Self-curing pavement base material based on modified household garbage incineration slag and preparation method thereof

Abstract

The invention discloses a self-curing pavement base material based on modified household garbage incineration slag and a preparation method thereof, belongs to the technical field of preparation of pavement base materials, and aims to solve the technical problem that the water-retaining property, crack resistance and durability of the pavement base material in the prior art need to be further improved. The method specifically comprises the following steps: uniformly dry-mixing cement, aggregate and hydrophilic modified slag aggregate in a mixer, adding mixing water, and uniformly mixing to obtain a mixture; according to the invention, the pretreated household garbage incineration slag is used as a functional aggregate, and a hydrophilic functional layer formed by a dopamine copolymer, self-repairing modified silica sol and sodium polyacrylate is introduced into pores of the functional aggregate, so that the aggregate-cement interface performance is synergistically enhanced, and the water-retaining property, crack resistance and durability of a base material are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pavement base material preparation, in particular to a self-curing pavement base material based on modified household waste incineration slag and a preparation method thereof. BACKGROUND

[0002] The pavement base material is mainly cement stabilized macadam, recycled aggregate stabilized material and various cement stabilized soil. The performance evaluation increasingly emphasizes the strength-volume stability-durability synergy. In engineering practice, in order to meet the requirements of rapid construction and long-term service, the early strength of the base material can be guaranteed by optimizing the gradation, cementitious system and curing conditions, but under the action of drying, temperature difference and repeated load, the drying shrinkage and temperature shrinkage caused by water loss in the base material are still easy to induce microcracks, and then form through cracks and reflection crack channels, which weaken the overall crack resistance and water stability. At the same time, the pore connectivity and interface transition zone defects accelerate the development of water seepage, freeze-thaw, salt corrosion and fatigue damage, which shows the problems of difficult shrinkage cracking control, fast durability decay and high curing dependence, so improving water retention, inhibiting cracking and enhancing long-term durability have become an important development direction of the base material.

[0003] At present, the industry selects low-heat or mineral admixture system to optimize the hydration product and pore structure, adds fibers to realize crack bridging and toughness improvement, uses shrinkage compensation / expansion agent, shrinkage reducing agent or air entraining agent to reduce drying shrinkage sensitivity, adds emulsion, SBR, EVA and other polymers to improve adhesion and impermeability, uses hydrophobic agent to reduce water absorption and capillary permeation, and uses recycled aggregate pre-wetting, internal addition of lightweight aggregate / water absorption resin and other methods to improve the internal water content and construction workability.

[0004] However, the mineral admixture and expansion / shrinkage system often depends on the curing conditions and hydration process, and it is difficult to continuously provide effective water source and interface stability in the dry environment of the base material. Excessive amount may cause slow strength growth or volume stability fluctuation. The fiber mainly inhibits crack propagation rather than reducing microcrack initiation from the source. When the interface adhesion is insufficient, the bridging efficiency decreases. The internal addition of lightweight aggregate / water absorption resin can be internally cured, but it often faces the problems of poor water release controllability, insufficient matching with the matrix interface, insufficient pore connectivity and durability synergy. SUMMARY

[0005] The purpose of the present application is to provide a self-curing pavement base material based on modified household waste incineration slag and a preparation method thereof, which solves the technical problem that the water retention, crack resistance and durability of the pavement base material in the prior art need to be further improved.

[0006] The purpose of the present application can be realized by the following technical scheme: a preparation method of a self-curing pavement base material based on modified household waste incineration slag, comprising the following steps: S1, put sodium polyacrylate and deionized water into the reaction kettle and stir, add self-repairing modified silica sol and dopamine copolymer, stir at room temperature for 20-40 min, add sodium hydroxide aqueous solution to adjust pH to 8-9, stand for 15-20 min, and get the composite modified liquid; S2, the pretreated household waste incineration slag is immersed in the composite modified liquid at an impregnation ratio of 30-35:1, vacuum impregnated for 0.5-1h, and low temperature cured to obtain hydrophilic modified slag aggregate; S3, the cement, aggregate and hydrophilic modified slag aggregate are uniformly dry mixed in a mixer, mixed water is added, and mixed uniformly to obtain a mixture; S4, the mixture is injected into a mold and vibrated and compacted to obtain a shaped body; S5, the road base material is maintained to obtain a road base material.

[0007] Further, in step S1, the amount of sodium polyacrylate, deionized water, self-repairing modified silica sol and dopamine copolymer is 10-12g:800-1000mL:40-60g:25-30g, and the concentration of sodium hydroxide aqueous solution is 0.5-1.0mol / L.

[0008] Further, in step S2, the preparation method of the hydrophilic modified slag aggregate is as follows: the pretreated household waste incineration slag is immersed in the composite modified liquid at an impregnation ratio of 30-35:1, vacuum impregnated at a negative pressure of-0.08MPa to-0.1MPa for 0.5-1h, the product is taken out and placed in an oven at 50-60℃ for 1-2h of pre-drying, the oven is heated to 80-90℃, and pre-cured for 1-2h to obtain the hydrophilic modified slag aggregate.

[0009] Further, in step S3, the amount of cement, aggregate, hydrophilic modified slag aggregate and mixed water is 95-100g:340-350g:240-250g:35-40mL, the cement is Portland cement, the aggregate is composed of coarse aggregate and fine aggregate in a mass ratio of 60-75:25-40, the coarse aggregate is one or more of gravel, pebbles and recycled coarse aggregate, the particle size is 5-30mm, the fine aggregate is one or more of natural sand, machine-made sand and recycled fine aggregate, the particle size is 0.1-4.75mm, and the mixed water is one or more of tap water, underground water and deionized water.

[0010] Further, in step S4, the injection mode of the mold is one or both of one-time injection and layered injection, and the vibration compaction mode is one or more of vibration table vibration, plug-in vibration and surface vibration.

