Solid waste-based expansion type recycled aggregate interface strengthening agent and its grouting method and application

Abstract

The application discloses a solid waste-based expansive recycled aggregate interface reinforcing agent and a slurry wrapping method and application thereof, belongs to the technical field of aggregate reinforcing regeneration, and is used for solving the technical problem that the strength of the recycled aggregate and the performance of the prepared concrete need to be further improved in the prior art. The solid waste-based expansive recycled aggregate interface reinforcing agent is composed of dry matrix powder and water, and the dry matrix powder comprises the following components in parts by weight: phosphogypsum 42-47 parts, blast furnace slag powder 50-55 parts, silicon powder 3-5 parts and carbide slag 1.8-2.2 parts. The application performs interface enhancement regeneration on the recycled aggregate by optimizing the composition of the interface reinforcing agent and the slurry wrapping method, effectively improves the comprehensive performance of the recycled aggregate, effectively improves the strength and fluidity of the concrete sample when the recycled aggregate is applied to concrete processing, and has low production cost and advantages of cost and environmental protection in the treatment of a large amount of recycled aggregate.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aggregate reinforcement recycling technology, in particular to a solid waste-based expansive recycled aggregate interface reinforcing agent and its slurry wrapping method and application. BACKGROUND

[0002] With the acceleration of global urbanization, the demand for building materials in the construction industry is increasing, and a large amount of construction waste is also generated. A large amount of construction waste is landfilled or illegally dumped, not only occupying a large amount of land, but also causing serious environmental pollution. In recent years, the resource utilization of construction waste has gradually attracted attention. The conversion of construction waste into recycled aggregate and its application in concrete production can realize efficient recycling of resources and significant reduction of carbon emissions.

[0003] However, the pores in the recycled aggregate include large pores (> 10 pm), capillary pores (50 nm ~ 10 pm), transition pores (10 nm ~ 50 nm) and gel pores (< 10 nm), among which the gel pores and transition pores have less effect on strength, and the capillary pores have a significant effect on mechanical properties and durability. The surface characteristics, porosity and water absorption of recycled aggregate and other factors cause defects in the bonding interface between the recycled aggregate and the cementitious material matrix of the concrete, which reduces the workability and mechanical properties of the concrete.

[0004] At present, the interface reinforcement methods of building solid waste recycled coarse aggregate mainly include physical reinforcement, chemical reinforcement, biological reinforcement and composite reinforcement. Physical reinforcement mainly improves the performance of recycled coarse aggregate through mechanical or thermal treatment, chemical reinforcement uses chemical solution or slurry to fill the pores of the aggregate and enhance the interface transition zone, and biological reinforcement uses microbial metabolites to deposit calcium carbonate to fill the pores. The above three methods all need high-value energy or additives, and they do not have cost and environmental protection advantages for large-scale recycled aggregate treatment. Moreover, the existing slurry with Portland cement as the hydration matrix mainly depends on the reaction of C3S and C2S with water to generate C-S-H gel and Ca(OH)2, which requires a large amount of water to participate in the rapid reaction in the early stage, and more water to maintain fluidity. Moreover, its setting time is extremely fast, which cannot provide enough operation time for the slurry, resulting in the need to further improve the strength of the recycled aggregate and the performance of the prepared concrete.

[0005] The present application adheres to the principle of treating waste with waste, and uses a solid waste-based inorganic expansive slurry to modify and reinforce the surface of recycled aggregate, optimize the performance of recycled aggregate for preparing concrete, and help solve the problem of construction waste treatment. In view of the technical defects in this regard, a solution is proposed. SUMMARY

[0006] The application aims to provide a solid waste-based expanded recycled aggregate interface reinforcing agent, a slurry coating method and application thereof, and solve the technical problem that the strength of the recycled aggregate and the performance of the prepared concrete need to be further improved in the prior art.

[0007] The application aims to provide a solid waste-based expanded recycled aggregate interface reinforcing agent, a slurry coating method and application thereof, and solve the technical problem that the strength of the recycled aggregate and the performance of the prepared concrete need to be further improved in the prior art.

