A method for preparing concrete based on construction waste

Abstract

This invention discloses a method for preparing concrete based on construction waste, specifically relating to the field of building materials technology. The concrete based on construction waste is prepared from recycled aggregate, sulfoaluminate cement, zeolite carrier internal curing agent, and saturated steam containing zwitterionic resin. The components and weight proportions of the raw materials for preparing the concrete based on construction waste are as follows: 100 parts recycled aggregate, 30-50 parts sulfoaluminate cement, 2-7 parts zeolite carrier internal curing agent, and 0.8-3 parts saturated steam containing zwitterionic resin. This invention achieves its goals by using an ethanol solution of composite cation exchange resin to purify harmful ions in the aggregate, an activating liquid to stimulate surface activity and promote gel formation, and a composite liquid containing polyvinyl alcohol and anion exchange resin to form a dense coating film to block erosion, enhance the interface's resistance to degradation, improve durability, and solve the problem of susceptibility to erosion.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and more specifically, to a method for preparing concrete based on construction waste. Background Technology

[0002] Concrete, as the most widely used man-made composite material in modern construction engineering, has seen its production and consumption become important indicators for measuring the scale of national infrastructure construction. Concrete is widely used in housing construction, bridge and tunnel construction, and road engineering, playing an irreplaceable role in ensuring urban and rural construction and promoting economic development. Therefore, developing a method for preparing recycled concrete is of great significance for improving utilization and enhancing concrete performance.

[0003] Recycled concrete in related technologies includes recycled coarse aggregate, cementitious materials, natural aggregate, water, and admixtures. Recycled coarse aggregate is used to replace natural sand and gravel, providing structural support for the concrete and reducing costs. Cement, as the core cementitious material, forms a hardened structural skeleton through hydration, determining the strength and durability of the concrete. Natural aggregate is used to compensate for the gradation defects of recycled aggregate and improve density. Mixing water participates in cement hydration and adjusts workability. Admixtures such as water-reducing agents are used to improve the fluidity of concrete and reduce water consumption.

[0004] However, it still has some drawbacks in practical use, such as poor durability. In traditional recycled concrete, the waste mortar attached to the surface of old aggregate does not bond well with the new cement paste, forming a porous and fragile interface that is easily penetrated by moisture and corrosive media, accelerating internal damage. It also has low strength. The surface of recycled aggregate is rough but covered with dust, and traditional processes cannot activate its surface, resulting in poor mechanical bonding and chemical adhesion with the new cement paste. After crushing, the recycled aggregate has many sharp edges and a lot of fine powder. Traditional proportions are not specifically optimized, resulting in poor packing density and weak areas after hardening. Furthermore, it has low utilization rate. Traditional processes are sensitive to chemical contaminants in aggregates, and in order to maintain performance, the dosage is forced to be reduced, limiting the waste substitution rate. Summary of the Invention

[0005] To improve the above-mentioned problems and reduce the issues of poor durability, low strength, and low utilization rate of recycled concrete in related technologies, this invention provides a concrete preparation method based on construction waste to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for preparing concrete based on construction waste includes the following steps:

[0008] A1. Add recycled aggregate, sulfoaluminate cement, and zeolite carrier internal curing agent into a planetary mixer and mix for 5-8 minutes at a revolution speed of 20-25 r / min and a rotation speed of 40-50 r / min. After pouring, cure for 24-48 hours at a temperature of 20-25℃ and a humidity of ≥95% to obtain demolded specimens.

[0009] A2. Place the demolded specimen into a steam curing kettle and heat it to 60°C at a heating rate of 10°C / h. During the constant temperature stage, inject saturated steam containing zwitterionic exchange resin and cure it for 6-8 hours at a pressure of 0.2-0.3MPa and a humidity of 100%. Finally, cool the temperature to room temperature at a cooling rate of less than 20°C / h to obtain concrete based on construction waste.

[0010] The preparation method of recycled aggregate includes the following steps:

[0011] C1. Place the crushed construction waste into a jaw crusher and crush it to a particle size of less than 50mm under a pressure of 15-20MPa. Then transfer it to a high-pressure cleaning tank and wash it for 10-15 minutes under a water pressure of 25-30MPa and a temperature of 40-50℃. After draining, place it in a vibrating screen and classify it under a vibration amplitude of 3-5mm and a frequency of 25Hz to obtain recycled aggregate.

[0012] C2. The recycled aggregate obtained in C1 is immersed in an ethanol solution of composite cation exchange resin and stirred for 30-45 minutes at a speed of 100-150 r / min and a temperature of 60-70℃ to obtain the stirred product. Then, it is placed on a 100-mesh polyester filter cloth filter device and filtered for 5 minutes under a vacuum of 0.07 MPa. After rinsing with deionized water at a flow rate of 2 L / min three times, the purified aggregate is obtained.

[0013] C3. Place the purified aggregate obtained in C2 in a microwave reactor, spray with activation liquid, and irradiate for 5-8 minutes at a microwave frequency of 2.45-2.50 GHz and a power of 8-10 kW. Control the aggregate temperature to rise to 75°C, discharge the residual liquid, and then blow the surface with compressed air at a pressure of 0.4 MPa to obtain activated aggregate.

[0014] C4. Transfer the activated aggregate obtained in C3 to a high-speed mixer. At a speed of 400-600 r / min, add the composite liquid containing polyvinyl alcohol and anion exchange resin through an atomizing nozzle at a dropping rate of 4 drops / s. After the dropping is completed, continue stirring at a temperature of 80-90℃ for 40-60 min to form recycled aggregate.

[0015] Preferably, the raw materials for preparing the concrete based on construction waste and their weight proportions are as follows: 100 parts recycled aggregate, 30-50 parts sulfoaluminate cement, 2-7 parts zeolite carrier internal curing agent, and 0.8-3 parts saturated vapor containing zwitterionic exchange resin.

[0016] Preferably, the raw materials for preparing the recycled aggregate and their weight proportions are as follows: 100 parts of construction waste, 10-20 parts of ethanol solution of composite cation exchange resin, 8-15 parts of activation liquid, and 4-8 parts of composite liquid containing polyvinyl alcohol and anion exchange resin.

[0017] Preferably, the ethanol solution of the composite cation exchange resin is composed of sulfonic acid cation exchange resin, carboxyl cation exchange resin, ethanol, disodium ethylenediaminetetraacetate, and alkylphenol polyoxyethylene ether in a weight ratio of 3.75-6:1.25-2:86-92:0.5-1.5:2.5-4.5.

[0018] Preferably, the activation solution is composed of nano-silica sol, sodium silicate, water, polycarboxylic acid ether dispersant, and zinc borate in a weight ratio of 10-15:3:77-82:3.5-4.5:0.5-1.5.

[0019] Preferably, the composite liquid containing polyvinyl alcohol and anion exchange resin is composed of polyvinyl alcohol, quaternary ammonium salt anion exchange resin, water, glycerol, and nano titanium dioxide in a weight ratio of 1.5-3:1-3.5:88.5-90:4-4.5:1.5-3.

[0020] Preferably, the sulfoaluminate cement is composed of limestone, bauxite, gypsum, iron powder, and fly ash in a weight ratio of 42:26:17:5:8.

[0021] Preferably, the curing agent in the zeolite carrier is composed of clinoptilolite, nano-silica sol, polyacrylamide, lithium carbonate, and water in a weight ratio of 70:15:5:2:8.

[0022] Preferably, the saturated vapor of the zwitterionic exchange resin is composed of sulfonic acid-quaternary ammonium salt copolymer, ethylene glycol, graphene oxide, 25% ammonia, and water in a weight ratio of 1.5:15:0.1:0.5:82.9.

[0023] 1. This invention removes harmful ions from aggregates through deep purification with composite cation exchange resin and plasma interfacial bonding purification, enhances surface activity with activation liquid, and blocks erosion channels with coating film, thereby improving the stability and resistance to degradation of the aggregate-cement interface. The ethanol solution of composite cation exchange resin permeates and purifies harmful ions from aggregates, the activation liquid stimulates surface activity and promotes gel formation, and the composite liquid containing polyvinyl alcohol and anion exchange resin forms a dense coating film to block erosion, thereby enhancing the interface's resistance to degradation, improving durability, and solving the problem of susceptibility to erosion.