[0011] Further, in step S5, the pavement base material is cured by one or more of natural curing, wet curing, standard curing, and steam curing.

[0012] Further, the self-repairing modified silica sol is prepared by the following steps: A1, the silica sol, ethanol and deionized water are placed in a reaction kettle and stirred, an aqueous acetic acid solution is added to adjust the pH to 4.2-4.8, stirred at room temperature for 5-10 min, dropwise addition of 3-aminopropyl triethoxysilane solution, stirring at room temperature for 1-2 h, post-processing to obtain amino-modified silica sol; A2, 4-carboxyphenylboronic acid, MES buffer, N-hydroxysuccinimide and 1-(3- dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride are placed in a reaction kettle, stirred at room temperature for 20-30 min to obtain a carboxyl activation solution; A3, the amino-modified silica sol and MES buffer are placed in a reaction kettle and stirred, the carboxyl activation solution is added, stirred at room temperature for 14-16 h, post-processing to obtain a self-repairing modified silica sol.

[0013] Further, in step A1, the amount ratio of the silica sol, ethanol, deionized water and 3- aminopropyl triethoxysilane solution is 15-20 g:10-15 mL:10-12 mL:8-10 mL, the 3- aminopropyl triethoxysilane solution is 10-20 wt% 3-aminopropyl triethoxysilane ethanol solution, the concentration of the aqueous acetic acid solution is 3-5 wt%, and the post-processing step includes: after the reaction is completed, the sol product is added to the upper chamber of a 30 kDa ultrafiltration tube, centrifuged at a centrifugal force of 3000-5000 g until the volume is reduced to one third of the original volume, supplemented with deionized water to the original volume, and the centrifugation and liquid supplementing process is repeated 3-5 times, finally supplemented with deionized water to a solid content of 5-10 wt% to obtain the amino-modified silica sol.

[0014] Further, in step A2, the amount ratio of the 4-carboxyphenylboronic acid, MES buffer, N- hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride is 1-2 g:100-120 mL:1.0-1.5 g:1.0-1.5 g, the concentration of the MES buffer is 0.05-0.10 mol / L, and the pH is 5.5-6.0.

[0015] Further, in step A3, the amino-modified silica sol, MES buffer and carboxyl-activated solution are used in a ratio of 8-10 g:5-7 mL:5-8 mL, the concentration of the MES buffer is 0.05-0.10 mol / L, the pH is 5.5-6.0, and the post-treatment step comprises: after the reaction is completed, 0.1-0.2 g of ethanolamine is added to terminate the reaction, the sol product is added to the upper chamber of a 30 kDa ultrafiltration tube, centrifuged at a centrifugal force of 3000-5000 g until the volume is reduced to one third of the original volume, deionized water is added to the original volume, and the centrifugation and liquid supplementing process is repeated 3-5 times, finally deionized water is added to a solid content of 5-10 wt%, to obtain the self-repairing modified silica sol.

[0016] Further, the dopamine copolymer is prepared by the following steps: B1, dopamine hydrochloride and N,N-dimethylformamide are placed in a reaction kettle and stirred, ice-bath to 0-5℃, triethylamine is added, ice-bath reaction for 10-15 min, dropwise addition of 2-methyl acrylate, room temperature reaction for 8-12 h, post-treatment to obtain dopamine copolymer precursor; B2, dopamine copolymer precursor, methacryloyloxyethyl trimethylammonium chloride, 3-(methacryloyloxy) propyl trimethoxysilane and methanol are placed in a reaction kettle protected by nitrogen atmosphere and stirred, azobisisobutyronitrile is added, the reaction kettle is heated to 60-70℃, and incubated for 6-10 h, post-treatment to obtain dopamine copolymer.

[0017] Further, in step B1, the dopamine hydrochloride, N,N-dimethylformamide, triethylamine and 2-methyl acrylate are used in a ratio of 10-12 g:180-200 mL:10-12 g:8-10 g, and the post-treatment step comprises: after the reaction is completed, suction filtration, the filtrate is poured into 10 times the volume of ethanol to precipitate, suction filtration, the filter cake is washed with ether for 2-4 times, and transferred to an oven with a temperature of 50-60℃ for drying until the weight is constant, to obtain the dopamine copolymer precursor.

[0018] Further, in step B2, the dopamine copolymer precursor, methacryloyloxyethyl trimethylammonium chloride, 3-(methacryloyloxy) propyl trimethoxysilane, methanol and azobisisobutyronitrile are used in a ratio of 10-12 g:8-10 g:2-4 g:200-250 mL:0.08-0.10 g, and the post-treatment step comprises: after the reaction is completed, the reaction kettle is cooled to room temperature, the reaction solution is slowly poured into 600-800 mL of anhydrous ether to precipitate, suction filtration, the filter cake is washed with anhydrous ether 2-4 times, and transferred to an oven for drying for 6-8 h, to obtain the dopamine copolymer.

[0019] Further, the pretreated household garbage incinerator slag is prepared by the following steps: C1, the household garbage incineration slag is subjected to magnetic separation, air separation and crushing and screening to obtain a coarse slag aggregate; C2, the coarse slag aggregate is uniformly laid in a refractory tray of a tubular furnace under inert gas protection, and high-temperature treatment is performed to obtain pretreated household garbage incineration slag.

[0020] Further, in step C1, the household garbage incineration slag contains 35-40% of silicon dioxide, 15-20% of calcium oxide, 5-15% of aluminum oxide and 5-12% of iron oxide, and the coarse slag aggregate is prepared by the following method: the household garbage incineration slag is fed into a magnetic separation device for magnetic separation to remove ferromagnetic metal impurities contained in the slag, the light impurities and unburned combustibles in the slag are separated by air separation, the slag subjected to air separation is fed into a crushing device for crushing, and the coarse slag aggregate with a particle size of 3-10 mm is obtained after screening.

