Concrete material based on industrial solid waste recycled materials and preparation method and application thereof

Abstract

The present application belongs to the technical field of solid waste resource utilization and building materials, and particularly relates to a concrete material based on industrial solid waste regenerated material and a preparation method and application thereof, the concrete material based on industrial solid waste regenerated material comprises the following components in parts by weight: 40-50 parts of industrial solid waste micro powder, 10-20 parts of passivated coarse aggregate, 180-200 parts of sol impregnated fine aggregate dispersion liquid, 30-40 parts of alkaline base liquid, 5-10 parts of composite microbial slow-release capsule and 0.1-0.2 parts of polycarboxylic acid water reducer. The microbial activator of the present application significantly improves the crack repair capacity of the solid waste-based concrete, fills the micro cracks of the aggregate with silicon sol, enhances the mechanical properties, improves the long-term strength and durability, and provides a reliable technical solution for green building materials and intelligent infrastructure.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solid waste resource utilization and building materials, and particularly relates to a concrete material based on industrial solid waste regenerated materials and a preparation method and application thereof. BACKGROUND

[0002] The concrete material based on industrial solid waste regenerated materials is concerned in the fields of resource utilization and environmental protection. At present, common industrial solid waste regenerated materials include fly ash (FA), slag (GGBS), steel slag (SS), silica fume (SF), red mud (RM), tailings (TM), and recycled aggregate of construction waste (RCA). However, the actual application of the concrete material based on industrial solid waste regenerated materials still faces the following key defects, which restrict its large-scale promotion and high-performance development. The main reasons are as follows:

[0003] Firstly, the industrial solid waste (such as steel slag, fly ash, and waste concrete) used in the current concrete material is only crushed as recycled aggregate. The internal microcracks and pores of the recycled aggregate lead to low compactness of the concrete, high water absorption rate compared with natural aggregate, and further poor performance of the recycled aggregate, resulting in poor mechanical properties and durability of the concrete. The surface of the recycled aggregate is attached with old cement paste or impurities, and the bonding strength of the interface transition zone (ITZ) between the recycled aggregate and the cement matrix is low (≤2.0 MPa), which easily becomes a crack propagation path and leads to weak interface bonding. The leaching concentration of heavy metals (Pb, Cr, and Cd) in metallurgical solid waste (such as red mud and carbide slag) exceeds the limit value, and direct use of the metallurgical solid waste poses a pollution risk.

[0004] Secondly, the existing concrete material based on industrial solid waste regenerated materials mostly relies on the addition of strong alkaline chemical activators (such as NaOH and KOH) to activate the activity of the solid waste. However, the efficiency of the activators is limited and the side effects are significant. This is because the strong alkaline solution has strong corrosion to the production equipment, and residual alkaline substances easily cause alkali-aggregate reaction, leading to expansion and cracking of the concrete. The activators only improve the cementitious activity and cannot solve the comprehensive needs of microcrack self-repairing and heavy metal solidification. Due to the insufficient activation efficiency, the replacement rate of the solid waste is limited, and the replacement ratio of the industrial solid waste to cement is usually <30%, which makes it difficult to realize high-content resource utilization.

[0005] In addition, the concrete lacks self-repairing ability. To improve the self-repairing ability, the existing concrete mostly uses microcapsules to encapsulate chemical repair agents (such as epoxy resin and silicate solution). However, these repair agents have high cost, poor compatibility with the solid waste system, low repair efficiency, and environmental unfriendliness. SUMMARY

[0006] The purpose of the present application is to provide a concrete material based on industrial solid waste regenerated materials and a preparation method and application thereof, so as to overcome the deficiencies of the prior art. The present application provides a concrete material based on industrial solid waste regenerated materials, which has high mechanical strength, self-repairing ability, environmental safety, and industrial feasibility.

[0007] To achieve the above object, the technical scheme of the present application is:

[0008] In a first aspect, the present application provides a concrete material based on industrial solid waste regenerated material, comprising the following components by weight fraction: industrial solid waste micro powder 40-50 parts, passivated coarse aggregate 10-20 parts, sol impregnated fine aggregate dispersion liquid 180-200 parts, alkaline base liquid 30-40 parts, composite microbial slow-release capsule 5-10 parts, and polycarboxylic acid water reducer 0.1-0.2 parts.

[0009] In the concrete material based on industrial solid waste regenerated material, the industrial solid waste micro powder replaces cement to provide cementitious activity and fill the pores of the passivated coarse aggregate. The stable phosphate mineral layer generated on the surface of the metallurgical solid waste in the passivated coarse aggregate can fix heavy metal ions, thereby reducing the leaching concentration of heavy metals (Pb, Cr, Cd) in metallurgical solid waste (such as red mud, carbide slag), and reducing the risk of environmental pollution caused by heavy metals. The sol impregnated fine aggregate dispersion liquid is used to fill the microcracks in the passivated coarse aggregate to improve the interfacial bonding strength and thus enhance the mechanical properties. The alkaline base liquid generates a dense gel through an alkali activation reaction to reduce porosity, improve impermeability and corrosion resistance, further reduce the amount of cement, thereby increasing the proportion of industrial solid waste replacing cement and achieving high-dosage resource utilization. In addition, it can also adjust the pH to stabilize the environment of the composite microbial capsule. The composite microbial slow-release capsule releases microorganisms slowly to promote the generation of CaCO3 self-healing at the cracks, significantly improving the crack repair ability of the solid waste-based concrete, filling the microcracks of the aggregate with silica sol, enhancing the mechanical properties, and improving the long-term strength and durability. The polycarboxylic acid water reducer can achieve efficient dispersion of the aggregate in the concrete, thereby significantly improving the workability and mechanical properties of the concrete. The concrete material based on industrial solid waste regenerated material of the present application constructs a "chemical-physical-biological" multidimensional system through the synergistic effect of the components, which can balance high mechanical strength, self-repairing ability, environmental safety, and industrial feasibility.