[0008] A solid waste-based expanded recycled aggregate interface reinforcing agent is composed of dry matrix powder and water, and has a viscosity of 8000-12000 cP, wherein the dry matrix powder comprises the following components in parts by weight: phosphogypsum 42-47 parts, blast furnace slag powder 50-55 parts, silicon powder 3-5 parts, and carbide slag 1.8-2.2 parts, wherein the silicon powder is composed of silica fume and siloxane monomer at a weight ratio of 7:1-2.

[0009] Further, the particle size of the phosphogypsum and the carbide slag is 0.1-0.6 mm; the calcium hydroxide content of the carbide slag is 70-85%; and the blast furnace slag powder is S95 grade slag powder.

[0010] Further, the preparation method of the silicon powder is as follows: the siloxane monomer and anhydrous ethanol are mixed and stirred to obtain a siloxane solution, then the silicon powder is added to the siloxane solution, and stirring and mixing are performed for 2-3 h, the temperature of the reaction system is increased to 50-60 DEG C, low-boiling substances are removed by reduced pressure evaporation, and the silicon powder is obtained, wherein the siloxane monomer comprises tetraethyl orthosilicate, methyl orthosilicate, triethoxysilane, and methyl triethoxysilane.

[0011] Further, the preparation method of the interface reinforcing agent is as follows: drinking water is added to the dry matrix powder, stirring is performed for 2-3 min, and standing is performed for 3-5 min to fully wet the solid particles, then drinking water is continuously added under stirring until the viscosity is 8000-12000 cP, the pH value of the reaction system is determined, and the pH value is adjusted to 12-13 to obtain the interface reinforcing agent.

[0012] A slurry coating method of a solid waste-based expanded recycled aggregate, wherein the solid waste-based expanded recycled aggregate interface reinforcing agent is coated on the outside of the recycled aggregate in the form of atomization.

[0013] Further, the slurry coating method of the solid waste-based expanded recycled aggregate comprises the following steps:

[0014] S1, building solid waste is crushed and sieved to obtain recycled aggregate of different particle sizes;

[0015] S2, the recycled aggregate is put into the mixer and stirred for 30-50s, the interfacial reinforcing agent is sprayed into the mixer in the form of atomized sprayed mortar, after spraying for 130-150s, the water reducing agent is added into the mixer, and stirring is carried out for 60-80min, and then the material is discharged, so that the first coated mortar aggregate is obtained;

[0016] S3, the first coated mortar aggregate is added into the vibrating screen, the interfacial reinforcing agent is sprayed into the vibrating screen in the form of atomized sprayed mortar, and the mortar is coated to the expected thickness, and then the material is discharged, so that the second coated mortar aggregate is obtained.

[0017] S4, the second coated mortar aggregate is cured for 14 days, so that the recycled aggregate is obtained.

[0018] Further, in step S1, the preparation method of the recycled aggregate is as follows: the construction waste is put into a pulverizer, after pulverization, the light impurities are removed by using the countercurrent air separation, the metal impurities are removed by using the magnetic roller separation, and then the screen mesh is used for screening, so that the coarse recycled aggregate with a particle size of 10-20mm and the fine recycled aggregate with a particle size of 5-10mm are obtained.

[0019] Further, in step S2, the mixer is a tilting double-shaft mixer, the inclination angle is 15°, the rotating speed is 18-20rpm, the temperature of the interfacial reinforcing agent is 25±2℃, the sprayed mortar pressure is 0.2MPa, the water reducing agent is a polycarboxylic acid water reducing agent, and the usage amount is 0.1% of the weight of the recycled aggregate.

[0020] Further, in step S3, the vibrating screen is a three-dimensional elliptical vibrating screen, the vibration frequency is 2000-2500 times / min, in the second coated mortar aggregate, the coating thickness of the coarse recycled aggregate is 1.2-1.8mm, and the coating thickness of the fine recycled aggregate is 0.1-0.3mm; in step S4, the curing temperature is 20±1℃, and the humidity is 95-98%.

[0021] The application of the solid waste-based expanded recycled aggregate, the recycled aggregate prepared by the coating method of the solid waste-based expanded recycled aggregate is used to improve the surface pore structure of the recycled aggregate, reduce the water absorption, and improve the working performance and mechanical properties of the concrete.

