A waste sintered brick reinforced recycled aggregate and a preparation method thereof

Abstract

The application discloses a kind of waste sintered brick reinforced recycled aggregate and its preparation method, its preparation method includes the following steps: (1) in situ solidification recycled micro powder: take the broken sintered brick recycled aggregate of good crushing, add recycled micro powder and silicon-rich aluminous industrial solid waste powder, aggregate, micro powder and powder are mixed in continuous tumbling state, and spray solution containing thickening water-retaining agent to it, the treated aggregate is cured, to obtain the recycled aggregate of coated solidified powder layer;(2) alkali-activated recycled micro powder: the above-mentioned recycled aggregate of coated solidified powder layer is continuously tumbled, while spraying liquid alkali activator on recycled aggregate, the treated recycled aggregate is cured for the second time, to obtain the waste sintered brick reinforced recycled aggregate.The method is modified to recycled aggregate, can significantly reduce its water absorption, improve particle strength and surface properties, and prepare high-quality recycled aggregate that can be used to prepare medium-high performance concrete.

Description

Technical Field

[0001] This invention relates to a reinforced recycled aggregate from waste sintered bricks and its preparation method, belonging to the field of building materials production technology. Background Technology

[0002] With the continuous advancement of urbanization and the upgrading of existing buildings, a large amount of construction waste originating from brick-concrete structures is generated during urban renewal and demolition. Among these, waste sintered bricks (including clay bricks and shale bricks) constitute a significant component of construction waste due to their age and wide distribution. Simply landfilling or stockpiling such waste not only occupies a large amount of land resources but also causes environmental pollution and resource waste. Therefore, resource utilization of this waste aligns with the strategic needs of sustainable development and a circular economy.

[0003] Currently, crushing and screening construction waste and incorporating it as recycled aggregate into cement concrete is one of the main technical approaches for disposing of large quantities of solid waste. This can alleviate the pressure of scarce natural sand and gravel aggregate resources and reduce the environmental burden of construction waste disposal. Against this backdrop, using crushed waste sintered bricks to prepare recycled brick aggregate and then using it in concrete preparation has become an important research and application direction.

[0004] Although utilizing waste sintered bricks as concrete aggregate has potential value, a series of key technical bottlenecks and defects remain in practical engineering applications and technology promotion, resulting in performance far inferior to natural aggregate concrete. An efficient, reliable, and large-scale utilization method has not yet been established. The shortcomings of existing technologies are mainly reflected in the following three aspects:

[0005] 1. Inherent defects in aggregates lead to an abnormal increase in the water demand of concrete.

[0006] After being crushed, waste sintered bricks retain the porous, microcracked structure formed during the sintering process. This porous structure results in extremely high water absorption (typically exceeding 10%, far higher than the 1-2% of natural aggregates). When this highly absorbent aggregate is added to concrete mixes, it rapidly absorbs mixing water during mixing and pouring, leading to a rapid loss of workability. To maintain the necessary slump and workability, the initial mixing water volume must be significantly increased. This not only disrupts the balance of conventional concrete mix design but also creates potential problems for subsequent performance.

[0007] 2. Causes significant deterioration in the mechanical strength and durability of concrete.

[0008] The increased water content directly leads to a higher actual water-cement ratio (water-binder ratio) in concrete, which is the primary reason for the decrease in concrete strength. Excess water, after evaporation, leaves more pores within the concrete, reducing the structure's density. Secondly, the strength of brick aggregate is generally lower than that of natural rock aggregate, becoming a "weak link" in the concrete. More seriously, the interface transition zone between brick aggregate and cement paste often becomes a weak point due to complex water migration and poor bonding properties. Therefore, concrete incorporating sintered brick aggregate generally exhibits a significant decrease in compressive strength, flexural strength, and modulus of elasticity, making it difficult to meet the requirements of structural engineering. Furthermore, high porosity also means a severe deterioration in durability indicators such as impermeability and freeze-thaw resistance.

[0009] 3. Existing pretreatment methods cannot fundamentally improve aggregate quality, nor can they effectively utilize recycled micro powder.

