A kind of recycled aggregate concrete and preparation method thereof

Abstract

The invention discloses a recycled aggregate concrete and a preparation method thereof. The recycled concrete comprises the following raw materials in parts by weight: 400-600 parts of cement, 1100-1200 parts of modified aggregate, 600-650 parts of sand, 150-200 parts of water, 5-8 parts of water reducer and 50-80 parts of modified additive. When the raw materials are blended, siloxane on the modified aggregate and the modified additive is hydrolyzed, reacts with active hydroxyl groups on the surface of surrounding inorganic substances or with adjacent silanol groups, enhances the coordination between the components, and further improves the strength of the concrete. The modified aggregate forms a polymer in gaps and cracks, so that the structure of the aggregate is more compact, and the surface contains an organic silicone resin segment, which can reduce the water absorption rate of the aggregate. The main body of the modified additive is a cage-type silsesquioxane structure and contains a dynamic disulfide bond, which can further improve the mechanical properties of the concrete material.

Description

Technical Field

[0001] The invention relates to the technical field of concrete preparation, and in particular to recycled aggregate concrete and a preparation method thereof. Background Art

[0002] In construction projects, concrete is used in the largest amount. Therefore, the amount of waste concrete demolished every year, waste concrete generated by new buildings, and waste concrete discharged by ready-mixed concrete plants and concrete prefabricated component plants is also huge. Among the several raw materials of concrete, aggregate usage ranks first. Therefore, using waste concrete as recycled aggregate to make concrete and realize the recycling of concrete materials has very important environmental and resource protection significance. The surface of recycled aggregate is wrapped with a considerable amount of cement mortar, and the surface is rough and has many edges and corners. Due to the large porosity and high water absorption of cement mortar, and the accumulation of damage in the process of disintegration and crushing of concrete blocks, there are a large number of microcracks inside the recycled aggregate, which leads to the density and apparent density of recycled aggregate being lower than that of ordinary aggregate, making the prepared concrete insufficient in strength. Summary of the invention

[0003] The purpose of the present invention is to provide a recycled aggregate concrete and a preparation method thereof, which solves the problem that the mechanical strength of the recycled aggregate concrete is low at present.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A method for preparing recycled aggregate concrete specifically comprises the following steps:

[0006] Step A1: crush the recycled aggregate and disperse it in an ethanol solution of methyl methacrylate. After ultrasonic treatment for 30-40 minutes at a frequency of 20-30kHz, add KH570 and cumene hydroperoxide, react for 20-25 hours at a temperature of 60-70°C to obtain a pretreated aggregate. Mix the pretreated aggregate, KH550, dimethyldiethoxysilane and anhydrous ethanol evenly, stir and add deionized water at a speed of 60-80r / min and a temperature of 65-70°C, react for 3-5 hours, heat to 120-130°C, and keep warm for 2-3 hours to obtain a functionalized aggregate.

[0007] Step A2: The functionalized aggregate, KH560 and toluene are mixed evenly, nitrogen is introduced for protection, and the reaction is carried out for 4-6 hours at a speed of 60-80 r / min, a temperature of 20-25° C., and a pH value of 8-9 to obtain a modified aggregate. The following raw materials are weighed in parts by weight: 400-600 parts of cement, 1100-1200 parts of modified aggregate, 600-650 parts of sand, 150-200 parts of water, 5-8 parts of water reducer and 50-80 parts of modified additive.

[0008] Furthermore, the amount ratio of the recycled aggregate powder and the ethanol solution of methyl methacrylate described in step A1 is 1g:10mL, the mass fraction of the ethanol solution of methyl methacrylate is 15%, and the amount ratio of the pretreated aggregate, KH550, dimethyldiethoxysilane and deionized water is 1g:10mmol:20mmol:20mL.

[0009] Furthermore, the dosage of the functionalized aggregate and KH560 described in step A2 is 1g:3mL, the cement model is P.O42.5, the particle size of the modified aggregate is 5mm, the sand is washed sand, the fineness modulus is 2.4, and the water reducer is sodium lignin sulfonate and magnesium lignin sulfonate.

