High-early-strength water-damage-resistant water-based epoxy cold-recycled mixture and preparation method thereof

Abstract

The invention discloses a water-based epoxy cold-recycled mixture with high early strength and water damage resistance and a preparation method thereof. The water-based epoxy cold-recycled mixture is prepared from water-based epoxy resin, emulsified asphalt, a water-based epoxy curing agent, an old asphalt mixture, mineral powder filler and a silane coupling agent aid, the water-borne epoxy resin and the emulsified asphalt are mixed according to the mass ratio of (1-5): (95-99) to form a modified base material, and the water-borne epoxy resin replaces traditional solvent type resin through the water solubility characteristic; the water-based epoxy curing agent and the water-based epoxy resin in the modified base material are subjected to a cross-linking reaction according to the mass ratio of (0.5-2): 1, and the bonding of the cementing material and the mineral aggregate interface is enhanced through the tackifying and anchoring effects. The modified base material is prepared from the water-borne epoxy resin and the emulsified asphalt according to a specific ratio, the curing agent crosslinking reaction is matched to optimize the performance of the cold-recycled mixture, VOC emission is avoided, the water damage resistance is enhanced, the early strength is improved through grading adjustment, normal-temperature preparation and construction are convenient and fast, resource recycling is further achieved, and traditional and polymer modification limitation is overcome.

Description

Technical Field

[0001] This invention relates to the field of road engineering materials, and in particular to a high early strength, water-resistant, water-recyclable epoxy cold-recycled mixture and its preparation method. Background Technology

[0002] Cold recycling technology for asphalt pavements has been widely used in the on-site recycling and repair of old asphalt pavements on highways, national and provincial roads, and urban roads due to its advantages such as resource conservation and convenient construction. Currently, traditional cold recycled mixtures mainly use emulsified asphalt as the binder; however, it faces many technical bottlenecks in practical applications.

[0003] From the perspective of existing technologies, the strength development of traditional emulsified asphalt cold recycled materials is slow, with a 7-day strength usually less than 2MPa. This forces delays in opening to traffic and seriously affects road traffic efficiency. Although solvent-based epoxy modification technology can improve performance to some extent, it requires the use of organic solvents such as acetone, which will cause VOC emissions to exceed standards and fail to meet environmental protection requirements. In humid environments, the asphalt-aggregate interface is prone to delamination, and the road surface is easily damaged during rainy season construction, with water damage problems being prominent.

[0004] Ordinary emulsified asphalt has slow strength development and long molding cycle, which cannot meet the needs of rapid construction; although polymer modification can improve performance to a certain extent, the improvement in high temperature resistance is limited and it is difficult to adapt to complex use environments; solvent-based epoxy modification process is complicated and has poor environmental performance, which limits its large-scale application. Therefore, a high early strength and water loss resistant waterborne epoxy cold recycling mixture and its preparation method are proposed. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high early strength, water-damage resistant waterborne epoxy cold recyclable mixture and its preparation method, thereby solving the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a high early strength, water-damage resistant waterborne epoxy cold-recycled mixture, comprising: Waterborne epoxy resin, emulsified asphalt, waterborne epoxy curing agent, recycled asphalt mixture, mineral filler and silane coupling agent additive; The waterborne epoxy resin and emulsified asphalt are mixed at a mass ratio of (1-5):(95-99) to form a modified base material. The waterborne epoxy resin, through its water-soluble properties, replaces traditional solvent-based resins, achieving zero-solvent modification to eliminate VOC pollution. The waterborne epoxy curing agent undergoes a cross-linking reaction with the waterborne epoxy resin in the modified base material at a mass ratio of (0.5-2):1. This reaction strengthens the bond between the binder and the aggregate interface through tackifying and anchoring effects, while simultaneously promoting the formation of a cross-linked network structure that penetrates the asphalt phase. This structure is achieved through a combination of chemical cross-linking and physical anchoring. The method improves the cohesive strength of the mixture; the old asphalt mixture, after being screened and graded and adjusted, meets the requirements for the recycling and repair of highways and urban roads; silane coupling agent is used to enhance the interfacial adhesion between the aggregate and the binder; the hydrophobicity of the cross-linked network structure and the active adsorption of the curing agent on the aggregate synergistically inhibit water erosion, and by controlling the reaction rate between the water-based epoxy and the curing agent, a strong skeleton is formed in a short time after the mixture is constructed; the porosity of the mixture is controlled at 3%-8% through gradation optimization and cross-linking control of the binder, forming a dense water-resistant structural system; When mixing waterborne epoxy resin and emulsified asphalt, a planetary mixer should be used. First, mix at a low speed of 300 r / min for 2 minutes, then increase to a high speed of 800 r / min for 10 minutes until a uniform and stable modified base material is formed. This method can ensure that the waterborne epoxy resin and emulsified asphalt are fully integrated to form a stable modified base material, which lays the foundation for subsequent crosslinking reaction and mixture preparation. High early strength and water-damage resistant waterborne epoxy cold recycling mixture achieves zero-solvent modification by replacing traditional solvent-based resin with waterborne epoxy resin, effectively eliminating VOC pollution and meeting environmental protection requirements. The waterborne epoxy curing agent undergoes a cross-linking reaction with the waterborne epoxy resin in the modified base material, forming a cross-linked network structure that significantly improves the cohesive strength of the mixture. At the same time, the old asphalt mixture meets the recycling and repair requirements after sieving and grading. The addition of silane coupling agent further enhances the interfacial adhesion between the aggregate and the binder. In addition, by controlling the reaction rate between waterborne epoxy and curing agent, the mixture can form a strong skeleton in a short time after construction, and the porosity is controlled at 3%-8%, forming a dense water-damage resistant structural system with both high thermal stability and low-temperature flexibility, making it suitable for recycling and repairing highways and urban roads.

