High-performance recycled aggregate concrete and preparation process thereof

Abstract

The invention relates to high-performance recycled aggregate concrete and a preparation process thereof, and the preparation raw materials of the high-performance recycled aggregate concrete comprise the following components in parts by weight: 300-400 parts of cement, 80-150 parts of an active mineral admixture, 800-1000 parts of modified recycled coarse aggregate, 600-750 parts of natural fine aggregate, 200-230 parts of water, 10-30 parts of a polymer emulsion, 5-10 parts of a water reducing agent, 2-2.5 parts of super absorbent resin and 0.5-2 parts of polypropylene fiber, the super absorbent resin is modified by graphene oxide. The super absorbent resin is modified by the graphene oxide and then is used in the recycled aggregate concrete, so that the interface bonding strength between the cement paste and the recycled coarse aggregate is greatly improved, and the anti-permeability performance of the recycled aggregate concrete is synchronously and remarkably enhanced.

Description

Technical Field

[0001] This application relates to the field of concrete preparation technology, and in particular to a high-performance recycled aggregate concrete and its preparation process. Background Technology

[0002] Aggregates, as the largest component in concrete, directly determine its mechanical properties and durability. With the acceleration of global urbanization and the continuous upgrading of infrastructure, the construction, demolition, and renovation of new and old buildings generate massive amounts of construction waste, of which waste concrete accounts for a significant proportion. Simultaneously, concrete mixing plants also produce large quantities of substandard waste concrete blocks during the production process. Traditionally, this waste concrete is mostly transported to suburban areas for dumping or landfilling, not only occupying vast amounts of land resources and polluting the environment but also representing a huge waste of natural mineral resources and the value of original building materials. Processing waste concrete blocks through crushing, screening, and washing to prepare recycled aggregates, which can then be used to partially or completely replace natural aggregates in concrete preparation—this is known as recycled aggregate concrete—is an important way to achieve the resource utilization and reduction of construction waste.

[0003] However, during the crushing process of waste concrete, numerous microcracks develop at the interface between the original natural aggregate and the surrounding old cement mortar. Simultaneously, some old mortar remains firmly attached to the surface of the virgin aggregate, giving recycled aggregate a high porosity and low density. This high porosity directly results in extremely high water absorption, which competes for mixing water during the mixing process, affecting cement hydration and reducing the quality of the interface transition zone. The high porosity and complex crack network provide convenient pathways for the intrusion of moisture and harmful ions (such as chloride and sulfate ions), leading to poor impermeability of traditional recycled aggregate concrete and severely impacting the service life of the structure. Furthermore, recycled aggregate itself has lower strength and is more prone to crushing before natural aggregate under high stress. Therefore, the current application of recycled aggregate concrete is largely limited to non-structural or secondary structural parts such as road base courses, non-load-bearing blocks, and low-strength subbases. Its application in structural engineering requiring high strength, high performance, and high impermeability is severely restricted.

[0004] Therefore, developing a high-performance recycled aggregate concrete that can effectively overcome the inherent defects of recycled aggregates and significantly improve the mechanical properties and durability of concrete has become the key to promoting the resource utilization of construction waste towards high value-added fields and breaking through the bottlenecks in industry development. Summary of the Invention

[0005] To improve the mechanical properties and impermeability of recycled aggregate concrete, this application provides a high-performance recycled aggregate concrete and its preparation process.

[0006] In the first aspect, this application provides a high-performance recycled aggregate concrete, which adopts the following technical solution: A high-performance recycled aggregate concrete comprises the following components in parts by weight: 300-400 parts cement, 80-150 parts active mineral admixture, 800-1000 parts modified recycled coarse aggregate, 600-750 parts natural fine aggregate, 200-230 parts water, 10-30 parts polymer emulsion, 5-10 parts water-reducing agent, 2-2.5 parts superabsorbent resin, and 0.5-2 parts polypropylene fiber, wherein the superabsorbent resin is modified with graphene oxide.