[0010] Further, the modified additive is prepared by the following steps:

[0011] Step B1: Methyltrimethoxysilane, sodium hydroxide, isopropanol and deionized water are mixed evenly, reacted at a speed of 120-150r / min and a temperature of 60-70°C for 3-5h, cooled to 20-25°C, reacted for 10-15h to obtain sodium tetrasiliconate, sodium tetrasiliconate, triethylamine and tetrahydrofuran are mixed evenly, nitrogen is introduced for protection, stirred and methyldichloroethane is added at a speed of 200-300r / min and a temperature of 0°C, reacted for 3-5h, heated to 20-25°C, and continued to react for 20-25h to obtain dihydrogen cage-type silsesquioxane;

[0012] Step B2: Evenly mix dihydrogen cage silsesquioxane, allyl alcohol, Custer catalyst and toluene, introduce nitrogen protection, react for 10-15 hours at a speed of 120-150 r / min and a temperature of 80-85° C. to obtain functionalized silsesquioxane, evenly mix functionalized backplane siloxane, eleostearic acid, p-toluenesulfonic acid and toluene, react for 8-10 hours at a speed of 60-80 r / min and a temperature of 110-120° C. to obtain a modifier;

[0013] Step B3: acrylic acid, dithiodiethanol, p-toluenesulfonic acid and toluene are mixed evenly, and the reaction is carried out for 6-8 hours at a speed of 60-80 r / min and a temperature of 110-120° C. to obtain an intermediate; the modifier, the intermediate, acrylic acid and DMF are mixed evenly, and ammonium persulfate is added under stirring at a speed of 120-150 r / min and a temperature of 70-80° C., and the reaction is carried out for 8-10 hours to obtain an additive; the additive, KH550, dicyclohexylcarbodiimide and DMF are mixed evenly, and the reaction is carried out for 4-6 hours at a speed of 150-200 r / min and a temperature of 25-30° C. to obtain a modified additive.

[0014] Furthermore, the amount ratio of methyltrimethoxysilane, isopropanol, deionized water and sodium hydroxide described in step B1 is 20g:100mL:5mL:3g, and the mass ratio of sodium tetrasiliconate, triethylamine and methyldichloroethane is 12:5:3.5.

[0015] Furthermore, the molar ratio of the Si-H bond on the dihydrogen cage silsesquioxane described in step B2 to acryl alcohol is 1:1, the amount of the Custer catalyst used is 1‰ of the mass of acryl alcohol, the molar ratio of the carboxyl group on the functionalized backplane siloxane to eleostearic acid is 1:1, and the amount of p-toluenesulfonic acid used is 1% of the mass of eleostearic acid.

[0016] Furthermore, the molar ratio of acrylic acid to dithiodiethanol in step B3 is 1:1, the amount of p-toluenesulfonic acid is 5‰ of the sum of the mass of acrylic acid and dithiodiethanol, and the molar ratio of carboxyl, KH550 and dicyclohexylcarbodiimide on the additive is 1:1:1.1.

[0017] Beneficial effects of the present invention: A recycled aggregate concrete disclosed in the present application comprises the following raw materials: cement, modified aggregate, sand, water, a water reducing agent and a modified additive; the modified aggregate is prepared by crushing recycled aggregate as raw material and soaking it in an ethanol solution of methyl methacrylate, so that the methyl methacrylate fills the voids and cracks of the recycled aggregate and polymerizes with KH570 to form a polymer with a siloxane structure in the voids and cracks to obtain a pretreated aggregate; the pretreated aggregate, KH550 and dimethyldiethoxysilane are hydrolyzed and condensed to form an organosilicon resin structure containing amino groups on the pretreated surface to obtain a functionalized aggregate; the functionalized aggregate and KH560 are reacted under alkaline conditions to react the amino groups on the functionalized aggregate with the epoxy groups on the KH560 to obtain a modified aggregate.