[0021] Further, in step C2, the pretreated household garbage incineration slag is prepared by the following method: the coarse slag aggregate is uniformly laid in a refractory tray of a tubular furnace under inert gas protection, the temperature is raised to 700-800 DEG C at a rate of 5-10 DEG C / min, and the temperature is maintained for 1-2 h, and the pretreated household garbage incineration slag is obtained after cooling to room temperature, and the inert gas is one or more of nitrogen, argon and helium.

[0022] In the present application, a self-curing pavement base material based on modified household garbage incineration slag is also provided, which is prepared by the above method.

[0023] The present application has the following advantages: 1. The dopamine structure unit retained in the dopamine copolymer molecule has the characteristics similar to the mussel adhesion protein, contains rich o-diphenol groups and amine groups, can form strong interface bonding with the slag aggregate, cement hydration products and the surface silanol groups of the silica sol through hydrogen bonds, coordination bonds and π-π interactions, improves the bonding strength between the modified slag aggregate and the cement matrix, improves the interface transition zone structure and reduces the interface defects, the introduced quaternary ammonium salt groups and hydrophilic polymer segments in the dopamine copolymer enhance the hydrophilicity and water absorption and retention capacity of the system, which helps to inhibit water migration during mixing and early curing stage, provides stable water source for continuous cement hydration, improves the water retention performance and early volume stability of the base material, and the dopamine copolymer and the self-repairing modified silica sol synergistically act in the weak alkaline environment, through the construction of dynamic non-covalent bonds and organic-inorganic composite network, the material has certain structure reconstruction ability when the microcracks or interface are damaged, and the durability and service reliability of the pavement base material are improved.

[0024] 2、The self-repairing modified silica sol of the present application takes silica sol as inorganic framework, and after introducing amino and phenylboronic acid groups on the surface, it not only maintains good water phase dispersibility, but also significantly improves the chemical reaction activity of the particle surface. In the composite modification liquid, the silica sol can form a continuous and stable inorganic-organic composite network on the surface of the aggregate and in the interface transition zone through condensation reaction between the silanol groups and the hydroxyl groups in the slag aggregate and cement hydration products, thereby improving the interface bonding state between the modified slag aggregate and the cement matrix, reducing the interface pores and weak interface defects. Secondly, the silica sol has small particle size and large specific surface area, which can fill the slag pores and micro-pores in the cement system, promote the densification of the slurry, and improve the impermeability and crack resistance of the pavement base material. Further, the reversible dynamic bond introduced by the phenylboronic acid group gives the silica sol system certain structure reconstruction ability, which can dynamically reorganize under the action of water and ions when micro-cracks or interface damage occur in the material during service, thereby helping to close the cracks and restore the interface performance.

[0025] 3、The present application also significantly removes the ferromagnetic metal, light impurities and unburned combustibles in the slag through magnetic separation, air flow separation and crushing screening, so that the aggregate composition is more pure and the particle size distribution is uniform, thereby effectively reducing the adverse effects of impurities on the cement hydration reaction and interface bonding. Secondly, high-temperature roasting treatment promotes the complete decomposition or oxidation of residual organic matter in the slag, and at the same time promotes the transformation of unstable phases to stable crystal phases, thereby reducing the risk of volume expansion, uneven chemical reaction or durability degradation in the later stage, and improving the long-term stability of the base material. Thirdly, the internal pore structure of the pretreated slag is more open and stable, which is conducive to the full vacuum impregnation and fixation of the composite modification liquid, and provides a good carrier for the formation of the subsequent hydrophilic modification layer, thereby enhancing the water storage and interface effect. During the cement mixing and hardening process, the pretreated slag can form a relatively stable interface structure with the hydration products, which not only plays a supporting role for the aggregate, but also participates in the construction of the overall dense structure. DETAILED DESCRIPTION

[0026] The technical solutions of the present application will be described below in conjunction with the embodiments, obviously, the described embodiments are only part 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 labor belong to the scope of protection of the present application.

[0027] The polyacrylic acid sodium used in the present application is purchased from Renqiu Shuangcheng Chemical Product Factory, the model number is 0687, and the density is 0.80 g / cm 3 ; The portland cement used in the present application is purchased from Shijiazhuang Yan Dong Mining Product Co., Ltd., the brand is 207-35, the purity is 90%, the density is 2.6 g / cm 3 , and the brand is Yan Dong Mining. The silica sol used in the present application is purchased from Hangzhou Zhemen New Material Co., Ltd., has an effective component content of 30%, and is a semi-transparent liquid with a particle size of 10 nm.

[0028] Example 1 The present embodiment provides a preparation method of pretreated household garbage incineration slag, comprising the following steps: Step I, preparation of slag aggregate crude product The household garbage incineration slag is sent into a magnetic separation device for magnetic separation treatment to remove ferromagnetic metal impurities contained in the slag, and the light impurities and unburnt combustibles in the slag are separated by airflow separation, and the slag after the air separation treatment is sent into a jaw crusher for crushing treatment, and the slag aggregate crude product with a particle size of 3-5 mm is obtained after screening.

[0029] Step II, preparation of pretreated household garbage incineration slag The slag aggregate crude product is uniformly placed in a refractory tray of a tube furnace under nitrogen protection, heated at a rate of 5 ℃ / min to 700 ℃, and kept for 1 h, and the pretreated household garbage incineration slag is obtained after cooling to room temperature.

[0030] The metal impurities, light impurities and unburnt combustibles in the slag are removed by magnetic separation and airflow separation, the slag aggregate crude product with uniform particle size is obtained by crushing and screening, and then the slag is calcined at high temperature under inert gas to decompose or oxidize the residual organic matter and promote the conversion of unstable phases, so that the pretreated household garbage incineration slag with stable composition and structure is obtained.

