stir it continuously with a long glass rod, then pour in the remaining 1 / 2 of the culture solution containing microorganisms until all the ceramsite is completely covered, soak for 21 hours, remove and wipe off the surface culture solution to obtain ceramsite loaded with microorganisms;

[0112] Step 3: Prepare packaging materials. The packaging materials are composed of nutrient solution, chitosan, desulfurized gypsum and polyacrylate plasticizer, and the content is: 150 parts of nutrient solution, 4 parts of chitosan, 200 parts of desulfurized gypsum, and 5 parts of polyacrylate plasticizer;

[0113] Step 4: evenly apply the encapsulation material on the surface of the ceramsite loaded with microorganisms, wait for the encapsulation material on the surface of the ceramsite to solidify, and obtain the preliminarily encapsulated ceramsite loaded with microorganisms;

[0114] Step 5: Weigh water and P.O42.5 cement in a mass ratio of 1:2, stir thoroughly to form cement slurry, put the preliminarily encapsulated microbial-loaded ceramsite into the cement slurry, stir thoroughly for 120 seconds to ensure that the surface of the preliminarily encapsulated microbial-loaded ceramsite is fully covered by the cement slurry, let it stand for 4 hours, and when the cement surface is smooth and strong, put it into water to separate the clumping particles, then fish it out, spread it flat and sprinkle water for curing, cover the surface with plastic wrap, and cure for 3 days to make modified microbial-loaded porous lightweight aggregate.

[0115] The preparation method of microbial enhanced waste concrete recycled aggregate is as follows:

[0116] The microbial enhanced waste concrete recycled aggregate is divided into microbial enhanced recycled fine aggregate and microbial enhanced recycled coarse aggregate. Ordinary recycled fine aggregate and ordinary recycled coarse aggregate are obtained by crushing, screening, washing and drying construction solid waste. The ordinary recycled fine aggregate and the ordinary recycled coarse aggregate are then respectively placed in two culture solutions containing microorganisms for immersion. The ordinary recycled fine aggregate is immersed for 2 hours, and the ordinary recycled coarse aggregate is immersed for 12 hours. After being fished out, they are naturally dried, left to stand and sprayed with microbial culture solution for curing for 3 days, and the rest is the same as Example 1.

[0117] In this example, microbial infiltration treatment is carried out on the recycled aggregate of microbial enhanced waste concrete, which can fill the pores of the aggregate and reduce the pore water and its pore water pressure. Because there is more pore water, it will freeze at a certain temperature and increase its volume, which will cause tension in the pores. When this tension exceeds the tensile strength of the concrete, the concrete will crack and peel off. The infiltration treatment can improve the frost resistance of the concrete and enhance the durability of the concrete.

[0118] After 50 freeze-thaw cycles at a temperature of -15℃-10℃, the compressive strength loss rate of the microbial-enhanced fully recycled concrete specimens was reduced by 15-20% and the mass loss rate was reduced by 10% compared with the ordinary fully recycled concrete specimens without microbial enhancement.

[0119] Embodiment 4:

[0120] The difference from Example 3 is that in the raw materials of this embodiment, 40 parts of modified microbial loaded porous lightweight aggregate are used. When preparing the modified microbial loaded ceramsite, the porous fly ash regenerated ceramsite in step 2 is soaked in the culture solution for 24 hours, and step 3 uses 200 parts of culture solution, 5 parts of chitosan, 300 parts of desulfurized gypsum, and 10 parts of polyacrylate plasticizer. In the high-alumina fly ash-slag cement, the mass of calcium peroxide accounts for 3% of the total mass of cement, and the rest is the same as in Example 3.

[0121] In this example, the calcium peroxide content is increased. Calcium peroxide can provide oxygen for microorganisms, improve the survival rate of microorganisms, and provide a calcium source. Experiments have confirmed that when the calcium peroxide concentration is in the range of 1%-3%, the crack repair effect is significantly improved. Among them, when the calcium peroxide addition amount reaches 3%, the maximum crack repair width can reach the maximum, which is 0.3mm. Compared with the microbial reinforced fully recycled concrete specimens without adding calcium peroxide, the thickness of the repair layer is increased by 25%-30%.