[0018] The modified additive is hydrolyzed and condensed with methyltrimethoxysilane to form an octamethyltetrasiloxane sodium tetrasiloxide structure to obtain sodium tetrasiloxide. The sodium tetrasiloxide is reacted with methyldichloroethane to make the sodium alcohol structure on the sodium tetrasiloxide react with the chlorine atom site on the methyldichloroethane to obtain dihydrogen cage silsesquioxane. The dihydrogen cage silsesquioxane is reacted with allyl alcohol to make the Si-H bond on the dihydrogen cage silsesquioxane react with the double bond on the allyl alcohol to obtain functionalized silsesquioxane. The invention relates to a method for preparing a modified agent, reacting a functionalized silsesquioxane with eleostearic acid to esterify a hydroxyl group on the functionalized silsesquioxane with a carboxyl group on the eleostearic acid, and obtaining a modified agent; reacting acrylic acid with dithiodiethanol to esterify a carboxyl group on the acrylic acid with a hydroxyl group on the dithiodiethanol, and obtaining a intermediate; polymerizing the modifier, the intermediate and acrylic acid to obtain an additive; reacting the additive with KH550 to dehydrate a carboxyl group on a side chain of the additive with an amino group on KH550, and obtaining a modified additive.

[0019] When the raw materials are blended, the siloxanes on the modified aggregates and modified additives will hydrolyze and react with the active hydroxyl groups on the surface of the surrounding inorganic substances or with the adjacent silanol groups to enhance the coordination between the components and thereby improve the strength of the concrete. The modified aggregates form polymers in the gaps and cracks, making the structure of the aggregates denser. At the same time, the silicone resin segments on the surface can reduce the water absorption of the aggregates. The main body of the modified additives is a cage-type silsesquioxane structure and contains dynamic disulfide bonds, which can further improve the mechanical properties of the concrete material. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Embodiment 1: A method for preparing recycled aggregate concrete, comprising the following steps:

[0022] Step A1: crush the recycled aggregate and disperse it in an ethanol solution of methyl methacrylate. After ultrasonic treatment for 30 minutes at a frequency of 20 kHz, add KH570 and cumene hydroperoxide, and react for 20 hours at a temperature of 60° C. to obtain a pretreated aggregate. The pretreated aggregate, KH550, dimethyldiethoxysilane and anhydrous ethanol are mixed uniformly, stirred at a speed of 60 r / min and a temperature of 65° C., and deionized water is added to react for 3 hours, and the temperature is raised to 120° C. and kept warm for 2 hours to obtain a functionalized aggregate.

[0023] Step A2: The functionalized aggregate, KH560 and toluene were mixed evenly, nitrogen was introduced for protection, and the reaction was carried out for 4 hours at a speed of 60 r / min, a temperature of 20° C. and a pH value of 8 to obtain a modified aggregate. The following raw materials were weighed in parts by weight: 400 parts of cement, 1100 parts of modified aggregate, 600 parts of sand, 150 parts of water, 5 parts of water reducer and 50 parts of modified additive.

[0024] The amount ratio of the recycled aggregate powder and the ethanol solution of methyl methacrylate described in step A1 is 1g:10mL, the mass fraction of the ethanol solution of methyl methacrylate is 15%, and the amount ratio of the pretreated aggregate, KH550, dimethyldiethoxysilane and deionized water is 1g:10mmol:20mmol:20mL.

[0025] The dosage of the functionalized aggregate and KH560 described in step A2 is 1g:3mL, the cement model is PO 42.5, the particle size of the modified aggregate is 5mm, the sand is washed sand, the fineness modulus is 2.4, and the water reducer is sodium lignin sulfonate.