[0024] 2. This invention achieves rapid bonding of sulfoaluminate cement, gel formation by activating liquid to strengthen interfacial bonding, and improved aggregate adhesion by coating layer, thereby synergistically enhancing structural load-bearing capacity and significantly increasing strength, thus solving the problem of low strength in traditional recycled concrete.

[0025] 3. This invention improves the performance of construction waste aggregates through full-process pretreatment and, combined with the utilization of solid waste such as zeolite, increases the overall utilization rate of construction waste, thus solving the problem of limited utilization rate of traditional recycled concrete. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to the embodiments of the present invention. Unless otherwise specified below, the raw materials used in the various examples and embodiments of the present invention are all commercially available common materials.

[0027] Preparation Examples 1-5

[0028] A recycled aggregate, the components and their corresponding proportions of which are shown in the table below, is prepared using the following method:

[0029] C1. The crushed construction waste is placed in a jaw crusher and crushed to a particle size of less than 50 mm under a pressure of 15 MPa. Then, it is transferred to a high-pressure cleaning tank and washed for 10 minutes under a water pressure of 25 MPa and a temperature of 40℃. After draining, it is placed in a vibrating screen and graded under a vibration amplitude of 3 mm and a frequency of 20 Hz to obtain recycled aggregate.

[0030] C2. The recycled aggregate obtained in C1 is immersed in an ethanol solution of composite cation exchange resin and stirred for 30 minutes at a speed of 100 r / min and a temperature of 60℃ to obtain the stirred product. Then, it is placed on a 100-mesh polyester filter cloth filter device and filtered for 5 minutes under a vacuum of 0.07 MPa. After that, it is rinsed 3 times with deionized water at a flow rate of 2 L / min to obtain purified aggregate.

[0031] The ethanol solution of the composite cation exchange resin is composed of sulfonic acid cation exchange resin, carboxyl cation exchange resin, ethanol, disodium ethylenediaminetetraacetate, and alkylphenol polyoxyethylene ether in a weight ratio of 3.75:1.25:92:0.5:2.5.

[0032] C3. Place the purified aggregate obtained in C2 in a microwave reactor, spray with activation liquid, irradiate for 5 minutes at a microwave frequency of 2.45 GHz and a power of 8 kW, control the aggregate temperature to rise to 75 ℃, discharge the residual liquid, and then blow the surface with compressed air at a pressure of 0.4 MPa to obtain activated aggregate.

[0033] The activation solution is composed of nano silica sol, sodium silicate, water, polycarboxylic acid ether dispersant, and zinc borate in a weight ratio of 10:3:82:3.5:1.5.

[0034] C4. The activated aggregate obtained in C3 is transferred to a high-speed mixer. At a speed of 400 r / min, the composite liquid containing polyvinyl alcohol and anion exchange resin is added through an atomizing nozzle at a dropping rate of 4 drops / s. After the dropping is completed, the mixture is stirred for 40 min at a temperature of 80℃ to form recycled aggregate.

[0035] The composite solution containing polyvinyl alcohol and anion exchange resin is composed of polyvinyl alcohol, quaternary ammonium salt anion exchange resin, water, glycerol, and nano titanium dioxide in a weight ratio of 3:1:90:4.5:1.5.

[0036] Table: Components and their mass ratios (kg) of the raw materials used in Preparation Examples 1-5

[0037]

[0038] Preparation Example 6

[0039] A recycled aggregate, differing from preparation example 1, is prepared using the following method:

[0040] C1. The crushed construction waste is placed in a jaw crusher and crushed to a particle size of less than 50 mm under a pressure of 18 MPa. Then, it is transferred to a high-pressure cleaning tank and washed for 12.5 min under a water pressure of 27 MPa and a temperature of 45℃. After draining, it is placed in a vibrating screen and graded under a vibration amplitude of 4 mm and a frequency of 22 Hz to obtain recycled aggregate.

[0041] C2. The recycled aggregate obtained in C1 is immersed in an ethanol solution of composite cation exchange resin and stirred for 30 minutes at a speed of 100 r / min and a temperature of 60℃ to obtain the stirred product. Then, it is placed on a 100-mesh polyester filter cloth filter device and filtered for 5 minutes under a vacuum of 0.07 MPa. After that, it is rinsed 3 times with deionized water at a flow rate of 2 L / min to obtain purified aggregate.

[0042] C3. Place the purified aggregate obtained in C2 in a microwave reactor, spray with activation liquid, irradiate for 5 minutes at a microwave frequency of 2.45 GHz and a power of 8 kW, control the aggregate temperature to rise to 75 ℃, discharge the residual liquid, and then blow the surface with compressed air at a pressure of 0.4 MPa to obtain activated aggregate.

[0043] C4. The activated aggregate obtained in C3 is transferred to a high-speed mixer. At a speed of 400 r / min, the composite liquid containing polyvinyl alcohol and anion exchange resin is added through an atomizing nozzle at a dropping rate of 4 drops / s. After the dropping is completed, the mixture is stirred for 40 min at a temperature of 80℃ to form recycled aggregate.

[0044] Preparation Example 7

[0045] A recycled aggregate, differing from preparation example 1, is prepared using the following method:

[0046] C1. The crushed construction waste is placed in a jaw crusher and crushed to a particle size of less than 50 mm under a pressure of 20 MPa. Then, it is transferred to a high-pressure cleaning tank and washed for 15 minutes under a water pressure of 30 MPa and a temperature of 50℃. After draining, it is placed in a vibrating screen and graded under a vibration amplitude of 5 mm and a frequency of 25 Hz to obtain recycled aggregate.

[0047] C2. The recycled aggregate obtained in C1 is immersed in an ethanol solution of composite cation exchange resin and stirred for 30 minutes at a speed of 100 r / min and a temperature of 60℃ to obtain the stirred product. Then, it is placed on a 100-mesh polyester filter cloth filter device and filtered for 5 minutes under a vacuum of 0.07 MPa. After that, it is rinsed 3 times with deionized water at a flow rate of 2 L / min to obtain purified aggregate.

[0048] C3. Place the purified aggregate obtained in C2 in a microwave reactor, spray with activation liquid, irradiate for 5 minutes at a microwave frequency of 2.45 GHz and a power of 8 kW, control the aggregate temperature to rise to 75 ℃, discharge the residual liquid, and then blow the surface with compressed air at a pressure of 0.4 MPa to obtain activated aggregate.

[0049] C4. The activated aggregate obtained in C3 is transferred to a high-speed mixer. At a speed of 400 r / min, the composite liquid containing polyvinyl alcohol and anion exchange resin is added through an atomizing nozzle at a dropping rate of 4 drops / s. After the dropping is completed, the mixture is stirred for 40 min at a temperature of 80℃ to form recycled aggregate.

[0050] Preparation Example 8

[0051] A recycled aggregate, differing from preparation example 1, is prepared using the following method:

[0052] C1. The crushed construction waste is placed in a jaw crusher and crushed to a particle size of less than 50 mm under a pressure of 15 MPa. Then, it is transferred to a high-pressure cleaning tank and washed for 10 minutes under a water pressure of 25 MPa and a temperature of 40℃. After draining, it is placed in a vibrating screen and graded under a vibration amplitude of 3 mm and a frequency of 20 Hz to obtain recycled aggregate.

[0053] C2. The recycled aggregate obtained in C1 is immersed in an ethanol solution of composite cation exchange resin and stirred for 40 minutes at a speed of 125 r / min and a temperature of 65℃ to obtain the stirred product. Then, it is placed on a 100-mesh polyester filter cloth filter device and filtered for 5 minutes under a vacuum of 0.07 MPa. After rinsing with deionized water at a flow rate of 2 L / min three times, the purified aggregate is obtained.

[0054] C3. Place the purified aggregate obtained in C2 in a microwave reactor, spray with activation liquid, irradiate for 5 minutes at a microwave frequency of 2.45 GHz and a power of 8 kW, control the aggregate temperature to rise to 75 ℃, discharge the residual liquid, and then blow the surface with compressed air at a pressure of 0.4 MPa to obtain activated aggregate.