[0022] The application has the following advantages:

[0023] 1. The solid waste-based expanded recycled aggregate interface reinforcing agent of the present application, the wrapping slurry material constructed by the phosphogypsum-slag-carbide slag-silicon powder system, the blast furnace slag powder and silicon powder are the main hydration raw materials in the dry matrix powder, the non-crystalline phase amorphous spherical shape of silica fume in silicon powder is relatively smooth, the hydrophobic organic silicon network is generated after the hydrolysis of silane monomer and the bonding of silica fume, the water absorption of aggregate is reduced, the interface water accumulation is reduced, the blast furnace slag powder forms a glass structure under the quenching process, the particles are usually spherical or near spherical, the surface is smooth, compared with the irregular or multi-angled morphology of silicate cement particles, it has obvious lubricating effect and packing density advantage, compared with traditional cement-based materials, it is easier to penetrate into the loose structure of recycled aggregate surface, and the low calcium composition of blast furnace slag powder requires less water, and the phosphogypsum and carbide slag in the present application have no independent hydration capacity, therefore, under the condition of maintaining the later mechanical properties of the matrix at the same water-cement ratio, the slurry system provided by the present application has more outstanding fluidity, so that the cementing system of the present application is more suitable for uniform infiltration of the loose interface structure of recycled aggregate, improves the surface density of recycled aggregate, reduces the water absorption, and improves the slump of concrete mixed with recycled aggregate.

[0024] 2. The solid waste-based expanded recycled aggregate interface reinforcing agent of the present application, the phosphogypsum in the interface reinforcing agent provides sulfate ions, the blast furnace slag powder provides aluminate source, the spherical particles promote slurry infiltration through lubricating effect, and provide calcium ions to participate in hydration reaction, the strong alkalinity of carbide slag can adjust the reaction system to be alkaline environment, so as to promote the ordered arrangement of ettringite crystals and avoid the premature wrapping of calcium silicate gel around unreacted particles, realize the reasonable volume expansion of relative hydration raw materials, form effective hydration product filling in the structure part not penetrated by slurry, reduce the water absorption and crushing index of recycled aggregate, and improve the compressive strength of concrete material.

[0025] 3. The solid waste-based expanded recycled aggregate wrapping slurry method of the present application, the recycled aggregate is regenerated by twice vibration wrapping slurry, the interface reinforcing agent is promoted to fully penetrate into the microcracks of construction waste, the hydration expansion of the interface reinforcing agent is fully filled, the interface filling effect is improved, and the interface reinforcing agent is mainly industrial solid waste (phosphogypsum, blast furnace slag, carbide slag), which reduces the land occupation and heavy metal leakage risk caused by traditional landfill disposal, and the performance of the treated recycled aggregate is significantly improved, so that the recycling rate of construction waste is improved, compared with the large energy consumption of traditional crushing process (breaking the surface mortar layer), the carbon emission is reduced, DETAILED DESCRIPTION

[0026] The technical solutions of the present application will be clearly and completely described below in conjunction with the embodiments, and obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0027] In the present application, the particle size of the phosphogypsum is 0.1-0.6mm, the content of calcium sulfate dihydrate is ≥80%, the content of water-soluble phosphorus pentoxide is ≤0.30%, the content of water-soluble fluoride ions is ≤0.20%, and the content of chloride ions is ≤0.04%;

[0028] In the present application, the particle size of the calcium hydroxide is 0.1-0.6mm, and the content of calcium hydroxide is 70-85%;

[0029] In the present application, the blast furnace slag powder is S95 grade slag powder, the specific surface area is ≥400m 2 / kg, the 7d strength activity index and the 28d strength activity index are greater than 70% and 95% respectively;

[0030] In the present application, the silica fume is selected from Kaiyuan City Hairui Refractory Material Co., Ltd., and the quality standard GB / T27690-2011 is executed, the content of silicon dioxide is 92-96%, the loss on ignition is ≤6%, and the content of Cl is ≤0.02%.

[0031] Example 1

[0032] The present embodiment provides a preparation method of a solid waste-based expanded recycled aggregate interface strengthening agent, comprising the following steps:

[0033] A1, preparing silica powder

[0034] Take: 10g of tetraethyl orthosilicate and 300mL of anhydrous ethanol are added to a reaction bottle and mixed and stirred, stirring and mixing for 20min at room temperature, 70g of silica fume is added to the reaction bottle, stirring and mixing for 2h, the temperature of the reaction bottle is increased to 50℃, and low boiling point substances are removed by reduced pressure evaporation, to obtain silica powder.