[0007] The inventors discovered that modifying superabsorbent polymers (SAPs) with graphene oxide and applying them to recycled aggregate concrete significantly improves the interfacial bonding strength between cement paste and recycled coarse aggregates, and substantially enhances the concrete's impermeability. Specifically, SAPs function as an internal curing agent in concrete. When the internal moisture of the concrete begins to decrease due to hydration, SAPs effectively compensate for this loss, fundamentally reducing the formation of microcracks caused by concrete drying shrinkage and improving the concrete's later-stage strength. However, the hydrogel formed by traditional SAPs is soft and brittle, easily rupturing prematurely under the intense shear forces of concrete mixing, pumping, and vibration, leading to the premature release of stored water and the failure of its internal curing function. In contrast, SAPs modified with graphene oxide possess a layered structure and good hydrophilicity, which strengthens the internal gel network of the SAP, effectively improving the structural strength of the hydrogel formed by water absorption and reducing the risk of premature hydrogel rupture under the intense shear forces of concrete mixing, pumping, and vibration. It fundamentally inhibits the generation of microcracks in the interface zone, enhances the internal curing effect of the modified superabsorbent resin, and thus improves the mechanical strength of concrete.

[0008] Graphene oxide sheets possess extremely high specific surface area and abundant functional groups (such as carboxyl, carbonyl, epoxy, and hydroxyl groups). The surface and interlayer of cement hydration products contain a large number of calcium ions. In the alkaline environment of hydration, the carboxyl groups on graphene oxide dissociate into carboxylate ions, which form ionic bonds with calcium ions, thus anchoring the modified superabsorbent resin onto the cement hydration products. The old cement paste adhering to the surface of recycled coarse aggregate contains a large number of silanol groups. Ring-opening reactions occur between the epoxy groups of graphene oxide and the silanol groups, and condensation reactions occur between the carboxyl groups and the silanol groups, thereby strengthening the interfacial bonding strength between the cement hydration products and the recycled coarse aggregate, further enhancing the mechanical strength of the concrete. Graphene oxide-modified superabsorbent resin, through its internal curing effect, greatly reduces penetrating shrinkage microcracks, cutting off the most convenient infiltration path for water and corrosive ions. At the same time, the graphene oxide sheets dispersed in the cement paste themselves constitute a nanoscale physical barrier, forcing water and ions to migrate around these sheets in a roundabout way, greatly extending the infiltration path and significantly improving the impermeability of recycled aggregate concrete.

[0009] This application utilizes graphene oxide-modified superabsorbent resin in recycled aggregate concrete. When combined with cement and recycled coarse aggregate, it synergistically and significantly enhances the mechanical properties and impermeability of the recycled aggregate concrete.

[0010] In one specific feasible implementation, the modification and preparation steps of the above-mentioned superabsorbent resin are as follows: S1-1. Under ice bath conditions, acrylic acid is dissolved in sodium hydroxide solution, and then acrylamide, graphene oxide aqueous solution, and N,N'-methylenebisacrylamide are added to dissolve the mixture. S2-1. The mixture obtained in step S1-1 is heated to 75-85°C, and potassium persulfate is added to react and obtain the modified superabsorbent resin.

[0011] The modified superabsorbent resin prepared through the above steps has excellent properties such as high liquid absorption rate, high gel strength, and stability.

[0012] In one specific feasible implementation, the preparation steps of the above-mentioned modified recycled coarse aggregate are as follows: The recycled coarse aggregate was immersed in a silane composite slurry and kept under vacuum for 15-30 minutes, then immersed under normal pressure for 10-20 minutes, and the modified recycled coarse aggregate was obtained by post-treatment.

[0013] The modified recycled coarse aggregate prepared through the above steps, when modified using a sequential "vacuum-atmospheric pressure" impregnation process, achieves excellent deep and uniform hydrophobicity and reinforcing effects. Specifically, air is extracted from the pores and cracks inside the recycled aggregate, creating negative pressure conditions for the entry of silane slurry. This allows the slurry to penetrate into the deeper pores of the aggregate, achieving deep treatment. After restoring atmospheric pressure, atmospheric pressure propels the slurry further into the aggregate, while simultaneously ensuring sufficient modified slurry adheres to the aggregate surface. This comprehensive hydrophobicity and reinforcing effect of the modified recycled coarse aggregate significantly improves the durability and reliability of the modification results. In one specific implementation, the aforementioned silane composite slurry comprises isobutyltriethoxysilane, nano-silica sol, and water.