[0055] C4. The activated aggregate obtained in C3 is transferred to a high-speed mixer. At a speed of 400 r / min, the composite liquid containing polyvinyl alcohol and anion exchange resin is added through an atomizing nozzle at a dropping rate of 4 drops / s. After the dropping is completed, the mixture is stirred for 40 min at a temperature of 80℃ to form recycled aggregate.

[0056] Preparation Example 9

[0057] A recycled aggregate, differing from preparation example 1, is prepared using the following method:

[0058] C1. The crushed construction waste is placed in a jaw crusher and crushed to a particle size of less than 50 mm under a pressure of 15 MPa. Then, it is transferred to a high-pressure cleaning tank and washed for 10 minutes under a water pressure of 25 MPa and a temperature of 40℃. After draining, it is placed in a vibrating screen and graded under a vibration amplitude of 3 mm and a frequency of 20 Hz to obtain recycled aggregate.

[0059] C2. The recycled aggregate obtained in C1 is immersed in an ethanol solution of composite cation exchange resin and stirred for 45 minutes at a speed of 150 r / min and a temperature of 70℃ to obtain the stirred product. Then, it is placed on a 100-mesh polyester filter cloth filter device and filtered for 5 minutes under a vacuum of 0.07 MPa. After that, it is rinsed three times with deionized water at a flow rate of 2 L / min to obtain purified aggregate.

[0060] C3. Place the purified aggregate obtained in C2 in a microwave reactor, spray with activation liquid, irradiate for 5 minutes at a microwave frequency of 2.45 GHz and a power of 8 kW, control the aggregate temperature to rise to 75 ℃, discharge the residual liquid, and then blow the surface with compressed air at a pressure of 0.4 MPa to obtain activated aggregate.

[0061] C4. The activated aggregate obtained in C3 is transferred to a high-speed mixer. At a speed of 400 r / min, the composite liquid containing polyvinyl alcohol and anion exchange resin is added through an atomizing nozzle at a dropping rate of 4 drops / s. After the dropping is completed, the mixture is stirred for 40 min at a temperature of 80℃ to form recycled aggregate.

[0062] Preparation Example 10

[0063] A recycled aggregate, differing from preparation example 1, is prepared using the following method:

[0064] C1. The crushed construction waste is placed in a jaw crusher and crushed to a particle size of less than 50 mm under a pressure of 15 MPa. Then, it is transferred to a high-pressure cleaning tank and washed for 10 minutes under a water pressure of 25 MPa and a temperature of 40℃. After draining, it is placed in a vibrating screen and graded under a vibration amplitude of 3 mm and a frequency of 20 Hz to obtain recycled aggregate.

[0065] C2. The recycled aggregate obtained in C1 is immersed in an ethanol solution of composite cation exchange resin and stirred for 30 minutes at a speed of 100 r / min and a temperature of 60℃ to obtain the stirred product. Then, it is placed on a 100-mesh polyester filter cloth filter device and filtered for 5 minutes under a vacuum of 0.07 MPa. After that, it is rinsed 3 times with deionized water at a flow rate of 2 L / min to obtain purified aggregate.

[0066] C3. Place the purified aggregate obtained in C2 in a microwave reactor, spray with activation liquid, irradiate for 7 minutes at a microwave frequency of 2.47 GHz and a power of 9 kW, control the aggregate temperature to rise to 75 ℃, discharge the residual liquid, and then blow the surface with compressed air at a pressure of 0.4 MPa to obtain activated aggregate.

[0067] C4. The activated aggregate obtained in C3 is transferred to a high-speed mixer. At a speed of 400 r / min, the composite liquid containing polyvinyl alcohol and anion exchange resin is added through an atomizing nozzle at a dropping rate of 4 drops / s. After the dropping is completed, the mixture is stirred for 40 min at a temperature of 80℃ to form recycled aggregate.

[0068] Preparation Example 11

[0069] A recycled aggregate, differing from preparation example 1, is prepared using the following method:

[0070] C1. The crushed construction waste is placed in a jaw crusher and crushed to a particle size of less than 50 mm under a pressure of 15 MPa. Then, it is transferred to a high-pressure cleaning tank and washed for 10 minutes under a water pressure of 25 MPa and a temperature of 40℃. After draining, it is placed in a vibrating screen and graded under a vibration amplitude of 3 mm and a frequency of 20 Hz to obtain recycled aggregate.

[0071] C2. The recycled aggregate obtained in C1 is immersed in an ethanol solution of composite cation exchange resin and stirred for 30 minutes at a speed of 100 r / min and a temperature of 60℃ to obtain the stirred product. Then, it is placed on a 100-mesh polyester filter cloth filter device and filtered for 5 minutes under a vacuum of 0.07 MPa. After that, it is rinsed 3 times with deionized water at a flow rate of 2 L / min to obtain purified aggregate.

[0072] C3. Place the purified aggregate obtained in C2 in a microwave reactor, spray with activation liquid, irradiate for 8 minutes at a microwave frequency of 2.50 GHz and a power of 10 kW, control the aggregate temperature to rise to 75 ℃, discharge the residual liquid, and then blow the surface with compressed air at a pressure of 0.4 MPa to obtain activated aggregate.

[0073] C4. The activated aggregate obtained in C3 is transferred to a high-speed mixer. At a speed of 400 r / min, the composite liquid containing polyvinyl alcohol and anion exchange resin is added through an atomizing nozzle at a dropping rate of 4 drops / s. After the dropping is completed, the mixture is stirred for 40 min at a temperature of 80℃ to form recycled aggregate.

[0074] Preparation Example 12

[0075] A recycled aggregate, differing from preparation example 1, is prepared using the following method:

[0076] C1. The crushed construction waste is placed in a jaw crusher and crushed to a particle size of less than 50 mm under a pressure of 15 MPa. Then, it is transferred to a high-pressure cleaning tank and washed for 10 minutes under a water pressure of 25 MPa and a temperature of 40℃. After draining, it is placed in a vibrating screen and graded under a vibration amplitude of 3 mm and a frequency of 20 Hz to obtain recycled aggregate.

[0077] C2. The recycled aggregate obtained in C1 is immersed in an ethanol solution of composite cation exchange resin and stirred for 30 minutes at a speed of 100 r / min and a temperature of 60℃ to obtain the stirred product. Then, it is placed on a 100-mesh polyester filter cloth filter device and filtered for 5 minutes under a vacuum of 0.07 MPa. After that, it is rinsed 3 times with deionized water at a flow rate of 2 L / min to obtain purified aggregate.

[0078] C3. Place the purified aggregate obtained in C2 in a microwave reactor, spray with activation liquid, irradiate for 8 minutes at a microwave frequency of 2.50 GHz and a power of 10 kW, control the aggregate temperature to rise to 75 ℃, discharge the residual liquid, and then blow the surface with compressed air at a pressure of 0.4 MPa to obtain activated aggregate.

[0079] C4. The activated aggregate obtained in C3 is transferred to a high-speed mixer. At a speed of 500 r / min, the composite liquid containing polyvinyl alcohol and anion exchange resin is added through an atomizing nozzle at a dropping rate of 4 drops / s. After the dropping is completed, the mixture is stirred for 50 min at a temperature of 85℃ to form recycled aggregate.

[0080] Preparation Example 13

[0081] A recycled aggregate, differing from preparation example 1, is prepared using the following method:

[0082] C1. The crushed construction waste is placed in a jaw crusher and crushed to a particle size of less than 50 mm under a pressure of 15 MPa. Then, it is transferred to a high-pressure cleaning tank and washed for 10 minutes under a water pressure of 25 MPa and a temperature of 40℃. After draining, it is placed in a vibrating screen and graded under a vibration amplitude of 3 mm and a frequency of 20 Hz to obtain recycled aggregate.

[0083] C2. The recycled aggregate obtained in C1 is immersed in an ethanol solution of composite cation exchange resin and stirred for 30 minutes at a speed of 100 r / min and a temperature of 60℃ to obtain the stirred product. Then, it is placed on a 100-mesh polyester filter cloth filter device and filtered for 5 minutes under a vacuum of 0.07 MPa. After that, it is rinsed 3 times with deionized water at a flow rate of 2 L / min to obtain purified aggregate.