[0031] Example 2 The present embodiment provides a preparation method of pretreated household garbage incineration slag, comprising the following steps: Step I, preparation of slag aggregate crude product The household garbage incineration slag is sent into a magnetic separation device for magnetic separation treatment to remove ferromagnetic metal impurities contained in the slag, and the light impurities and unburnt combustibles in the slag are separated by airflow separation, and the slag after the air separation treatment is sent into a jaw crusher for crushing treatment, and the slag aggregate crude product with a particle size of 3-5 mm is obtained after screening.

[0032] Step II, preparation of pretreated household garbage incineration slag The slag aggregate crude product is uniformly placed in a refractory tray of a tube furnace under nitrogen protection, heated at a rate of 5 ℃ / min to 700 ℃, and kept for 1 h, and the pretreated household garbage incineration slag is obtained after cooling to room temperature.

[0033] Example 3 The present embodiment provides a preparation method of pretreated household garbage incineration slag, comprising the following steps: Step I, preparation of slag aggregate crude product The household waste incineration slag is sent into a magnetic separation device for magnetic separation treatment to remove ferromagnetic metal impurities contained in the slag, and the light impurities and incompletely combusted combustible materials in the slag are separated by airflow separation, and the slag treated by air separation is sent into a jaw crusher for crushing treatment, and the slag aggregate crude product with a particle size of 7.5-10 mm is obtained after screening.

[0034] Step II, preparation of pretreated household waste incineration slag The slag aggregate crude product is uniformly laid in a refractory tray of a tubular furnace under nitrogen protection, heated to 800℃ at a rate of 10℃ / min, and kept for 2h, and the pretreated household waste incineration slag is obtained after cooling to room temperature.

[0035] Example 4 The present embodiment provides a preparation method of dopamine copolymer, comprising the following steps: Step ①, preparation of dopamine copolymer precursor Take: dopamine hydrochloride 100g and N,N-dimethylformamide 1800mL are placed in a reaction kettle for stirring, ice bath to 0℃, add triethylamine 100g, ice bath reaction 10min, drop 2-methyl acrylate 80g, room temperature reaction 8h, after the reaction is completed, filter, the filtrate is poured into 10 times the volume of ethanol to precipitate, filter, the filter cake is washed with ether 2 times, transferred to the oven with a temperature of 50℃, dried to constant weight, to obtain dopamine copolymer precursor.

[0036] Step ②, preparation of dopamine copolymer Take: dopamine copolymer precursor 100g, methacryloyloxyethyl trimethyl ammonium chloride 80g, 3-(methacryloyloxy) propyl trimethoxysilane 20g and methanol 1800mL are placed in a reaction kettle under nitrogen atmosphere protection for stirring, add azobisisobutyronitrile 0.8g, the reaction kettle is heated to 60℃, and kept for 6h, after the reaction is completed, the reaction kettle is cooled to room temperature, and the reaction solution is slowly poured into 6000mL of anhydrous ether to precipitate, filtered, the filter cake is washed with anhydrous ether 2 times, transferred to the oven, and dried for 6h to obtain dopamine copolymer.

[0037] Under low temperature alkaline conditions, the phenolic hydroxyl group and amino group in dopamine hydrochloride are activated, acylated with 2-methyl acrylate, and a free radical polymerizable methacryloyl group is introduced into the molecular structure to obtain dopamine copolymer precursor, and then under nitrogen protection, azobisisobutyronitrile is used as an initiator, and free radical copolymerization occurs between the precursor, methacryloyloxyethyl trimethyl ammonium chloride and 3-(methacryloyloxy) propyl trimethoxysilane to generate dopamine copolymer containing dopamine structure unit, quaternary ammonium salt group and silane functional group.

[0038] The methyl methacryl group is introduced into the dopamine molecule to make the dopamine molecule have polymerization activity, and the quaternary ammonium salt group and the silane functional group are cooperatively grafted into the dopamine skeleton through free radical copolymerization, so that the integration and structure fixation of the functional units are realized, and the dopamine copolymer is obtained.

[0039] Example 5 The embodiment provides a preparation method of a dopamine copolymer, and the method comprises the following steps: Step 1, preparing a dopamine copolymer precursor Take 110 g of dopamine hydrochloride and 1900 mL of N,N-dimethylformamide, and place them in a reaction kettle for stirring. Ice bath to 3 DEG C, add 110 g of triethylamine, ice bath reaction for 13 min, drop 90 g of 2-methyl acrylate anhydride, room temperature reaction for 10 h, after the reaction is completed, filter, pour the filtrate into 10 times the volume of ethanol to precipitate, filter, and wash the filter cake with ether 3 times, and then transfer to an oven with a temperature of 55 DEG C, and dry until the weight is constant. Thus, the dopamine copolymer precursor is obtained.

[0040] Step 2, preparing a dopamine copolymer Take 110 g of dopamine copolymer precursor, 90 g of methacryloyloxyethyl trimethyl ammonium chloride, 30 g of 3-(methacryloyloxy) propyl trimethoxysilane and 1900 mL of methanol, and place them in a reaction kettle protected by nitrogen atmosphere for stirring. Add 0.9 g of azobisisobutyronitrile, and heat the reaction kettle to 65 DEG C. Keep the temperature for 8 h. After the reaction is completed, the reaction kettle is cooled to room temperature, and the reaction solution is slowly poured into 7000 mL of anhydrous ether to precipitate. Filter, wash the filter cake with anhydrous ether 3 times, and then transfer to an oven for drying for 7 h. Thus, the dopamine copolymer is obtained.

