Preparation method of road base mixture curing agent based on construction waste recycled aggregate

Abstract

The invention discloses a preparation method of a road base mixture curing agent based on construction waste recycled aggregate, and relates to the technical field of modified composite materials. According to the method, the construction waste recycled aggregate is collected and treated, and crushing and grinding are performed after impurities are removed, so that a proper particle size is obtained. Then, mixing the modified epoxy resin, a silane coupling agent, nano silicate, an organic silicon water repellent, a surfactant, a defoaming agent and water according to a preset proportion to form a silicate solution; in the preparation process of the modified epoxy resin, an epoxy resin emulsion reacts with other additives in a nitrogen atmosphere, so that the generated curing agent is ensured to have excellent mechanical properties and water resistance. The final curing agent is formed by adding boric acid into a silicate solution, heating and reacting, and drying. The curing agent not only improves the strength and stability of the road base mixture, but also effectively utilizes the construction waste, realizes resource recycling, and meets the requirements of sustainable development.

Description

Technical Field

[0001] The invention relates to the technical field of modified composite materials, in particular to a method for preparing a road base mixture curing agent based on recycled aggregates of construction waste. Background Art

[0002] The generation of construction waste is an inevitable phenomenon in the process of urbanization. With the acceleration of urban construction, the amount of construction waste has increased year by year and has become an important part of urban solid waste. According to statistics, construction waste accounts for 30% to 40% of the total urban waste, and most of the construction waste is dumped without treatment, causing serious environmental pollution and waste of resources. Therefore, how to effectively treat and utilize construction waste has become a problem that needs to be solved in today's society.

[0003] Construction waste mainly includes concrete, bricks, sand and gravel, wood, metal and other components. These materials are generated in large quantities during demolition, renovation and new construction projects. Due to their complex composition, direct landfill or incineration not only wastes resources, but also causes secondary pollution to the environment. In particular, inorganic materials such as concrete and bricks have great potential for recycling. Through reasonable treatment processes, these wastes can be converted into recycled aggregates, thereby reducing dependence on natural resources.

[0004] The preparation of recycled aggregate from construction waste usually includes the following steps:

[0005] Preliminary screening: Use equipment such as vibrating screens to separate fine materials and impurities from construction waste to improve the efficiency of subsequent processing.

[0006] Crushing process: The construction waste that has been preliminarily screened is crushed to obtain a particle size suitable for the production of recycled aggregate.

[0007] Grading and screening: The crushed materials are screened at multiple levels and divided into different grades of recycled aggregates according to their particle size.

[0008] Impurity removal: During the screening process, impurities such as metals and plastics are removed through magnetic separation, wind separation and other means to improve the purity of recycled aggregates.

[0009] Strengthening treatment: In order to address the problem of insufficient physical and mechanical properties of recycled aggregates, chemical modification or physical modification methods can be used to strengthen them in order to improve their strength and durability.

[0010] Polymer modified materials refer to a type of material that is modified by physical, chemical or a combination of both methods to improve the performance of basic polymer materials. In the construction industry, polymer modified materials are widely used in building materials such as concrete and mortar to improve their performance and scope of application.

[0011] The modification methods are usually as follows: Additive modification: By adding specific additives such as plasticizers and antioxidants, the flexibility, weather resistance and aging resistance of polymer materials can be improved. Blending modification: Different types of polymer materials are mixed in a certain proportion to form a new material with excellent comprehensive properties. For example, by mixing rigid polymers with flexible polymers, a composite material with both rigidity and flexibility can be obtained. Surface modification: By changing the properties of the surface of polymer materials, its compatibility with other materials is improved, thereby enhancing the overall performance of the composite material.

[0012] With the increasing awareness of environmental protection, more and more countries have begun to pay attention to the application of recycled aggregates from construction waste in road base. Studies have shown that using recycled aggregates in road base mixtures can not only improve the strength and stability of road structures, but also reduce construction costs and achieve resource recycling.

[0013] In summary, the preparation method of road base mixture curing agent based on recycled aggregates from construction waste not only meets the requirements of sustainable development, but also can effectively solve the problem of large amounts of construction waste generated in urban construction. With the development and innovation of technology, this field is expected to achieve more efficient and environmentally friendly resource utilization and provide new solutions for future urban construction. Summary of the invention

[0014] The present invention solves the problems existing in the prior art through an innovative technical solution, which not only improves the performance of the road base mixture curing agent in terms of water resistance and heat resistance, but also provides a feasible method for the efficient utilization of construction waste resources, thus contributing to sustainable development.