[0084] C3. Place the purified aggregate obtained in C2 in a microwave reactor, spray with activation liquid, irradiate for 8 minutes at a microwave frequency of 2.50 GHz and a power of 10 kW, control the aggregate temperature to rise to 75 ℃, discharge the residual liquid, and then blow the surface with compressed air at a pressure of 0.4 MPa to obtain activated aggregate.

[0085] C4. Transfer the activated aggregate obtained in C3 to a high-speed mixer. At a speed of 600 r / min, add the composite liquid containing polyvinyl alcohol and anion exchange resin through an atomizing nozzle at a dropping rate of 4 drops / s. After the dropping is completed, continue stirring at a temperature of 90℃ for 60 min to form recycled aggregate.

[0086] Preparation Example 14

[0087] A type of recycled aggregate differs from Preparation Example 1 in that the ethanol solution of the composite cation exchange resin is composed of sulfonic acid cation exchange resin, carboxyl cation exchange resin, ethanol, disodium ethylenediaminetetraacetate, and alkylphenol polyoxyethylene ether in a weight ratio of 4.9:1.6:90:1:3.

[0088] Preparation Example 15

[0089] A type of recycled aggregate differs from Preparation Example 1 in that the ethanol solution of the composite cation exchange resin is composed of sulfonic acid cation exchange resin, carboxyl cation exchange resin, ethanol, disodium ethylenediaminetetraacetate, and alkylphenol polyoxyethylene ether in a weight ratio of 6:2:86:1.5:4.5.

[0090] Preparation Example 16

[0091] A type of recycled aggregate, which differs from Preparation Example 1, is provided in that the activation solution is composed of nano-silica sol, sodium silicate, water, polycarboxylic acid ether dispersant, and zinc borate in a weight ratio of 12.5:3:79.5:4:1.

[0092] Preparation Example 17

[0093] A type of recycled aggregate, which differs from Preparation Example 1 in that the activation solution is composed of nano-silica sol, sodium silicate, water, polycarboxylic acid ether dispersant, and zinc borate in a weight ratio of 15:3:77:4.5:0.5.

[0094] Preparation Example 18

[0095] A type of recycled aggregate differs from Preparation Example 1 in that the composite liquid containing polyvinyl alcohol and anion exchange resin is composed of polyvinyl alcohol, quaternary ammonium salt anion exchange resin, water, glycerol, and nano titanium dioxide in a weight ratio of 2.5:2.5:89:4:2.

[0096] Preparation Example 19

[0097] A type of recycled aggregate differs from Preparation Example 1 in that the composite liquid containing polyvinyl alcohol and anion exchange resin is composed of polyvinyl alcohol, quaternary ammonium salt anion exchange resin, water, glycerol, and nano titanium dioxide in a weight ratio of 1.5:3.5:88.5:4.5:3.

[0098] Preparation Examples 20-24

[0099] A type of concrete based on construction waste, the components and their corresponding proportions of which are shown in the table below, is prepared using the following method:

[0100] A1. Add recycled aggregate, sulfoaluminate cement, and zeolite carrier internal curing agent into a planetary mixer and mix for 5 minutes at a revolution speed of 20 r / min and a rotation speed of 40 r / min. After pouring, cure for 24 hours at a temperature of 20℃ and a humidity of ≥95% to obtain demolded specimens.

[0101] The recycled aggregate was prepared in Preparation Example 1;

[0102] Sulfoaluminate cement is composed of limestone, bauxite, gypsum, iron powder, and fly ash in a weight ratio of 42:26:17:5:8.

[0103] The zeolite carrier internal curing agent is composed of clinoptilolite, nano silica sol, polyacrylamide, lithium carbonate, and water in a weight ratio of 70:15:5:2:8.

[0104] A2. Place the demolded specimen into a steam curing autoclave and heat it to 60°C at a heating rate of 10°C / h. During the constant temperature stage, inject saturated steam containing zwitterionic exchange resin and cure it for 6 hours at a pressure of 0.2 MPa and a humidity of 100%. Finally, cool the temperature to room temperature at a cooling rate of less than 20°C / h to obtain concrete based on construction waste.

[0105] The saturated vapor of the zwitterionic exchange resin is composed of sulfonic acid-quaternary ammonium salt copolymer, ethylene glycol, graphene oxide, 25% ammonia, and water in a weight ratio of 1.5:15:0.1:0.5:82.9.

[0106] Table: Components and their mass ratios (kg) of the raw materials used in Preparation Examples 20-24

[0107]

[0108] Preparation Example 25

[0109] A type of concrete based on construction waste, which differs from preparation example 20 in that its preparation method is as follows:

[0110] A1. Add recycled aggregate, sulfoaluminate cement, and zeolite carrier internal curing agent into a planetary mixer and mix for 6 minutes at a revolution speed of 22 r / min and a rotation speed of 45 r / min. After pouring, cure for 36 hours at a temperature of 22℃ and a humidity of ≥95% to obtain demolded specimens.

[0111] A2. Place the demolded specimen into a steam curing autoclave and heat it to 60°C at a heating rate of 10°C / h. During the constant temperature stage, inject saturated steam containing zwitterionic exchange resin and cure it for 6 hours at a pressure of 0.2 MPa and a humidity of 100%. Finally, cool the temperature to room temperature at a cooling rate of less than 20°C / h to obtain concrete based on construction waste.

[0112] Preparation Example 26

[0113] A type of concrete based on construction waste, which differs from preparation example 20 in that its preparation method is as follows:

[0114] A1. Add recycled aggregate, sulfoaluminate cement, and zeolite carrier internal curing agent into a planetary mixer and mix for 8 minutes at a revolution speed of 25 r / min and a rotation speed of 50 r / min. After pouring, cure for 48 hours at a temperature of 25℃ and a humidity of ≥95% to obtain demolded specimens.

[0115] A2. Place the demolded specimen into a steam curing autoclave and heat it to 60°C at a heating rate of 10°C / h. During the constant temperature stage, inject saturated steam containing zwitterionic exchange resin and cure it for 6 hours at a pressure of 0.2 MPa and a humidity of 100%. Finally, cool the temperature to room temperature at a cooling rate of less than 20°C / h to obtain concrete based on construction waste.

[0116] Preparation Example 27

[0117] A type of concrete based on construction waste, which differs from preparation example 20 in that its preparation method is as follows:

[0118] A1. Add recycled aggregate, sulfoaluminate cement, and zeolite carrier internal curing agent into a planetary mixer and mix for 5 minutes at a revolution speed of 20 r / min and a rotation speed of 40 r / min. After pouring, cure for 24 hours at a temperature of 20℃ and a humidity of ≥95% to obtain demolded specimens.

[0119] A2. Place the demolded specimen into a steam curing autoclave and heat it to 60°C at a heating rate of 10°C / h. During the constant temperature stage, inject saturated steam containing zwitterionic exchange resin and cure it for 7 hours at a pressure of 0.25 MPa and a humidity of 100%. Finally, cool the temperature to room temperature at a cooling rate of less than 20°C / h to obtain concrete based on construction waste.

[0120] Preparation Example 28

[0121] A type of concrete based on construction waste, which differs from preparation example 20 in that its preparation method is as follows:

[0122] A1. Add recycled aggregate, sulfoaluminate cement, and zeolite carrier internal curing agent into a planetary mixer and mix for 5 minutes at a revolution speed of 20 r / min and a rotation speed of 40 r / min. After pouring, cure for 24 hours at a temperature of 20℃ and a humidity of ≥95% to obtain demolded specimens.

[0123] A2. Place the demolded specimen into a steam curing autoclave and heat it to 60°C at a heating rate of 10°C / h. During the constant temperature stage, inject saturated steam containing zwitterionic exchange resin and cure it for 8 hours at a pressure of 0.3MPa and a humidity of 100%. Finally, cool the temperature to room temperature at a cooling rate of less than 20°C / h to obtain concrete based on construction waste.

[0124] Preparation Examples 29-46

[0125] A type of concrete based on construction waste differs from preparation example 20 in that the use of recycled aggregates in its components is different, as shown in the table below.