[0035] A2, preparing interface strengthening agent

[0036] Take: 42 parts of phosphogypsum, 50 parts of blast furnace slag powder, 3 parts of silica powder and 1.8 parts of calcium carbide slag are mixed and stirred according to weight parts, to obtain dry matrix powder;

[0037] The dry matrix powder is added to the reaction bottle and stirred, then 0.4 times the weight of drinking water of the dry matrix powder is added to the reaction bottle, stirring for 2min, standing for 3min, so that the solid particles are fully wetted, stirring, and under the stirring state, continue to add drinking water until the viscosity is 8000cP, measure the pH of the reaction system, and adjust the pH of the system to 12, to obtain the interface strengthening agent.

[0038] Example 2

[0039] The embodiment provides a preparation method of a solid waste-based expanded recycled aggregate interface reinforcing agent, and the method comprises the following steps:

[0040] A1, preparing silicon powder

[0041] Take: methyl orthosilicate 15g, anhydrous ethanol 300mL is added to the reaction bottle for mixing and stirring, stirring and mixing at room temperature for 25min, 70g of silica ash is added to the reaction bottle, stirring and mixing for 2.5h, the temperature of the reaction bottle is increased to 55℃, and low boiling point substances are removed by evaporation under reduced pressure to obtain silicon powder.

[0042] A2, preparing interface reinforcing agent

[0043] Take by weight: 44.5 parts of phosphogypsum, 52.5 parts of blast furnace slag powder, 4 parts of silicon powder and 2.0 parts of carbide slag are uniformly mixed to obtain dry matrix powder;

[0044] The dry matrix powder is added to the reaction bottle for stirring, then 0.4 times the weight of drinking water of the dry matrix powder is added to the reaction bottle, stirring for 2.5min, standing for 4min, so that the solid particles are fully wetted, stirring, and under the stirring state, continue to add drinking water until the viscosity is 10000cP, measure the acidity and alkalinity of the reaction system, and adjust the pH of the system to 12.5 to obtain the interface reinforcing agent.

[0045] Example 3

[0046] The embodiment provides a preparation method of a solid waste-based expanded recycled aggregate interface reinforcing agent, and the method comprises the following steps:

[0047] A1, preparing silicon powder

[0048] Take: methyl triethoxysilane 20g, anhydrous ethanol 300mL is added to the reaction bottle for mixing and stirring, stirring and mixing at room temperature for 30min, 70g of silica ash is added to the reaction bottle, stirring and mixing for 3h, the temperature of the reaction bottle is increased to 60℃, and low boiling point substances are removed by evaporation under reduced pressure to obtain silicon powder.

[0049] A2, preparing interface reinforcing agent

[0050] Take by weight: 44.5 parts of phosphogypsum, 52.5 parts of blast furnace slag powder, 4 parts of silicon powder and 2.0 parts of carbide slag are uniformly mixed to obtain dry matrix powder;

[0051] The dry base powder is added to the reaction bottle and stirred, then 0.4 times the weight of the dry base powder of drinking water is added to the reaction bottle, stirred for 3 min, and left to stand for 5 min to fully wet the solid particles, then stirred, and under the stirring state, continue to add drinking water to the system until the viscosity reaches 12000 cP, measure the pH of the reaction system, and adjust the pH of the system to 13 to obtain the interface strengthening agent.

[0052] Example 4

[0053] The present embodiment provides a slurry wrapping method for solid waste-based expanded recycled aggregate, comprising the following steps:

[0054] Step 1, construction waste sorting

[0055] The construction waste is put into a crusher, after crushing, the light impurities are removed by using countercurrent air separation, the metal impurities are removed by using magnetic drum separation, and then the screen is used to obtain coarse recycled aggregate with a particle size of 10-20 mm and fine recycled aggregate with a particle size of 5-10 mm.