[0014] The inventors discovered that the combined use of isobutyltriethoxysilane and nano-silica sol can produce a dual synergistic modification effect on recycled coarse aggregate, resulting in both chemical hydrophobicity and physical reinforcement. Specifically, the silanol generated after the hydrolysis of isobutyltriethoxysilane reacts with the hydroxyl groups on the aggregate surface to form a robust siloxane hydrophobic film, significantly reducing the surface energy of the aggregate and changing it from hydrophilic to hydrophobic. The nano-silica sol contains nano-sized silica particles that effectively fill the microcracks and pores on the surface of the recycled aggregate, physically making the aggregate surface denser and stronger. The two work synergistically: the nano-silica fills the pores of the recycled coarse aggregate, providing a smoother and stronger substrate for the silane hydrophobic film; while the silane film encapsulates both the nano-silica and the recycled coarse aggregate, endowing them with excellent hydrophobicity. Ultimately, a hydrophobic and high-strength composite protective layer is formed on the aggregate surface and its shallow layer.

[0015] In one specific implementation, the aforementioned active mineral admixture includes silica fume and fly ash.

[0016] The combined use of silica fume and fly ash as active mineral admixtures results in concrete with a denser microstructure and higher later-stage strength. Silica fume, with its extremely fine particle size, primarily exerts an ultrafine aggregate filling effect and a highly active pozzolanic effect, rapidly consuming the hydration product calcium hydroxide to generate more hydrogel, significantly improving the strength and density of early-stage recycled aggregate concrete. Fly ash, with its relatively fine particle size, primarily functions as a physical filler in the early stages. Later, its active components interact with calcium hydroxide to create a secondary pozzolanic effect, continuously enhancing the later-stage strength of the concrete, optimizing the pore structure, and reducing the risk of long-term shrinkage.

[0017] The two complement each other in terms of particle size and activity. Silica fume takes effect quickly, making up for the low contribution of fly ash to early strength; while fly ash contributes to the continuous increase of long-term strength and the improvement of workability. The two work synergistically to achieve a "seamless connection" in the development of concrete strength and continuous optimization of microstructure.

[0018] In one specific feasible implementation, the mass ratio of silica fume to fly ash is 1:(1-2).

[0019] By strictly controlling the mass ratio of silica fume and fly ash within the above range, the immediate strengthening effect of silica fume and the later strengthening and lubrication effect of fly ash are optimized, ensuring that the concrete has sufficient strength in the early stage. At the same time, the spherical particle effect of fly ash can effectively improve the workability of the mixture, reduce viscosity, and is conducive to the development of long-term durability.

[0020] If the proportion of silica fume is too high, it will lead to a significant increase in the water demand of concrete, a sharp rise in viscosity, poor workability, and increased susceptibility to cracking. Excessive early reactivity may also cause concentrated heat of hydration, increasing the risk of temperature shrinkage. Simultaneously, costs will also increase significantly.

[0021] If the proportion of fly ash is too high, it means that there is relatively too little silica fume, which will slow down the early strength development of concrete and make it difficult to meet the requirements for demolding or early load. At the same time, the immediate strengthening effect on the interface zone of recycled aggregate is weakened, which is not conducive to the rapid formation of overall performance.

[0022] In one specific implementation scheme, the water-reducing agent is selected from one or more of polycarboxylate water-reducing agents, naphthalene-based water-reducing agents, and aliphatic water-reducing agents; preferably, the water-reducing agent is a polycarboxylate water-reducing agent.

[0023] By adopting the above technical solutions, polycarboxylate superplasticizers, due to their excellent dispersibility and slump retention, can be well compatible with polymer emulsions, active admixtures, etc., to jointly ensure the fluidity and stability of fresh concrete, laying the foundation for achieving high strength and high performance.

[0024] In one specific implementation, the polymer emulsion is a hydroxybutyric acid (HEPA) latex.

[0025] By adopting the above technical solution, hydroxyl-butyl styrene latex demulsifies and forms a film during cement hydration, creating an organic polymer network that penetrates the inorganic cement paste matrix. This network can bridge microcracks, dissipate fracture energy, and form a toughening system that combines macroscopic and microscopic elements with polypropylene fibers, significantly improving the toughness, crack resistance, and impact resistance of concrete.

[0026] Secondly, this application provides a preparation process for high-performance recycled aggregate concrete, employing the following technical solution: A process for preparing high-performance recycled aggregate concrete includes the following steps: S1-2. Mix cement, active mineral admixtures, modified recycled coarse aggregate, natural fine aggregate, modified superabsorbent resin and polypropylene fiber evenly to obtain premixed dry material. S2-2. Mix water, polymer emulsion and water-reducing agent evenly to form a mixed liquid; S3-2. Add the premixed dry material obtained in step S1 to the mixed liquid material obtained in step S2 and mix to obtain the high-performance recycled aggregate concrete.