[0007] Preferably, the crosslinking density of the crosslinked network structure is controlled at 0.8-1.2 mol / kg by adjusting the reaction time of the waterborne epoxy and the curing agent, so that the compressive strength of the mixture reaches 1.5 MPa 24 hours after construction; In the crosslinking reaction control step, the reaction temperature is precisely controlled at 15-35℃ by circulating water bath, and the reaction time is adjusted to 10-30min according to the type of curing agent (such as aliphatic amines or aromatic amines) to ensure that the waterborne epoxy and curing agent react fully to form a network structure with the required crosslinking density. By controlling the crosslinking density of the crosslinked network structure to 0.8-1.2 mol / kg, this technical solution significantly improves the early strength and durability of the mixture. By controlling the reaction time, the mixture can reach a compressive strength of 1.5 MPa within 24 hours after construction, greatly shortening the construction cycle and improving project efficiency. At the same time, the formed crosslinked network structure enhances the interfacial bonding between the binder and the aggregate, improves the cohesive strength and water resistance of the mixture, and ensures the stability and safety of the road during long-term use. In addition, this technical solution also effectively reduces VOC pollution and meets environmental protection requirements.

[0008] Preferably, the amount of the silane coupling agent is 0.5%-2% of the mineral powder mass. After silane hydrolysis, it reacts with the hydroxyl groups on the surface of the mineral to form covalent bonds, further enhancing the interfacial bonding strength. During the mixing stage, the silane coupling agent is dissolved in an appropriate amount of water to form a hydrolysate. It is then accurately weighed and added at 0.5%-2% of the mineral powder mass. The silane is fully hydrolyzed by stirring and then mixed with the mineral. The chemical reaction between the silane hydrolysis products and the hydroxyl groups on the surface of the mineral forms a stable covalent bond, which significantly enhances the interfacial bonding strength between the mineral and the binder, ensuring the stability and durability of the overall performance of the mixture. Silane coupling agents form covalent bonds with the hydroxyl groups on the surface of mineral aggregates through hydrolysis, which not only enhances the interfacial bonding strength but also promotes a tighter bond between the binder and the mineral aggregates. This technological advantage is reflected in several aspects: First, it effectively improves the overall strength and durability of the mixture and reduces performance degradation caused by poor interfacial bonding; second, the use of silane coupling agents improves the water resistance of the mixture and extends the service life of the road; third, by precisely controlling the dosage of silane coupling agents, cost-effectiveness is maximized, ensuring both performance and cost control.

[0009] Preferably, the mixture has a dynamic stability of not less than 2000 cycles / mm at 60℃ and a bending strain of not less than 2000με at -10℃, thus possessing both high thermal stability and low-temperature flexibility. The key to achieving these properties lies in the optimization of the mixture gradation, the regulation of the crosslinking of the binder, and the precise control of the porosity. By optimizing the mass ratio of waterborne epoxy resin to emulsified asphalt, the amount of waterborne epoxy curing agent added and the reaction conditions, as well as the enhancing effect of silane coupling agent on the interfacial adhesion between the aggregate and the binder, it can be ensured that the mixture remains stable at high temperatures and still has good flexibility at low temperatures. Its dynamic stability at 60℃ is no less than 2000 cycles / mm, indicating that it can still maintain a high resistance to rutting under high temperature conditions, effectively extending the service life of roads; the bending strain at -10℃ is no less than 2000με, which ensures the flexibility of the mixture in low temperature environment and reduces cracks caused by temperature changes. This characteristic of combining high thermal stability and low temperature flexibility makes the mixture adaptable to various extreme climatic conditions, providing a more reliable repair and construction solution for roads. At the same time, through gradation optimization and cross-linking control of binder, the mixture forms a dense water-resistant structural system.

[0010] Preferably, the proportion of particles with a diameter greater than 4.75 mm in the old asphalt mixture does not exceed 30%, and the gradation optimization makes the mixture skeleton structure more compact and improves its resistance to deformation. The proportion of particles larger than 4.75mm in the old asphalt mixture should not exceed 30%. The old asphalt mixture can be crushed to a maximum particle size of ≤9.5mm by an impact crusher, and then screened by a vibrating screen to ensure that the proportion of particles larger than 4.75mm does not exceed 30%. For the missing part of particles smaller than 0.075mm after screening, it should be supplemented by adding 5%-8% of mineral powder to meet the gradation requirements of the AC-13 type asphalt mixture specification, thereby optimizing the skeleton structure of the mixture and improving its density and deformation resistance. By strictly controlling the proportion of particles larger than 4.75mm in the old asphalt mixture to no more than 30%, and by using gradation optimization technology to make the mixture skeleton structure more compact, this improvement significantly enhances the mixture's resistance to deformation, ensuring that the road can maintain good stability and durability under heavy loads and traffic pressure. At the same time, the optimized gradation helps reduce the voids inside the mixture, improves water loss resistance, and extends the service life of the road. In addition, this improvement also meets environmental protection requirements, reducing resource consumption and waste generation during road construction by reducing the use of large particles, thus promoting the sustainable development of road engineering.