[0010] Optionally, the concrete material based on industrial solid waste regenerated material comprises the following components by weight fraction: industrial solid waste micro powder 40-45 parts, passivated coarse aggregate 10-15 parts, sol impregnated fine aggregate dispersion liquid 180-190 parts, alkaline base liquid 30-35 parts, composite microbial slow-release capsule 5-8 parts, and polycarboxylic acid water reducer 0.1-0.15 parts. The concrete material based on industrial solid waste regenerated material within the component range has better high mechanical strength, self-repairing ability, environmental safety, and industrial feasibility.

[0011] Further optionally, the concrete material based on industrial solid waste regenerated materials comprises, by weight fraction, the following components: 40 parts of industrial solid waste micro-powder, 10 parts of passivated coarse aggregate, 180 parts of sol impregnated fine aggregate dispersion liquid, 30 parts of alkaline base liquid, 5 parts of composite microbial slow-release capsule, and 0.1 part of polycarboxylate superplasticizer. The concrete material based on industrial solid waste regenerated materials in the component range has the best high mechanical strength, self-repairing ability, environmental safety, and industrial feasibility.

[0012] The polycarboxylate superplasticizer used can be a methoxy polyethylene glycol ester polycarboxylate superplasticizer.

[0013] In some other embodiments, the industrial solid waste micro-powder comprises steel slag and fly ash, and the mass ratio of the steel slag to the fly ash is 3: (1-2); the particle size of the industrial solid waste micro-powder is ≤100 μm; and the industrial solid waste micro-powder in this component uses steel slag and fly ash to replace cement, which can provide cementitious activity and fill pores.

[0014] Alternatively, the passivated coarse aggregate is a metallurgical solid waste soaked with phosphate, and the particle size of the passivated coarse aggregate is 5-20 mm. The stable phosphate mineral layer generated on the surface of the metallurgical solid waste in the passivated coarse aggregate can fix heavy metal ions, thereby reducing the leaching concentration of heavy metals (Pb, Cr, Cd) in the metallurgical solid waste (such as red mud, carbide slag), and triggering the risk of heavy metal environmental pollution.

[0015] In some other embodiments, the sol impregnated fine aggregate dispersion liquid comprises waste concrete, nano-silica sol, and a dispersant, and the mass ratio of the waste concrete to the nano-silica sol is 1: (3-4);

[0016] The particle size of the waste concrete is 1-5 mm;

[0017] The solid content of the nano-silica sol is 10 wt%-15 wt%;

[0018] The dispersant is one of Span-80, PEG 200, sodium polyacrylate, Tween-60, and Tween-80, and the addition amount of the dispersant is 0.5%-1.0% of the mass of the nano-silica sol. The sol impregnated fine aggregate dispersion liquid is used to fill micro-cracks in the passivated coarse aggregate, improve the interfacial bonding strength, and thus enhance the mechanical properties.

[0019] In some other embodiments, the composite microbial slow-release capsule comprises a core material and a wall material wrapped on the surface of the core material, and the particle size of the composite microbial slow-release capsule is 50-100 μm;

[0020] The core material comprises Bacillus pasteurii spores, calcium lactate, and yeast extract, and the mass ratio of the Bacillus pasteurii spores to the calcium lactate to the yeast extract is (3-4): 1: 1;

[0021] The viable concentration of the Bacillus pasteurii spores is >10 6 CFU / g.

[0022] The wall material is sodium alginate.

[0023] The encapsulated composite microbial slow-release capsule is isolated from the alkaline medium by the sodium alginate wall material, so that the Bacillus pasteurii spores remain in a dormant state before the hardening of the concrete and are activated only after the occurrence of cracks in the presence of water, thereby avoiding the destruction of the activity of the microorganisms due to the early hydration heat of the concrete when mixed directly, and effectively protecting the sensitive active components; the capsule is broken due to mechanical stress when the concrete cracks, and the internal microorganisms and nutrients are released, thereby repairing the cracks in a targeted manner, and the release timing can be accurately controlled, and the response on demand is realized. The sodium alginate wall material isolates the sol-impregnated fine aggregate dispersion liquid and the Bacillus pasteurii spores, the nanosilica sol in the sol-impregnated fine aggregate dispersion liquid is specialized in interface enhancement, and the encapsulated composite microorganism independently performs repair, thereby realizing “time-sharing and partitioning” cooperation. The direct mixing avoids the functional offset of the two. In addition, the traditional liquid activator needs to be strictly protected from light and controlled in temperature during storage, while the dry composite microbial slow-release capsule of the present application can be stored at room temperature for >6 months, thereby reducing the transportation and storage costs; the encapsulation technology solves the problems of activity loss, functional conflict and complex process of the traditional activator by the design of “protection-control release-cooperation”, thereby providing key technical support for the industrialization of the solid waste-based high-performance concrete.

[0024] In some other embodiments, the alkaline base liquid consists of the following components by weight percentage: water glass 10-15%, alkali residue 20-25%, and the balance being water.

[0025] The modulus of the water glass is 1.2-1.8; the particle size of the alkali residue is ≤45 μm, and the alkali residue is an industrial by-product containing Ca(OH)2 and CaCO3 active components. The alkaline base liquid prepared from the water glass and the alkali residue can stimulate the activity of the solid waste micro-powder and simultaneously adjust the pH to stabilize the environment of the microbial capsule. Exemplarily, the alkali residue is an industrial by-product obtained by precipitation from the waste liquid generated in the process of producing soda ash by the ammonia-soda method.

[0026] In a second aspect, the present application provides a preparation method of the concrete material based on the regenerated material of industrial solid waste according to the first aspect, which comprises the following steps:

[0027] (1) dry mixing the industrial solid waste micro-powder and the passivated coarse aggregate to obtain a premix;

[0028] (2) mixing the sol-impregnated fine aggregate dispersion liquid and the alkaline base liquid, and then adding the composite microbial slow-release capsule to obtain a mixture by stirring;

[0029] (3) adding the premix into the mixture, then adding the polycarboxylic acid water reducing agent, and pouring and curing to obtain the concrete material based on the industrial solid waste regenerated material.

[0030] The preparation method is simple to operate, the components can be prepared in advance, the mixing mode of the components can be adjusted to improve the dispersion uniformity of the components, and thus the concrete material based on the industrial solid waste regenerated material is prepared, which has high mechanical strength, self-repairing capability, environmental safety, and industrial feasibility.