[0041] Example 6 The embodiment provides a preparation method of a dopamine copolymer, and the method comprises the following steps: Step 1, preparing a dopamine copolymer precursor Take 120 g of dopamine hydrochloride and 2000 mL of N,N-dimethylformamide, and place them in a reaction kettle for stirring. Ice bath to 5 DEG C, add 120 g of triethylamine, ice bath reaction for 15 min, drop 100 g of 2-methyl acrylate anhydride, room temperature reaction for 12 h, after the reaction is completed, filter, pour the filtrate into 10 times the volume of ethanol to precipitate, filter, and wash the filter cake with ether 4 times, and then transfer to an oven with a temperature of 60 DEG C, and dry until the weight is constant. Thus, the dopamine copolymer precursor is obtained.

[0042] Step 2, preparing a dopamine copolymer Weigh dopamine copolymer precursor 120 g, methacryloyloxyethyl trimethyl ammonium chloride 100 g, 3-(methacryloyloxy) propyl trimethoxysilane 40 g and methanol 2000 mL into a reaction kettle protected by nitrogen atmosphere and stir, add azobisisobutyronitrile 1 g, heat the reaction kettle to 70℃, and keep the temperature for 10 h. After the reaction is completed, slowly pour the reaction liquid into 8000 mL of anhydrous ether for precipitation, and then filter, transfer to an oven, and dry for 8 h to obtain the dopamine copolymer.

[0043] Example 7 The present example provides a preparation method of a self-repairing modified silica sol, comprising the following steps: Step 1, preparation of amino-modified silica sol Weigh silica sol 150 g, ethanol 100 mL and deionized water 100 mL into a reaction kettle and stir, add 3 wt% acetic acid aqueous solution to adjust the pH to 4.2, stir at room temperature for 5 min, drop 10 wt% 3-aminopropyl triethoxysilane ethanol solution 80 mL, stir at room temperature for 1 h, and after the reaction is completed, add the sol product to the upper chamber of a 30 kDa ultrafiltration tube, centrifuge at a centrifugal force of 3000 g until the volume is reduced to one third of the original volume, add deionized water to the original volume, repeat the centrifugation and liquid supplementing process 3 times, and finally add deionized water to a solid content of 5 wt% to obtain the amino-modified silica sol.

[0044] Step 2, preparation of carboxyl activation solution Weigh 4-carboxyphenylboronic acid 10 g, 0.05 mol / L MES buffer 1000 mL, N-hydroxysuccinimide 10 g and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride 10 g into a reaction kettle, stir at room temperature for 20 min, and obtain the carboxyl activation solution.

[0045] Step 3, preparation of self-repairing modified silica sol Weigh amino-modified silica sol 80 g and 0.05 mol / L MES buffer 50 mL into a reaction kettle and stir, add carboxyl activation solution 50 mL, stir at room temperature for 14 h, after the reaction is completed, add 1 g of ethanolamine to the reaction liquid to terminate the reaction, add the sol product to the upper chamber of a 30 kDa ultrafiltration tube, centrifuge at a centrifugal force of 3000 g until the volume is reduced to one third of the original volume, add deionized water to the original volume, repeat the centrifugation and liquid supplementing process 3 times, and finally add deionized water to a solid content of 5 wt% to obtain the self-repairing modified silica sol.

[0046] Under weak acid conditions, the silanol groups on the surface of the silica sol undergo hydrolysis-condensation reaction with 3-aminopropyl triethoxysilane, covalently introducing amino organosilica segments onto the surface of the silica sol to form an amino-modified silica sol. Subsequently, in the MES buffer system, the carboxyl groups of 4-carboxyphenylboronic acid are activated to form an active ester under the action of N-hydroxysuccinimide / 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride. The active ester further undergoes amidation reaction with the amino groups on the surface of the amino-modified silica sol, while the phenylboronic acid group is retained, to obtain a self-repairing modified silica sol.

[0047] A stable amino functional layer is introduced onto the surface of the silica sol through silane coupling reaction to enhance the reactivity and water-phase dispersibility of the particle surface and to provide controllable reaction sites for subsequent covalent connection. Further, the carboxyl groups in the 4-carboxyphenylboronic acid molecule are converted into highly reactive intermediates using an N-hydroxysuccinimide / 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride system, enabling the phenylboronic acid structure to efficiently participate in subsequent coupling reaction under mild conditions. Through the amidation reaction of the amino groups with the activated carboxyl groups, the phenylboronic acid group is anchored to the surface of the silica sol, introducing a reversible dynamic bonding unit to endow the sol system with structural reconstruction and self-repairing characteristics while maintaining colloidal stability.

[0048] Example 8 The present example provides a preparation method of a self-repairing modified silica sol, comprising the following steps: Step 1, preparation of an amino-modified silica sol Take 175 g of silica sol, 125 mL of ethanol and 110 mL of deionized water and place them in a reaction kettle for stirring. Add 4 wt% aqueous acetic acid to adjust the pH to 4.6. Stir at room temperature for 7 min. Add 90 mL of 15 wt% 3-aminopropyl triethoxysilane ethanol solution dropwise. Stir at room temperature for 1.5 h. After the reaction is completed, add the sol product to the upper chamber of a 30 kDa ultrafiltration tube. Centrifuge at a centrifugal force of 4000 g until the volume is reduced to one third of the original volume. Add deionized water to the original volume. Repeat the centrifugation and liquid supplementing process 4 times. Finally, add deionized water to a solid content of 7.5 wt% to obtain an amino-modified silica sol.

[0049] Step 2, preparation of a carboxyl activation solution Take 15 g of 4-carboxyphenylboronic acid, 1100 mL of 0.075 mol / L MES buffer, 12.5 g of N-hydroxysuccinimide and 12.5 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and place them in a reaction kettle. Stir at room temperature for 25 min to obtain a carboxyl activation solution.