[0126] Table: Comparison of Recycled Aggregate Usage in Preparation Examples 29-46

[0127] Group Recycled aggregate Preparation Example 29 Prepared from Preparation Example 2 Preparation Example 30 Prepared from Preparation Example 3 Preparation Example 31 Prepared from Preparation Example 4 Preparation Example 32 Prepared from Preparation Example 5 Preparation Example 33 Prepared from Preparation Example 6 Preparation Example 34 Prepared from Preparation Example 7 Preparation Example 35 Prepared from Preparation Example 8 Preparation Example 36 Prepared from Preparation Example 9 Preparation Example 37 Prepared from Preparation Example 10 Preparation Example 38 Prepared from Preparation Example 11 Preparation Example 39 Prepared from Preparation Example 12 Preparation Example 40 Prepared from Preparation Example 13 Preparation Example 41 Prepared from Preparation Example 14 Preparation Example 42 Prepared from Preparation Example 15 Preparation Example 43 Prepared from Preparation Example 16 Preparation Example 44 Prepared from Preparation Example 17 Preparation Example 45 Prepared from Preparation Example 18 Preparation Example 46 Prepared from Preparation Example 19

[0128] Performance testing

[0129] The concrete samples prepared from construction waste in each embodiment were selected for testing. The test subjects were 270 concrete samples from construction waste, with 10 samples in each group. Their durability, strength, and utilization rate were tested. The specific testing steps are as follows:

[0130] Durability:

[0131] First, samples were taken from the construction waste-based concrete prepared in the examples and tested using a stepwise pressure method. Φ150mm×150mm cylindrical specimens were prepared and cured under standard conditions for 28 days. Then, they were placed in a permeability tester. Starting from 0.1MPa, the water pressure was increased by 0.1MPa every 8 hours until water seepage was observed at 3 end faces out of 6 specimens. The water pressure value at this point was recorded to characterize the durability of the construction waste-based concrete. The test results and evaluation criteria are as follows:

[0132] Impermeability grade ≥ P10 (considered as high durability);

[0133] P8≤permeability grade<P10 (considered as average durability);

[0134] Impermeability grade < P8 (considered as poor durability).

[0135] strength:

[0136] First, samples of the construction waste-based concrete prepared in the examples were taken and 150mm×150mm×150mm cubic specimens were made. These specimens were tested at 28 days of age. A compression testing machine was used to apply a load at a rate of 0.5MPa / s, and the maximum load at specimen failure was recorded to characterize the strength of the construction waste-based concrete. The test results and evaluation criteria are as follows:

[0137] Compressive strength ≥ 45 MPa (considered high strength);

[0138] 30MPa ≤ Strength < 45MPa (considered as a general defect rate);

[0139] Compressive strength <30MPa (considered low strength).

[0140] Utilization rate:

[0141] First, samples were taken from the construction waste-derived concrete prepared in the examples. The total mass of all construction waste-derived components in the concrete was counted, divided by the total mass of the concrete, and the mass percentage was calculated. This was used to characterize the utilization rate of the construction waste-derived concrete. The test results and evaluation criteria are as follows:

[0142] Waste content ≥70% (considered high utilization rate);

[0143] Waste content <70% (considered low utilization rate).

[0144] It should be specifically noted that the above-mentioned concrete based on construction waste is produced in accordance with normal production methods. Any defective concrete based on construction waste produced will be discarded.

[0145] Examples 1-5

[0146] The table below shows the corresponding relationships between the preparation methods used for a type of concrete based on construction waste.

[0147] Table: Comparison of Concrete Usage Based on Construction Waste in Examples 1-5

[0148] Group Concrete based on construction waste Example 1 Prepared from Preparation Example 20 Example 2 Prepared from Preparation Example 21 Example 3 Prepared from Preparation Example 22 Example 4 Prepared from Preparation Example 23 Example 5 Prepared from Preparation Example 24

[0149] The concrete based on construction waste in Examples 1-5 above was extracted and its impermeability grade, compressive strength and waste content were tested according to the above measurement steps and standards. The average value of the test results was recorded in the table below.

[0150] Table: Performance test results of impermeability grade, compressive strength and utilization rate in Examples 1-5

[0151]

[0152] As can be seen from the table above, the concrete preparation processes based on construction waste in Examples 1-5 all effectively improve the production efficiency of concrete based on construction waste. Construction waste, as a core aggregate source, is transformed into functional aggregates after crushing and screening, resulting in a significant proportion in the concrete and directly improving utilization, laying the foundation for overall performance improvement. The ethanol solution of the composite cation exchange resin, through the permeability of ethanol, allows the resin to penetrate deep into the aggregate pores, adsorbing soluble salts and heavy metals through ion exchange, reducing salting out, corrosion, and expansion cracking, thus improving durability. Simultaneously, the purified aggregate surface provides a uniform substrate for subsequent processing, enhancing interfacial bonding strength and supporting higher admixture dosages. This further improves utilization. The nano-silica sol in the activating solution penetrates to the aggregate surface and pores through microwave irradiation, reacting with aggregate components to form a gel, increasing surface activity, enhancing chemical bonding with cement hydration products, improving interfacial transition zone strength, and simultaneously reducing aggregate porosity to enhance durability. The increased activity also allows the aggregate to accommodate a higher proportion of cementitious materials, further contributing to improved utilization. The composite liquid containing polyvinyl alcohol and anion exchange resin forms a coating film on the aggregate surface. The polar groups of polyvinyl alcohol form a binding force with related components, while the anion exchange resin adsorbs components from the cement, enhancing interfacial shear strength. The coating film blocks the communication between the internal pores of the aggregate and the outside environment, reducing volume deformation caused by wet-dry cycles. It adsorbs harmful ions to improve durability, and the volume stability of the coated aggregate is enhanced, allowing for a higher proportion in concrete and significantly improving utilization. Sulfoaluminate cement, as a fast-hardening and early-strength cementitious material, has a rapid hydration rate, and its hydration products are compatible with the coating layer, quickly filling aggregate gaps and forming a strong bonding interface, thus improving overall strength. Its low alkalinity reduces reaction with potential active components in recycled aggregates, lowering the risk of cracking. Its efficient bonding ability is suitable for high proportions of resin-coated aggregates, supporting high-proportion utilization of construction waste. The zeolite carrier internal curing agent, through its porous structure, slowly releases moisture during concrete hardening, reducing plastic shrinkage cracks caused by surface drying and improving durability. Promoting sufficient cement hydration to enhance strength, zeolite itself can utilize industrial waste, further broadening the channels for solid waste utilization and improving utilization rate; saturated steam containing amphoteric ion exchange resin carries resin molecules to penetrate into the pores of concrete during the curing stage, adsorbing harmful ions through ion exchange, and the resin polymer chains form a network structure in the pores to fill capillaries, improving impermeability. At the same time, high-temperature steam promotes secondary hydration of cement, making the hydration products more evenly distributed, enhancing frost resistance and strength. Steam curing can compensate for the problem of low early performance of concrete with a high proportion of recycled aggregate, support higher dosages of recycled aggregate, and further improve the utilization rate of construction waste; thus achieving the goal of improving the production effect of concrete based on construction waste.

[0153] Their impermeability grade is all above P10, which is considered to be strong durability; their compressive strength is 46.2-50.4 MPa, which is considered to be high strength; the waste content of preparation examples 1 and 3 is higher than 70%, which is considered to be strong stability; the waste content of preparation examples 2, 4 and 5 is lower than 70%, which is considered to be weak stability.

[0154] It is evident that, given a fixed amount of raw materials, the production efficiency of construction waste-based concrete can be increased by adjusting the proportions of these materials. Based on the data in the table above, it is clear that when preparing construction waste-based concrete, the concrete prepared using 100 parts recycled aggregate, 35 parts sulfoaluminate cement, 3 parts zeolite carrier internal curing agent, and 1 part saturated steam containing zwitterionic ion exchange resin exhibits the strongest stability and strength, but its utilization rate is lower. This is because the 35 parts sulfoaluminate cement can fully coat the surface of the recycled aggregate, forming a tight bond with it and reducing defects in the interface transition zone. Meanwhile, the dosage of 3 parts of curing agent in zeolite carrier and 1 part of saturated steam containing amphoteric ion exchange resin can precisely match the cement hydration requirements. It promotes full hydration by slow-release water and enhances structural density by ion exchange and pore filling, thereby ensuring stability and strength. The dosage of sulfoaluminate cement is well-suited to recycled aggregate. As a cementing material, it can fully cover the surface of recycled aggregate. The products generated during hydration can be tightly bonded to the coating layer on the surface of aggregate, filling the interfacial gaps between aggregates, reducing pores and microcracks in the interfacial transition zone, thereby strengthening the overall structural bonding force, as obtained from Examples 1-5.