[0031] In some other embodiments, in step (1), the preparation method of the industrial solid waste micro powder is as follows: the steel slag and the fly ash are mixed to obtain a mixture, the iron impurities are removed by magnetic separation, and then the mixture is crushed to obtain the industrial solid waste micro powder;

[0032] The mixing mass ratio of the steel slag and the fly ash is 3: (1-2), and the particle size of the crushed product is ≤100 μm.

[0033] Alternatively, the preparation method of the passivated coarse aggregate is as follows: the metallurgical solid waste is crushed, then soaked in a phosphate solution, and dried after discharging to obtain the passivated coarse aggregate.

[0034] The particle size of the crushed metallurgical solid waste is 5-20 mm, the concentration of the phosphate solution is 0.4-0.6 mol / L, and the soaking time is 20-24 h.

[0035] In some other embodiments, in step (2), the preparation method of the sol-impregnated fine aggregate dispersion liquid is as follows:

[0036] Alternatively, the waste concrete is crushed and then added to the nanosilica sol, and then a dispersant is added and ultrasonic treatment is performed to obtain the sol-impregnated fine aggregate dispersion liquid.

[0037] The mass ratio of the waste concrete and the nanosilica sol is 1: (3-4).

[0038] The particle size of the waste concrete is 1-5 mm.

[0039] The solid content of the nanosilica sol is 10 wt%-15 wt%.

[0040] The dispersant is one of Span-80, PEG 200, sodium polyacrylate, Tween-60, and Tween-80, and the addition amount of the dispersant is 0.5%-1.0% of the mass of the nanosilica sol.

[0041] The frequency of the ultrasonic treatment is 35-45 kHz, and the time is 20-40 min.

[0042] Alternatively, the preparation method of the alkaline base liquid is as follows: the water glass and the alkali residue are sequentially added to the heated water, and a suspension liquid is prepared after magnetic stirring to obtain the alkaline base liquid.

[0043] The modulus of the water glass is 1.2-1.8; the particle size of the alkali residue is less than or equal to 45 microns; the alkali residue is an industrial by-product containing Ca(OH)2 and CaCO3 active components;

[0044] The temperature of the heated water is 30-35 DEG C, the stirring speed of the magnetic stirring is 450-550 rpm, the time is 30-35 min, and the pH of the suspension is 12.5-13;

[0045] Alternatively, the preparation method of the composite microbial slow-release capsule is as follows: the Bacillus pasteurii spores, calcium lactate and yeast extract are mixed to obtain a core material; the core material is added into a sodium alginate aqueous solution, and a cross-linking reaction is performed after adding a CaCl2 solution to obtain the composite microbial slow-release capsule.

[0046] The particle size of the composite microbial slow-release capsule is 50-100 microns.

[0047] The mass ratio of the Bacillus pasteurii spores, calcium lactate and yeast extract is (3-4):1:1.

[0048] The viable bacterial concentration of the Bacillus pasteurii spores is greater than 10 6 CFU / g.

[0049] The concentration of the sodium alginate aqueous solution is 2-3 wt %, and the concentration of the CaCl2 solution is 4-5 wt %.

[0050] The temperature of the cross-linking reaction is 20-30 DEG C, and the time of the cross-linking reaction is 25-30 min.

[0051] Alternatively, in step (2), the stirring speed is 100-200 rpm, and the time is 15-25 min.

[0052] Alternatively, in step (3), the curing is performed in a CO2 gas with a concentration of 10-20% for 2-3 h, and then standard curing is performed for 7 days.

[0053] In a third aspect, the application provides an application of the concrete material based on the industrial solid waste regenerated material in solid waste resource utilization and building materials, preferably, an application in concrete crack repair. The application can significantly improve the crack repair capacity of the solid waste-based concrete, fill the micro-cracks of the aggregate, enhance the mechanical properties, improve the long-term strength and durability, and provide a reliable technical solution for green building materials and intelligent infrastructure.

[0054] In a fourth aspect, the application provides a crack repair method of concrete. The concrete material based on the industrial solid waste regenerated material is placed in a concrete crack, the environmental humidity is greater than or equal to 80%, the temperature is 25 DEG C, and the repair time is 7-28 days. The method can significantly improve the crack repair rate and strength.

[0055] The beneficial effects of the present application are:

[0056] (1) The concrete material based on industrial solid waste regenerated materials of the present application can improve the crack repair ability of solid waste-based concrete, fill the micro cracks of silica sol with aggregate, enhance the mechanical properties, and improve the long-term strength and durability, thereby providing a reliable technical solution for green building materials and intelligent infrastructure.

[0057] (2) The encapsulation of the present application separates the alkaline medium by sodium alginate wall material, ensures that the spores remain dormant before the concrete hardens, and are activated only when cracks appear; thus avoiding the destruction of microbial activity by early hydration heat of concrete when mixed directly, effectively protecting sensitive active components; the capsule is broken due to mechanical stress when the concrete cracks, releasing internal microorganisms and nutrients, and repairing cracks specifically, which can accurately control the release timing and achieve on-demand response; the addition of nano-silicon dioxide in the present application may interfere with microbial metabolism due to its high surface activity, and direct mixing may result in functional offsetting, the present application creatively proposes encapsulation to isolate the two, nano-materials focus on interface enhancement, and microorganisms independently perform repair to achieve "time and area" coordination; traditional liquid activators need to be strictly protected from light and controlled temperature storage, while the dry capsules of the present application can be stored at room temperature for more than 6 months, reducing transportation and storage costs; the encapsulation technology of the present application solves the problems of activity loss, functional conflict and complex process of traditional activators by the design of "protection-control-coordination", and provides key technical support for the industrialization of solid waste-based high-performance concrete.

[0058] (3) The preparation method of the concrete material based on industrial solid waste regenerated materials of the present application is simple to operate, and each component can be prefabricated in advance, and the mixing method of each component can be adjusted to improve the dispersion uniformity of each component, thereby obtaining a concrete material based on industrial solid waste regenerated materials with high mechanical strength, self-repairing ability, environmental safety and industrial feasibility.