[0050] Step 3, preparation of a self-repairing modified silica sol Weigh 90g of amino-modified silica sol and 60mL of 0.075mol / L MES buffer and place them in a reaction vessel. Stir and add 65mL of carboxyl activation solution. Stir at room temperature for 15h. After the reaction is complete, add 1.5g of ethanolamine to the reaction solution to terminate the reaction. Add the sol product to the upper chamber of a 30kDa ultrafiltration tube and centrifuge at 4000g until the volume is reduced to one-third of the original volume. Add deionized water to the original volume. Repeat the centrifugation and replenishment process 4 times. Finally, add deionized water to the solid content until it is 7.5wt%, and obtain the self-healing modified silica sol.

[0051] Example 9 This embodiment provides a method for preparing a self-healing modified silica sol, including the following steps: Step 1: Preparation of amino-modified silica sol Weigh 200g of silica sol, 150mL of ethanol and 120mL of deionized water and place them in a reaction vessel and stir. Add 5wt% acetic acid aqueous solution to adjust the pH to 4.8 and stir at room temperature for 10min. Add 100mL of 20wt% 3-aminopropyltriethoxysilane ethanol solution and stir at room temperature for 2h. After the reaction is complete, add the sol product to the upper chamber of a 30kDa ultrafiltration tube and centrifuge at 5000g until the volume is reduced to one-third of the original volume. Add deionized water to the original volume and repeat the centrifugation and replenishment process 5 times. Finally, add deionized water to the solid content to obtain amino-modified silica sol.

[0052] Step 2: Preparation of carboxyl activation solution Weigh out 20g of 4-carboxyphenylboronic acid, 1200mL of 0.10mol / L MES buffer, 15g of N-hydroxysuccinimide and 15g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and place them in a reaction vessel. Stir at room temperature for 30min to obtain a carboxyl-activated solution.

[0053] Step 3: Preparation of self-healing modified silica sol Weigh 100g of amino-modified silica sol and 70mL of 0.10mol / L MES buffer and place them in a reaction vessel. Stir and add 80mL of carboxyl activation solution. Stir at room temperature for 16h. After the reaction is complete, add 2g of ethanolamine to the reaction solution to terminate the reaction. Add the sol product to the upper chamber of a 30kDa ultrafiltration tube and centrifuge at 5000g until the volume is reduced to one-third of the original volume. Add deionized water to the original volume. Repeat the centrifugation and replenishment process 5 times. Finally, add deionized water to the solid content until it is 10wt% to obtain the self-healing modified silica sol.

[0054] Example 10 This embodiment provides a method for preparing a self-curing road base material based on modified municipal solid waste incinerator slag, including the following steps: Step one, preparation of composite modification liquid Take: 100 g of sodium polyacrylate and 8000 mL of deionized water in a reaction kettle and stir, add 400 g of self-repairing modified silica sol prepared in Example 7 and 250 g of dopamine copolymer prepared in Example 4, stir at room temperature for 20 min, add 0.5 mol / L sodium hydroxide aqueous solution to adjust the pH to 8, stand for 15 min, get the composite modification liquid.

[0055] Step two, preparation of hydrophilic modified slag aggregate The pretreated household waste incineration slag prepared in Example 1 is immersed in the composite modification liquid at an impregnation ratio of 30:1, vacuum impregnated at a negative pressure of-0.08 MPa for 0.5 h, the product is taken out and placed in an oven at 50℃ for pre-drying for 1 h, the oven is heated to 80℃, and pre-cured for 1 h to obtain the hydrophilic modified slag aggregate.

[0056] Step three, preparation of mixture Mix 5-10 mm crushed stone and 0.1-1.0 mm natural sand at a mass ratio of 60:25 to obtain the aggregate. Take: 950 g of Portland cement, 3400 g of aggregate and 2400 g of hydrophilic modified slag aggregate in a blender and mix evenly, add 350 mL of tap water, mix evenly to obtain the mixture.

[0057] Step four, preparation of shaped body Pour the mixture into the mold once, and use a vibration table to vibrate and compact to obtain the shaped body.

[0058] Step five, preparation of pavement base material After demolding, the shaped body is standard cured at 18℃ and relative humidity of 95%, covered with film and supplemented with water regularly to obtain the pavement base material.

[0059] In the aqueous phase system, sodium polyacrylate forms a stable dispersion network through carboxylate chain segments, self-repairing modified silica sol and dopamine copolymer cooperatively construct the composite modification liquid through hydrogen bonding, electrostatic interaction and silanol-organic group interaction under weak alkaline conditions, and the composite modification liquid penetrates into the pores of pretreated household waste incineration slag and undergoes physical solidification and local condensation reaction during the heating process, forming a continuous hydrophilic functional layer on the surface of the aggregate. Subsequently, in the cement system, the modified slag aggregate and natural aggregate, cement particles are combined through hydration products, silanol condensation and polymer chain entanglement, and then the shaped body is formed by vibration and wet curing, and the cement hydration reaction continues to proceed and build a dense structure, finally obtaining a stable pavement base material.

[0060] By constructing a stable aqueous dispersion system, introducing silanol, dynamic bonds and dopamine adhesion units, promoting interfacial interaction in weak alkaline environment and forming a stable composite modification liquid system, further through vacuum impregnation and heat treatment, the composite modification liquid enters the slag pore and forms a continuous hydrophilic layer on the surface, realizes the synergistic combination of modified slag and cementitious system during cement mixing, improves the packing density and interface contact of aggregate through vibration compaction, and finally promotes the continuous hydration reaction and forms a dense and stable pavement base material through wet curing.