[0026] The modified additive is prepared by the following steps:

[0027] Step B1: Methyltrimethoxysilane, sodium hydroxide, isopropanol and deionized water are mixed evenly, reacted at a speed of 120 r / min and a temperature of 60° C. for 3 h, cooled to 20° C., reacted for 10 h, and obtained sodium tetrasiliconate; sodium tetrasiliconate, triethylamine and tetrahydrofuran are mixed evenly, nitrogen is introduced for protection, stirred and methyldichloroethane is added at a speed of 200 r / min and a temperature of 0° C., reacted for 3 h, heated to 20° C., and continued to react for 20 h to obtain dihydrogen cage-type silsesquioxane;

[0028] Step B2: Dihydrogen cage silsesquioxane, allyl alcohol, Custer catalyst and toluene are mixed evenly, nitrogen is introduced for protection, and the reaction is carried out for 10 hours at a speed of 120 r / min and a temperature of 80° C. to obtain functionalized silsesquioxane; functionalized backplane siloxane, eleostearic acid, p-toluenesulfonic acid and toluene are mixed evenly, and the reaction is carried out for 8 hours at a speed of 60 r / min and a temperature of 110° C. to obtain a modifier;

[0029] Step B3: acrylic acid, dithiodiethanol, p-toluenesulfonic acid and toluene are mixed evenly, and the reaction is carried out at a speed of 60 r / min and a temperature of 110°C for 6 hours to obtain an intermediate; the modifier, the intermediate, acrylic acid and DMF are mixed evenly, and ammonium persulfate is added under stirring at a speed of 120 r / min and a temperature of 70°C, and the reaction is carried out for 8 hours to obtain an additive; the additive, KH550, dicyclohexylcarbodiimide and DMF are mixed evenly, and the reaction is carried out at a speed of 150 r / min and a temperature of 25°C for 4 hours to obtain a modified additive.

[0030] The amount ratio of methyltrimethoxysilane, isopropanol, deionized water and sodium hydroxide described in step B1 is 20g:100mL:5mL:3g, and the mass ratio of sodium tetrasiliconate, triethylamine and methyldichloroethane is 12:5:3.5.

[0031] The molar ratio of Si-H bonds on the dihydrogen cage-type silsesquioxane described in step B2 to acryl alcohol is 1:1, the amount of Custer catalyst used is 1‰ of the mass of acryl alcohol, the molar ratio of carboxyl groups on the functionalized backplane siloxane to eleostearic acid is 1:1, and the amount of p-toluenesulfonic acid used is 1% of the mass of eleostearic acid.

[0032] The molar ratio of acrylic acid to diethyl thioate in step B3 is 1:1, the amount of p-toluenesulfonic acid is 5‰ of the sum of the mass of acrylic acid and diethyl thioate, and the molar ratio of the carboxyl group, KH550 and dicyclohexylcarbodiimide on the additive is 1:1:1.1.

[0033] Embodiment 2: A method for preparing recycled aggregate concrete, comprising the following steps:

[0034] Step A1: crush the recycled aggregate and disperse it in an ethanol solution of methyl methacrylate. After ultrasonic treatment for 35 minutes at a frequency of 25 kHz, add KH570 and cumene hydroperoxide, and react for 25 hours at a temperature of 65° C. to obtain a pretreated aggregate. Mix the pretreated aggregate, KH550, dimethyldiethoxysilane and anhydrous ethanol evenly, stir and add deionized water at a speed of 60 r / min and a temperature of 68° C., react for 4 hours, heat to 125° C., and keep warm for 3 hours to obtain a functionalized aggregate.

[0035] Step A2: The functionalized aggregate, KH560 and toluene were mixed evenly, nitrogen was introduced for protection, and the reaction was carried out for 5 hours at a speed of 60 r / min, a temperature of 25° C. and a pH value of 9 to obtain a modified aggregate. The following raw materials were weighed in parts by weight: 500 parts of cement, 1150 parts of modified aggregate, 630 parts of sand, 180 parts of water, 6 parts of water reducer and 65 parts of modified additive.

[0036] The amount ratio of the recycled aggregate powder and the ethanol solution of methyl methacrylate described in step A1 is 1g:10mL, the mass fraction of the ethanol solution of methyl methacrylate is 15%, and the amount ratio of the pretreated aggregate, KH550, dimethyldiethoxysilane and deionized water is 1g:10mmol:20mmol:20mL.

[0037] The dosage of the functionalized aggregate and KH560 described in step A2 is 1g:3mL, the cement model is PO 42.5, the particle size of the modified aggregate is 5mm, the sand is washed sand, the fineness modulus is 2.4, and the water reducer is sodium lignin sulfonate.