[0010] Currently, the pretreatment of waste sintered bricks is usually limited to simple mechanical crushing and grading, which is a change in physical form and does not address the fundamental properties of their porosity and high water absorption. Some technologies attempt to alleviate the problem by using admixtures or adjusting the mixing process, such as using water-reducing agents or pre-wetting the aggregate. However, these methods only treat the symptoms, not the root cause: while pre-wetting can reduce water absorption during mixing, the aggregate remains a water-storing "hidden danger" in hardened concrete, potentially affecting long-term performance; and relying solely on chemical admixtures cannot strengthen the aggregate itself, increases costs, and has limited effectiveness. More importantly, the crushing process of waste sintered bricks generates a large amount of recycled microparticles, which mostly adhere to the surface of the particles and the internal pores and microcracks. To prevent this from further increasing the water demand of the mixed concrete, the recycled aggregate particles often need to be manually washed, which places higher demands on the disposal process and also generates a certain amount of wastewater containing recycled microparticles.

[0011] Therefore, existing technologies focus primarily on "how to incorporate" rather than "how to optimize" the brick aggregate itself. There is a lack of effective and cost-efficient mature processes for fundamentally sealing or strengthening the pore structure of sintered brick aggregate through systematic physical, chemical, or composite modification methods, enhancing its surface properties and bulk strength, and forming a strong bond with the cement matrix. This results in unstable quality of crushed sintered brick aggregate, poor predictability of its application performance, and engineers cannot reliably design and calculate it like they would with natural aggregate, severely hindering its large-scale application in formal building engineering, especially in load-bearing structures.

[0012] Due to the aforementioned technical limitations, most waste sintered brick aggregates can currently only be used in low-strength, non-load-bearing concrete products (such as paving bricks and permeable bricks) or as roadbed filler materials, resulting in low added value. This "downgraded utilization" model fails to fully realize the potential value of sintered bricks as artificial silicate materials, leading to low resource utilization efficiency. Furthermore, the increased cement usage or shortened lifespan of concrete due to performance issues may actually weaken its environmental benefits from a life-cycle perspective.

[0013] In summary, the main shortcomings of existing technologies are: the comprehensive deterioration of concrete workability, mechanical properties and durability caused directly by the inherent high water absorption, porosity and low strength characteristics of sintered brick aggregates; and the large amount of recycled micro powder generated during the crushing process. There is still a lack of a systematic solution that can fundamentally improve aggregate quality, form performance enhancement and synergistic utilization of aggregate micro powder. Summary of the Invention

[0014] Objective of the Invention: To address the problems existing in the prior art, this invention provides a method for preparing reinforced recycled aggregate from waste sintered bricks. This invention targets the fundamental deficiencies in the prior art, aiming to provide an effective method for preparing reinforced recycled aggregate from sintered bricks. Through targeted modification treatment, its water absorption rate is significantly reduced, and particle strength and surface properties are improved. Furthermore, without washing the recycled aggregate particles, the method utilizes the recycled micro-powder generated during the crushing process to prepare high-quality recycled aggregate suitable for preparing medium- and high-performance concrete, truly realizing the high-value-added resource utilization of waste sintered bricks.

[0015] Technical solution: To achieve the above objectives, the present invention adopts the following technical solution:

[0016] This invention provides a method for preparing reinforced recycled aggregate from waste sintered bricks, comprising the following steps:

[0017] (1) In-situ solidified recycled micro powder: Take the crushed sintered brick recycled aggregate, add recycled micro powder and silicon-alumina industrial solid waste powder. The aggregate, micro powder and powder are mixed in a continuous rolling state, and a solution containing thickening and water-retaining agent is sprayed into it to ensure that the powder can adhere to or fill the surface of the crushed sintered brick recycled aggregate. The treated aggregate is cured to obtain recycled aggregate coated with solidified powder layer.

[0018] (2) Alkali-activated regenerated micro powder: The above-mentioned recycled aggregate coated with solidified powder layer is continuously tumbled, and liquid alkali activator is sprayed onto the recycled aggregate. The treated recycled aggregate is then cured a second time to obtain the waste sintered brick reinforced recycled aggregate.

[0019] As a specific implementation plan, steps (1) and (2) can be repeated several times; preferably, they can be repeated 1 to 5 times.