[0056] Step 2, coarse recycled aggregate slurry wrapping

[0057] The coarse recycled aggregate is put into an inclined double-shaft mixer with an inclination angle of 15° and a rotation speed of 18 rpm and stirred for 30 s, the interface strengthening agent prepared in Example 1 is sprayed into the mixer after atomization at a pressure of 0.2 MPa, after spraying for 130 s, 0.1% polycarboxylate superplasticizer by weight of the coarse recycled aggregate is added to the mixer and stirred for 60 min, and then the product is discharged to obtain the first slurry-wrapped coarse aggregate;

[0058] The first slurry-wrapped coarse aggregate is added to a three-dimensional elliptical vibrating screen, the vibration frequency is set to 2000 times / min, the interface strengthening agent is sprayed in the form of atomized slurry onto the first slurry-wrapped coarse aggregate, and the slurry wrapping is performed until the slurry thickness reaches 1.2 mm, then the product is discharged to obtain the second slurry-wrapped coarse aggregate.

[0059] Step 3, fine recycled aggregate slurry wrapping

[0060] The fine recycled aggregate is put into an inclined double-shaft mixer with an inclination angle of 15° and a rotation speed of 18 rpm and stirred for 30 s, the interface strengthening agent prepared in Example 1 is sprayed into the mixer after atomization at a pressure of 0.2 MPa, after spraying for 130 s, 0.1% polycarboxylate superplasticizer by weight of the coarse recycled aggregate is added to the mixer and stirred for 60 min, and then the product is discharged to obtain the first slurry-wrapped coarse aggregate;

[0061] The first slurry-wrapped coarse aggregate is added to a three-dimensional elliptical vibrating screen, the vibration frequency is set to 2000 times / min, the interface strengthening agent is sprayed in the form of atomized slurry onto the first slurry-wrapped coarse aggregate, and the slurry wrapping is performed until the slurry thickness reaches 1.2 mm, then the product is discharged to obtain the second slurry-wrapped coarse aggregate.

[0062] Step 4, preparation of recycled aggregate

[0063] The secondary coated slurry coarse aggregate and the secondary coated slurry fine aggregate are mixed in a weight ratio of 4:9, and then placed in a curing box, the temperature of the curing box is set to 20℃, the humidity is set to 95%, and the curing is carried out for 14 days, then the material is discharged to obtain the recycled aggregate.

[0064] Example 5

[0065] The present embodiment provides a slurry coating method for solid waste-based expanded recycled aggregate, comprising the following steps:

[0066] Step 1, sorting of construction waste

[0067] The construction waste is put into a crusher, crushed, and then subjected to countercurrent air separation to remove light impurities, magnetic drum separation to remove metal impurities, and screen meshing to obtain coarse recycled aggregate with a particle size of 10-20mm and fine recycled aggregate with a particle size of 5-10mm.

[0068] Step 2, coating of coarse recycled aggregate

[0069] The coarse recycled aggregate is placed in an inclined double-shaft mixer with an inclination angle of 15° and a rotation speed of 19rpm, and stirred for 40s, the interfacial strengthening agent prepared in Example 2 is sprayed into the mixer after being atomized at a pressure of 0.2MPa, and after 140s of spraying, 0.1% polycarboxylate superplasticizer by weight of the coarse recycled aggregate is added to the mixer, and stirred for 70min, and then the material is discharged to obtain the primary coated coarse aggregate.

[0070] The primary coated coarse aggregate is added to a three-dimensional elliptical vibrating screen, the vibration frequency is set to 2250times / min, and the interfacial strengthening agent is sprayed in the form of atomized slurry onto the primary coated coarse aggregate, and the coating is carried out until the coating thickness reaches 1.5mm, and then the material is discharged to obtain the secondary coated coarse aggregate.

[0071] Step 3, coating of fine recycled aggregate

[0072] The fine recycled aggregate is placed in an inclined double-shaft mixer with an inclination angle of 15° and a rotation speed of 19rpm, and stirred for 40s, the interfacial strengthening agent prepared in Example 2 is sprayed into the mixer after being atomized at a pressure of 0.2MPa, and after 140s of spraying, 0.1% polycarboxylate superplasticizer by weight of the coarse recycled aggregate is added to the mixer, and stirred for 70min, and then the material is discharged to obtain the primary coated fine aggregate.

[0073] The primary coated fine aggregate is added to a three-dimensional elliptical vibrating screen, the vibration frequency is set to 2250times / min, and the interfacial strengthening agent is sprayed in the form of atomized slurry onto the primary coated coarse aggregate, and the coating is carried out until the coating thickness reaches 0.2mm, and then the material is discharged to obtain the secondary coated fine aggregate.