[0122] Embodiment 5:

[0123] The difference from Example 3 is that the raw materials in this embodiment include 400 parts of water, 20 parts of modified microbial loaded porous lightweight aggregate, and 1900 parts of microbially reinforced waste concrete recycled aggregate by mass fraction. The microbially reinforced waste concrete recycled aggregate is divided into microbially reinforced recycled fine aggregate and microbially reinforced recycled coarse aggregate, with 700 parts of microbially reinforced recycled fine aggregate and 1200 parts of microbially reinforced recycled coarse aggregate. In the preparation of microbially reinforced recycled fine aggregate and microbially reinforced recycled coarse aggregate, the immersion time of microbially reinforced fine aggregate is 4 hours, and the immersion time of microbially reinforced coarse aggregate is 24 hours. When preparing the modified microbially loaded porous lightweight aggregate, the porous fly ash regenerated ceramsite in step 2 is soaked in the culture solution for 18 hours, and the rest is the same as in Example 3.

[0124] In this example, microbial infiltration treatment is performed on the recycled aggregate of microbial enhanced waste concrete.

[0125] The impregnation treatment can strengthen the recycled aggregate of waste concrete itself, and in Example 5, the old interface transition zone of the recycled aggregate (the interface between the original aggregate and cement) is further strengthened. Compared with Example 3, by extending the immersion time of fine aggregate by 2 hours and the immersion time of coarse aggregate by 12 hours, the amount of lightweight aggregate is reduced by 10 parts and the immersion time is reduced by 3 hours. The focus is on further strengthening the old interface transition zone of the recycled aggregate by extending the immersion time of coarse and fine aggregates recycled from waste concrete, that is, using CaCO3 precipitation produced by microbial metabolism and mineralization to fill the pores at the interface between the original aggregate and cement in the recycled aggregate, making the old interface transition zone more compact, thereby improving the resistance to chloride ion penetration and carbonization in concrete durability.

[0126] The electric flux method was used to determine its resistance to chloride ion corrosion. A NaCl solution with a mass concentration of 3% and a NaOH solution with a mass concentration of 0.3 mol / L were prepared. One side of the NaCl solution was connected to the cathode of the power supply and the other side of the NaOH solution was connected to the anode of the power supply. The electric flux of the specimen was measured every 5 minutes. The final results showed that compared with ordinary fully recycled concrete specimens without microbial enhancement, the electric flux of the microbially enhanced fully recycled concrete specimens was reduced by 30%.

[0127] A rapid carbonization test was carried out on the specimens. The humidity, CO2 concentration and temperature of the carbonization test were set so that the relative humidity in the box was 65% to 75%, the CO2 concentration was 17% to 23%, and the temperature was 18°C ​​to 22°C. The results showed that after 28 days of carbonization, the compressive strength increased by 15%, the tensile strength increased by 23%, and the carbonization depth decreased by 26.5%.

[0128] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing self-healing microbial fully regenerated concrete, characterized in that The steps include: Step S101: adding culture solution to a first container containing modified microorganism-loaded porous lightweight aggregate, so that the surface of the porous lightweight aggregate is soaked with the culture solution; Step S102: adding water into the first container until the liquid in the first container completely covers the modified microorganism-loaded porous lightweight aggregate, and preparing the liquid into a modified microorganism-loaded porous lightweight aggregate suspension; Step S103: adding aluminum fly ash-slag cement, microbial enhanced waste concrete recycled aggregate and water into a second container and stirring evenly; Step S104: adding the suspension into the second container, and gradually adding water, measuring the slump of concrete by the slump method per unit time, and stopping adding when the slump of concrete reaches a threshold value, thereby obtaining a mixed material; Step S105: Curing and shaping the mixed material to obtain self-healing microbial fully regenerated concrete.