[0011] A method for preparing a high early strength, water-loss resistant waterborne epoxy cold-recycled compound, based on the above-mentioned high early strength, water-loss resistant waterborne epoxy cold-recycled compound, includes the following steps: Step 1: Preparation of Modified Base Material Weigh the raw materials according to the mass ratio of waterborne epoxy resin to emulsified asphalt (1-5): (95-99), and mix them at a stirring speed of 300-800 r / min for 5-15 min to obtain the modified base material. Step 2, Crosslinking Reaction Control: Add waterborne epoxy curing agent (mass ratio of waterborne epoxy resin to waterborne epoxy resin 0.5-2:1) to the modified base material, react at 15-35℃ for 10-30 min to form a cross-linked network structure binder; Step 3: Mixing the ingredients: The old asphalt mixture is crushed and screened to a particle size > 4.75mm with a particle size of ≤ 30%. Mineral powder filler is added according to the gradation, and the mixture is mixed with binder and silane coupling agent at room temperature for 3-8 minutes. The porosity is controlled at 3%-8% to obtain cold recycled material. In the preparation of modified base material, a planetary mixer is used for stirring, with low speed followed by high speed to ensure uniformity; the crosslinking reaction temperature is precisely controlled by a circulating water bath, and heating or cooling is adjusted according to the ambient temperature; when mixing the mixture, it is added in the order of binder, old material, and filler, and a torque sensor is used to monitor the mixing resistance to ensure uniform mixing. By mixing waterborne epoxy resin with emulsified asphalt in a specific ratio, an environmentally friendly and high-performance modified base material is formed, eliminating VOC pollution. The crosslinking reaction is precisely controlled, forming a strong and tough crosslinked network structure, which improves the cohesive strength and water resistance of the mixture. During the mixing process, the gradation and porosity of the old asphalt mixture are strictly controlled to ensure that the mixture is dense and has stable performance. This method not only effectively utilizes old asphalt mixtures and saves resources, but also produces a mixture with both high thermal stability and low-temperature flexibility, which is suitable for the recycling and repair of highways and urban roads, improving road service life and safety, while reducing environmental pollution, in line with the concept of green and sustainable development.

[0012] Preferably, the mixing in step one is carried out using a planetary mixer. The mixing speed is initially set at 300 r / min for 2 minutes, then increased to 800 r / min for 10 minutes for high-speed dispersion, until the waterborne epoxy resin and emulsified asphalt form a uniform and stable modified base material. First, mix at a low speed of 300 r / min for 2 minutes to allow the waterborne epoxy resin and emulsified asphalt to initially come into contact and mix. Then, increase the stirring speed to 800 r / min for high-speed dispersion for 10 minutes. During this process, the mixer ensures that the materials are fully sheared and mixed until a uniform and stable modified base material is formed. The waterborne epoxy resin and emulsified asphalt are evenly distributed in this base material, with no particle aggregation or sedimentation. The use of a planetary mixer and staged speed control plays a crucial role in the preparation of high early strength and water-damage resistant waterborne epoxy cold recycled mixture. The low-speed mixing stage ensures initial uniform contact between the waterborne epoxy resin and emulsified asphalt, avoiding material splashing or uneven mixing that may occur with direct high-speed mixing. The subsequent high-speed dispersion stage further ensures the uniformity and stability of the modified base material, which is essential for the subsequent crosslinking reaction and the overall performance of the mixture. Through such stirring control, not only is the quality of the modified base material improved, but the effective interaction between the waterborne epoxy resin and the emulsified asphalt is also promoted.

[0013] Preferably, the reaction temperature in step two is controlled by a circulating water bath. When the ambient temperature is below 15°C, the heating device is activated, and when it is above 35°C, the cooling system is activated. The reaction time is adjusted according to the type of curing agent. For aliphatic amine curing agents, the time is controlled at 10-15 minutes, and for aromatic amine curing agents, the time is controlled at 20-30 minutes. When controlling the reaction temperature in a circulating water bath, a high-precision temperature sensor should be used to monitor the water bath temperature in real time, and the output of the heating or cooling device should be precisely adjusted through an automated control system to maintain the temperature within the set range and ensure that the fluctuation does not exceed ±1℃, thereby ensuring the stability and repeatability of the reaction conditions. By combining a circulating water bath with a high-precision temperature sensor and an automated control system, precise control of the reaction temperature is achieved. When the ambient temperature is below 15°C, the system automatically activates the heating device to ensure that the reaction temperature does not drop too low and affect the reaction rate. When the ambient temperature is above 35°C, the cooling system is activated to prevent the reaction temperature from becoming too high and causing side reactions. In addition, the reaction time is flexibly adjusted according to the type of curing agent (such as aliphatic amines or aromatic amines), which can ensure that the reaction proceeds fully and effectively avoid over-reaction, thereby improving the performance stability and preparation efficiency of the mixture. This precise temperature control method provides a strong guarantee for the preparation of high-quality, high-early-strength, water-damage-resistant waterborne epoxy cold-recycled mixtures.