[0015] To achieve the above object, the present invention provides the following technical solutions:

[0016] A method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, comprising the following steps:

[0017] (1) Collect recycled aggregates from construction waste, conduct preliminary screening and cleaning to remove impurities and pollutants;

[0018] (2) crushing and grinding the washed construction waste recycled aggregate to obtain a particle size suitable for the curing agent;

[0019] (3) mixing the modified epoxy resin, silane coupling agent, nano-silicate, silicone hydrophobic agent, surfactant, defoaming agent and water in a predetermined ratio to form a silicate solution;

[0020] The preset weight ratio between the modified epoxy resin, the silane coupling agent, the nanosilicate, the silicone hydrophobic agent, the surfactant, the defoaming agent and the water is (400-600): (200-300): (500-700): (50-80): (10-40): (10-40): (300-500);

[0021] The preparation method of the modified epoxy resin is as follows:

[0022] Epoxy resin emulsion, iron oxide powder, 2-ethylimidazole (CAS No.: 1072-62-4) and hexafluorobutyl methacrylate (CAS No.: 36405-47-7), wherein the mass ratio of each material is (40-60): (2-5): (2-10): (10-25), are mixed and added into a flask equipped with a condenser and a stirrer, and stirred at 75°C for 1h-2h under a nitrogen atmosphere. Then, the temperature is raised to 80°C and the reaction is continued for 6h-10h. Subsequently, the temperature is lowered to 40°C and deionized water is slowly added dropwise with stirring at a speed of 1000 rpm, wherein the mass of the deionized water added is 0.2-0.4 times the mass of the epoxy resin emulsion. After the reaction is completed, the target product is obtained.

[0023] Epoxy resin emulsion is the main component, and epoxy resin provides the structural basis required after curing. Its epoxy group can undergo cross-linking reaction with other reactants during the curing process to form a three-dimensional network structure, thereby giving the material excellent mechanical properties and chemical resistance. Iron oxide powder is used as a filler. Iron oxide can not only improve the physical properties of the material, but also enhance its heat resistance and UV resistance. In addition, iron oxide may also interact with epoxy resin to a certain extent during the curing process to promote cross-linking reaction. 2-Ethylimidazole is used as a curing agent. Imidazole compounds have high reactivity and can promote the curing of epoxy resin at a lower temperature. Its nitrogen atom can undergo a ring-opening reaction with the epoxy group, thereby accelerating the curing process. Hexafluorobutyl methacrylate is used as a modifier, which can improve the hydrophobicity and heat resistance of the final product. After the introduction of fluorine-containing groups, the surface energy of the material is significantly reduced, thereby improving the anti-fouling ability.

[0024] For the preparation process, mixing and preliminary reaction: the above components are mixed in a preset ratio and placed in a flask equipped with a condenser and agitator. Heat to 75°C and stir for 1-2h under a nitrogen atmosphere. This process is designed to ensure that the components are fully mixed and to create good conditions for subsequent reactions. At this temperature, some components will have preliminary physical interactions, laying the foundation for subsequent chemical reactions. Heating and main reaction: The temperature rises to 80°C and the reaction continues for 6-10h. At this stage, a relatively active ring-opening reaction occurs between the epoxy group and components such as imidazole and iron oxide. As the temperature rises, the reaction rate accelerates, which helps to form a more stable cross-linked structure. At this time, the imidazole curing agent combines with the epoxy group through its active hydrogen atoms to promote the curing process. Cooling and water dripping: After the temperature is lowered to 40°C, deionized water is slowly dripped at a speed of 1000rpm. The amount of deionized water added is 0.2 to 0.4 times the mass of the epoxy resin emulsion. In this process, water, as a solvent, helps to dilute the system and promote certain reactions. At the same time, the addition of water molecules may cause some unreacted epoxy groups to undergo nucleophilic substitution reactions with water, thereby improving the toughness of the final product. Through analysis, the reaction mechanism is as follows:

[0025] Epoxy ring opening: Under the catalytic action of imidazole curing agents, the epoxy groups in the epoxy resin undergo a ring-opening reaction. This process usually involves a nucleophilic attack on the nitrogen atom, which causes the epoxy group to open and form a new hydroxyl or amino group. Cross-linked network formation: As the ring-opening reaction proceeds, multiple epoxy groups form a three-dimensional network structure through cross-linking. This network structure not only improves the mechanical strength of the material, but also improves its heat resistance and water resistance. Boric acid modification: In a subsequent step, boric acid is added to the silicate solution and heated so that the boric acid can interact with the silicate. The generated boron-oxygen tetrahedron helps to repair defects in the silicate network and improve the overall performance of the curing agent. The final product characteristics, the modified epoxy resin prepared through the above steps has the following advantages:

[0026] Excellent mechanical properties: The cross-linked structure enhances the strength and toughness of the material.

[0027] Water resistance and heat resistance: The introduction of fluorine-containing groups improves the hydrophobicity of the material surface and enhances its high temperature resistance.

[0028] UV resistance: By adding modifiers (such as hexafluorobutyl methacrylate), the stability of the material during outdoor use is improved.

[0029] (4) Adding boric acid to the silicate solution under stirring, reacting for 0.25 h to 1 h, then heating to 60° C. to 95° C., and continuing the reaction until the boric acid is completely dissolved;

[0030] (5) Then, after continuing the reaction for 1 h to 3 h, the boric acid-modified silicate solution is filtered and dried to obtain the final curing agent.