2. The method for preparing self-healing microbial fully regenerated concrete according to claim 1, characterized in that: The microorganism is Bacillus pasteurianus, and the microorganism culture solution includes distilled water, casein peptone, urea, sodium chloride, agar powder, and soybean casein. The ratio of the microorganism culture solution is 15g casein peptone, 20g urea, 5g sodium chloride, 20g agar powder, and 5g soybean casein per 1L of distilled water, and the pH value of the microorganism culture solution is 8-10; The preparation of the modified microbial-loaded porous lightweight aggregate comprises the following steps: Step S201: pour the microbial culture solution containing microorganisms into a vacuum filtration bottle, then pour the porous fly ash regenerated ceramsite into it, stir it, then add the remaining microbial culture solution containing microorganisms to the vacuum filtration bottle and cover the ceramsite, filter it through the vacuum filtration bottle to allow the microorganisms to be adsorbed on the ceramsite, and then, after the pressure in the bottle returns to normal, clean the microbial culture solution remaining in the porous fly ash regenerated ceramsite to obtain ceramsite loaded with microorganisms; Step S202: evenly apply packaging material on the surface of the ceramsite loaded with microorganisms, and after the packaging material is solidified, a preliminary packaging ceramsite loaded with microorganisms is obtained; Step S203: Put the preliminarily encapsulated microorganism-loaded ceramsite into cement slurry, stir it thoroughly, let it stand, and after the cement surface is smooth and strong, put it into water to separate the ceramsite, fish it out, and cure it to obtain modified microorganism-loaded porous lightweight aggregate.

3. The method for preparing self-healing microbial fully regenerated concrete according to claim 1, characterized in that: The microorganism is Bacillus coli, and the microorganism culture solution includes distilled water, creatinine, sodium chloride, sodium citrate, ammonium chloride, calcium chloride, peptone, and beef extract. The ratio of the microorganism culture solution is 2.5g creatinine, 5g sodium chloride, 5g sodium citrate, 5g ammonium chloride, 5g calcium chloride, 20g peptone, and 15g beef extract per 1L of distilled water, and the pH value of the microorganism culture solution is 7-9; The preparation of the modified microbial-loaded porous lightweight aggregate comprises the following steps: Step S301: adding the microbial culture solution containing microorganisms into a beaker, pouring into the porous fly ash regenerated ceramsite, stirring, then pouring into the remaining microbial culture solution containing microorganisms and covering the ceramsite, taking out after soaking, cleaning the microbial culture solution remaining in the porous fly ash regenerated ceramsite, and obtaining ceramsite loaded with microorganisms; Step S302: evenly apply packaging material on the surface of the ceramsite loaded with microorganisms, and wait for the packaging material to solidify to obtain preliminary packaging of the ceramsite loaded with microorganisms; Step S303: Put the preliminarily encapsulated microorganism-loaded ceramsite into cement slurry, stir it thoroughly, let it stand, and after the cement surface is smooth and strong, put it into water to separate the ceramsite, fish it out, and cure it to obtain modified microorganism-loaded porous lightweight aggregate.

4. A method for preparing self-healing microbial fully regenerated concrete according to claim 2 or 3, characterized in that: The microorganism culture temperature is 30°C, the bacterial solution concentration is above 108 cells / ml, the spore production rate is above 90%, and the bacterial solution absorbance is reduced by 50% compared with the initial state of the bacterial solution.

5. A method for preparing self-healing microbial fully regenerated concrete according to claim 2 or 3, characterized in that: The packaging material comprises microbial nutrient solution, chitosan, desulfurized gypsum and polyacrylate plasticizer, and the content thereof is: 150-200 parts of nutrient solution, 3-5 parts of chitosan, 200-300 parts of desulfurized gypsum and 5-10 parts of polyacrylate plasticizer.