[0014] Preferably, in the pretreatment of old asphalt mixture in step three, an impact crusher is used to crush the material to a maximum particle size of ≤9.5mm. After screening by a vibrating screen, the missing particles below 0.075mm are supplemented by adding 5%-8% mineral powder to ensure that the gradation meets the requirements of the AC-13 type asphalt mixture specification. During the pretreatment process, precise weighing equipment must be used to add mineral powder to ensure that the amount of missing particles smaller than 0.075mm is strictly controlled within the range of 5%-8% of the total amount of mineral powder added. Continuous stirring is used to fully integrate the added mineral powder with the old asphalt mixture to meet the gradation specifications of AC-13 type asphalt mixture. The old asphalt mixture is crushed to a maximum particle size of ≤9.5mm using an impact crusher and then screened by a vibrating screen. This process effectively ensures the uniformity of particle size in the mixture and improves its overall performance. For particles smaller than 0.075mm, 5%-8% mineral powder is added to compensate for deficiencies in the gradation, enhancing the density and stability of the mixture. This ensures that the mixture gradation meets the requirements of the AC-13 asphalt mixture specification, thereby improving the mixture's high-temperature stability, low-temperature crack resistance, and water stability. This provides a high-quality material option for road repair and recycling projects, extending the service life of roads.

[0015] Preferably, in step three, the binder, old material, and filler are added in the order of mixing. First, the cross-linked binder is mixed with the old asphalt mixture for 3 minutes to initially coat the mineral aggregate. Then, mineral powder and silane coupling agent (0.5%-2% of the mineral powder mass) are added and mixed for another 5 minutes. The mixing resistance is monitored by a torque sensor to ensure uniformity. During the mixing process, the working status of the mixing equipment should be checked regularly to ensure that the mixing blades are not worn and that there is no residual old material on the inner wall of the mixing drum, so as to ensure the mixing quality. At the same time, the mixing site should be kept clean to prevent impurities from mixing into the mixture. The mixing process involves adding binder, recycled material, and filler in that order. This scientifically designed process first mixes the cross-linked binder with the old asphalt mixture to initially coat the aggregate, which helps the binder to be evenly distributed on the surface of the aggregate and enhances adhesion. Then, mineral powder and silane coupling agent are added and mixing continues. The silane coupling agent further improves the interfacial bonding strength. By monitoring the mixing resistance with a torque sensor, the uniformity of mixing can be monitored in real time, ensuring the stability of the mixture quality. This mixing method not only improves production efficiency but also guarantees the various performance indicators of the mixture, such as compressive strength, dynamic stability, and flexural strain, providing high-quality materials for road regeneration and repair.

[0016] In summary, compared with the prior art, the present invention provides a high early strength and water-loss resistant waterborne epoxy cold recycling mixture and its preparation method, which has the following beneficial effects: This invention optimizes and upgrades the performance of traditional cold-recycled mixtures by mixing water-based epoxy resin and emulsified asphalt in a specific mass ratio to form a modified base material. A water-based epoxy curing agent then cross-links with the water-based epoxy resin in the modified base material, achieving this optimization. The water-based epoxy resin, with its water-soluble properties, replaces traditional solvent-based resins, eliminating the use of organic solvents such as acetone. This fundamentally avoids the risk of excessive VOC emissions associated with solvent-based epoxy modification. The cross-linked network structure formed by the cross-linking reaction, penetrating the asphalt phase, strengthens the bond between the binder and the aggregate interface, giving the mixture excellent hydrophobicity. Combined with the active adsorption of the aggregate by the curing agent, this effectively inhibits water intrusion, solving the water damage problems of traditional emulsified asphalt cold-recycled mixtures, such as easy separation from aggregates in humid environments and easy road surface damage during rainy seasons. This significantly enhances the water resistance of the mixture and extends the service life of the road. By using recycled asphalt mixtures after grading and adjusting their gradation, combined with gradation optimization and binder crosslinking control, the porosity of the mixture is controlled within a reasonable range, resulting in a significant improvement in the early strength of the mixture. This mixture can quickly reach a high strength, meeting the needs of rapid construction. Furthermore, this preparation method operates at room temperature, requiring no complex processes or high-temperature conditions, making construction convenient and reducing construction costs. At the same time, it utilizes recycled asphalt mixtures to achieve resource recycling, saving raw materials and reducing project costs. This innovation not only solves the problem of slow strength development in traditional cold recycled mixtures, but also overcomes the limitations of polymer-modified high-temperature resistance and difficulty in adapting to complex usage environments. Attached Figure Description

[0017] Figure 1 This is a step diagram of the preparation method of the high early strength and water-damage resistant water-based epoxy cold recyclable mixture of the invention. Detailed Implementation