[0020] As a specific implementation plan, in steps (1) and (2), the continuous tumbling can be achieved by using a drum washing machine. The material is placed into the drum of the drum washing machine, the equipment is operated, and the drum is rotated to achieve the continuous tumbling.

[0021] The rotational speed for the continuous tumbling is set at 15-60 r / min.

[0022] As a specific implementation plan, in step (1), the particle size of the recycled aggregate from crushed sintered bricks is controlled within the range of 20-30 mm; the surface and internal pores of the recycled aggregate from crushed sintered bricks are still covered or filled with recycled micro powder.

[0023] As a specific implementation plan, in step (1), the recycled micro powder is the recycled micro powder generated and separated during the crushing process of sintered bricks, and the mass ratio of recycled micro powder to recycled aggregate is controlled within the range of 0.1-0.25. The silicon-rich aluminum industrial solid waste is selected from fly ash or slag, and its addition amount is 25-50% of the mass of recycled micro powder.

[0024] As a specific implementation plan, in step (1), the solution containing the thickening and water-retaining agent has a mass concentration of 0.5-2% and a spraying amount of 10-20% of the mass of the regenerated micro powder;

[0025] In the solution containing a thickening and water-retaining agent, the thickening and water-retaining agent is selected from hydroxypropyl methylcellulose (HPMC), sodium carboxymethyl cellulose (CMC), or hydroxyethyl cellulose (HEC).

[0026] Preferably, the viscosity of HPMC is 40,000-200,000 mPa·s, the viscosity of CMC is 1,500-3,000 mPa·s, and the viscosity of HEC is 2,000-4,000 mPa·s.

[0027] As a specific implementation plan, in step (1), the curing conditions are: drying for 2-12 hours at a temperature of 20-50℃.

[0028] As a specific implementation plan, in step (2), the liquid alkaline activator is selected from NaOH solution or sodium silicate solution, with a mass concentration of 5-15%, and the spraying amount is 20-35% of the total mass of the regenerated micro powder used in step (1).

[0029] As a specific implementation plan, in step (2), the curing conditions are: drying for 2-12 hours at a temperature of 20-50℃.

[0030] The present invention also provides a waste sintered brick reinforced recycled aggregate, which is prepared by the above preparation method.

[0031] The main principles and innovations of the method of this invention are as follows:

[0032] The first step, "in-situ solidification of recycled micro-powder," involves loading crushed sintered brick recycled aggregate, with its surface and internal pores still adhered to or filled with recycled micro-powder, into a tumbling and rotating device such as a drum washing machine or drum screen. Simultaneously, a certain amount of separated recycled micro-powder and silica-alumina-rich industrial solid waste (such as fly ash and slag) is added to the device. The machinery operates, and the crushed particles and powder tumble within the long drum with the blades. At this time, a small amount of a solution of non-ionic cellulose ether compounds mixed with a thickening and water-retaining agent is sprayed into the drum, allowing the cellulose ether solution to impregnate the recycled micro-powder mixed with the silica-alumina-rich industrial solid waste. The treated recycled aggregate is then dried and cured at room temperature or high temperature to evaporate the moisture introduced by the thickening and water-retaining agent, forming a layer of recycled micro-powder and silica-alumina-rich powder material with a certain degree of adhesion on the surface and in the internal pores. These steps can be adjusted and repeated according to the characteristics of the recycled micro-powder and recycled aggregate until good adhesion and pore-filling effects are achieved.

[0033] The second step, "alkali-activated regenerated micropowder": The regenerated aggregate prepared in the first step, coated with a layer of regenerated micropowder and a solidified layer of silicon-rich alumina powder, is further fed into a tumbling and rotating device. While the machine is running, a liquid alkali activator (such as sodium hydroxide or sodium silicate solution) is sprayed into the drum. This activator impregnates the solidified layer of regenerated micropowder mixed with silicon-rich alumina industrial solid waste, which adheres to the surface or fills the pores. Then, the regenerated aggregate is removed and dried and cured at room temperature or high temperature. The moisture introduced by the liquid alkali activator evaporates, and the alkali-activated reaction solidifies the regenerated micropowder and silicon-rich alumina powder formed on the surface and in the internal pores, forming a hardened geopolymer product layer with a certain strength. These steps can be adjusted and repeated with alkali activation based on the characteristics of the regenerated micropowder and regenerated aggregate until a good aggregate coating and hardening effect is achieved.