6. A method for preparing self-healing microbial fully regenerated concrete according to claim 2 or 3, characterized in that: The preparation of the porous fly ash regenerated ceramsite comprises the following steps: Step S401: When the sludge moisture content reaches 75%, the sludge is sealed for curing, and after the clay is fully dried to a dehydrated state, it is crushed into powder; Step S402: firstly take fly ash and sludge and mix them evenly, then add clay and mix them evenly, and then age them; Step S403: breaking up and stirring the aged ingredients to produce granular balls, and then shaping and screening them, with the screened particle size being 5 mm to 10 mm; Step S404: preheating and roasting the granular balls that have passed the screening, cooling them after they are fully expanded and have a particle size of 5mm-20mm, and then screening out porous fly ash regenerated ceramsite of different particle sizes.

7. The method for preparing self-healing microbial fully regenerated concrete according to claim 1, characterized in that: The microbial enhanced waste concrete recycled aggregate includes microbial enhanced recycled fine aggregate and microbial enhanced recycled coarse aggregate. The average particle size of the microbial enhanced recycled fine aggregate is 1mm-3mm; the particle size of the microbial enhanced recycled coarse aggregate is 5mm-20mm; the microbial enhanced recycled fine aggregate and the microbial enhanced recycled coarse aggregate are obtained by crushing, screening, washing and drying construction solid waste to obtain ordinary recycled fine aggregate and ordinary recycled coarse aggregate, and then infiltrating with microbial culture solution. The treatment method is as follows: Ordinary recycled fine aggregate and ordinary recycled coarse aggregate are respectively immersed in two culture solutions containing microorganisms, taken out and dried, and then left to stand and sprayed with microorganism culture solution for curing.

8. A self-healing microbial fully regenerated concrete prepared by the method for preparing self-healing microbial fully regenerated concrete according to claim 1, comprising fly ash-slag cement, microbial reinforced waste concrete recycled aggregate, water and modified microbial loaded porous lightweight aggregate, characterized in that: The fly ash-slag cement is 400-600 parts by weight of aluminum fly ash-slag cement, 1400-2000 parts by weight of microbial enhanced waste concrete recycled aggregate, 300-500 parts by weight of water, and 20-40 parts by weight of modified microbial loaded porous lightweight aggregate.

9. The self-healing microbial fully regenerated concrete according to claim 8, characterized in that: The aluminum fly ash-slag cement is high-aluminum fly ash-slag cement, comprising high-aluminum fly ash, slag, and calcium peroxide, wherein the mass ratio of high-aluminum fly ash to slag is 2:1, the calcium peroxide accounts for 1%-3% of the total mass of the high-aluminum fly ash-slag cement, and the Al2O3 content in the high-aluminum fly ash is 35%-40%; The modified microbial-loaded porous lightweight aggregate comprises porous fly ash regenerated ceramsite, microorganisms, microbial culture solution, packaging materials and a cement thin layer, wherein the raw materials used in the porous fly ash regenerated ceramsite include fly ash, sludge and clay in a mass ratio of 7:2:1, and the particle size of the porous fly ash regenerated ceramsite is 5mm-20mm, and the density is 300kg / m 3 -500kg / m 3 , mass adsorption rate is 300%-400%, water absorption rate is 10%-15%; The microorganisms in the recycled aggregate of the microbial reinforced waste concrete are Bacillus pasteurianus, which hydrolyzes urea into CO3 through the urease produced by its own metabolism. 2- and NH4 + ,CO3 2- The Ca in the concrete 2+ Combined to form CaCO3 precipitate.

10. The self-healing microbial fully regenerated concrete according to claim 8, characterized in that: The microorganisms in the microbial reinforced waste concrete recycled aggregate are Bacillus coli, which converts organic acid carbon into calcium carbonate and releases carbon dioxide during metabolism. Carbon dioxide continuously generates CO3 in an alkaline environment. 2- And further with the Ca in the concrete 2+ Combined to form CaCO3 precipitate.

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