[0031] In the method for preparing a road base mixture curing agent based on recycled aggregates from construction waste, the components of the recycled aggregates from construction waste in step (1) are as follows in weight percentage:

[0032] Silicon dioxide accounts for 55%-65%, calcium oxide accounts for 10%-25%, aluminum oxide accounts for 5%-10%, and the balance is iron oxide;

[0033] The particle size of recycled aggregate from construction waste is 0.15mm-2.5mm.

[0034] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the aperture of the sieve initially screened in step (1) is 1.0 mm;

[0035] The cleaning method in step (1) is rinsing with warm water.

[0036] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the particle size after crushing and grinding in step (2) is 100 nm.

[0037] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the crushing equipment in step (2) is a jaw crusher; the working principle of the jaw crusher: the jaw crusher is a device that crushes materials by the mutual movement between the movable jaw and the stationary jaw. When the motor drives the pulley to rotate, the eccentric shaft drives the movable jaw to perform periodic reciprocating motion. The material is crushed by multiple actions such as extrusion, splitting and impact between the two jaw plates. The specific process is as follows: feeding: the material to be crushed enters the crushing chamber through the feed port. Extrusion crushing: when the movable jaw approaches the fixed jaw, the material is squeezed between the two to form smaller particles. Discharge: when the movable jaw leaves the fixed jaw, the crushed material is discharged from the discharge port by gravity. Application to recycled aggregate from construction waste: in the present invention, a jaw crusher is used to perform preliminary crushing of construction waste, the purpose of which is to crush large pieces of construction waste (such as concrete, bricks, etc.) into small particles suitable for subsequent grinding treatment. By controlling the feed particle size and the gap between the discharge port, the desired particle size can be obtained, thereby providing a basis for subsequent treatment.

[0038] The equipment for grinding in step (2) is a drum mill. Working principle of drum mill: drum mill is a device that uses the principles of friction and grinding to grind materials. It is mainly composed of a rotating cylinder and internal grinding media (such as steel balls or ceramic balls). The working process is as follows: Feeding: The material to be ground enters the drum through the feed port. Grinding: As the drum rotates, the grinding media and the material collide and rub against each other, so that the material is gradually ground into fine particles. Discharge: The ground material is discharged through the discharge port. Application to construction waste recycled aggregate: In the present invention, a drum mill is used to further grind the initially crushed construction waste recycled aggregate to obtain a particle size suitable for the preparation of a curing agent (such as 100nm). Such fine particles not only help to increase the reaction surface area of ​​the curing agent, but also improve the mechanical properties and chemical stability of the final product.

[0039] The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, wherein the silane coupling agent in step (3) is isobutyltriethoxysilane (CAS No.: 17980-47-1), 3-(2,3-epoxypropyl)trimethoxysilane (CAS No.: 2530-83-8) or styryltrimethoxysilane (CAS No.: 2943-75-1);

[0040] In step (3), the nano-silicate is nano-silicon dioxide or nano-montmorillonite, and its particle size is 50nm-100nm;

[0041] In step (3), the organic silicon water repellent is polydimethylsiloxane (CAS No.: 9016-00-6) or triethoxysilane (CAS No.: 998-30-1);

[0042] In step (3), the surfactant is sodium dodecyl sulfate or octylphenol polyoxyethylene ether (CAS No.: 9036-19-5);

[0043] In step (3), the defoaming agent is octyl alcohol (CAS No.: 111-87-5);

[0044] The parameter conditions of the epoxy resin emulsion (CAS No.: 25068-38-6) in step (3) are as follows:

[0045] EP-380 type, solid content is 59%, viscosity: 2000mPa·s.

[0046] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the mass of boric acid added in step (4) is 0.3 to 0.4 times the mass of the silicate solution;

[0047] The mass percentage of boric acid in step (4) is 3%-5%.

[0048] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the stirring conditions in step (4) are as follows:

[0049] The reactor was sealed and the rotation speed was 60-80 rpm.

[0050] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the drying method in step (5) is spray drying;

[0051] The spray drying temperature is 60℃-70℃;

[0052] The spray drying time is 24h-28h.

[0053] Beneficial Effects

[0054] Resource recycling:

[0055] The present invention uses recycled aggregates from construction waste as the main raw material of the curing agent, effectively reducing the impact of construction waste on the environment and realizing the recycling of resources. The use of recycled aggregates from construction waste not only reduces dependence on natural resources, but also reduces environmental pollution caused by landfill and incineration.

[0056] Excellent mechanical properties:

[0057] The curing agent prepared by using modified epoxy resin and other additives forms a three-dimensional cross-linked network structure with high strength and good toughness after curing. This structure significantly improves the compressive strength and durability of the road base mixture and extends the service life of the road.

[0058] Enhanced Water and Heat Resistance:

[0059] By introducing boric acid-modified silicate, the curing agent shows good stability in water molecule penetration and high temperature environment. The curing agent has excellent water resistance and heat resistance, and can effectively resist the damage caused by the external environment to the road base material.