[0027] The high-performance recycled aggregate concrete prepared through the above steps possesses high mechanical strength and high impermeability.

[0028] In one specific implementation, in step S3-2, a portion of the mixed liquid material prepared in step S2-2 is first added to the premixed dry material obtained in step S1-2 and stirred evenly, and then the remaining mixed liquid material prepared in step S2-2 is added and stirred evenly.

[0029] By adopting the above technical solution, the first addition of a portion of the liquid material followed by prolonged stirring ensures that all dry materials, especially the superabsorbent resin and polypropylene fibers, are initially wetted and achieve preliminary uniform distribution. This avoids localized over-wetting and clumping that might occur with adding all the liquid at once. The second addition of the remaining liquid material, followed by stirring, allows for a shorter stirring time than the first addition, thus achieving final homogenization and avoiding the introduction of excessive air bubbles through over-stirring. This stepwise stirring process achieves uniform wetting and efficient mixing of the materials from the inside out, preventing the superabsorbent resin from absorbing large amounts of water instantly and affecting overall uniformity.

[0030] In summary, this application includes at least one of the following beneficial technical effects: 1. This application improves the interfacial bonding strength between cement paste and recycled coarse aggregate by modifying superabsorbent resin with graphene oxide and then using it in recycled aggregate concrete, thereby significantly enhancing the impermeability of the concrete.

[0031] 2. This application modifies recycled coarse aggregate by using a silane composite slurry composed of isobutyltriethoxysilane, nano-silica sol and water, so that the recycled coarse aggregate can obtain excellent effects of deep and uniform hydrophobicity and reinforcement.

[0032] 3. By strictly controlling the mass ratio of silica fume and fly ash within the above-mentioned range, this application achieves the optimal ratio of the immediate strengthening effect of silica fume and the later strengthening and lubrication effect of fly ash, ensuring that the concrete has sufficient strength in the early stage. At the same time, the spherical particle effect of fly ash can effectively improve the workability of the mixture, reduce viscosity, and is conducive to the development of long-term durability. Detailed Implementation

[0033] The present application will be further described in detail below with reference to embodiments and comparative examples: Some of the raw materials used in the examples and comparative examples: Nano-silica sol (model: VK-S01B alkaline, purchased from Xuancheng Jingrui New Materials Co., Ltd.); recycled coarse aggregate is 8-10mm aggregate obtained from construction waste after crushing, screening, and grading; graphene oxide aqueous solution (item number: TF-12055, purchased from Suzhou Carbon-Feng Graphene Technology Co., Ltd.); natural fine aggregate is construction sand with a particle size of 0.25-0.5mm; polycarboxylate superplasticizer (model: PCE-11, purchased from Shandong Yousuo Chemical Technology Co., Ltd.); hydroxyl styrene-butadiene latex (brand: FSDB48, purchased from Yutai County Bili Chemical Products Sales Department); ordinary superabsorbent polymer (item number: D105, purchased from Guangzhou Yourun Chemical Co., Ltd.).

[0034] Unless otherwise specified, all raw materials used in the examples and comparative examples are commercially available products.

[0035] Preparation Example 1 The modified recycled coarse aggregate is prepared as follows: Dissolve 12.5 parts by weight of isobutyltriethoxysilane in 80 parts by weight of water, add 7.5 parts by weight of nano-silica sol and mix evenly to obtain a silane composite slurry; immerse the recycled coarse aggregate in the above silane composite slurry, maintain vacuum for 30 minutes, then restore normal pressure and soak for 15 minutes, drain on a sieve, and dry in an oven at 70°C for 1.5 hours to obtain modified recycled coarse aggregate.

[0036] Preparation Example 2 The modified preparation of superabsorbent resin is as follows: S1-1. Under ice bath conditions, 7.2 g of acrylic acid was dissolved in 15.6 mL of sodium hydroxide solution (the concentration of sodium hydroxide in water is 5 mol / L), 1.44 g of acrylamide was added and stirred until dissolved, 20 mL of graphene oxide aqueous solution (the concentration of graphene oxide in water is 0.1 wt%) was added and stirred until dissolved, and 0.01296 g of N,N'-methylenebisacrylamide was added and stirred until dissolved to obtain a mixture. S2-1. Heat the mixture obtained in step S1 to 80°C, add 0.216g of potassium persulfate solution (the concentration of potassium persulfate in water is 2.5wt%), react for 3 hours, place it in a 55°C oven to dry to constant weight, and grind to obtain modified superabsorbent resin. Example