[0038] The modified additive is prepared by the following steps:

[0039] Step B1: Methyltrimethoxysilane, sodium hydroxide, isopropanol and deionized water are mixed evenly, reacted at a speed of 120 r / min and a temperature of 65°C for 4 hours, cooled to 25°C, reacted for 13 hours to obtain sodium tetrasiliconate, sodium tetrasiliconate, triethylamine and tetrahydrofuran are mixed evenly, nitrogen is introduced for protection, stirred and methyldichloroethane is added at a speed of 200 r / min and a temperature of 0°C, reacted for 4 hours, heated to 25°C, and continued to react for 20 hours to obtain dihydrogen cage-type silsesquioxane;

[0040] Step B2: Dihydrogen cage silsesquioxane, allyl alcohol, Custer catalyst and toluene are mixed evenly, nitrogen is introduced for protection, and the reaction is carried out for 13 hours at a speed of 120 r / min and a temperature of 85° C. to obtain functionalized silsesquioxane; functionalized backplane siloxane, eleostearic acid, p-toluenesulfonic acid and toluene are mixed evenly, and the reaction is carried out for 9 hours at a speed of 60 r / min and a temperature of 115° C. to obtain a modifier;

[0041] Step B3: acrylic acid, dithiodiethanol, p-toluenesulfonic acid and toluene are mixed evenly, and the reaction is carried out at a speed of 60 r / min and a temperature of 115°C for 7 hours to obtain an intermediate; the modifier, the intermediate, acrylic acid and DMF are mixed evenly, and ammonium persulfate is added under stirring at a speed of 120 r / min and a temperature of 75°C, and the reaction is carried out for 9 hours to obtain an additive; the additive, KH550, dicyclohexylcarbodiimide and DMF are mixed evenly, and the reaction is carried out at a speed of 200 r / min and a temperature of 25°C for 5 hours to obtain a modified additive.

[0042] The amount ratio of methyltrimethoxysilane, isopropanol, deionized water and sodium hydroxide described in step B1 is 20g:100mL:5mL:3g, and the mass ratio of sodium tetrasiliconate, triethylamine and methyldichloroethane is 12:5:3.5.

[0043] The molar ratio of Si-H bonds on the dihydrogen cage-type silsesquioxane described in step B2 to acryl alcohol is 1:1, the amount of Custer catalyst used is 1‰ of the mass of acryl alcohol, the molar ratio of carboxyl groups on the functionalized backplane siloxane to eleostearic acid is 1:1, and the amount of p-toluenesulfonic acid used is 1% of the mass of eleostearic acid.

[0044] The molar ratio of acrylic acid to diethyl thioate in step B3 is 1:1, the amount of p-toluenesulfonic acid is 5‰ of the sum of the mass of acrylic acid and diethyl thioate, and the molar ratio of the carboxyl group, KH550 and dicyclohexylcarbodiimide on the additive is 1:1:1.1.

[0045] Embodiment 3: A method for preparing recycled aggregate concrete, comprising the following steps:

[0046] Step A1: crush the recycled aggregate and disperse it in an ethanol solution of methyl methacrylate. After ultrasonic treatment for 40 minutes at a frequency of 30 kHz, add KH570 and cumene hydroperoxide, and react for 25 hours at a temperature of 70°C to obtain a pretreated aggregate. The pretreated aggregate, KH550, dimethyldiethoxysilane and anhydrous ethanol are mixed uniformly, stirred at a speed of 80 r / min and a temperature of 70°C, and deionized water is added to react for 5 hours, and the temperature is raised to 130°C and kept warm for 3 hours to obtain a functionalized aggregate.

[0047] Step A2: The functionalized aggregate, KH560 and toluene were mixed evenly, nitrogen was introduced for protection, and the reaction was carried out for 6 hours at a speed of 80 r / min, a temperature of 25° C., and a pH value of 9 to obtain a modified aggregate. The following raw materials were weighed in parts by weight: 600 parts of cement, 1200 parts of modified aggregate, 650 parts of sand, 200 parts of water, 8 parts of water reducer, and 80 parts of modified additive.