[0018] This invention provides a technical solution: a high early strength, water-damage resistant waterborne epoxy cold-recycling mixture, as shown in the figure, comprising: Waterborne epoxy resin, emulsified asphalt, waterborne epoxy curing agent, recycled asphalt mixture, mineral filler and silane coupling agent additive; A modified base material is formed by mixing waterborne epoxy resin and emulsified asphalt at a mass ratio of (1-5):(95-99). The waterborne epoxy resin, through its water-soluble properties, replaces traditional solvent-based resins, achieving zero-solvent modification to eliminate VOC pollution. A cross-linking reaction occurs between the waterborne epoxy curing agent and the waterborne epoxy resin in the modified base material at a mass ratio of (0.5-2):1. This reaction strengthens the bond between the binder and the aggregate interface through tackifying and anchoring effects, while simultaneously promoting the formation of a cross-linked network structure that penetrates the asphalt phase. This structure achieves bonding through chemical cross-linking and physical anchoring. The method of combining different types of asphalt mixtures enhances the cohesive strength of the mixture. After screening and grading, the old asphalt mixture meets the requirements for the recycling and repair of highways and urban roads. Silane coupling agents are used to enhance the interfacial adhesion between the aggregate and the binder. The hydrophobicity of the cross-linked network structure and the active adsorption of the curing agent on the aggregate synergistically inhibit water erosion. Furthermore, by controlling the reaction rate between the water-based epoxy and the curing agent, the mixture forms a strong skeleton in a short time after construction. Through gradation optimization and cross-linking control of the binder, the porosity of the mixture is controlled at 3%-8%, forming a dense and water-resistant structural system. When mixing waterborne epoxy resin and emulsified asphalt, a planetary mixer should be used. First, mix at a low speed of 300 r / min for 2 minutes, then increase to a high speed of 800 r / min for 10 minutes until a uniform and stable modified base material is formed. This method can ensure that the waterborne epoxy resin and emulsified asphalt are fully integrated to form a stable modified base material, which lays the foundation for subsequent crosslinking reaction and mixture preparation. High early strength and water-damage resistant waterborne epoxy cold recycling mixture achieves zero-solvent modification by replacing traditional solvent-based resin with waterborne epoxy resin, effectively eliminating VOC pollution and meeting environmental protection requirements. The waterborne epoxy curing agent undergoes a cross-linking reaction with the waterborne epoxy resin in the modified base material, forming a cross-linked network structure that significantly improves the cohesive strength of the mixture. At the same time, the old asphalt mixture meets the recycling and repair requirements after sieving and grading. The addition of silane coupling agent further enhances the interfacial adhesion between the aggregate and the binder. In addition, by controlling the reaction rate between waterborne epoxy and curing agent, the mixture can form a strong skeleton in a short time after construction, and the porosity is controlled at 3%-8%, forming a dense water-damage resistant structural system with both high thermal stability and low-temperature flexibility, making it suitable for recycling and repairing highways and urban roads.

[0019] Please see Figure 1 The crosslinking density of the crosslinked network structure is controlled at 0.8-1.2 mol / kg by adjusting the reaction time of waterborne epoxy and curing agent, so that the compressive strength of the mixture reaches 1.5 MPa 24 hours after construction; In the crosslinking reaction control step, the reaction temperature is precisely controlled at 15-35℃ by circulating water bath, and the reaction time is adjusted to 10-30min according to the type of curing agent (such as aliphatic amines or aromatic amines) to ensure that the waterborne epoxy and curing agent react fully to form a network structure with the required crosslinking density. By controlling the crosslinking density of the crosslinked network structure to 0.8-1.2 mol / kg, this technical solution significantly improves the early strength and durability of the mixture. By controlling the reaction time, the mixture can reach a compressive strength of 1.5 MPa within 24 hours after construction, greatly shortening the construction cycle and improving project efficiency. At the same time, the formed crosslinked network structure enhances the interfacial bonding between the binder and the aggregate, improves the cohesive strength and water resistance of the mixture, and ensures the stability and safety of the road during long-term use. In addition, this technical solution also effectively reduces VOC pollution and meets environmental protection requirements.

[0020] Please see Figure 1 The amount of silane coupling agent is 0.5%-2% of the mineral powder mass. After silane hydrolysis, it reacts with the hydroxyl groups on the surface of the mineral to form covalent bonds, which further enhances the interfacial bonding strength. During the mixing stage, the silane coupling agent is dissolved in an appropriate amount of water to form a hydrolysate. It is then accurately weighed and added at 0.5%-2% of the mineral powder mass. The silane is fully hydrolyzed by stirring and then mixed with the mineral. The chemical reaction between the silane hydrolysis products and the hydroxyl groups on the surface of the mineral forms a stable covalent bond, which significantly enhances the interfacial bonding strength between the mineral and the binder, ensuring the stability and durability of the overall performance of the mixture. Silane coupling agents form covalent bonds with the hydroxyl groups on the surface of mineral aggregates through hydrolysis, which not only enhances the interfacial bonding strength but also promotes a tighter bond between the binder and the mineral aggregates. This technological advantage is reflected in several aspects: First, it effectively improves the overall strength and durability of the mixture and reduces performance degradation caused by poor interfacial bonding; second, the use of silane coupling agents improves the water resistance of the mixture and extends the service life of the road; third, by precisely controlling the dosage of silane coupling agents, cost-effectiveness is maximized, ensuring both performance and cost control.