[0034] Based on the two-step processing method described above, the recycled micropowder generated during the crushing of sintered bricks can be fully utilized to fill the pores and microcracks on the surface of recycled aggregates. The geopolymer hardened body coated on the surface of recycled aggregates has high strength, which can effectively improve the strength and crushing value of recycled aggregates; at the same time, the dense microstructure of the geopolymer can effectively reduce the water absorption rate of recycled aggregates; finally, it can also effectively improve the bonding ability between recycled aggregates and cement-based materials, further improving the mechanical properties and structural density of recycled aggregate concrete.

[0035] Technical Effects: Compared to existing technologies, this invention first places recycled micro-powder and industrial waste into a roller mill. A thickener is added to pre-coat the recycled aggregate within the rolling mill. Then, in the second step, an alkali-activated reaction is carried out within the roller by spraying an alkali activator. This reaction utilizes the mechanical means of roller rolling, effectively integrating mechanical activation and chemical activation methods. It allows the recycled micro-powder particles and the mixture to undergo a building-up reaction under the mechanical mode of rolling and extrusion, which is far different from the traditional cementitious material mixing method of simply mixing the alkali activator with the recycled micro-powder and the mixture. Therefore, this invention is a completely different technical process compared to existing processes. The reason for coating the recycled aggregate with powder during the dynamic grinding process in this invention is to achieve a technical process that combines strong mechanical and chemical bonding. More importantly, the main objective of this invention is to achieve the synergistic utilization of recycled micro-powder and recycled aggregate through the synergistic treatment of both, which differs from the technical starting point of simply preparing components from recycled micro-powder. Meanwhile, the method of the present invention, by combining mechanical activation and chemical activation, can effectively reduce the amount of alkali activator, improve the activation effect, strengthen the strength of the recycled micro-powder base polymer shell formed on the outer layer of recycled aggregate, and is more conducive to improving the crushing value and water absorption rate of recycled aggregate.

[0036] In summary, the significant advantages of this invention are:

[0037] Through the above two-step, multi-cycle, controllable process, the micro-powder from the waste bricks themselves and external industrial solid waste are fully utilized, ultimately forming a "reinforced outer shell" made of geopolymer on the surface of the recycled aggregate. This hardened shell layer:

[0038] 1) Significantly improves the strength and crush resistance of aggregate (the problem of high crushing value is improved);

[0039] 2) Due to its dense microstructure, it greatly blocks the channels for water intrusion (the problem of high water absorption rate is completely solved).

[0040] 3) It is an inorganic cementitious material with good chemical compatibility with cement paste, which can form strong mechanical interlocking and chemical bonding (the problem of weak interface is strengthened).

[0041] This allows the treated reinforced recycled aggregate to be directly used in the formulation of concrete with excellent workability, high strength, and good durability, truly realizing the leap from "waste" to "high-quality resource." All process parameters are variables and can be precisely optimized according to specific raw material performance and economic requirements, demonstrating the flexibility and universality of this method.

[0042] This invention aims to provide a systematic strengthening method for recycled aggregates from waste sintered bricks, addressing their core defects of high water absorption, low strength, and weak interfacial adhesion with the cement matrix. The core concept of this invention lies in employing a two-step process: "physical adhesion layering followed by chemical activation and curing." This utilizes the micro-powder generated from the brick's own crushing process, along with industrial solid waste, to construct a dense, high-strength, low-permeability geopolymer hardened shell layer in situ on the aggregate surface and within its pores. This method not only achieves 100% resource utilization of waste sintered brick aggregates and micro-powder but also improves performance to meet or approach the engineering application standards of natural aggregates. Attached Figure Description

[0043] Figure 1 This is a flowchart illustrating the technical route of the present invention. Detailed Implementation

[0044] The invention will be further illustrated below with specific examples.