[0048] The amount ratio of the recycled aggregate powder and the ethanol solution of methyl methacrylate described in step A1 is 1g:10mL, the mass fraction of the ethanol solution of methyl methacrylate is 15%, and the amount ratio of the pretreated aggregate, KH550, dimethyldiethoxysilane and deionized water is 1g:10mmol:20mmol:20mL.

[0049] The dosage of the functionalized aggregate and KH560 described in step A2 is 1g:3mL, the cement model is PO 42.5, the particle size of the modified aggregate is 5mm, the sand is washed sand, the fineness modulus is 2.4, and the water reducer is magnesium lignin sulfonate.

[0050] The modified additive is prepared by the following steps:

[0051] Step B1: Methyltrimethoxysilane, sodium hydroxide, isopropanol and deionized water are mixed evenly, reacted at a speed of 150 r / min and a temperature of 70°C for 5 hours, cooled to 25°C, reacted for 15 hours to obtain sodium tetrasiliconate, sodium tetrasiliconate, triethylamine and tetrahydrofuran are mixed evenly, nitrogen is introduced for protection, stirred and methyldichloroethane is added at a speed of 300 r / min and a temperature of 0°C, reacted for 5 hours, heated to 25°C, and continued to react for 25 hours to obtain dihydrogen cage-type silsesquioxane;

[0052] Step B2: Evenly mix dihydrogen cage-type silsesquioxane, allyl alcohol, Custer catalyst and toluene, introduce nitrogen protection, react for 15 hours at a speed of 150 r / min and a temperature of 85° C. to obtain functionalized silsesquioxane; evenly mix functionalized backplane siloxane, eleostearic acid, p-toluenesulfonic acid and toluene, react for 10 hours at a speed of 80 r / min and a temperature of 120° C. to obtain a modifier;

[0053] Step B3: acrylic acid, dithiodiethanol, p-toluenesulfonic acid and toluene are mixed evenly, and the reaction is carried out at a speed of 80 r / min and a temperature of 120°C for 8 hours to obtain an intermediate; the modifier, the intermediate, acrylic acid and DMF are mixed evenly, and ammonium persulfate is added under stirring at a speed of 150 r / min and a temperature of 80°C, and the reaction is carried out for 10 hours to obtain an additive; the additive, KH550, dicyclohexylcarbodiimide and DMF are mixed evenly, and the reaction is carried out at a speed of 200 r / min and a temperature of 30°C for 6 hours to obtain a modified additive.

[0054] The amount ratio of methyltrimethoxysilane, isopropanol, deionized water and sodium hydroxide described in step B1 is 20g:100mL:5mL:3g, and the mass ratio of sodium tetrasiliconate, triethylamine and methyldichloroethane is 12:5:3.5.

[0055] The molar ratio of Si-H bonds on the dihydrogen cage-type silsesquioxane described in step B2 to acryl alcohol is 1:1, the amount of Custer catalyst used is 1‰ of the mass of acryl alcohol, the molar ratio of carboxyl groups on the functionalized backplane siloxane to eleostearic acid is 1:1, and the amount of p-toluenesulfonic acid used is 1% of the mass of eleostearic acid.

[0056] The molar ratio of acrylic acid to diethyl thioate in step B3 is 1:1, the amount of p-toluenesulfonic acid is 5‰ of the sum of the mass of acrylic acid and diethyl thioate, and the molar ratio of the carboxyl group, KH550 and dicyclohexylcarbodiimide on the additive is 1:1:1.1.

[0057] Comparative Example 1: Compared with Example 1, this comparative example uses recycled aggregate instead of modified aggregate, and the other steps are the same.

[0058] Comparative Example 2: Compared with Example 1, no intermediate was added in this comparative example, and the remaining steps were the same.

[0059] Comparative Example 3: Compared with Example 1, this comparative example uses an additive instead of a modified additive, and the remaining steps are the same.