[0021] Please see Figure 1 The mixture exhibits a dynamic stability of no less than 2000 cycles / mm at 60℃ and a bending strain of no less than 2000με at -10℃, combining high thermal stability with low-temperature flexibility. The key to achieving these properties lies in the optimization of the mixture gradation, the regulation of the crosslinking of the binder, and the precise control of the porosity. By optimizing the mass ratio of waterborne epoxy resin to emulsified asphalt, the amount of waterborne epoxy curing agent added and the reaction conditions, as well as the enhancing effect of silane coupling agent on the interfacial adhesion between the aggregate and the binder, it can be ensured that the mixture remains stable at high temperatures and still has good flexibility at low temperatures. Its dynamic stability at 60℃ is no less than 2000 cycles / mm, indicating that it can still maintain a high resistance to rutting under high temperature conditions, effectively extending the service life of roads; its bending strain at -10℃ is no less than 2000με, which ensures the flexibility of the mixture in low temperature environments and reduces cracks caused by temperature changes. This characteristic of combining high thermal stability and low-temperature flexibility enables the mixture to adapt to various extreme climatic conditions, providing a more reliable repair and construction solution for roads. At the same time, through gradation optimization and cross-linking control of binders, the mixture forms a dense water-resistant structural system.

[0022] Please see Figure 1 In old asphalt mixtures, particles with a diameter greater than 4.75 mm account for no more than 30% of the total. By optimizing the gradation, the skeleton structure of the mixture is made denser, thus improving its resistance to deformation. The proportion of particles larger than 4.75mm in the old asphalt mixture should not exceed 30%. The old asphalt mixture can be crushed to a maximum particle size of ≤9.5mm by an impact crusher, and then screened by a vibrating screen to ensure that the proportion of particles larger than 4.75mm does not exceed 30%. For the missing part of particles smaller than 0.075mm after screening, it should be supplemented by adding 5%-8% of mineral powder to meet the gradation requirements of the AC-13 type asphalt mixture specification, thereby optimizing the skeleton structure of the mixture and improving its density and deformation resistance. By strictly controlling the proportion of particles larger than 4.75mm in the old asphalt mixture to no more than 30%, and by using gradation optimization technology to make the mixture skeleton structure more compact, this improvement significantly enhances the mixture's resistance to deformation, ensuring that the road can maintain good stability and durability under heavy loads and traffic pressure. At the same time, the optimized gradation helps reduce the voids inside the mixture, improves water loss resistance, and extends the service life of the road. In addition, this improvement also meets environmental protection requirements, reducing resource consumption and waste generation during road construction by reducing the use of large particles, thus promoting the sustainable development of road engineering.

[0023] A method for preparing a high early strength, water-loss resistant waterborne epoxy cold-recycled compound, based on the above-mentioned high early strength, water-loss resistant waterborne epoxy cold-recycled compound, please refer to [link to relevant documentation]. Figure 1 It includes the following steps: Step 1: Preparation of Modified Base Material Weigh the raw materials according to the mass ratio of waterborne epoxy resin to emulsified asphalt (1-5): (95-99), and mix them at a stirring speed of 300-800 r / min for 5-15 min to obtain the modified base material. Step 2, Crosslinking Reaction Control: Add waterborne epoxy curing agent (mass ratio of waterborne epoxy resin to waterborne epoxy resin 0.5-2:1) to the modified base material, react at 15-35℃ for 10-30 min to form a cross-linked network structure binder; Step 3: Mixing the ingredients: The old asphalt mixture is crushed and screened to a particle size > 4.75mm with a particle size of ≤ 30%. Mineral powder filler is added according to the gradation, and the mixture is mixed with binder and silane coupling agent at room temperature for 3-8 minutes. The porosity is controlled at 3%-8% to obtain cold recycled material. In the preparation of modified base material, a planetary mixer is used for stirring, with low speed followed by high speed to ensure uniformity; the crosslinking reaction temperature is precisely controlled by a circulating water bath, and heating or cooling is adjusted according to the ambient temperature; when mixing the mixture, it is added in the order of binder, old material, and filler, and a torque sensor is used to monitor the mixing resistance to ensure uniform mixing. By mixing waterborne epoxy resin with emulsified asphalt in a specific ratio, an environmentally friendly and high-performance modified base material is formed, eliminating VOC pollution. The crosslinking reaction is precisely controlled, forming a strong and tough crosslinked network structure, which improves the cohesive strength and water resistance of the mixture. During the mixing process, the gradation and porosity of the old asphalt mixture are strictly controlled to ensure that the mixture is dense and has stable performance. This method not only effectively utilizes old asphalt mixtures and saves resources, but also produces a mixture with both high thermal stability and low-temperature flexibility, which is suitable for the recycling and repair of highways and urban roads, improving road service life and safety, while reducing environmental pollution, in line with the concept of green and sustainable development.