[0045] The method for preparing reinforced recycled aggregate from waste sintered bricks according to the present invention is as follows:

[0046] 1. First step: "In-situ solidification and regeneration of micro powder" – constructing a uniform pre-coating layer

[0047] Crushed sintered brick recycled aggregate with a particle size controlled within the range of 20-30 mm is loaded into a drum washing machine or similar tumbling and rolling equipment. During the crushing process of the sintered bricks, a certain amount of recycled micro-powder will naturally adhere to the surface and internal pores of the recycled aggregate. Its weight is difficult to measure and is different from the recycled micro-powder added in this invention. Therefore, unless otherwise specified, the recycled micro-powder added in this invention, as well as the recycled micro-powder described in the mass ratio, are all additionally added recycled micro-powder. The equipment rotation speed is set within an adjustable range of 15-60 r / min to ensure that the aggregate undergoes sufficient tumbling and mixing within the drum, achieving uniform processing.

[0048] During this process, recycled micro-powder is added to the equipment, with the mass ratio of recycled micro-powder to recycled aggregate controlled within the range of 0.1-0.25. Simultaneously, specific types of silicon-alumina-rich industrial solid waste, such as fly ash or slag, are added, with the addition amount being 25-50% of the mass of the recycled micro-powder adhering to the aggregate surface. These two solid wastes are rich in active SiO2 and Al2O3, serving as the silicon-alumina source for subsequent geological polymerization reactions.

[0049] Subsequently, while the aggregate and powder continue to tumble, a specially formulated viscous solution is sprayed into the drum. This solution is prepared by dissolving a thickening and water-retaining agent in water, and can be selected from hydroxypropyl methylcellulose (HPMC), sodium carboxymethyl cellulose (CMC), or hydroxyethyl cellulose (HEC). The viscosity of the solution is controlled according to the type: 40,000-200,000 mPa·s for HPMC, 1,500-3,000 mPa·s for CMC, and 2,000-4,000 mPa·s for HEC, with a solution mass concentration of 0.5-2%. The amount of this solution sprayed is 10-20% of the mass of the regenerated micro-powder.

[0050] The key to this step is that the high-viscosity cellulose ether solution effectively wets and adheres to the regenerated micropowder and added silica-rich alumina powder on the aggregate surface, forming a uniform and stable moist pre-coating layer on the aggregate surface and within the pores. Subsequently, the treated aggregate is cured at 20-50°C for 2-12 hours. This process evaporates moisture, allowing the thickening and water-retaining agent to act as a binder, forming an initial cured powder layer with a certain bonding strength. Depending on the initial porosity of the aggregate and the amount of micropowder adhered, this "in-situ curing" step can be repeated 1-5 times to progressively fill the pores and increase the pre-coating thickness.

[0051] 2. Second step: "Alkali-activated regenerated micro powder" – forming a geopolymer-reinforced shell.

[0052] The recycled aggregate prepared in the first step, with a solidified powder layer already coated on its surface, is then placed in a tumbling and rolling device. While tumbling at the same rotational speed (15-60 r / min), a liquid alkali activator is sprayed onto the aggregate. The alkali activator is either NaOH solution or sodium silicate (water glass) solution, with a mass concentration of 5-15%, and the amount sprayed is 20-35% of the total mass of the recycled micro powder used in the first step.

[0053] The alkali activator will quickly wet and penetrate the powder curing layer, where the highly alkaline environment ( This process activates the recycled micro-powder and silica-alumina-rich solid waste (fly ash / slag) in the powder layer, causing a series of geopolymerization reactions such as dissolution, recombination, and condensation. After uniform spraying, the aggregate is removed and subjected to secondary curing, which can also be carried out under drying conditions at 20-50℃ for 2-12 hours. This process promotes moisture evaporation, accelerates the geopolymerization reaction, and ultimately forms a hard, dense geopolymer (similar to artificial stone) product layer on the surface and inside the pores of the aggregate. This "alkali activation" step can also be repeated 1-5 times depending on the final strength and density requirements of the target coating layer to achieve a cumulative strengthening effect.

[0054] Examples 1-4 are performed according to the above method.