[0061] Example 11 The present embodiment provides a preparation method of a self-curing pavement base material based on modified household waste incineration slag, comprising the following steps: Step one, preparation of composite modification liquid Take 110 g of sodium polyacrylate and 9000 mL of deionized water and place them in a reaction kettle for stirring, add 500 g of self-repairing modified silica sol prepared in Example 8 and 275 g of dopamine copolymer prepared in Example 5, stir at room temperature for 30 min, add 0.75 mol / L sodium hydroxide solution to adjust the pH to 8.5, and let stand for 17 min to remove bubbles, to obtain the composite modification liquid.

[0062] Step two, preparation of hydrophilic modified slag aggregate The pretreated household waste incineration slag prepared in Example 2 is placed into the composite modification liquid at an impregnation ratio of 32:1, vacuum impregnated at a negative pressure of-0.09 MPa for 1 h, and the product is taken out and placed in an oven at 55℃ for pre-drying for 1.5 h, and the oven is heated to 85℃ for pre-curing for 1.5 h, to obtain the hydrophilic modified slag aggregate.

[0063] Step three, preparation of mixture Mix 10-20 mm crushed stone and 1-2.5 mm natural sand at a mass ratio of 67.5:32.5 to obtain the aggregate; Take 975 g of Portland cement, 3450 g of aggregate and 2450 g of hydrophilic modified slag aggregate and mix them evenly in a blender, add 375 mL of tap water and mix evenly to obtain the mixture.

[0064] Step four, preparation of shaped body Pour the mixture into the mold and compact it by vibration to obtain the shaped body.

[0065] Step five, preparation of pavement base material After demolding, the shaped body is cured at 20℃ and a relative humidity of 96.5%, and the film is covered and water is added regularly to obtain the pavement base material.

[0066] Example 12 The embodiment provides a preparation method of a self-curing pavement base material based on modified household garbage incineration slag. Step one, preparation of a composite modified liquid Take 120 g of sodium polyacrylate and 10000 mL of deionized water and place them in a reaction kettle for stirring, add 600 g of the self-repairing modified silica sol prepared in Example 9 and 300 g of the dopamine copolymer prepared in Example 6, stir at room temperature for 40 min, add 1.0 mol / L sodium hydroxide aqueous solution to adjust the pH to 9, and stand for 20 min to remove bubbles, to obtain a composite modified liquid.

[0067] Step two, preparation of hydrophilic modified slag aggregate The pretreated household garbage incineration slag prepared in Example 3 is put into the composite modified liquid at an impregnation ratio of 35:1, vacuum impregnation is carried out at a negative pressure of-0.1 MPa for 1 h, the product is taken out and placed in an oven at 60 DEG C for pre-drying for 2 h, the oven is heated to 90 DEG C, and pre-curing is carried out for 2 h, to obtain a hydrophilic modified slag aggregate.

[0068] Step three, preparation of a mixture The 20-30 mm crushed stone and the 2.5-4.75 mm natural sand are mixed uniformly at a mass ratio of 75:40 to obtain an aggregate. Take 1000 g of Portland cement, 3500 g of the aggregate and 2500 g of the hydrophilic modified slag aggregate and dry mix them uniformly in a mixer, add 400 mL of tap water, and mix uniformly to obtain a mixture.

[0069] Step four, preparation of a shaped body The mixture is injected into a mold once, and vibration table vibration compaction is carried out to obtain a shaped body.

[0070] Step five, preparation of a pavement base material After the shaped body is demolded, standard curing is carried out under the condition of 22 DEG C and a relative humidity of 98%, a film is covered and water is replenished regularly to obtain a pavement base material.

[0071] Comparative Example 1 The difference between the comparative example and Example 12 lies in that the dopamine copolymer is not used in the preparation of the composite modified liquid in step one.

[0072] Comparative Example 2 The difference between the comparative example and Example 12 lies in that the self-repairing modified silica sol is replaced by an amino-modified silica sol in an equal amount in the preparation of the composite modified liquid in step one.

[0073] Comparative Example 3 The difference between the comparative example and Example 12 lies in that the hydrophilic modified slag aggregate is replaced by pretreated household garbage incineration slag in an equal amount in the preparation of the mixture in step three.

[0074] Performance test: The contact method shrinkage, total cracking area per unit area (anti-cracking performance), compressive fatigue deformation performance and water penetration height of the pavement base material sample prepared from Examples 10-12 and Comparative Examples 1-3 were tested according to the standard GB / T 50082-2024 "Standard for Testing Methods for Long-term Performance and Durability of Concrete". The water retention rate of the mixture prepared from Examples 10-12 and Comparative Examples 1-3 was tested according to the standard JGJ / T 70-2009 "Standard for Testing Methods for Basic Performance of Building Mortar", and the specific data are shown in Table 1.

[0075] Table 1 - Performance test data table of each sample Data analysis: Comparative analysis of the data in Table 1 above shows that the shrinkage of the pavement base material prepared by the present application is 3.26x10 -4 %, 2 the total cracking area per unit area is 5.7mm -2 , the compressive fatigue cumulative deformation rate is 0.19%, and the water penetration height is 6.0mm, while the water retention rate of the mixture is 94.8, all of which are better than the comparative examples. Therefore, the present application uses pretreated household waste incinerator slag as functional aggregate, eliminates adverse phases through high-temperature stabilization treatment, introduces a composite modified liquid composed of dopamine copolymer, self-repairing modified silica sol and sodium polyacrylate into the pores, forms a continuous hydrophilic functional layer, utilizes dopamine adhesion, dynamic bonding of self-repairing silica sol and water storage effect of slag pores to realize synergistic reinforcement of aggregate-cement interface, effectively improves the water retention, crack resistance and durability of the base material, and promotes high-value utilization of solid waste resources.

[0076] 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 do not limit the present application to only the specific embodiments. Obviously, many modifications and changes can be made according to the content of the present application. The present application 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 entire scope and equivalents.