[0059] (4) The concrete material based on industrial solid waste regenerated materials of the present application can significantly improve the crack repair ability of solid waste-based concrete, fill the micro cracks of silica sol with aggregate, enhance the mechanical properties, and improve the long-term strength and durability, thereby providing a reliable technical solution for green building materials and intelligent infrastructure.

[0060] (5) The application provides a concrete crack repairing method, which directly places a concrete material based on an industrial solid waste regenerated material in a concrete crack, and can significantly improve the crack repairing rate and strength under the conditions of ambient humidity ≥ 80%, temperature 25℃, and repairing time 7-28 days. BRIEF DESCRIPTION OF DRAWINGS

[0061] The accompanying drawings, which form a part of this specification, are included to provide a further understanding of the application and are incorporated herein by reference. The illustrations are of exemplary embodiments of the application and are not intended to limit the scope of the application.

[0062] Figure 1 The figures are physical pictures of the cracks before and after repair in Example 1 of the application, wherein a is before repair, and b is after repair. DETAILED DESCRIPTION

[0063] Those skilled in the art will understand that the following examples are for illustrative purposes only and should not be construed as limiting the scope of the application. If no specific conditions are specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If no manufacturer of the components used is specified, all are conventional products that can be obtained on the market. Among them, the metallurgical solid waste uses blast furnace slag of Jinan Iron and Steel Group, the waste concrete uses concrete from the waste building garbage landfill site of Xinglongshan in Jinan, the Bacillus pasteurii spores are purchased from Shanghai Preservation Microorganism Center, the yeast extract uses yeast powder YEAST EXTRACT produced by Oxoid Company, and the alkali residue uses industrial by-products produced after epoxypropane production of Binhua Group. The polycarboxylic acid water reducing agent uses methoxy polyethylene glycol ester polycarboxylic acid water reducing agent.

[0064] In view of the core problems such as low performance, high risk and single function of the current industrial solid waste regenerated concrete technology, which restricts its large-scale promotion and high-performance development, the main reasons are analyzed as follows:

[0065] (1) The poor performance of recycled aggregates leads to poor mechanical properties and durability of concrete. This is because the industrial solid waste (such as steel slag, fly ash, and waste concrete) used in the current concrete material is only crushed as recycled aggregate, which has the following problems: first, high porosity and water absorption. The internal micro-cracks and pores of the aggregate lead to low density of the concrete, and the water absorption rate is 30-50% higher than that of natural aggregate, which significantly reduces the compressive strength (usually ≤40 MPa) and frost resistance (mass loss >5% after 200 freeze-thaw cycles); second, weak interfacial bonding. The old cement paste or impurities attached to the surface of the recycled aggregate have low interfacial transition zone (ITZ) bonding strength (≤2.0 MPa), which easily becomes a crack propagation path; third, environmental risk of heavy metals. The leaching concentration of heavy metals (Pb, Cr, Cd) in metallurgical solid waste (such as red mud, calcium carbide slag) exceeds the limit value, and direct use has pollution risk.

[0066] (2) Traditional activator systems have limited effectiveness and significant side effects. Existing industrial solid waste recycled concrete materials mostly rely on adding strong alkaline chemical activators (such as NaOH and KOH) to activate solid waste activity, but they have the following drawbacks: First, they are highly corrosive and environmentally burdensome. Strong alkaline solutions are highly corrosive to production equipment, and residual alkaline substances can easily trigger alkali-aggregate reactions, leading to concrete expansion and cracking. Second, they have a single function, only improving cementitious activity, and cannot solve comprehensive needs such as micro-crack self-repair and heavy metal solidification. Third, the solid waste replacement rate is limited. Due to insufficient activation efficiency, the proportion of industrial solid waste replacing cement is usually <30%, making it difficult to achieve high-volume resource utilization.

[0067] (3) Self-healing technology is costly and has poor compatibility with solid waste systems. Existing self-healing concrete often uses microcapsules to encapsulate chemical repair agents (such as epoxy resin and silicate solution), but it has the following bottlenecks: First, the repair efficiency is low. After the repair agent is released, it can only seal cracks with a width of ≤0.1mm and the repair rate is <50%, which cannot meet the engineering requirements. Second, it is not environmentally friendly. The production process of chemical repair agents has high carbon emissions, which is contrary to the green concept of solid waste concrete. Third, it has poor compatibility. The interface between the repair agent and solid waste aggregate is weak, and it is easy to peel off and fail during long-term service.

[0068] This invention provides a systematic solution that balances high mechanical strength, self-healing capability, environmental safety, and industrial feasibility, as detailed below:

[0069] An embodiment of the present invention provides a concrete material based on recycled industrial solid waste, comprising the following components by weight: 40-50 parts of industrial solid waste powder, 10-20 parts of passivated coarse aggregate, 180-200 parts of sol-impregnated fine aggregate dispersion, 30-40 parts of alkaline base liquid, 5-10 parts of composite microbial slow-release capsules, and 0.1-0.2 parts of polycarboxylate superplasticizer.

[0070] Other embodiments of the present invention provide a method for preparing concrete materials based on recycled industrial solid waste, comprising the following steps:

[0071] (1) The industrial solid waste powder and passivated coarse aggregate are dry-mixed to obtain a premix;

[0072] (2) After mixing the sol-impregnated fine aggregate dispersion and the alkaline base solution, add the composite microbial sustained-release capsules and stir to obtain the mixture;

[0073] (3) Add the premix to the mixture, then add the polycarboxylate superplasticizer, pour and cure to obtain concrete material based on industrial solid waste recycled material.

[0074] Some other embodiments of the present application provide an application of the concrete material based on industrial solid waste regenerated materials in solid waste resource utilization and building materials, preferably in concrete crack repair.

[0075] Some other embodiments of the present application provide a method for repairing concrete cracks, placing the concrete material based on industrial solid waste regenerated materials in the concrete cracks, the environmental humidity is greater than or equal to 80%, the temperature is 25℃, and the repair time is 7-28 days. The method can significantly improve the crack repair rate and strength.