[0037] Example 1 The preparation of high-performance recycled aggregate concrete is as follows: S1-2. 350 parts by weight of cement, 46 parts by weight of silica fume, 69 parts by weight of fly ash, 900 parts by weight of modified recycled coarse aggregate prepared in Preparation Example 1, 675 parts by weight of natural fine aggregate, 2.25 parts by weight of superabsorbent resin prepared in Preparation Example 2 and 1.25 parts by weight of polypropylene fiber are mixed evenly to obtain a premixed dry material. S2-2. Mix 215 parts by weight of water, 20 parts by weight of hydroxyl styrene-butadiene latex and 7.5 parts by weight of polycarboxylate superplasticizer evenly to form a mixed liquid. S3-2. Add part of the mixed liquid material prepared in step S2-2 to the premixed dry material obtained in step S1-2 and mix and stir evenly. Then add the remaining mixed liquid material prepared in step S2-2 and stir evenly to obtain high-performance recycled aggregate concrete.

[0038] Example 2 The only difference between Example 2 and Example 1 is that in Example 2, 46 parts by weight of silica fume and 69 parts by weight of fly ash in steps S1-2 are replaced with 60 parts by weight of silica fume and 55 parts by weight of fly ash.

[0039] Example 3 The only difference between Example 3 and Example 1 is that in Example 3, 46 parts by weight of silica fume and 69 parts by weight of fly ash in steps S1-2 are replaced with 35 parts by weight of silica fume and 80 parts by weight of fly ash.

[0040] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that in steps S1-2 of Comparative Example 1, 900 parts by weight of the modified recycled coarse aggregate prepared in Example 1 is replaced with 900 parts by weight of recycled coarse aggregate.

[0041] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that in steps S1-2 of Comparative Example 2, 2.25 parts by weight of the superabsorbent resin prepared in Example 2 is replaced with 2.25 parts by weight of ordinary superabsorbent resin.

[0042] The high-performance recycled aggregate concrete slurry prepared in Examples 1-3 and Comparative Examples 1-2 was poured into molds to form standard test blocks (150mm×150mm×150mm cubic standard specimens). After standard curing for 28 days, tests were conducted according to the following standards: 1. The compressive strength and splitting tensile strength of the standard test blocks were tested in accordance with GB / T 50081-2016 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete". The test results are recorded in Table 1.

[0043] 2. The chloride ion penetration depth and water penetration depth of the standard test blocks were tested in accordance with GB / T 50082-2009 "Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete". The test results are recorded in Table 1.

[0044] Table 1. Performance test data for each embodiment and comparative example. Test Project Compressive strength (MPa) Splitting tensile strength (MPa) Chloride ion penetration depth (mm) Seepage depth (mm) Example 1 73.2 9.61 1.2 4.1 Example 2 68.5 8.92 8.5 6.3 Example 3 63.1 8.05 14.2 9.8 Comparative Example 1 51.4 6.12 28.5 22.3 Comparative Example 2 65.8 7.98 18.9 15.6 Combining Examples 1 and 2-3, and referring to Table 1, it can be seen that the performance of Example 1 is superior to that of Examples 2-3. This is likely because the mass ratio of silica fume to fly ash (1:1.5) in Example 1 is within the optimal synergistic range. This ratio allows the early ultrafine filling and highly active pozzolanic effect of silica fume to optimally complement the later continuous hydration and microbead lubrication effect of fly ash, thus forming the densest microstructure. In Example 2, the excessively high proportion of silica fume may lead to an increase in the system's water demand and a decrease in fluidity, slightly affecting the molding density; in Example 3, the excessively high proportion of fly ash weakens the early hydration strength and the immediate strengthening effect on the interface of recycled aggregate, resulting in insufficient early structural development and a decline in macroscopic performance.

[0045] Combining Example 1 and Comparative Example 1, and referring to Table 1, it can be seen that the performance of Example 1 is superior to that of Comparative Example 1. This may be because Comparative Example 1 did not modify the recycled coarse aggregate, which is porous internally, and the old mortar adhering to its surface has low strength and strong hydrophilicity, becoming a weak point in the concrete stress and a rapid channel for water migration. In contrast, the silane / nano-SiO2 composite modified aggregate used in Example 1, on the one hand, improves the stiffness of the aggregate itself by filling surface defects with nanoparticles; on the other hand, the hydrophobic effect of silane effectively blocks the penetration of water along the aggregate-mortar interface, and synergistically strengthens the interfacial transition zone with graphene oxide, thereby fundamentally improving the integrity, strength, and impermeability of the concrete.