[0060] Improved chemical stability:

[0061] The modified epoxy resin used in the present invention and its formula design make the final product have good chemical stability and can resist the corrosion of various chemical substances (such as acid, alkali, etc.), thereby maintaining its performance unchanged.

[0062] UV resistance and hydrophobic properties:

[0063] The introduction of nano-titanium dioxide makes the curing agent have good UV resistance, which can effectively prevent material aging caused by UV radiation. At the same time, the use of silicone hydrophobic agent improves the hydrophobicity of the material surface, reduces water penetration, and improves overall durability.

[0064] Easy construction:

[0065] Compared with traditional curing agents, the curing agent prepared by the present invention has better fluidity and operability, can achieve rapid stirring and molding during the construction process, improves construction efficiency, and reduces labor costs.

[0066] Environmental characteristics:

[0067] Since the present invention adopts a water-based system and does not contain an organic solvent, no harmful gas will be released during the construction process, which is more in line with modern environmental protection requirements and helps to improve the construction environment.

[0068] Economic benefits:

[0069] Using recycled aggregate from construction waste as raw materials not only reduces the cost of raw materials, but also reduces the cost of waste disposal. By improving the performance of road base mixture, it can reduce the cost of later maintenance and improve economic benefits.

[0070] In summary, the present invention not only solves the problems of traditional road base mixture curing agents in terms of water resistance and heat resistance through innovative technical solutions, but also provides a feasible method for the efficient utilization of construction waste resources, thus contributing to sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 This is a scanning electron microscope image of the product prepared in Example 5 of the present invention. DETAILED DESCRIPTION

[0072] The weight or mass ratio involved in the present invention is based on kilogram (Kg) as the reference weight unit.

[0073] Example 1

[0074] The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste comprises the following steps:

[0075] (1) Collect recycled aggregates from construction waste, conduct preliminary screening and cleaning to remove impurities and pollutants;

[0076] In the method for preparing a road base mixture curing agent based on recycled aggregates from construction waste, the components of the recycled aggregates from construction waste in step (1) are as follows in weight percentage:

[0077] Silicon dioxide accounts for 55%, calcium oxide accounts for 10%, aluminum oxide accounts for 5%, and the balance is iron oxide;

[0078] The particle size of the recycled aggregate from construction waste is 0.15mm.

[0079] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the aperture of the sieve initially screened in step (1) is 1.0 mm;

[0080] The cleaning method in step (1) is rinsing with warm water.

[0081] (2) crushing and grinding the washed construction waste recycled aggregate to obtain a particle size suitable for the curing agent;

[0082] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the particle size after crushing and grinding in step (2) is 100 nm.

[0083] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the crushing equipment in step (2) is a jaw crusher;

[0084] The equipment for grinding in step (2) is a drum mill.

[0085] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the silane coupling agent in step (3) is isobutyltriethoxysilane;

[0086] (3) mixing the modified epoxy resin, silane coupling agent, nano-silicate, silicone hydrophobic agent, surfactant, defoaming agent and water in a predetermined ratio to form a silicate solution;

[0087] The preset weight ratio between the modified epoxy resin, the silane coupling agent, the nanosilicate, the silicone hydrophobic agent, the surfactant, the defoaming agent and water is 400:200:500:50:10:10:300;

[0088] The preparation method of the modified epoxy resin is as follows:

[0089] Epoxy resin emulsion, iron oxide powder, 2-ethylimidazole and hexafluorobutyl methacrylate, wherein the mass ratio of each material is 40:2:2:10, are mixed and added into a flask equipped with a condenser and a stirrer, and stirred at 75°C for 1 hour under a nitrogen atmosphere, then the temperature is raised to 80°C, and the reaction is continued for 6 hours, then the temperature is lowered to 40°C, and deionized water is slowly added dropwise under stirring at a speed of 1000 rpm, wherein the mass of the added deionized water is 0.2 times the mass of the epoxy resin emulsion, and after the reaction is completed, the target product is obtained;

[0090] In step (3), the nanosilicate is nano silicon dioxide, and its particle size is 50 nm;

[0091] In step (3), the organic silicon water repellent is polydimethylsiloxane;

[0092] In step (3), the surfactant is sodium dodecyl sulfate;

[0093] In step (3), the defoaming agent is octyl alcohol;

[0094] The parameter conditions of the epoxy resin emulsion in step (3) are as follows:

[0095] EP-380 type, solid content is 59%, viscosity: 2000mPa·s.

[0096] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the mass of boric acid added in step (4) is 0.3 times the mass of the silicate solution;

[0097] (4) Adding boric acid to the silicate solution under stirring, reacting for 0.25 h, then heating to 60° C., and continuing the reaction until the boric acid is completely dissolved;

[0098] The mass percentage of boric acid in step (4) is 3%.

[0099] The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste,

[0100] The stirring conditions in step (4) are as follows:

[0101] The reactor was sealed and the rotation speed was 60 rpm.

[0102] (5) Then, after the reaction is continued for 1 hour, the boric acid-modified silicate solution is filtered and dried to obtain the final curing agent.