[0076] The technical solutions of the present application are further described below through specific embodiments:

[0077] Embodiment 1

[0078] 1. A concrete material based on industrial solid waste regenerated materials, comprising the following components as shown in Table 1 by weight fraction: industrial solid waste micro powder 40 parts, passivated coarse aggregate 10 parts, sol impregnated fine aggregate dispersion liquid 180 parts, alkaline base liquid 30 parts, composite microbial slow-release capsule 5 parts, polycarboxylic acid water reducer 0.1 part;

[0079] The industrial solid waste micro powder comprises steel slag and fly ash (the mixed mass ratio of steel slag and fly ash is 3:1), and the particle size of the industrial solid waste micro powder is less than or equal to 100 μm. The preparation method of the industrial solid waste micro powder is as follows: the steel slag and fly ash with a weight ratio of 3:1 are mixed, the iron impurities are removed by a magnetic separation device, and the mixture is crushed to less than or equal to 100 μm by a crusher.

[0080] The passivated coarse aggregate is a metallurgical solid waste soaked in phosphate, and the particle size of the passivated coarse aggregate is 5-20 mm. The preparation method of the passivated coarse aggregate is as follows: the metallurgical solid waste is crushed to a particle size of 5-20 mm by a multi-stage crusher, soaked in a 0.5 mol / L phosphate solution for 20 hours, and then dried after discharging.

[0081] The sol impregnated fine aggregate dispersion liquid comprises waste concrete, nano-silica sol and a dispersing agent (span-80). The mass ratio of the waste concrete and the nano-silica sol is 1:3, the addition amount of the dispersing agent is 0.5% of the mass of the nano-silica sol, and the particle size of the waste concrete is 3 mm. The solid content of the nano-silica sol is 10%. The preparation method of the sol impregnated fine aggregate dispersion liquid is as follows: the waste concrete is crushed to a particle size of 3 mm by a multi-stage crusher, added to 3 times the weight of the nano-silica sol with a solid content of 10%, and added with the dispersing agent with a weight of 0.5% of the nano-silica sol, and then ultrasonically treated for 30 minutes at 40 kHz to obtain the sol impregnated fine aggregate dispersion liquid.

[0082] The composite microorganism slow-release capsule comprises a core material and a wall material wrapped on the surface of the core material, and the particle size of the composite microorganism slow-release capsule is 50-100 μm; the core material comprises Bacillus pasteurii spores, calcium lactate and yeast extract, the mass ratio of the Bacillus pasteurii spores, the calcium lactate and the yeast extract is 3:1:1, and the viable bacterial concentration of the Bacillus pasteurii spores is 10 6 CFU / g; the wall material is a sodium alginate aqueous solution, and the concentration of the sodium alginate aqueous solution is 2 wt%; and the preparation method of the composite microorganism slow-release capsule comprises the following steps:

[0083] (1) Core material preparation: mix Bacillus pasteurii spores (viable bacterial concentration is 10 6 CFU / g) with calcium lactate and yeast extract at a mass ratio of 3:1:1 to serve as a self-repairing active substance;

[0084] (2) Wall material coating: prepare a microcapsule with a particle size of 50-100 μm by using a sodium alginate aqueous solution (concentration is 2 wt%) as a wall material and a CaCl2 solution (concentration is 4 wt%) as a crosslinking agent.

[0085] The alkaline base liquid is composed of the following components in terms of weight percentage: water glass 10% (modulus is 1.2), alkali residue 20%, and the rest is deionized water. The preparation method of the alkaline base liquid is as follows: grind the alkali residue to a particle size of ≤45 μm and remove impurities by sieving; heat the deionized water to 30℃, and then add the water glass and alkali residue powder in sequence, and magnetically stir at 500 rpm for 30 minutes until a uniform suspension is formed, and then adjust the pH to 12.8.

[0086] 2. A preparation method of a concrete material based on an industrial solid waste regenerated material, comprising the following steps:

[0087] (1) Dry mix the industrial solid waste micro-powder and the passivated coarse aggregate to obtain a premix;

[0088] (2) Mix the sol impregnated fine aggregate dispersion liquid and the alkaline base liquid, stir uniformly, and then add the composite microorganism slow-release capsule, and stir at a low speed of 100-200 rpm for 10-20 minutes to avoid mechanical damage;

[0089] (3) Add the premix to the mixture of step (2), add a polycarboxylic acid water reducing agent, and then pour and cast, and then pass in CO2 gas with a concentration of 10% for curing for 2 hours in the initial setting stage, and then place in an environment with a humidity of ≥80% for repair after standard curing for 7 days.

[0090] Example 2

[0091] A concrete material based on an industrial solid waste regenerated material comprises the following components in terms of weight percentage as shown in Table 1:

[0092] Industrial solid waste powder 40 parts, passivated coarse aggregate 20 parts, sol impregnated fine aggregate dispersion liquid 200 parts, alkaline base liquid 30 parts, composite microbial slow-release capsule 10 parts, 0.2 parts of polycarboxylic acid water reducing agent;

[0093] The industrial solid waste powder includes steel slag and fly ash (the mass ratio of steel slag to fly ash is 3:2), and the particle size of the industrial solid waste powder is ≤100 μm. The preparation method of the industrial solid waste powder is as follows: the steel slag and the fly ash with a weight ratio of 3:2 are mixed, the iron impurities are removed by a magnetic separation device, and the mixture is crushed to ≤100 μm by a crusher.

[0094] The passivated coarse aggregate is a metallurgical solid waste soaked in a phosphate solution, and the particle size of the passivated coarse aggregate is 5-20 mm. The preparation method of the passivated coarse aggregate is as follows: the metallurgical solid waste is crushed to a particle size of 5-20 mm by a multi-stage crusher, soaked in a phosphate solution with a concentration of 0.5 mol / L for 24 hours, and dried after discharging.

[0095] The sol impregnated fine aggregate dispersion liquid includes waste concrete, nano-silica sol and a dispersant. The mass ratio of the waste concrete, the nano-silica sol and the dispersant is 1:4, the addition amount of the dispersant is 1% of the mass of the nano-silica sol, and the particle size of the waste concrete is 3 mm. The solid content of the nano-silica sol is 10-15%, and the dispersant is Span-80. The preparation method of the sol impregnated fine aggregate dispersion liquid is as follows: the waste concrete is crushed to a particle size of 3 mm by a multi-stage crusher, added into nano-silica sol with a solid content of 12% and a weight of 4 times that of the waste concrete, and added with a dispersant with a weight of 1% of the nano-silica sol, and then ultrasonically treated for 30 min at 40 kHz.