[0046] Combining Example 1 and Comparative Example 2, and referring to Table 1, it can be seen that the performance of Example 1 is superior to that of Comparative Example 2. This may be because the ordinary superabsorbent polymer used in Comparative Example 2 has low gel strength and poor stability in alkaline, high-calcium environments, making it prone to breakage or insufficient water absorption during stirring, resulting in the failure or incompleteness of its internal curing function and its inability to effectively suppress shrinkage microcracks. Furthermore, ordinary resins do not possess nano-reinforcement capabilities. In contrast, the graphene oxide-modified superabsorbent polymer used in Example 1 not only reliably and stably fulfills its internal curing function by leveraging the graphene oxide-reinforced grid structure, eliminating shrinkage crack sources, but its contained graphene oxide sheets also exert a nano-bridging and filling effect in the cement matrix, directly enhancing the toughness and density of the matrix.

[0047] This application improves the mechanical strength and water resistance of recycled aggregate concrete by introducing silane / nano-SiO2 composite modified recycled aggregate to strengthen the core and block permeation, combining graphene oxide modified superabsorbent resin to achieve intelligent internal curing and nano-scale toughening, and optimizing the proportion of active mineral admixtures to construct the densest matrix.

[0048] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A high-performance recycled aggregate concrete, characterized in that, The product comprises the following components in parts by weight: 300-400 parts cement, 80-150 parts active mineral admixture, 800-1000 parts modified recycled coarse aggregate, 600-750 parts natural fine aggregate, 200-230 parts water, 10-30 parts polymer emulsion, 5-10 parts water-reducing agent, 2-2.5 parts superabsorbent resin, and 0.5-2 parts polypropylene fiber, wherein the superabsorbent resin is modified with graphene oxide.

2. The high-performance recycled aggregate concrete according to claim 1, characterized in that, The modification and preparation steps of the superabsorbent resin are as follows: S1-1. Under ice bath conditions, acrylic acid is dissolved in sodium hydroxide solution, and then acrylamide, graphene oxide aqueous solution, and N,N'-methylenebisacrylamide are added to dissolve the mixture. S2-1. The mixture obtained in step S1-1 is heated to 75-85°C, and potassium persulfate is added to react and obtain the modified superabsorbent resin.

3. The high-performance recycled aggregate concrete according to claim 1, characterized in that, The preparation steps of the modified recycled coarse aggregate are as follows: The recycled coarse aggregate was immersed in a silane composite slurry and kept under vacuum for 15-30 minutes, then immersed under normal pressure for 10-20 minutes, and the modified recycled coarse aggregate was obtained by post-treatment.

4. The high-performance recycled aggregate concrete according to claim 3, characterized in that, The silane composite slurry comprises isobutyltriethoxysilane, nano-silica sol, and water.

5. The high-performance recycled aggregate concrete according to claim 1, characterized in that, The active mineral admixtures include silica fume and fly ash.

6. The high-performance recycled aggregate concrete according to claim 5, characterized in that, The mass ratio of silica fume to fly ash is 1:(1-2).

7. The high-performance recycled aggregate concrete according to claim 1, characterized in that, The water-reducing agent is selected from one or more of polycarboxylate water-reducing agents, naphthalene-based water-reducing agents, and aliphatic water-reducing agents.

8. The high-performance recycled aggregate concrete according to claim 1, characterized in that, The polymer emulsion is hydroxybutyrate latex.

9. A process for preparing high-performance recycled aggregate concrete according to any one of claims 1-8, characterized in that, Includes the following steps: S1-2. Mix cement, active mineral admixtures, modified recycled coarse aggregate, natural fine aggregate, superabsorbent resin and polypropylene fiber evenly to obtain premixed dry material. S2-2. Mix water, polymer emulsion and water-reducing agent evenly to form a mixed liquid; S3-2. Add the premixed dry material obtained in step S1 to the mixed liquid material obtained in step S2 and mix to obtain the high-performance recycled aggregate concrete.

10. The preparation process of high-performance recycled aggregate concrete according to claim 9, characterized in that, In step S3-2, a portion of the mixed liquid material prepared in step S2-2 is first added to the premixed dry material obtained in step S1-2 and stirred evenly. Then, the remaining mixed liquid material prepared in step S2-2 is added and stirred evenly.