[0103] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the drying treatment in step (5) is performed by spray drying; the spray drying temperature is 60° C.; and the spray drying time is 24 hours.

[0104] Example 2

[0105] The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste comprises the following steps:

[0106] (1) Collect recycled aggregates from construction waste, conduct preliminary screening and cleaning to remove impurities and pollutants;

[0107] In the method for preparing a road base mixture curing agent based on recycled aggregates from construction waste, the components of the recycled aggregates from construction waste in step (1) are as follows in weight percentage:

[0108] Silicon dioxide accounts for 65%, calcium oxide accounts for 25%, and aluminum oxide accounts for 10%;

[0109] The particle size of the recycled aggregate from construction waste is 2.5mm.

[0110] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the aperture of the sieve initially screened in step (1) is 1.0 mm;

[0111] The cleaning method in step (1) is rinsing with warm water.

[0112] (2) crushing and grinding the washed construction waste recycled aggregate to obtain a particle size suitable for the curing agent;

[0113] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the particle size after crushing and grinding in step (2) is 100 nm.

[0114] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the crushing equipment in step (2) is a jaw crusher;

[0115] The equipment for grinding in step (2) is a drum mill.

[0116] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the silane coupling agent in step (3) is styryltrimethoxysilane;

[0117] (3) mixing the modified epoxy resin, silane coupling agent, nano-silicate, silicone hydrophobic agent, surfactant, defoaming agent and water in a predetermined ratio to form a silicate solution;

[0118] The preset weight ratio between the modified epoxy resin, silane coupling agent, nanosilicate, silicone hydrophobic agent, surfactant, defoaming agent and water is 600:300:700:80:40:40:500;

[0119] The preparation method of the modified epoxy resin is as follows:

[0120] Epoxy resin emulsion, iron oxide powder, 2-ethylimidazole and hexafluorobutyl methacrylate, wherein the mass ratio of each material is 60:5:10:25, are mixed and added into a flask equipped with a condenser and a stirrer, and stirred at 75°C for 2 hours under a nitrogen atmosphere, then the temperature is raised to 80°C, and the reaction is continued for 10 hours, then the temperature is lowered to 40°C, and deionized water is slowly added dropwise under stirring at a speed of 1000 rpm, wherein the mass of the added deionized water is 0.4 times the mass of the epoxy resin emulsion, and after the reaction is completed, the target product is obtained;

[0121] In step (3), the nano-silicate is nano-montmorillonite, and its particle size is 100 nm;

[0122] In step (3), the organosilicon water repellent is triethoxysilane;

[0123] In step (3), the surfactant is octylphenol polyoxyethylene ether;

[0124] In step (3), the defoaming agent is octyl alcohol;

[0125] The parameter conditions of the epoxy resin emulsion in step (3) are as follows:

[0126] EP-380 type, solid content is 59%, viscosity: 2000mPa·s.

[0127] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the mass of boric acid added in step (4) is 0.4 times the mass of the silicate solution;

[0128] (4) Adding boric acid to the silicate solution under stirring, reacting for 1 hour, then heating to 95° C., and continuing the reaction until the boric acid is completely dissolved;

[0129] The mass percentage of boric acid in step (4) is 5%.

[0130] The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste,

[0131] The stirring conditions in step (4) are as follows:

[0132] The reactor was sealed and the rotation speed was 80 rpm.

[0133] (5) Then, after continuing the reaction for 3 hours, the boric acid-modified silicate solution is filtered and dried to obtain the final curing agent.

[0134] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the drying treatment in step (5) is performed by spray drying; the spray drying temperature is 70° C.; and the spray drying time is 28 hours.

[0135] Example 3

[0136] The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste comprises the following steps:

[0137] (1) Collect recycled aggregates from construction waste, conduct preliminary screening and cleaning to remove impurities and pollutants;

[0138] In the method for preparing a road base mixture curing agent based on recycled aggregates from construction waste, the components of the recycled aggregates from construction waste in step (1) are as follows in weight percentage:

[0139] Silicon dioxide accounts for 55%, calcium oxide accounts for 25%, aluminum oxide accounts for 5%, and the balance is iron oxide;

[0140] The particle size of the recycled aggregate from construction waste is 0.15mm.

[0141] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the aperture of the sieve initially screened in step (1) is 1.0 mm;

[0142] The cleaning method in step (1) is rinsing with warm water.

[0143] (2) crushing and grinding the washed construction waste recycled aggregate to obtain a particle size suitable for the curing agent;

[0144] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the particle size after crushing and grinding in step (2) is 100 nm.

[0145] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the crushing equipment in step (2) is a jaw crusher;

[0146] The equipment for grinding in step (2) is a drum mill.