Claims

1. A method for preparing a self-curing pavement base material based on modified household waste incinerator slag, characterized in that, Comprise the following steps: S1, polyacrylic acid sodium and deionized water are placed in a reaction kettle and stirred, self-repairing modified silica sol and dopamine copolymer are added, stirred at room temperature for 20-40 min, sodium hydroxide aqueous solution is added to adjust the pH to 8-9, and the mixture is left to deaerate for 15-20 min to obtain a composite modified liquid; S2, the pretreated household waste incineration slag is immersed in the composite modified liquid at an immersion ratio of 30-35:1, vacuum immersed for 0.5-1h, and hot cured to obtain hydrophilic modified slag aggregate; S3, the cement, aggregate and hydrophilic modified slag aggregate are uniformly dry mixed in a mixer, mixed water is added, and the mixture is uniformly mixed to obtain a mixture; S4, the mixture is poured into a mold and vibrated and compacted to obtain a shaped body; S5, the road base material is maintained to obtain a road base material.

2. The method for preparing a self-curing pavement base material based on modified household garbage incineration slag according to claim 1, characterized in that, In step S1, the amount ratio of polyacrylic acid sodium, deionized water, self-repairing modified silica sol and dopamine copolymer is 10-12g:800-1000mL:40-60g:25-30g, and the concentration of sodium hydroxide aqueous solution is 0.5-1.0mol / L.

3. The method for preparing a self-maintaining pavement base material based on modified household garbage incineration slag according to claim 1, characterized in that, The self-repairing modified silica sol is prepared by the following steps: A1, silica sol, ethanol and deionized water are placed in a reaction kettle and stirred, the pH is adjusted to 4.2-4.8 by adding acetic acid aqueous solution, stirred at room temperature for 5-10 min, 3-aminopropyl triethoxysilane solution is added dropwise, stirred at room temperature for 1-2h, and the product is obtained after post-treatment to obtain amino-modified silica sol; A2, 4-carboxyphenylboronic acid, MES buffer, N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride are placed in a reaction kettle, stirred at room temperature for 20-30 min to obtain a carboxyl activation liquid; A3, the amino-modified silica sol and the MES buffer are placed in a reaction kettle and stirred, the carboxyl activation liquid is added, and the mixture is stirred at room temperature for 14-16h, and the product is obtained after post-treatment to obtain a self-repairing modified silica sol.

4. The method for preparing a self-curing pavement base material based on modified household garbage incineration slag according to claim 3, characterized in that, In step A1, the amount ratio of silica sol, ethanol, deionized water and 3-aminopropyl triethoxysilane solution is 15-20g:10-15mL:10-12mL:8-10mL, the 3-aminopropyl triethoxysilane solution is 10-20wt% 3-aminopropyl triethoxysilane ethanol solution, and the concentration of acetic acid aqueous solution is 3-5wt%.

5. The method for preparing a self-maintaining pavement base material based on modified household garbage incineration slag according to claim 3, characterized in that, In step A2, the amount ratio of 4-carboxyphenylboronic acid, MES buffer, N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride is 1-2g:100-120mL:1.0-1.5g:1.0-1.5g, the concentration of MES buffer is 0.05-0.10mol / L, and the pH is 5.5-6.

0.

6. The method for preparing a self-curing pavement base material based on modified household garbage incineration slag according to claim 3, characterized in that, In step A3, the amount ratio of amino-modified silica sol, MES buffer and carboxyl activation liquid is 8-10g:5-7mL:5-8mL, the concentration of MES buffer is 0.05-0.10mol / L, and the pH is 5.5-6.

0.

7. The method for preparing a self-maintaining pavement base material based on modified household garbage incineration slag according to claim 1, characterized in that, The dopamine copolymer is prepared by the following steps: B1, dopamine hydrochloride and N, N-dimethylformamide are placed in a reaction kettle and stirred, ice-bath to 0-5℃, triethylamine is added, ice-bath reaction for 10-15min, dropwise addition of 2-methyl acrylate, room temperature reaction for 8-12h, post-processing to obtain dopamine copolymer precursor; B2, dopamine copolymer precursor, methacryloyloxyethyl trimethyl ammonium chloride, 3-(methacryloyloxy) propyl trimethoxysilane and methanol are placed in a reaction kettle protected by nitrogen atmosphere and stirred, azobisisobutyronitrile is added, the reaction kettle is heated to 60-70℃, and the reaction is carried out for 6-10h, and post-processing to obtain dopamine copolymer.

8. The method for preparing a self-curing pavement base material based on modified household garbage incineration slag according to claim 7, characterized in that, In step B1, the weight ratio of dopamine copolymer precursor, methacryloyloxyethyl trimethyl ammonium chloride, 3-(methacryloyloxy) propyl trimethoxysilane, methanol and azobisisobutyronitrile is 10-12g:8-10g:2-4g:200-250mL:0.08-0.10g; in step B2, the weight ratio of dopamine copolymer precursor, methacryloyloxyethyl trimethyl ammonium chloride, 3-(methacryloyloxy) propyl trimethoxysilane, methanol and azobisisobutyronitrile is 10-12:8-10:2-4:0.08-0.

10.

9. The method for preparing a self-maintaining pavement base material based on modified household garbage incineration slag according to claim 1, characterized in that, The pretreated household garbage incineration slag is prepared by the following steps: C1, the household garbage incineration slag is subjected to magnetic separation, air separation and crushing and screening to obtain a crude slag aggregate; C2, the crude slag aggregate is uniformly placed in a refractory tray of a tube furnace protected by inert gas, and high-temperature treatment is carried out to obtain the pretreated household garbage incineration slag.

10. A self-curing pavement base material based on modified domestic waste incinerator slag, characterized in that, The self-curing pavement base material based on modified household garbage incineration slag is prepared by the preparation method of the self-curing pavement base material based on modified household garbage incineration slag according to any one of claims 1-9.

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