[0096] The composite microbial slow-release capsule includes a core material and a wall material wrapped on the surface of the core material. The particle size of the composite microbial slow-release capsule is 50-100 μm. The core material includes Bacillus pasteurii spores, calcium lactate and yeast extract. The mass ratio of the Bacillus pasteurii spores, the calcium lactate and the yeast extract is 4:1:1. The viable bacterial concentration of the Bacillus pasteurii spores is 10 6 CFU / g. The wall material is a sodium alginate aqueous solution with a concentration of 3 wt%. The preparation method of the composite microbial slow-release capsule includes the following steps:

[0097] (1) Core material preparation: mix the Bacillus pasteurii spores, the calcium lactate and the yeast extract according to a mass ratio of 4:1:1 as self-repairing active substances.

[0098] (2) Wall material coating: use the sodium alginate aqueous solution as the wall material and a 5 wt% CaCl2 solution as a crosslinking agent to prepare microcapsules with a particle size of 50-100 μm.

[0099] The alkaline base liquid is composed of the following components in the weight percentage: water glass 15% (modulus 1.8), alkali residue 25%, and the rest is deionized water. The preparation method of the alkaline base liquid is as follows: the alkali residue is ground to a particle size of ≤45 μm, and the impurities are removed by sieving; the deionized water is heated to 35℃, and the water glass and alkali residue powder are added in turn, and the magnetic stirring is carried out at 500 rpm for 35 minutes, until a uniform suspension is formed, and the pH is adjusted to 13.

[0100] 2. A preparation method of a concrete material based on industrial solid waste regenerated material, comprising the following steps:

[0101] (1) mixing industrial solid waste micro powder and passivated coarse aggregate dry, to obtain a premix;

[0102] (2) mixing the sol-impregnated fine aggregate dispersion liquid and the alkaline base liquid, stirring uniformly, adding the composite microbial slow-release capsule, low-speed stirring at 200 rpm for 20 minutes to avoid mechanical damage;

[0103] (3) adding the premix to the mixture of step (2), adding polycarboxylic acid water reducer, and after pouring, passing in 20% CO2 gas for curing for 3 hours in the initial setting stage, and then placing in an environment with a humidity of ≥80% for repair after standard curing for 7 days.

[0104] Example 3

[0105] A concrete material based on industrial solid waste regenerated material, which is different from example 1 in that the components are shown in table 1 by weight fraction, and the preparation method is consistent with example 1.

[0106] Example 4

[0107] A concrete material based on industrial solid waste regenerated material, which is different from example 1 in that the components are shown in table 1 by weight fraction, and the preparation method is consistent with example 1.

[0108] Comparative example 1

[0109] A concrete material based on industrial solid waste regenerated material, which includes the following components by weight fraction as shown in table 1:

[0110] Industrial solid waste micro powder 50 parts, passivated coarse aggregate 20 parts, sol-impregnated fine aggregate dispersion liquid 200 parts, and 0.2 parts of polycarboxylic acid water reducer.

[0111] Among them, the industrial solid waste micro powder includes steel slag and fly ash (the mixing mass ratio of steel slag and fly ash is 3:1), and the particle size of the industrial solid waste micro powder is ≤100 μm; the preparation method of the industrial solid waste micro powder is as follows: mixing steel slag and fly ash in a weight ratio of 3:1, removing iron impurities by magnetic separation equipment, and crushing to ≤100 μm by a crusher.

[0112] The passivated coarse aggregate is a metallurgical solid waste modified by soaking in phosphate (sodium phosphate), and the particle size of the passivated coarse aggregate is 20 mm; the preparation method of the passivated coarse aggregate is as follows: the metallurgical solid waste is crushed into particles with a particle size of 20 mm through multiple stages, soaked in a 0.5 mol / L sodium phosphate solution for 24 hours, and dried after discharging.

[0113] The sol-impregnated fine aggregate dispersion liquid comprises waste concrete, nano-silica sol and a dispersant, the mass ratio of the waste concrete, the nano-silica sol and the dispersant is 1:4, the addition amount of the dispersant is 1% of the mass of the nano-silica sol, the particle size of the waste concrete is 0-5 mm; the solid content of the nano-silica sol is 15%, and the dispersant is Span-80; the preparation method of the sol-impregnated fine aggregate dispersion liquid is as follows: the waste concrete is crushed into particles with a particle size of 0-5 mm through multiple stages, added into nano-silica sol with a solid content of 15% and a weight of 4 times that of the waste concrete, and added with a dispersant with a weight of 1% of the nano-silica sol, and then ultrasonically treated at 40 kHz for 30 min.

[0114] 2. A preparation method of a concrete material based on industrial solid waste regenerated materials, comprising the following steps:

[0115] (1) dry mixing the industrial solid waste micro-powder and the passivated coarse aggregate, adding the sol-impregnated fine aggregate dispersion liquid, and stirring uniformly;

[0116] (2) adding a polycarboxylic acid water reducing agent, and after pouring, passing in 10% CO2 gas for curing for 2 hours in the initial setting stage, and then placing in an environment with a humidity of ≥80% for repair after standard curing for 7 days.

[0117] Comparative Example 2

[0118] A concrete material based on industrial solid waste regenerated materials, which is different from Example 1 in that the components are as shown in Table 1 in terms of weight fractions, and the preparation method is consistent with that of Example 1.

[0119] Comparative Example 3

[0120] A concrete material based on industrial solid waste regenerated materials, which is different from Example 1 in that the components are as shown in Table 1 in terms of weight fractions, and the preparation method is consistent with that of Example 1.

[0121] Comparative Example 4

[0122] A concrete material based on industrial solid waste regenerated materials, which is different from Example 1 in that the components are as shown in Table 1 in terms of weight fractions, and the preparation method is consistent with that of Example 1.

[0123] Comparative Example 5

[0124] A concrete material based on industrial solid waste recycled materials, different from example 1, the components are shown in Table 1 by weight fraction, the preparation method is consistent with example 1.