[0074] Step 4, preparation of recycled aggregate

[0075] The secondary coated aggregate and the secondary coated fine aggregate are mixed in a weight ratio of 5:9.5, and then placed in a curing box, the temperature of the curing box is set to 20°C, the humidity is set to 97%, and the curing is carried out for 14 days, then the material is discharged to obtain the recycled aggregate.

[0076] Example 6

[0077] The present embodiment provides a slurry coating method for solid waste-based expanded recycled aggregate, comprising the following steps:

[0078] Step 1, sorting of construction waste

[0079] The construction waste is put into a crusher, after crushing, the light impurities are removed by using countercurrent air separation, the metal impurities are removed by using a magnetic drum separator, and then the screen is used to obtain coarse recycled aggregate with a particle size of 10-20mm and fine recycled aggregate with a particle size of 5-10mm.

[0080] Step 2, coating of coarse recycled aggregate

[0081] The coarse recycled aggregate is placed in an inclined double-shaft mixer with an inclination angle of 15° and a rotation speed of 20rpm, and stirred for 50s, the interfacial strengthening agent prepared in Example 3 is sprayed into the mixer after being atomized at an atomizing pressure of 0.2MPa, after spraying for 150s, 0.1% polycarboxylate superplasticizer by weight of the coarse recycled aggregate is added to the mixer, and stirred for 80min, then the material is discharged to obtain the primary coated coarse aggregate;

[0082] The primary coated coarse aggregate is added to a three-dimensional elliptical vibrating screen, the vibration frequency is set to 2500times / min, and the interfacial strengthening agent is sprayed in the form of atomized slurry onto the primary coated coarse aggregate, the coating is carried out until the coating thickness reaches 1.8mm, then the material is discharged to obtain the secondary coated coarse aggregate.

[0083] Step 3, coating of fine recycled aggregate

[0084] The fine recycled aggregate is placed in an inclined double-shaft mixer with an inclination angle of 15° and a rotation speed of 20rpm, and stirred for 50s, the interfacial strengthening agent prepared in Example 3 is sprayed into the mixer after being atomized at an atomizing pressure of 0.2MPa, after spraying for 150s, 0.1% polycarboxylate superplasticizer by weight of the coarse recycled aggregate is added to the mixer, and stirred for 80min, then the material is discharged to obtain the primary coated fine aggregate;

[0085] The primary coated fine aggregate is added to a three-dimensional elliptical vibrating screen, the vibration frequency is set to 2500times / min, and the interfacial strengthening agent is sprayed in the form of atomized slurry onto the primary coated coarse aggregate, the coating is carried out until the coating thickness reaches 0.3mm, then the material is discharged to obtain the secondary coated fine aggregate.

[0086] Step 4, preparation of recycled aggregate

[0087] The secondary coated coarse aggregate and the secondary coated fine aggregate were mixed in a weight ratio of 6:10, and then placed in a curing box with a temperature of 21℃ and a humidity of 98%. After 14 days of curing, the recycled aggregate was obtained by discharging.

[0088] Comparative Example 1

[0089] The difference between this comparative example and Example 6 is that the amount of phosphogypsum added during the preparation of the interfacial strengthening agent is 65 parts.

[0090] Comparative Example 2

[0091] The difference between this comparative example and Example 6 is that the silicate cement is used to replace the blast furnace slag powder and silicon powder in the preparation of the interfacial strengthening agent.

[0092] Comparative Example 3

[0093] The difference between this comparative example and Example 6 is that the silica fume in Step A1 is used to replace the silicon powder in Step A2 in the preparation of the interfacial strengthening agent.

[0094] Comparative Example 4

[0095] The difference between this comparative example and Example 6 is that both Step 2 and Step 3 are cancelled, and the desired coating thickness is obtained directly by one-time coating.

[0096] Performance test:

[0097] The initial setting time and final setting time of the interfacial strengthening agent used in Examples 4-6 and Comparative Examples 1-3 were determined according to the standard GB / T 1346-2011 "Cement Standard Consistency Water Content, Setting Time, and Stability Test Method".