[0147] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the silane coupling agent in step (3) is styryltrimethoxysilane;

[0148] (3) mixing the modified epoxy resin, silane coupling agent, nano-silicate, silicone hydrophobic agent, surfactant, defoaming agent and water in a predetermined ratio to form a silicate solution;

[0149] The preset weight ratio between the modified epoxy resin, silane coupling agent, nanosilicate, silicone hydrophobic agent, surfactant, defoaming agent and water is 400:300:500:80:10:40:300;

[0150] The preparation method of the modified epoxy resin is as follows:

[0151] Epoxy resin emulsion, iron oxide powder, 2-ethylimidazole and hexafluorobutyl methacrylate, wherein the mass ratio of each material is 40:5:2:25, are mixed and added into a flask equipped with a condenser and a stirrer, and stirred at 75°C for 1 hour under a nitrogen atmosphere, then the temperature is raised to 80°C, and the reaction is continued for 6 hours, then the temperature is lowered to 40°C, and deionized water is slowly added dropwise under stirring at a speed of 1000 rpm, wherein the mass of the added deionized water is 0.2 times the mass of the epoxy resin emulsion, and after the reaction is completed, the target product is obtained;

[0152] In step (3), the nanosilicate is nano silicon dioxide, and its particle size is 50 nm;

[0153] In step (3), the organic silicon water repellent is polydimethylsiloxane;

[0154] In step (3), the surfactant is sodium dodecyl sulfate;

[0155] In step (3), the defoaming agent is octyl alcohol;

[0156] The parameter conditions of the epoxy resin emulsion in step (3) are as follows:

[0157] EP-380 type, solid content is 59%, viscosity: 2000mPa·s.

[0158] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the mass of boric acid added in step (4) is 0.3 times the mass of the silicate solution;

[0159] (4) Adding boric acid to the silicate solution under stirring, reacting for 0.25 h, then heating to 95° C., and continuing the reaction until the boric acid is completely dissolved;

[0160] The mass percentage of boric acid in step (4) is 3%.

[0161] The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste,

[0162] The stirring conditions in step (4) are as follows:

[0163] The reactor was sealed and the rotation speed was 60 rpm.

[0164] (5) Then, after the reaction is continued for 1 hour, the boric acid-modified silicate solution is filtered and dried to obtain the final curing agent.

[0165] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the drying treatment in step (5) is performed by spray drying; the spray drying temperature is 60° C.; and the spray drying time is 28 hours.

[0166] Example 4

[0167] The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste comprises the following steps:

[0168] (1) Collect recycled aggregates from construction waste, conduct preliminary screening and cleaning to remove impurities and pollutants;

[0169] In the method for preparing a road base mixture curing agent based on recycled aggregates from construction waste, the components of the recycled aggregates from construction waste in step (1) are as follows in weight percentage:

[0170] Silicon dioxide accounts for 65%, calcium oxide accounts for 10%, aluminum oxide accounts for 10%, and the balance is iron oxide;

[0171] The particle size of the recycled aggregate from construction waste is 2.5mm.

[0172] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the aperture of the sieve initially screened in step (1) is 1.0 mm;

[0173] The cleaning method in step (1) is rinsing with warm water.

[0174] (2) crushing and grinding the washed construction waste recycled aggregate to obtain a particle size suitable for the curing agent;

[0175] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the particle size after crushing and grinding in step (2) is 100 nm.

[0176] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the crushing equipment in step (2) is a jaw crusher;

[0177] The equipment for grinding in step (2) is a drum mill.

[0178] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the silane coupling agent in step (3) is isobutyltriethoxysilane or 3-(2,3-epoxypropyl)trimethoxysilane;

[0179] (3) mixing the modified epoxy resin, silane coupling agent, nano-silicate, silicone hydrophobic agent, surfactant, defoaming agent and water in a predetermined ratio to form a silicate solution;

[0180] The preset weight ratio between the modified epoxy resin, silane coupling agent, nanosilicate, silicone hydrophobic agent, surfactant, defoaming agent and water is 600:200:700:50:40:10:500;

[0181] The preparation method of the modified epoxy resin is as follows:

[0182] Epoxy resin emulsion, iron oxide powder, 2-ethylimidazole and hexafluorobutyl methacrylate, wherein the mass ratio of each material is 60:2:10:10, are mixed and added into a flask equipped with a condenser and a stirrer, and stirred at 75°C for 2 hours under a nitrogen atmosphere, then the temperature is raised to 80°C, and the reaction is continued for 10 hours, then the temperature is lowered to 40°C, and deionized water is slowly added dropwise under stirring at a speed of 1000 rpm, wherein the mass of the added deionized water is 0.4 times the mass of the epoxy resin emulsion, and after the reaction is completed, the target product is obtained;

[0183] In step (3), the nano-silicate is nano-montmorillonite, and its particle size is 100 nm;

[0184] In step (3), the organosilicon water repellent is triethoxysilane;

[0185] In step (3), the surfactant is octylphenol polyoxyethylene ether;

[0186] In step (3), the defoaming agent is octyl alcohol;

[0187] The parameter conditions of the epoxy resin emulsion in step (3) are as follows:

[0188] EP-380 type, solid content is 59%, viscosity: 2000mPa·s.