[0155] Examples 6-9

[0156] The table below shows the corresponding relationships between the preparation methods used for a type of concrete based on construction waste.

[0157] Table: Comparison of Concrete Usage Based on Construction Waste in Examples 6-9

[0158]

[0159] Extract concrete samples from the above Examples 6-9 based on construction waste, and test their impermeability grade, compressive strength, and waste content rate according to the above measurement steps and standards. The average value of the test results is recorded in the table below.

[0160] Table: Performance test results of impermeability grade, compressive strength and utilization rate in Examples 1, 6-9

[0161]

[0162] As can be seen from the table above, the concrete preparation processes based on construction waste in Examples 1 and 6-9 all effectively improve the production efficiency of concrete based on construction waste. Construction waste, as a core aggregate source, is transformed into functional aggregates after crushing and screening, resulting in a significant proportion in the concrete and directly improving utilization, laying the foundation for overall performance improvement. The ethanol solution of the composite cation exchange resin, through the permeability of ethanol, allows the resin to penetrate deep into the aggregate pores, adsorbing soluble salts and heavy metals through ion exchange, reducing salting out, corrosion, and expansion cracking, thus improving durability. Simultaneously, the purified aggregate surface provides a uniform substrate for subsequent processing, enhancing interfacial bonding strength and supporting higher adsorption levels. This process further improves utilization efficiency. The nano-silica sol in the activation solution penetrates to the aggregate surface and pores through microwave irradiation, reacting with aggregate components to form a gel. This increases surface activity, enhances chemical bonding with cement hydration products, and improves the strength of the interfacial transition zone. Simultaneously, it reduces aggregate porosity to enhance durability. The increased activity also allows the aggregate to accommodate a higher proportion of cementitious materials, further boosting utilization. The composite solution containing polyvinyl alcohol and anion exchange resin forms a coating film on the aggregate surface. The polar groups of polyvinyl alcohol bind with related components, while the anion exchange resin adsorbs components from the cement, enhancing interfacial shear strength. The coating film blocks the connection between the aggregate's internal pores and the external environment, reducing volume changes caused by wet-dry cycles. The coating process enhances durability by adsorbing harmful ions and improves the volume stability of aggregates, allowing for higher proportions in concrete and significantly increasing utilization. Sulfoaluminate cement, as a fast-hardening and early-strength cementitious material, exhibits rapid hydration, and its hydration products are highly compatible with the coating layer. It quickly fills aggregate gaps and forms a strong bonding interface, improving overall strength. Its low alkalinity reduces reaction with potential active components in recycled aggregates, lowering the risk of cracking. Furthermore, its efficient bonding ability allows for high proportions of resin-coated aggregates, supporting high utilization of construction waste. The zeolite-carrier internal curing agent, through its porous structure, slowly releases moisture during concrete hardening, reducing plastic shrinkage cracks caused by surface drying and improving durability. Promoting sufficient cement hydration to enhance strength, zeolite itself can utilize industrial waste, further broadening the channels for solid waste utilization and improving utilization rate; saturated steam containing amphoteric ion exchange resin carries resin molecules to penetrate into the pores of concrete during the curing stage, adsorbing harmful ions through ion exchange, and the resin polymer chains form a network structure in the pores to fill capillaries, improving impermeability. At the same time, high-temperature steam promotes secondary hydration of cement, making the hydration products more evenly distributed, enhancing frost resistance and strength. Steam curing can compensate for the problem of low early performance of concrete with a high proportion of recycled aggregate, support higher dosages of recycled aggregate, and further improve the utilization rate of construction waste; thus achieving the goal of improving the production effect of concrete based on construction waste.

[0163] Their impermeability grades are all above P10, which is considered to indicate high durability; their compressive strength is 47.2-49.8 MPa, which is considered to indicate high strength; and their waste content is 71.9%, which is considered to indicate high stability.

[0164] It is evident that, given a fixed amount of raw materials, the production efficiency of construction waste-based concrete can be increased by adjusting the preparation conditions. Based on the data in the table above, it is clear that increasing the mixing speed, rotation speed, mixing time, pouring temperature, curing time, and steam curing pressure and time during the mixing process improves the stability and strength of the resulting concrete. This is because increasing the mixing speed enhances the shearing and mixing effects between raw materials, resulting in more uniform dispersion of recycled aggregates, cementitious materials, and various additives. This reduces structural defects caused by localized aggregate aggregation or uneven distribution, allowing the cementitious materials to more fully coat the surface of the recycled aggregates, strengthening interfacial bonding and laying the foundation for strength and stability. Increasing the pouring temperature accelerates the early hydration reaction rate of cement, promoting the rapid production of hydration products. Generates and fills the gaps between aggregates, reducing structural looseness caused by hydration lag due to low pouring temperature; extending the curing time ensures more complete cement hydration, especially considering the numerous pores on the surface of recycled aggregates that require more hydration products to fill, reducing microcracks caused by insufficient hydration and enhancing the overall structural density; increasing the pressure and duration of the steam curing process, the high temperature and high pressure environment can accelerate secondary cement hydration, promoting more hydration products to be evenly distributed in the pores inside the concrete, while also driving saturated steam containing zwitterionic exchange resin to penetrate deeper into the micropores, allowing the resin to more fully adsorb harmful ions and fill the capillaries through polymer chains, improving impermeability and frost resistance, and the pressure can make the curing components carried by the steam bind more tightly with the internal components of the concrete, further strengthening structural stability, thereby comprehensively improving the strength and stability of the concrete, as obtained from Examples 1 and 6-9.

[0165] Examples 10-13

[0166] The table below shows the corresponding relationships between the preparation methods used for a type of concrete based on construction waste.

[0167] Table: Comparison of Concrete Usage Based on Construction Waste in Examples 10-13

[0168]

[0169] Extract concrete from the above examples 10-13 based on construction waste, and test its impermeability grade, compressive strength and waste content rate according to the above measurement steps and standards. The average value of the test results is recorded in the table below.

[0170] Table: Performance test results of impermeability grade, compressive strength and utilization rate in Examples 1 and 10-13

[0171]

[0172] As can be seen from the table above, the concrete preparation processes based on construction waste in Examples 1 and 10-13 all effectively improve the production efficiency of concrete based on construction waste. Construction waste, as a core aggregate source, is transformed into functional aggregates after crushing and screening, resulting in a significant proportion in the concrete and directly improving utilization, laying the foundation for overall performance improvement. The ethanol solution of the composite cation exchange resin, through the permeability of ethanol, allows the resin to penetrate deep into the aggregate pores, adsorbing soluble salts and heavy metals through ion exchange, reducing salting out, corrosion, and expansion cracking, thus improving durability. Simultaneously, the purified aggregate surface provides a uniform substrate for subsequent processing, enhancing interfacial bonding strength and supporting more... High adsorption capacity further improves utilization rate; the nano-silica sol in the activation solution penetrates to the surface and pores of the aggregate through microwave irradiation, reacting with the components in the aggregate to form a gel, increasing surface activity, enhancing chemical bonding with cement hydration products, improving the strength of the interfacial transition zone, and reducing aggregate porosity to enhance durability. The increased activity also allows the aggregate to accommodate a higher proportion of cementitious materials, further contributing to improved utilization. The composite liquid containing polyvinyl alcohol and anion exchange resin forms a coating film on the aggregate surface. The polar groups of polyvinyl alcohol form a binding force with related components, while the anion exchange resin adsorbs components in the cement, enhancing interfacial shear strength. The coating film blocks the communication between the internal pores of the aggregate and the outside environment, reducing volume loss due to wet-dry cycles. The coating process enhances durability by deforming and adsorbing harmful ions, while also improving the volume stability of the aggregate, allowing for higher proportions in concrete and significantly increasing utilization. Sulfoaluminate cement, as a fast-hardening and early-strength cementitious material, exhibits rapid hydration, and its hydration products are highly compatible with the coating layer. It quickly fills aggregate gaps and forms a strong bonding interface, improving overall strength. Its low alkalinity reduces reaction with potential active components in recycled aggregates, lowering the risk of cracking. Furthermore, its efficient bonding ability allows for high proportions of resin-coated aggregates, supporting high-proportion utilization of construction waste. The zeolite-carrier internal curing agent, through its porous structure, slowly releases moisture during concrete hardening, reducing plastic shrinkage cracks caused by surface drying and improving durability. This process promotes full cement hydration to enhance strength. Zeolite itself can be utilized from industrial waste, further broadening the channels for solid waste utilization and improving utilization rate. Saturated steam containing amphoteric ion exchange resin carries resin molecules to penetrate into the pores of concrete during the curing stage. Through ion exchange, harmful ions are adsorbed, and the resin polymer chains form a network structure within the pores to fill capillaries, improving impermeability. At the same time, high-temperature steam promotes secondary cement hydration, making the hydration products more evenly distributed, enhancing frost resistance and strength. Steam curing can compensate for the problem of low early performance in concrete with a high proportion of recycled aggregate, supporting higher dosages of recycled aggregate and further improving the utilization rate of construction waste. Thus, the goal of improving the production efficiency of concrete based on construction waste is achieved.