[0098] The crushing index of the recycled aggregate prepared in Examples 4-6 and Comparative Examples 1-4 was determined according to the standard GB / T 14685-2022 "Construction Pebbles and Crushed Stones".

[0099] The recycled aggregate was placed in a blast drying oven at a temperature of 45℃ and dried to a constant weight, with the weight recorded as m1. Then the dried recycled aggregate was placed in a vacuum water retention machine for 18h vacuum water retention, with the weight recorded as m2. The saturated water absorption rate of the recycled aggregate prepared in Examples 4-6 and Comparative Examples 1-4 was tested according to the formula

[0100] The specific test results are shown in Table 1 below.

[0101] Table 1 - Performance test data table of recycled aggregate

[0102] ​

[0103] Data analysis:

[0104] Comparative analysis of the data in Table 1 above, the initial setting time of the interface reinforcing agent prepared by the application reaches 725 min, the final setting time reaches 890 min, the crushing index of the recycled aggregate wrapped with the interface reinforcing agent reaches 11%, and the saturated water absorption rate is reduced to 3.5%. The performance test data is better than that of the comparative example, which shows that the interface reinforcing agent with normal setting time is obtained by optimizing the composition of the interface reinforcing agent, and the recycled aggregate is regenerated by the interface enhancement method. The strength of the recycled aggregate is effectively improved, and the water absorption rate of the recycled aggregate is reduced.

[0105] The recycled aggregate prepared in Examples 4-6 and Comparative Examples 1-4 is used as fine aggregate to prepare C30 concrete samples, and the coarse recycled aggregate and fine recycled aggregate prepared in Example 6 Step 1 are graded according to the weight ratio of 6:10 to participate in the preparation of C30 concrete as a blank example;

[0106] The slump of the concrete sample prepared by using the recycled aggregate prepared in Examples 4-6 and Comparative Examples 1-4 as fine aggregate is determined according to the standard GB / T 50080-2016 "Standard Test Methods for Performance of Ordinary Concrete Mixture".

[0107] The concrete sample prepared by using the recycled aggregate prepared in Examples 4-6 and Comparative Examples 1-4 as fine aggregate is prepared into a 25mm×25mm×280mm size test piece according to the test piece preparation and curing in the standard GB / T 50081-2019 "Standard Test Methods for Physical and Mechanical Properties of Concrete", and the compressive strength of the test sample after 3 days and 28 days of curing is determined.

[0108] The specific test results are shown in Table 2 below.

[0109] Table 2-Performance test data of C30 concrete sample prepared from recycled aggregate

[0110]

[0111] Data analysis:

[0112] Comparative analysis of the data in Table 2 above, the slump of the C30 concrete sample prepared from the recycled aggregate reaches 230mm, the 3-day compressive strength reaches 35.1MPa, and the 28-day compressive strength reaches 52.2MPa. The performance test data is better than that of the comparative example and the blank example, which shows that the recycled aggregate is prepared by optimizing the composition of the interface reinforcing agent and the wrapping method, and is used to prepare C30 concrete. Not only the fluidity is effectively improved, but also the compressive strength of the concrete sample is improved.

[0113] The above merely illustrates and describes the structure of the present application, and those skilled in the art can make various modifications, additions or substitutions to the specific embodiments described or use similar ways to replace, as long as the modifications, additions or substitutions do not deviate from the structure of the present application or exceed the scope defined by the claims, and should be within the protection scope of the present application.

[0114] In the description of the present specification, the description referring to the terms "one embodiment", "an example", "a specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0115] The preferred embodiments of the present application disclosed above are only used to help explain the present application. The preferred embodiments do not describe all the details and limit the present application to the specific embodiments. Obviously, many modifications and changes can be made according to the content of the present specification. The present specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well understand and utilize the present application. The present application is limited only by the claims and their full scope and equivalents.