[0189] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the mass of boric acid added in step (4) is 0.4 times the mass of the silicate solution;

[0190] (4) Adding boric acid to the silicate solution under stirring, reacting for 1 hour, then heating to 60° C., and continuing the reaction until the boric acid is completely dissolved;

[0191] The mass percentage of boric acid in step (4) is 5%.

[0192] The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste,

[0193] The stirring conditions in step (4) are as follows:

[0194] The reactor was sealed and the rotation speed was 80 rpm.

[0195] (5) Then, after continuing the reaction for 3 hours, the boric acid-modified silicate solution is filtered and dried to obtain the final curing agent.

[0196] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the drying treatment in step (5) is performed by spray drying; the spray drying temperature is 70° C.; and the spray drying time is 24 hours.

[0197] Example 5

[0198] The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste comprises the following steps:

[0199] (1) Collect recycled aggregates from construction waste, conduct preliminary screening and cleaning to remove impurities and pollutants;

[0200] In the method for preparing a road base mixture curing agent based on recycled aggregates from construction waste, the components of the recycled aggregates from construction waste in step (1) are as follows in weight percentage:

[0201] Silicon dioxide accounts for 60%, calcium oxide accounts for 15%, aluminum oxide accounts for 8%, and the balance is iron oxide;

[0202] The particle size of the recycled aggregate from construction waste is 1.0mm.

[0203] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the aperture of the sieve initially screened in step (1) is 1.0 mm;

[0204] The cleaning method in step (1) is rinsing with warm water.

[0205] (2) crushing and grinding the washed construction waste recycled aggregate to obtain a particle size suitable for the curing agent;

[0206] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the particle size after crushing and grinding in step (2) is 100 nm.

[0207] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the crushing equipment in step (2) is a jaw crusher;

[0208] The equipment for grinding in step (2) is a drum mill.

[0209] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the silane coupling agent in step (3) is 3-(2,3-epoxypropyl)trimethoxysilane;

[0210] (3) mixing the modified epoxy resin, silane coupling agent, nano-silicate, silicone hydrophobic agent, surfactant, defoaming agent and water in a predetermined ratio to form a silicate solution;

[0211] The preset weight ratio between the modified epoxy resin, silane coupling agent, nanosilicate, silicone hydrophobic agent, surfactant, defoaming agent and water is 500:250:600:70:30:25:400;

[0212] The preparation method of the modified epoxy resin is as follows:

[0213] Epoxy resin emulsion, iron oxide powder, 2-ethylimidazole and hexafluorobutyl methacrylate, wherein the mass ratio of each material is 50:4:7:18, are mixed and added into a flask equipped with a condenser and a stirrer, and stirred at 75°C for 1.5 hours under a nitrogen atmosphere, then the temperature is raised to 80°C, and the reaction is continued for 8 hours, then the temperature is lowered to 40°C, and deionized water is slowly added dropwise under stirring at a speed of 1000 rpm, wherein the mass of the added deionized water is 0.3 times the mass of the epoxy resin emulsion, and after the reaction is completed, the target product is obtained;

[0214] In step (3), the nanosilicate is nano silicon dioxide, and its particle size is 80 nm;

[0215] In step (3), the organic silicon water repellent is polydimethylsiloxane;

[0216] In step (3), the surfactant is sodium dodecyl sulfate;

[0217] In step (3), the defoaming agent is octyl alcohol;

[0218] The parameter conditions of the epoxy resin emulsion in step (3) are as follows:

[0219] EP-380 type, solid content is 59%, viscosity: 2000mPa·s.

[0220] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the mass of boric acid added in step (4) is 0.3 times the mass of the silicate solution;

[0221] (4) Adding boric acid to the silicate solution under stirring, reacting for 0.65 h, then heating to 80° C., and continuing the reaction until the boric acid is completely dissolved;

[0222] The mass percentage of boric acid in step (4) is 4%.

[0223] The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste,

[0224] The stirring conditions in step (4) are as follows:

[0225] The reactor was sealed and the rotation speed was 70 rpm.

[0226] (5) Then, after continuing the reaction for 2 hours, the boric acid-modified silicate solution is filtered and dried to obtain the final curing agent.

[0227] In the method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, the drying treatment in step (5) is performed by spray drying; the spray drying temperature is 65° C.; and the spray drying time is 26 hours.

[0228] Comparative Example 1

[0229] Basically the same as Example 5, except that:

[0230] The epoxy resin was not subjected to any modification treatment.

[0231] Comparative Example 2

[0232] Basically the same as Example 5, except that:

[0233] No 2-ethylimidazole is added in the preparation method of the modified epoxy resin.

[0234] Comparative Example 3

[0235] Basically the same as Example 5, except that:

[0236] Hexafluorobutyl methacrylate is not added in the preparation method of the modified epoxy resin.