[0055] Example 1

[0056] The particle size of the recycled aggregate from crushed sintered bricks is in the range of 20-30 mm, and the equipment speed is set at 45 r / min; the mass ratio of recycled micro powder to recycled aggregate is 0.15; the silica-alumina-rich industrial solid waste is fly ash, and the addition amount is 50% of the mass of recycled micro powder; the thickening and water-retaining agent is sodium carboxymethyl cellulose (CMC) with a viscosity of 3,000 mPa·s, and the solution mass concentration is set at 2%, and the spraying amount of this solution is 15% of the mass of recycled micro powder; the first curing is carried out at 30℃ for 4 hours; the alkali activator is sodium silicate solution with a mass concentration of 10%, and the spraying amount is 30% of the total mass of recycled micro powder used in the first step; the second curing is carried out at 30℃ for 4 hours; based on the above steps, the wrapping is repeated twice (including the first and second steps).

[0057] Example 2

[0058] The particle size of the recycled aggregate from crushed sintered bricks is in the range of 20-30 mm, and the equipment speed is set at 20 r / min; the mass ratio of recycled powder to recycled aggregate is 0.2; the silicon-alumina-rich industrial solid waste is selected from fly ash and granulated blast furnace slag, with a mass ratio of 1 / 1, and the addition amount is 25% of the mass of recycled powder; the thickening and water-retaining agent is sodium carboxymethyl cellulose (CMC) with a viscosity of 1,500 mPa·s, and the solution mass concentration is set to 1%, and the spraying amount of this solution is 10% of the mass of recycled powder; the first curing is carried out at 20℃ for 2 hours; the alkali activator is selected from sodium silicate solution with a mass concentration of 10%, and the spraying amount is 30% of the total mass of recycled powder used in the first step; the second curing is carried out at 20℃ for 2 hours; based on the above operations, only one wrapping is required (including the first and second steps).

[0059] Example 3

[0060] The particle size of the recycled aggregate from crushed sintered bricks is in the range of 20-30 mm, and the equipment speed is set at 60 r / min; the mass ratio of recycled micro powder to recycled aggregate is 0.15; the silicon-alumina-rich industrial solid waste is selected from granulated blast furnace slag, and the addition amount is 25% of the mass of recycled micro powder; the thickening and water-retaining agent is hydroxyethyl cellulose (HEC) with a viscosity of 3,500 mPa·s and a solution mass concentration of 1%, and the spraying amount of this solution is 10% of the mass of recycled micro powder; the first curing is carried out at 40℃ for 2 hours; the alkali activator is selected from NaOH solution with a mass concentration of 10%, and the spraying amount is 30% of the total mass of recycled micro powder used in the first step; the second curing is carried out at 40℃ for 2 hours; based on the above operations, only one wrapping is required (including the first and second steps).

[0061] Example 4

[0062] The particle size of the recycled aggregate from crushed sintered bricks is in the range of 20-30 mm, and the equipment speed is set at 40 r / min; the mass ratio of recycled powder to recycled aggregate is 0.20; the silica-alumina-rich industrial solid waste is selected from fly ash and granulated blast furnace slag, with a mass ratio of 1 / 1, and the addition amount is 40% of the mass of recycled powder; the thickening and water-retaining agent is hydroxypropyl methylcellulose (HPMC) with a viscosity of 8,000 mPa·s and a solution mass concentration of 1.5%, and the spraying amount of this solution is 10% of the mass of recycled powder; the first curing is carried out at 40℃ for 2 hours; the alkali activator is selected from sodium silicate solution with a mass concentration of 15%, and the spraying amount is 20% of the total mass of recycled powder used in the first step; the second curing is carried out at 40℃ for 2 hours; based on the above operations, the coating is applied twice (including the first and second steps).

[0063] Performance testing of recycled aggregate in test cases

[0064] The apparent density, water absorption rate and crushing index of aggregates were tested in accordance with GB / T 14685-2022 "Construction Gravel and Crushed Stone", and the results are shown in Table 1 below.