[0173] Their impermeability grades are all above P10, which is considered to indicate high durability; their compressive strength is 46.4-49.4 MPa, which is considered to indicate high strength; and their waste content is 71.9%, which is considered to indicate high stability.

[0174] It is evident that, given a fixed amount of raw materials, the production efficiency of concrete based on construction waste can be increased by adjusting the proportions of these materials. Based on the data in the table above, it is clear that when preparing recycled aggregates, the concrete prepared using 100 parts construction waste, 12 parts ethanol solution of composite cation exchange resin, 8 parts activation liquid, and 7 parts composite liquid containing polyvinyl alcohol and anion exchange resin exhibits the highest stability. The reason for this is that the proportion of the composite liquid containing polyvinyl alcohol and anion exchange resin is moderately high. Polyvinyl alcohol can form a continuous thin film coating on the surface of the recycled aggregates, filling the gaps in the aggregate structure. The original pores of the aggregate are reduced and microcracks in the interface transition zone are decreased, enhancing the overall structural integrity. The anion exchange resin can adsorb harmful anions inside the concrete that may cause expansion or corrosion. At the same time, the ethanol solution and activation liquid of the composite cation exchange resin are balanced: the cation exchange resin can moderately purify the soluble cation impurities remaining on the surface of the aggregate, avoiding local structural looseness caused by ion aggregation; the activation liquid can gently enhance the surface activity of the aggregate, promote its chemical combination with cement hydration products, and avoid excessive activation to prevent excessive dissolution of the aggregate surface and the generation of new defects, reducing the risk of long-term deterioration. This was obtained from Examples 1 and 10-13.

[0175] It is evident that, given a fixed amount of raw materials, the production efficiency of concrete based on construction waste can be increased by adjusting the proportions of the raw materials used. Based on the data in the table above, it is clear that when preparing recycled aggregates, using 100 parts construction waste, 18 parts ethanol solution of composite cation exchange resin, 12 parts activation liquid, and 4 parts composite liquid containing polyvinyl alcohol and anion exchange resin, the resulting concrete based on construction waste exhibits the highest strength. The reason for this is that the amount of ethanol solution of composite cation exchange resin and activation liquid is significantly increased in this proportion: more cation exchange resin can deeply purify the surface of recycled aggregates, removing oil, dust, and soluble salt impurities that affect adhesion, greatly improving the cleanliness of the aggregate surface and laying the foundation for interfacial bonding; the increased amount of activation liquid can more fully stimulate the potential activity of the aggregate surface, promoting chemical bonding with products such as ettringite and CSH gel generated during cement hydration, forming a stronger "aggregate-hydration product" interfacial transition zone, rather than simple physical bonding, reducing the risk of long-term deterioration, as obtained in Examples 1 and 10-13.

[0176] Examples 14-27

[0177] The table below shows the corresponding relationships between the preparation methods used for a type of concrete based on construction waste.

[0178] Table: Comparison of Concrete Usage Based on Construction Waste in Examples 14-27

[0179] Group Concrete based on construction waste Example 14 Prepared from Preparation Example 33 Example 15 Prepared from Preparation Example 34 Example 16 Prepared from Preparation Example 35 Example 17 Prepared from Preparation Example 36 Example 18 Prepared from Preparation Example 37 Example 19 Prepared from Preparation Example 38 Example 20 Prepared from Preparation Example 39 Example 21 Prepared from Preparation Example 40 Example 22 Prepared from Preparation Example 41 Example 13 Prepared from Preparation Example 42 Example 24 Prepared from Preparation Example 43 Example 25 Prepared from Preparation Example 44 Example 26 Prepared from Preparation Example 45 Example 27 Prepared from Preparation Example 46

[0180] The concrete based on construction waste in Examples 14-27 above was extracted and its impermeability grade, compressive strength and waste content were tested according to the above measurement steps and standards. The average value of the test results was recorded in the table below.

[0181] Table: Performance test results of impermeability grade, compressive strength and utilization rate in Examples 1 and 14-27

[0182]

[0183] As can be seen from the table above, the concrete preparation processes based on construction waste in Examples 1 and 14-27 all effectively improve the production efficiency of concrete based on construction waste. Construction waste, as a core aggregate source, is transformed into functional aggregates after crushing and screening, resulting in a significant proportion in the concrete and directly improving utilization, laying the foundation for overall performance improvement. The ethanol solution of the composite cation exchange resin, through the permeability of ethanol, allows the resin to penetrate deep into the aggregate pores, adsorbing soluble salts and heavy metals through ion exchange, reducing salting out, corrosion, and expansion cracking, thus improving durability. Simultaneously, the purified aggregate surface provides a uniform substrate for subsequent processing, enhancing interfacial bonding strength and supporting more... High adsorption capacity further improves utilization rate; the nano-silica sol in the activation solution penetrates to the surface and pores of the aggregate through microwave irradiation, reacting with the components in the aggregate to form a gel, increasing surface activity, enhancing chemical bonding with cement hydration products, improving the strength of the interfacial transition zone, and reducing aggregate porosity to enhance durability. The increased activity also allows the aggregate to accommodate a higher proportion of cementitious materials, further contributing to improved utilization. The composite liquid containing polyvinyl alcohol and anion exchange resin forms a coating film on the aggregate surface. The polar groups of polyvinyl alcohol form a binding force with related components, while the anion exchange resin adsorbs components in the cement, enhancing interfacial shear strength. The coating film blocks the communication between the internal pores of the aggregate and the outside environment, reducing volume loss due to wet-dry cycles. The coating process enhances durability by deforming and adsorbing harmful ions, while also improving the volume stability of the aggregate, allowing for higher proportions in concrete and significantly increasing utilization. Sulfoaluminate cement, as a fast-hardening and early-strength cementitious material, exhibits rapid hydration, and its hydration products are highly compatible with the coating layer. It quickly fills aggregate gaps and forms a strong bonding interface, improving overall strength. Its low alkalinity reduces reaction with potential active components in recycled aggregates, lowering the risk of cracking. Furthermore, its efficient bonding ability allows for high proportions of resin-coated aggregates, supporting high-proportion utilization of construction waste. The zeolite-carrier internal curing agent, through its porous structure, slowly releases moisture during concrete hardening, reducing plastic shrinkage cracks caused by surface drying and improving durability. This process promotes full cement hydration to enhance strength. Zeolite itself can be utilized from industrial waste, further broadening the channels for solid waste utilization and improving utilization rate. Saturated steam containing amphoteric ion exchange resin carries resin molecules to penetrate into the pores of concrete during the curing stage. Through ion exchange, harmful ions are adsorbed, and the resin polymer chains form a network structure within the pores to fill capillaries, improving impermeability. At the same time, high-temperature steam promotes secondary cement hydration, making the hydration products more evenly distributed, enhancing frost resistance and strength. Steam curing can compensate for the problem of low early performance in concrete with a high proportion of recycled aggregate, supporting higher dosages of recycled aggregate and further improving the utilization rate of construction waste. Thus, the goal of improving the production efficiency of concrete based on construction waste is achieved.