[0125] Comparative example 6

[0126] A concrete material based on industrial solid waste recycled materials, different from example 1, the components are shown in Table 1 by weight fraction, wherein the passivated coarse aggregate does not undergo phosphate soaking modification, and directly uses metallurgical solid waste, the preparation method is consistent with example 1.

[0127] Comparative example 7

[0128] A concrete material based on industrial solid waste recycled materials, different from example 1, the components are shown in Table 1 by weight fraction, wherein the strong alkaline chemical activator NaOH is used to replace the alkaline base liquid,

[0129] The preparation method is consistent with example 1.

[0130] Table 1 Composition of concrete material based on industrial solid waste recycled materials

[0131]

[0132] The following is a comparative example on the influence of microbial activator on the performance of concrete, including experimental design, test standard, data comparison and conclusion analysis, highlighting its technical advantages in crack repair rate and strength improvement:

[0133] Performance test:

[0134] Test piece preparation: prepare 100 μm x 100 μm x 100 μm cubic test pieces according to GB / T 50081-2016 standard; curing condition: standard curing room (20±2℃, humidity≥95%) to 28 days of age.

[0135] Crack repair rate test: (1) preset artificial cracks (width 0.2±0.05mm, depth 10mm) on the surface of the test piece; (2) exposed to humidity 80% environment, temperature 25℃; (3) observe the change of crack width with time by microscope (ASTM C1582 standard). Evaluation standard: crack width is restored to ≤0.05mm is considered to be repaired, calculate the repair rate. The crack repair rate test results are shown in Table 2.

[0136] Table 2 Crack repair rate test results

[0137]

[0138] As can be seen from Table 2, by comparing Examples 1 and 2, the water consumption will decrease after the addition of the polycarboxylic acid water reducing agent, which will result in a decrease in the early repair rate compared with Example 1; in Example 3, with the increase in the content of the industrial solid waste micro-powder, the effective active cement component increases, and the early repair effect is slightly improved; in Comparative Example 4, the base liquid is increased, and the effective calcium carbonate component is correspondingly increased, and the early repair effect is slightly improved.

[0139] In Comparative Example 1, no alkali base liquid and no composite microbial slow-release capsules are added, and the early repair effect is 0, and the repair effect at 28 days is also not ideal. This is because the alkali base liquid is difficult to stimulate the formation of a dense gel between the aggregates, resulting in a large porosity, which reduces the impermeability and corrosion resistance. The absence of the composite microbial slow-release capsules results in a lack of self-repairing ability of the concrete, and the concrete cannot fill the micro-cracks of the aggregates with silica sol, resulting in poor mechanical properties, long-term strength and durability. In Comparative Example 2, only the alkali base liquid is added without the composite microbial slow-release capsules, and the effect is slightly improved compared with Comparative Example 1, but without the long-term effect of the composite microbial slow-release capsules, the repair effect at 28 days is still not ideal. In Comparative Example 3, only the composite microbial slow-release capsules are added without the alkali base liquid, which is similar to Comparative Example 2, and neither of them can exert the effect of the combined action of the two. In Comparative Example 4, the content of the industrial solid waste micro-powder is less than that of the examples, and the early repair effect is slightly lower than that of Example 1, which is analyzed to be caused by the decrease in the cement effect of the industrial solid waste micro-powder.

[0140] In Comparative Example 5, the industrial solid waste micro-powder, the passivated coarse aggregate and the composite microbial slow-release capsules are added in excess, and the water reducing agent is not correspondingly increased, which will result in no decrease in water, and the density is not enough, so the repair effect is poorer than that of the examples.

[0141] In Comparative Example 6, the passivated coarse aggregate is not modified by phosphate soaking, and metallurgical solid waste is directly used. The internal micro-cracks and pores of the aggregate result in low density of the concrete, high water absorption of the natural aggregate, and further result in insufficient performance of the recycled aggregate, leading to poor mechanical properties and durability of the concrete; the old cement paste or impurities attached to the surface of the recycled aggregate result in low bonding strength at the interface transition zone of the cement matrix, which is easy to become a crack propagation channel, resulting in weak interface bonding; the leaching concentration of heavy metals (Pb, Cr, Cd) in the metallurgical solid waste (such as red mud, calcium carbide slag) exceeds the limit value, and direct use poses a pollution risk.

[0142] In Comparative Example 7, a strong alkaline chemical activator such as NaOH is used to replace the alkali base liquid, which has limited efficiency and significant side effects. This is because the strong alkali solution has strong corrosion to the production equipment, and residual alkaline substances can easily cause alkali aggregate reaction, resulting in expansion and cracking of the concrete; it can only improve the cementitious activity, but cannot solve the comprehensive needs of micro-crack self-repairing and heavy metal solidification; due to the insufficient activation efficiency, the replacement rate of solid waste is limited, and the replacement ratio of industrial solid waste to cement is usually <30%, which is difficult to achieve high-content resource utilization.

[0143] Compressive strength test: 28-day and 365-day compressive strength tests were performed using a universal testing machine, and the test results are shown in Table 3.

[0144] Table 3 Compressive strength test results

[0145]

[0146] As can be seen from Table 3, the compressive strength trend is basically the same as the crack repair rate test results in Table 2, which also indicates that the higher the crack repair rate, the greater the compressive strength value, thereby verifying the repair effect.

[0147] Through the comparison of the examples, it is verified that the microbial activator significantly improves the crack repair ability of the solid waste-based concrete, fills the micro-cracks of the aggregate with the silica sol, enhances the mechanical properties, and improves the long-term strength and durability, thereby providing a reliable technical solution for green building materials and intelligent infrastructure.

[0148] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A concrete material based on industrial solid waste recycled materials, characterized by, The industrial solid waste micro powder, the passivated coarse aggregate, the sol impregnated fine aggregate dispersion liquid, the alkaline base liquid, the composite microbial slow-release capsule, and the polycarboxylic acid water reducing agent are respectively 40-50 parts, 10-20 parts, 180-200 parts, 30-40 parts, 5-10 parts, 0.1-0.2 parts by weight. The industrial solid waste micro powder comprises steel slag and fly ash. The passivated coarse aggregate is a metallurgical solid waste modified by phosphate immersion. The sol impregnated fine aggregate dispersion liquid comprises waste concrete, nano-silica sol, and a dispersant. The composite microbial slow-release capsule comprises core material and wall material wrapped on the surface of the core material, the core material comprises Bacillus pasteurii spores, calcium lactate, and yeast extract, and the wall material is sodium alginate. The alkaline base liquid comprises water glass, alkali residue, and water in a weight percentage of 10-15%, 20-25%, and the balance, respectively.