[0024] Please see Figure 1 In step one, a planetary mixer is used for mixing. The mixing speed is initially 300 r / min for 2 minutes, then increased to 800 r / min for 10 minutes for high-speed dispersion, until the waterborne epoxy resin and emulsified asphalt form a uniform and stable modified base material. First, mix at a low speed of 300 r / min for 2 minutes to allow the waterborne epoxy resin and emulsified asphalt to initially come into contact and mix. Then, increase the stirring speed to 800 r / min for high-speed dispersion for 10 minutes. During this process, the mixer ensures that the materials are fully sheared and mixed until a uniform and stable modified base material is formed. The waterborne epoxy resin and emulsified asphalt are evenly distributed in this base material, with no particle aggregation or sedimentation. The use of a planetary mixer and staged speed control plays a crucial role in the preparation of high early strength and water-damage resistant waterborne epoxy cold recycled mixture. The low-speed mixing stage ensures initial uniform contact between the waterborne epoxy resin and emulsified asphalt, avoiding material splashing or uneven mixing that may occur with direct high-speed mixing. The subsequent high-speed dispersion stage further ensures the uniformity and stability of the modified base material, which is essential for the subsequent crosslinking reaction and the overall performance of the mixture. Through such stirring control, not only is the quality of the modified base material improved, but the effective interaction between the waterborne epoxy resin and the emulsified asphalt is also promoted.

[0025] Please see Figure 1 In step two, the reaction temperature is controlled by a circulating water bath. When the ambient temperature is below 15°C, the heating device is activated, and when it is above 35°C, the cooling system is activated. The reaction time is adjusted according to the type of curing agent. For aliphatic amine curing agents, the time is controlled at 10-15 minutes, and for aromatic amine curing agents, the time is controlled at 20-30 minutes. When controlling the reaction temperature in a circulating water bath, a high-precision temperature sensor should be used to monitor the water bath temperature in real time, and the output of the heating or cooling device should be precisely adjusted through an automated control system to maintain the temperature within the set range and ensure that the fluctuation does not exceed ±1℃, thereby ensuring the stability and repeatability of the reaction conditions. By combining a circulating water bath with a high-precision temperature sensor and an automated control system, precise control of the reaction temperature is achieved. When the ambient temperature is below 15°C, the system automatically activates the heating device to ensure that the reaction temperature does not drop too low and affect the reaction rate. When the ambient temperature is above 35°C, the cooling system is activated to prevent the reaction temperature from becoming too high and causing side reactions. In addition, the reaction time is flexibly adjusted according to the type of curing agent (such as aliphatic amines or aromatic amines), which can ensure that the reaction proceeds fully and effectively avoid over-reaction, thereby improving the performance stability and preparation efficiency of the mixture. This precise temperature control method provides a strong guarantee for the preparation of high-quality, high-early-strength, water-damage-resistant waterborne epoxy cold-recycled mixtures.

[0026] Please see Figure 1 In step three, during the pretreatment of the old asphalt mixture, an impact crusher is used to crush it to a maximum particle size of ≤9.5mm. After screening by a vibrating screen, the missing particles below 0.075mm are supplemented by adding 5%-8% mineral powder to ensure that the gradation meets the requirements of the AC-13 type asphalt mixture specification. During the pretreatment process, precise weighing equipment must be used to add mineral powder to ensure that the amount of missing particles smaller than 0.075mm is strictly controlled within the range of 5%-8% of the total amount of mineral powder added. Continuous stirring is used to fully integrate the added mineral powder with the old asphalt mixture to meet the gradation specifications of AC-13 type asphalt mixture. The old asphalt mixture is crushed to a maximum particle size of ≤9.5mm using an impact crusher and then screened by a vibrating screen. This process effectively ensures the uniformity of particle size in the mixture and improves its overall performance. For particles smaller than 0.075mm, 5%-8% mineral powder is added to compensate for deficiencies in the gradation, enhancing the density and stability of the mixture. This ensures that the mixture gradation meets the requirements of the AC-13 asphalt mixture specification, thereby improving the mixture's high-temperature stability, low-temperature crack resistance, and water stability. This provides a high-quality material option for road repair and recycling projects, extending the service life of roads.

[0027] Please see Figure 1 In step three, the binder, old material and filler are added in the order of mixing. First, the cross-linked binder and old asphalt mixture are mixed for 3 minutes to initially coat the minerals. Then, mineral powder and silane coupling agent (0.5%-2% of the mineral powder mass) are added and mixed for another 5 minutes. The mixing resistance is monitored by a torque sensor to ensure uniformity. During the mixing process, the working status of the mixing equipment should be checked regularly to ensure that the mixing blades are not worn and that there is no residual old material on the inner wall of the mixing drum, so as to ensure the mixing quality. At the same time, the mixing site should be kept clean to prevent impurities from mixing into the mixture. The mixing process involves adding binder, recycled material, and filler in that order. This scientifically designed process first mixes the cross-linked binder with the old asphalt mixture to initially coat the aggregate, which helps the binder to be evenly distributed on the surface of the aggregate and enhances adhesion. Then, mineral powder and silane coupling agent are added and mixing continues. The silane coupling agent further improves the interfacial bonding strength. By monitoring the mixing resistance with a torque sensor, the uniformity of mixing can be monitored in real time, ensuring the stability of the mixture quality. This mixing method not only improves production efficiency but also guarantees the various performance indicators of the mixture, such as compressive strength, dynamic stability, and flexural strain, providing high-quality materials for road regeneration and repair.