[0060] Comparative Example 4: Compared with Example 1, no modifier was added in this comparative example, and the remaining steps were the same.

[0061] Comparative Example 5: Compared with Example 1, no modifying additive was added in this comparative example, and the remaining steps were the same.

[0062] The concrete obtained in Examples 1-3 and Comparative Examples 1-5 was made into 100mm×100mm×100mm specimens according to the standard of GB / T50081-2019, and the compressive strength after curing for 7 days, 28 days and 56 days was tested. The test results are shown in Table 1 below.

[0063] Table 1

[0064]

[0065] It can be seen from the above table that the present application has good mechanical strength.

[0066] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing recycled aggregate concrete, characterized in that: The specific steps include: Step A1: crush the recycled aggregate and disperse it in an ethanol solution of methyl methacrylate, add KH570 and cumene hydroperoxide after ultrasonic treatment, react to obtain pretreated aggregate, mix the pretreated aggregate, KH550, dimethyldiethoxysilane and anhydrous ethanol, stir, add deionized water, react to obtain functionalized aggregate; Step A2: functionalized aggregate, KH560 and toluene are uniformly mixed, nitrogen is introduced for protection, and the reaction is carried out to obtain modified aggregate. The following raw materials are weighed in parts by weight: 400-600 parts of cement, 1100-1200 parts of modified aggregate, 600-650 parts of sand, 150-200 parts of water, 5-8 parts of water reducer and 50-80 parts of modified additive; The modified additive is prepared by the following steps: Step B1: Methyltrimethoxysilane, sodium hydroxide, isopropanol and deionized water are mixed to react to obtain sodium tetrasiliconate, sodium tetrasiliconate, triethylamine and tetrahydrofuran are mixed evenly, nitrogen is introduced for protection, methyldichloroethane is added while stirring, and a reaction is carried out to obtain dihydrogen cage-type silsesquioxane; Step B2: Mixing dihydrogen cage silsesquioxane, allyl alcohol, Custer catalyst and toluene to obtain functionalized silsesquioxane, and mixing functionalized silsesquioxane, eleostearic acid, p-toluenesulfonic acid and toluene to obtain a modifier; Step B3: acrylic acid, dithiodiethanol, p-toluenesulfonic acid and toluene are mixed and reacted to obtain an intermediate, the modifier, the intermediate, acrylic acid and DMF are mixed and stirred, and ammonium persulfate is added to react to obtain an additive, and the additive, KH550, dicyclohexylcarbodiimide and DMF are mixed and reacted to obtain a modified additive.

2. The method for preparing recycled aggregate concrete according to claim 1, characterized in that: The amount ratio of the recycled aggregate powder and the ethanol solution of methyl methacrylate described in step A1 is 1g:10mL, and the amount ratio of the pretreated aggregate, KH550, dimethyldiethoxysilane and deionized water is 1g:10mmol:20mmol:20mL.

3. The method for preparing recycled aggregate concrete according to claim 1, characterized in that: The amount of functionalized aggregate and KH560 used in step A2 is 1 g:3 mL.

4. The method for preparing recycled aggregate concrete according to claim 1, characterized in that: The amount ratio of methyltrimethoxysilane, isopropanol, deionized water and sodium hydroxide described in step B1 is 20g:100mL:5mL:3g, and the mass ratio of sodium tetrasiliconate, triethylamine and methyldichloroethane is 12:5:3.

5.

5. The method for preparing recycled aggregate concrete according to claim 1, characterized in that: The molar ratio of Si-H bonds on the dihydrogen cage silsesquioxane and acryl alcohol in step B2 is 1:1, and the molar ratio of carboxyl groups on the functionalized silsesquioxane and eleostearic acid is 1:

1.

6. The method for preparing recycled aggregate concrete according to claim 1, characterized in that: The molar ratio of acrylic acid to diethyl disulfide in step B3 is 1:1, and the molar ratio of carboxyl group, KH550 and dicyclohexylcarbodiimide on the additive is 1:1:1.

1.

7. A recycled aggregate concrete, characterized in that: Prepared according to any one of claims 1 to 6.

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