2. The industrial solid waste regenerated material-based concrete material according to claim 1, wherein a mass ratio of the steel slag to the fly ash is 3: (1-2); and a particle size of the industrial solid waste micro powder is ≤100 μm. A particle size of the passivated coarse aggregate is 5-20 mm. A mass ratio of the waste concrete to the nano-silica sol is 1: (3-4).

3. The concrete material based on industrial solid waste recycled aggregates according to claim 1, characterized in that, A particle size of the waste concrete is 1-5 mm. A solid content of the nano-silica sol is 10 wt%-15 wt%. The dispersant is one of Span-80, PEG 200, sodium polyacrylate, Tween-60, and Tween-80, and an addition amount of the dispersant is 0.5%-1.0% of a mass of the nano-silica sol. A particle size of the composite microbial slow-release capsule is 50-100 μm.

4. The concrete material based on industrial solid waste recycled aggregates according to claim 1, characterized in that, A mass ratio of the Bacillus pasteurii spores, calcium lactate, and yeast extract is (3-4): 1:

1. A modulus of the water glass is 1.2-1.8; a particle size of the alkali residue is ≤45 μm; the alkali residue is an industrial byproduct; and the industrial byproduct contains active ingredients of Ca (OH) 2 and CaCO 3. The viable cell concentration of the B. pasteurii spores is >10 6 CFU / g.

5. The concrete material based on industrial solid waste recycled aggregates according to claim 1, characterized in that, The method comprises the following steps:

6. A method of producing a concrete material based on industrial solid waste recycled material according to any one of claims 1 to 5, characterized in that, (1) dry mixing the industrial solid waste micro powder and the passivated coarse aggregate to obtain a premix; (2) mixing the sol impregnated fine aggregate dispersion liquid and the alkaline base liquid, adding the composite microbial slow-release capsule, and stirring to obtain a mixture; (3) adding the premix to the mixture, adding the polycarboxylic acid water reducing agent, pouring, and curing to obtain the industrial solid waste regenerated material-based concrete material. In step (1), the industrial solid waste micro powder is prepared by mixing steel slag and fly ash to obtain a mixture, removing iron impurities by magnetic separation, and crushing to obtain the industrial solid waste micro powder.

7. The method of producing a concrete material based on industrial solid waste recycled materials according to claim 6, characterized in that, A mixing mass ratio of the steel slag to the fly ash is 3: (1-2), and a particle size of the crushed industrial solid waste micro powder is ≤100 μm. Alternatively, the passivated coarse aggregate is prepared by crushing metallurgical solid waste, immersing the crushed metallurgical solid waste in a phosphate solution, and drying the obtained material. A particle size of the crushed metallurgical solid waste is 5-20 mm, a concentration of the phosphate solution is 0.4-0.6 mol / L, and an immersion time is 20-24 h. In step (2), the sol impregnated fine aggregate dispersion liquid is prepared by mixing waste concrete and nano-silica sol, and adding a dispersant.

8. The method of producing a concrete material based on industrial solid waste recycled materials according to claim 6, characterized in that, ​ The waste concrete is crushed and added into nano-silica sol, then a dispersant is added and ultrasonic treatment is performed to obtain the same. The mass ratio of the waste concrete to the nano-silica sol is 1: (3-4). The particle size of the waste concrete is 1-5 mm. The solid content of the nano-silica sol is 10 wt%-15 wt%. The dispersant is one of Span-80, PEG 200, sodium polyacrylate, Tween-60 and Tween-80, and the addition amount of the dispersant is 0.5%-1.0% of the mass of the nano-silica sol. The frequency of the ultrasonic treatment is 35-45 kHz, and the time is 20-40 min. Alternatively, the alkaline base liquid is prepared by the following method: water is heated, then water glass and alkali residue are sequentially added into the water, and a suspension is prepared by magnetic stirring to obtain the alkaline base liquid. The modulus of the water glass is 1.2-1.8; the particle size of the alkali residue is ≤45 μm; the alkali residue is an industrial by-product; and the industrial by-product contains active components of Ca (OH) 2 and CaCO3. The temperature of the heated water is 30-35 ℃; the stirring speed of the magnetic stirring is 450-550 rpm; the time of the magnetic stirring is 30-35 min; and the pH of the suspension is 12.5-13. Alternatively, the composite microbial slow-release capsule is prepared by the following method: spores of Bacillus pasteurii, calcium lactate and yeast extract are mixed to obtain a core material; the core material is added into an aqueous sodium alginate solution, and a cross-linking reaction is performed after adding a CaCl2 solution to obtain the composite microbial slow-release capsule. The particle size of the composite microbial slow-release capsule is 50-100 μm. The mass ratio of the spores of Bacillus pasteurii, calcium lactate and yeast extract is (3-4) : 1:

1. The viable cell concentration of the B. pasteurii spores is >10 6 CFU / g; The concentration of the aqueous sodium alginate solution is 2-3 wt%, and the concentration of the CaCl2 solution is 4-5 wt%; or, in step (2), the stirring speed is 100-200 rpm, and the time is 15-25 min. Alternatively, in step (3), the curing is performed in a CO2 gas with a concentration of 10-20% for 2-3 h, and then standard curing is performed for 7 days.

9. Use of the concrete material based on the regenerated material of industrial solid waste according to any one of claims 1-5 in solid waste resource utilization and building materials.

10. Use according to claim 9, characterized in that, The use is the use in concrete crack repair.

11. A method of repairing a concrete crack, characterized by, The concrete material based on the regenerated material of industrial solid waste according to any one of claims 1-5 is placed in a concrete crack, the environmental humidity is ≥80%, the temperature is 25 ℃, and the repair time is 7-28 days.

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