[0184] Their impermeability grades are all above P10, which is considered to indicate high durability; their compressive strength is 46.7-48.5MPa, which is considered to indicate high strength; and their waste content rate is 71.9%, which is considered to indicate high stability.

[0185] It is evident that, given a fixed amount of raw materials, the production efficiency of concrete based on construction waste can be increased by adjusting the preparation conditions. Based on the data in the table above, it is clear that when preparing recycled aggregate, increasing the crushing pressure, water pressure, temperature, rinsing time, amplitude, and frequency during the pretreatment process; the rotation speed, temperature, and stirring time during the purification process; the microwave frequency, power, and irradiation time during the activation process; and the rotation speed, dripping speed, temperature, and stirring time during the coating process, results in concrete with improved stability and strength. This is because increasing the crushing pressure, water pressure, temperature, rinsing time, amplitude, and frequency during the pretreatment process allows for more uniform crushing of the construction waste, resulting in a more reasonable particle size distribution and reducing structural stress concentration. Simultaneously, it removes old mortar and impurities from the surface, enhances the removal of dust, oil, and soluble salts, and improves the surface cleanliness and exposure of the virgin surface, creating favorable conditions for subsequent processing. Increasing the rotation speed, temperature, and stirring time during the purification process enhances the recovery of the aggregate. Increasing the contact frequency between cation exchange resin and aggregate accelerates ion diffusion rate and ensures that harmful cations in deep pores are fully adsorbed and exchanged, reducing structural deterioration caused by ion aggregation in the later stage. Increasing the microwave frequency, power, and irradiation time during the activation process can activate the reactivity of silicon, aluminum, and other components on the aggregate surface through high-frequency electromagnetic oscillation, promoting their reaction with cement hydration products to generate more cementitious products and enhancing the compactness of the aggregate-cement paste interface transition zone. Increasing the rotation speed, dripping speed, temperature, and stirring time during the coating process can make the composite liquid containing polyvinyl alcohol and anion exchange resin uniformly cover the aggregate surface, forming a continuous and tough film to seal pores, while promoting the adsorption of harmful ions by the anion exchange resin. The improvement of these parameters, through the synergistic effect of optimizing particle morphology, purifying surface impurities, activating chemical activity, and strengthening interface protection, improves the stability and strength of concrete from multiple aspects such as physical structure, chemical bonding, and anti-deterioration ability, as obtained from Examples 1 and 14-21.

[0186] It is evident that, given a fixed amount of raw materials, the production efficiency of concrete based on construction waste can be increased by adjusting the preparation conditions. Based on the data in the table above, it is clear that when preparing recycled aggregates, the following ratios are used: sulfonic acid cation exchange resin, carboxyl cation exchange resin, ethanol, disodium ethylenediaminetetraacetate, and alkylphenol polyoxyethylene ether in a weight ratio of 3.75:1.25:92:0.5:2.5; nano-silica sol, sodium silicate, water, polycarboxylic acid ether dispersant, and zinc borate in a weight ratio of 10:3:82:3.5:1.5; and polyvinyl alcohol, quaternary ammonium salt anion exchange resin, water, glycerol, and nano-titanium dioxide in a weight ratio of 3:1:90:4.5:1.5. These ratios result in concrete based on construction waste with improved stability and strength, as shown in Examples 1 and 22-27.

[0187] This specific embodiment is merely an explanation of the present invention and not a limitation thereof. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A method for preparing concrete based on construction waste, characterized in that, Includes the following steps: A1. Add recycled aggregate, sulfoaluminate cement, and zeolite carrier internal curing agent into a planetary mixer and mix for 5-8 minutes at a revolution speed of 20-25 r / min and a rotation speed of 40-50 r / min. After pouring, cure for 24-48 hours at a temperature of 20-25℃ and a humidity of ≥95% to obtain demolded specimens. A2. Place the demolded specimen into a steam curing kettle and heat it to 60°C at a heating rate of 10°C / h. During the constant temperature stage, inject saturated steam containing zwitterionic exchange resin and cure it for 6-8 hours at a pressure of 0.2-0.3MPa and a humidity of 100%. Finally, cool the temperature to room temperature at a cooling rate of less than 20°C / h to obtain concrete based on construction waste. The preparation method of recycled aggregate includes the following steps: C1. Place the crushed construction waste into a jaw crusher and crush it to a particle size of less than 50mm under a pressure of 15-20MPa. Then transfer it to a high-pressure cleaning tank and wash it for 10-15 minutes under a water pressure of 25-30MPa and a temperature of 40-50℃. After draining, place it in a vibrating screen and classify it under a vibration amplitude of 3-5mm and a frequency of 25Hz to obtain recycled aggregate. C2. The recycled aggregate obtained in C1 is immersed in an ethanol solution of composite cation exchange resin and stirred for 30-45 minutes at a speed of 100-150 r / min and a temperature of 60-70℃ to obtain the stirred product. Then, it is placed on a 100-mesh polyester filter cloth filter device and filtered for 5 minutes under a vacuum of 0.07 MPa. After rinsing with deionized water at a flow rate of 2 L / min three times, the purified aggregate is obtained. C3. Place the purified aggregate obtained in C2 in a microwave reactor, spray with activation liquid, and irradiate for 5-8 minutes at a microwave frequency of 2.45-2.50 GHz and a power of 8-10 kW. Control the aggregate temperature to rise to 75°C, discharge the residual liquid, and then blow the surface with compressed air at a pressure of 0.4 MPa to obtain activated aggregate. C4. Transfer the activated aggregate obtained in C3 to a high-speed mixer. Under the condition of 400-600 r / min, add the composite liquid containing polyvinyl alcohol and anion exchange resin through the atomizing nozzle at a dropping rate of 4 drops / s. After the dropping is completed, continue stirring at a temperature of 80-90℃ for 40-60 min to form recycled aggregate. The ethanol solution of the composite cation exchange resin is composed of sulfonic acid cation exchange resin, carboxyl cation exchange resin, ethanol, disodium ethylenediaminetetraacetate, and alkylphenol polyoxyethylene ether in a weight ratio of 3.75-6:1.25-2:86-92:0.5-1.5:2.5-4.

5. The activation solution is composed of nano-silica sol, sodium silicate, water, polycarboxylic acid ether dispersant, and zinc borate in a weight ratio of 10-15:3:77-82:3.5-4.5:0.5-1.

5. The composite solution containing polyvinyl alcohol and anion exchange resin is composed of polyvinyl alcohol, quaternary ammonium salt anion exchange resin, water, glycerol, and nano titanium dioxide in a weight ratio of 1.5-3:1-3.5:88.5-90:4-4.5:1.5-3. The saturated vapor of the zwitterionic exchange resin is composed of sulfonic acid-quaternary ammonium salt copolymer, ethylene glycol, graphene oxide, 25% ammonia, and water in a weight ratio of 1.5:15:0.1:0.5:82.

9.

2. The method for preparing concrete based on construction waste according to claim 1, characterized in that: The components and weight proportions of the raw materials for preparing the concrete based on construction waste are as follows: 100 parts recycled aggregate, 30-50 parts sulfoaluminate cement, 2-7 parts zeolite carrier internal curing agent, and 0.8-3 parts saturated vapor containing zwitterionic exchange resin.

3. The method for preparing concrete based on construction waste according to claim 1, characterized in that: The components and weight proportions of the raw materials for preparing the recycled aggregate are as follows: 100 parts of construction waste, 10-20 parts of ethanol solution of composite cation exchange resin, 8-15 parts of activation solution, and 4-8 parts of composite solution containing polyvinyl alcohol and anion exchange resin.

4. The method for preparing concrete based on construction waste according to claim 1, characterized in that: The sulfoaluminate cement is composed of limestone, bauxite, gypsum, iron powder, and fly ash in a weight ratio of 42:26:17:5:

8.

5. The method for preparing concrete based on construction waste according to claim 1, characterized in that: The zeolite carrier internal curing agent is composed of clinoptilolite, nano silica sol, polyacrylamide, lithium carbonate, and water in a weight ratio of 70:15:5:2:8.

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