[0237] Test Case

[0238] The composites were subjected to vertical flame test (UL-94) according to ASTM D3801 standard to obtain the fire resistance of the materials, and the sample size was 130×13×3mm. At the same time, the thermal conductivity was tested with reference to ISO 22007-2 to obtain the thermal conductivity coefficient. In addition, the water contact angle on the film surface was determined by drop shape analysis using a contact angle meter (JCY-2, Shanghai Fangrui Instrument Co., Ltd., Shanghai, China); a deionized water droplet with a volume of 5uL was used in the measurement, and the test was performed at room temperature; a micro-syringe was used to deposit the deionized water droplet on the sample surface, and the reported contact angle value was the average of five measurements.

[0239] Table 1 Test report

[0240]

[0241] In summary, the examples significantly improve the fire resistance, heat insulation and hydrophobicity of the materials through appropriate modification and additive combination, while the comparative examples show deficiencies in these aspects. This shows the effectiveness and importance of modified epoxy resin in the preparation of curing agent for recycled aggregate from construction waste. In addition, the scanning electron microscope image of the product prepared in Example 5 is as follows: Figure 1 shown.

[0242] The above describes in detail the preferred implementation of this patent, but this patent is not limited to the above implementation. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of this patent.

Claims

1. A method for preparing a road base mixture curing agent based on recycled aggregate from construction waste, comprising the following steps: (1) Collect recycled aggregates from construction waste, conduct preliminary screening and cleaning to remove impurities and pollutants; (2) crushing and grinding the washed construction waste recycled aggregate to obtain a particle size suitable for the curing agent; (3) mixing the modified epoxy resin, silane coupling agent, nano-silicate, silicone hydrophobic agent, surfactant, defoaming agent and water in a predetermined ratio to form a silicate solution; The preset weight ratio between the modified epoxy resin, the silane coupling agent, the nanosilicate, the silicone hydrophobic agent, the surfactant, the defoaming agent and the water is (400-600): (200-300): (500-700): (50-80): (10-40): (10-40): (300-500); The preparation method of the modified epoxy resin is as follows: Epoxy resin emulsion, iron oxide powder, 2-ethylimidazole and hexafluorobutyl methacrylate, wherein the mass ratio of each material is (40-60): (2-5): (2-10): (10-25), are mixed and added into a flask equipped with a condenser and a stirrer, and stirred at 75°C for 1h-2h under a nitrogen atmosphere, then the temperature is raised to 80°C, and the reaction is continued for 6h-10h, then the temperature is lowered to 40°C, and deionized water is slowly added dropwise with stirring at a speed of 1000 rpm, wherein the mass of the deionized water added is 0.2-0.4 times the mass of the epoxy resin emulsion, and after the reaction is completed, the target product is obtained; (4) Adding boric acid to the silicate solution under stirring, reacting for 0.25 h to 1 h, then heating to 60° C. to 95° C., and continuing the reaction until the boric acid is completely dissolved; (5) Then, after continuing the reaction for 1 h to 3 h, the boric acid-modified silicate solution is filtered and dried to obtain the final curing agent.

2. The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste according to claim 1, characterized in that: The components of the construction waste recycled aggregate in step (1) are as follows in weight percentage: Silicon dioxide accounts for 55%-65%, calcium oxide accounts for 10%-25%, aluminum oxide accounts for 5%-10%, and the balance is iron oxide; The particle size of recycled aggregate from construction waste is 0.15mm-2.5mm.

3. The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste according to claim 1, characterized in that: The sieve aperture of the preliminary screening in step (1) is 1.0 mm; The cleaning method in step (1) is rinsing with warm water.

4. The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste according to claim 1, characterized in that: The particle size after crushing and grinding in step (2) is 100 nm.

5. The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste according to claim 1, characterized in that: The crushing equipment in step (2) is a jaw crusher; The equipment for grinding in step (2) is a drum mill.

6. The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste according to claim 1, characterized in that: In step (3), the silane coupling agent is isobutyltriethoxysilane, 3-(2,3-epoxypropyl)trimethoxysilane or styryltrimethoxysilane; In step (3), the nano-silicate is nano-silicon dioxide or nano-montmorillonite, and its particle size is 50nm-100nm; In step (3), the organic silicon water repellent is polydimethylsiloxane or triethoxysilane; In step (3), the surfactant is sodium dodecyl sulfate or octylphenol polyoxyethylene ether; In step (3), the defoaming agent is octyl alcohol; The parameter conditions of the epoxy resin emulsion in step (3) are as follows: EP-380 type, solid content is 59%, viscosity: 2000mPa·s.

7. The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste according to claim 1, characterized in that: In step (4), the mass of boric acid added is 0.3 to 0.4 times the mass of the silicate solution; The mass percentage of boric acid in step (4) is 3%-5%.

8. The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste according to claim 1, characterized in that: The stirring conditions in step (4) are as follows: The reactor was sealed and the rotation speed was 60-80 rpm.

9. The method for preparing a road base mixture curing agent based on recycled aggregate from construction waste according to claim 1, characterized in that: The drying method in step (5) is spray drying; The spray drying temperature is 60℃-70℃; The spray drying time is 24h-28h.

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