[0065] Table 1. Basic properties of recycled aggregates before and after treatment

[0066]

[0067] As can be seen from the results in the table above, Example 4 exhibits superior performance, with the lowest water absorption rate of the treated recycled aggregate at 0.25% and the lowest crushing index at 15.6%. This is a result of the selected comprehensive process. Specifically, fly ash and granulated blast furnace slag should be used together for the silica-alumina-rich solid waste; HPMC should be used as the thickener; sodium silicate solution should be used as the activator; and finally, double coating will effectively improve the aggregate performance.

[0068] The embodiments of the present invention have been described in detail above with reference to specific examples. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for preparing reinforced recycled aggregate from waste sintered bricks, characterized in that, Includes the following steps: (1) In-situ solidified recycled micro powder: Take the crushed sintered brick recycled aggregate, add recycled micro powder and silicon-alumina industrial solid waste powder, mix the aggregate, micro powder and powder under continuous tumbling, and spray a solution containing thickening and water-retaining agent into it, and cure the treated aggregate to obtain recycled aggregate coated with solidified powder layer. (2) Alkali-activated regenerated micro powder: The above-mentioned recycled aggregate coated with solidified powder layer is continuously tumbled, and liquid alkali activator is sprayed onto the recycled aggregate. The treated recycled aggregate is then cured a second time to obtain the waste sintered brick reinforced recycled aggregate.

2. The method for preparing reinforced recycled aggregate from waste sintered bricks according to claim 1, characterized in that, Both steps (1) and (2) can be repeated several times; preferably, they can be repeated 1 to 5 times.

3. The method for preparing reinforced recycled aggregate from waste sintered bricks according to claim 1, characterized in that, In steps (1) and (2), the continuous tumbling can be achieved by using a drum washing machine. The material is placed into the drum of the drum washing machine, the equipment is operated, and the drum is rotated to achieve the continuous tumbling. The rotational speed for the continuous tumbling is set at 15-60 r / min.

4. The method for preparing reinforced recycled aggregate from waste sintered bricks according to claim 1, characterized in that, In step (1), the particle size of the recycled aggregate from crushed sintered bricks is controlled within the range of 20-30 mm; the surface and internal pores of the recycled aggregate from crushed sintered bricks are still covered or filled with recycled micro powder.

5. The method for preparing reinforced recycled aggregate from waste sintered bricks according to claim 1, characterized in that, In step (1), the recycled micro powder is the recycled micro powder generated and separated during the crushing process of sintered bricks. The mass ratio of the recycled micro powder and recycled aggregate is controlled within the range of 0.1-0.

25. The silicon-rich aluminum industrial solid waste is selected from fly ash or slag, and its addition amount is 25-50% of the mass of the recycled micro powder.

6. The method for preparing reinforced recycled aggregate from waste sintered bricks according to claim 1, characterized in that, In step (1), the solution containing the thickening and water-retaining agent has a mass concentration of 0.5-2%, and the spraying amount is 10-20% of the mass of the regenerated micro powder; In the solution containing a thickening and water-retaining agent, the thickening and water-retaining agent is selected from hydroxypropyl methylcellulose (HPMC), sodium carboxymethyl cellulose (CMC), or hydroxyethyl cellulose (HEC). Preferably, the viscosity of HPMC is 40,000-200,000 mPa·s, the viscosity of CMC is 1,500-3,000 mPa·s, and the viscosity of HEC is 2,000-4,000 mPa·s.

7. The method for preparing reinforced recycled aggregate from waste sintered bricks according to claim 1, characterized in that, In step (1), the curing conditions are: drying for 2-12 hours at a temperature of 20-50℃.

8. The method for preparing reinforced recycled aggregate from waste sintered bricks according to claim 1, characterized in that, In step (2), the liquid alkali activator is selected from NaOH solution or sodium silicate solution, with a mass concentration of 5-15%, and the spraying amount is 20-35% of the total mass of the regenerated micro powder used in step (1).

9. The method for preparing reinforced recycled aggregate from waste sintered bricks according to claim 1, characterized in that, In step (2), the curing conditions are: drying for 2-12 hours at a temperature of 20-50℃.

10. A type of recycled aggregate reinforced from waste sintered bricks, characterized in that, The waste sintered brick reinforced recycled aggregate is prepared by the preparation method described in any one of claims 1-9.

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