Claims

1. A solid waste-based expanded recycled aggregate interfacial strengthening agent, characterized by, The solid waste-based expanded recycled aggregate interface strengthening agent is composed of dry matrix powder and water, and has a viscosity of 8000-12000 cP, the dry matrix powder is composed of phosphogypsum, blast furnace slag powder, silicon powder and carbide slag, wherein the phosphogypsum is 42-47 parts by weight, the blast furnace slag powder is 50-55 parts by weight, the silicon powder is 3-5 parts by weight, and the carbide slag is 1.8-2.2 parts by weight, the silicon powder is composed of silica fume and siloxane monomer at a weight ratio of 7:1-2; The preparation method of the silicon powder is as follows: the siloxane monomer and anhydrous ethanol are mixed and stirred to obtain a siloxane solution, then the silica fume is added to the siloxane solution, and stirred and mixed for 2-3 hours, the temperature of the reaction system is raised to 50-60℃, and low boiling point substances are removed by vacuum distillation to obtain the silicon powder, the siloxane monomer is any one of tetraethyl orthosilicate, tetramethyl orthosilicate and triethoxysilane.

2. The solid waste-based expanded recycled aggregate interfacial strengthening agent according to claim 1, characterized by, The particle size of the phosphogypsum and the carbide slag is 0.1-0.6 mm; the calcium hydroxide content of the carbide slag is 70-85%; and the blast furnace slag powder is S95 grade slag powder.

3. The solid waste-based interfacial strengthening agent for expanded recycled aggregate according to claim 1, characterized by, The preparation method of the interface strengthening agent is as follows: drinking water is added to the dry matrix powder, stirred for 2-3 minutes, and then left for 3-5 minutes to fully wet the solid particles, then drinking water is continuously added under stirring until the viscosity reaches 8000-12000 cP, the pH value of the reaction system is measured and adjusted to 12-13 to obtain the interface strengthening agent.

4. A method of slurry coating solid waste-based expanded recycled aggregate, characterized by, The solid waste-based expanded recycled aggregate interface strengthening agent of any one of claims 1-3 is used in the form of atomization to coat a layer of wrapped slurry on the recycled aggregate.

5. A method of coating a solid waste-based expanded recycled aggregate according to claim 4, characterized by, The method comprises the following steps: S1, crushing and screening the building solid waste to obtain recycled aggregates of different particle sizes; S2, putting the recycled aggregate into a stirrer and stirring for 30-50 seconds, spraying the interface strengthening agent in the form of atomized sprayed slurry into the stirrer, adding a water reducing agent into the stirrer after spraying for 130-150 seconds, and stirring for 60-80 minutes to obtain a first wrapped slurry aggregate; S3, adding the first wrapped slurry aggregate into a vibrating screen, spraying the interface strengthening agent in the form of atomized sprayed slurry into the vibrating screen, and wrapping the slurry to the desired thickness to obtain a second wrapped slurry aggregate; S4, curing the second wrapped slurry aggregate for 14 days to obtain a recycled aggregate.

6. A method of coating a solid waste-based expanded recycled aggregate according to claim 5, characterized by, In step S1, the preparation method of the recycled aggregate is as follows: the building waste is put into a crusher, crushed, and then the light impurities are removed by using the countercurrent air separation, the metal impurities are removed by using the magnetic drum separation, and then the screen mesh is used to obtain coarse recycled aggregates with a particle size of 10-20 mm and fine recycled aggregates with a particle size of 5-10 mm.

7. The method of claim 5, wherein the method further comprises, In step S2, the stirrer is an inclined double-shaft stirrer with an inclination angle of 15° and a rotation speed of 18-20 rpm, the temperature of the interface strengthening agent is 25±2℃, the spraying pressure is 0.2 MPa, the water reducing agent is a polycarboxylic acid water reducing agent, and the usage amount is 0.1% of the weight of the recycled aggregate.

8. The method of claim 5, wherein the method further comprises, In step S3, the vibrating screen is a three-dimensional elliptical vibrating screen, the vibration frequency is 2000-2500 times / min, the slurry coating thickness of the coarse recycled aggregate in the secondary slurry coating aggregate is 1.2-1.8mm, and the slurry coating thickness of the fine recycled aggregate is 0.1-0.3mm; in step S4, the curing temperature is 20±1℃, and the humidity is 95-98%.

9. Use of solid waste based expanded recycled aggregate characterized in that, The recycled aggregate prepared by the slurry coating method of the solid waste-based expanded recycled aggregate according to any one of claims 4-8 is used to improve the surface pore structure of the recycled aggregate, reduce the water absorption, and improve the working performance and mechanical properties of the concrete.

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