[0028] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0029] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A high early strength, water-loss resistant, water-based epoxy cold-recycled mixture, characterized in that, include: Waterborne epoxy resin, emulsified asphalt, waterborne epoxy curing agent, recycled asphalt mixture, mineral filler and silane coupling agent additive; The waterborne epoxy resin and emulsified asphalt are mixed at a mass ratio of (1-5):(95-99) to form a modified base material, wherein the waterborne epoxy resin replaces the traditional solvent-based resin through its water-soluble properties. The waterborne epoxy curing agent and the waterborne epoxy resin in the modified base material undergo a cross-linking reaction at a mass ratio of (0.5-2):

1. This reaction strengthens the bonding between the binder and the mineral aggregate through tackification and anchoring effects, while also promoting the formation of a cross-linked network structure that penetrates the asphalt phase. The old asphalt mixture, after being screened, graded, and adjusted, meets the requirements for the recycling and restoration of highways and urban roads. The hydrophobicity of the cross-linked network structure and the active adsorption of the curing agent on the mineral material synergistically inhibit moisture erosion. The porosity of the mixture is controlled at 3%-8% through gradation optimization and cross-linking regulation of the binder.

2. The high early strength, water-loss resistant waterborne epoxy cold-recycling mixture according to claim 1, characterized in that: The crosslinking density of the crosslinked network structure is controlled at 0.8-1.2 mol / kg by adjusting the reaction time of the waterborne epoxy and the curing agent, so that the compressive strength of the mixture reaches 1.5 MPa 24 hours after construction.

3. The high early strength, water-loss resistant waterborne epoxy cold-recycled mixture according to claim 1, characterized in that: The amount of the silane coupling agent is 0.5%-2% of the mineral powder mass. After silane hydrolysis, it reacts with the hydroxyl groups on the surface of the mineral to form covalent bonds.

4. The high early strength, water-loss resistant waterborne epoxy cold-recycled mixture according to claim 1, characterized in that: The mixture has a dynamic stability of not less than 2000 cycles / mm at 60℃ and a bending strain of not less than 2000με at -10℃.

5. The high early strength, water-loss resistant waterborne epoxy cold-recycled mixture according to claim 1, characterized in that: The proportion of particles with a diameter greater than 4.75 mm in the old asphalt mixture shall not exceed 30%.

6. A method for preparing a high early strength, water-loss resistant waterborne epoxy cold-recycled mixture, based on the high early strength, water-loss resistant waterborne epoxy cold-recycled mixture as described in any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Preparation of Modified Base Material Weigh the raw materials according to the mass ratio of waterborne epoxy resin to emulsified asphalt (1-5): (95-99), and mix them at a stirring speed of 300-800 r / min for 5-15 min to obtain the modified base material. Step 2, Crosslinking Reaction Control: Add water-based epoxy curing agent to the modified base material and react at 15-35℃ for 10-30 minutes to form a cross-linked network structure binder. Step 3: Mixing the ingredients: The old asphalt mixture is crushed and screened to a particle size > 4.75mm with a particle size of ≤ 30%. Mineral powder filler is added according to the gradation, and the mixture is mixed with binder and silane coupling agent at room temperature for 3-8 minutes. The porosity is controlled at 3%-8% to obtain cold recycled material.

7. The method for preparing a high early strength, water-loss resistant waterborne epoxy cold-recycled mixture according to claim 6, characterized in that: In step one, a planetary mixer is used for mixing. The mixing speed is initially set at 300 r / min for 2 minutes, then increased to 800 r / min for 10 minutes for high-speed dispersion, until the waterborne epoxy resin and emulsified asphalt form a uniform and stable modified base material.

8. The method for preparing a high early strength, water-loss resistant waterborne epoxy cold-recycled mixture according to claim 6, characterized in that: The reaction temperature in step two is controlled by a circulating water bath. When the ambient temperature is below 15°C, the heating device is activated, and when it is above 35°C, the cooling system is activated. The reaction time is adjusted according to the type of curing agent. For aliphatic amine curing agents, the time is controlled at 10-15 minutes, and for aromatic amine curing agents, the time is controlled at 20-30 minutes.

9. The method for preparing a high early strength, water-loss resistant waterborne epoxy cold-recycled mixture according to claim 6, characterized in that: In the pretreatment of old asphalt mixture in step three, an impact crusher is used to crush the material to a maximum particle size of ≤9.5mm. After screening by a vibrating screen, the missing particles below 0.075mm are supplemented by adding 5%-8% mineral powder.

10. The method for preparing a high early strength, water-loss resistant waterborne epoxy cold-recycled mixture according to claim 6, characterized in that: In step three, the binder, old material, and filler are added in the order of mixing. First, the cross-linked binder is mixed with the old asphalt mixture for 3 minutes to initially coat the mineral aggregate. Then, mineral powder and silane coupling agent are added and mixing is continued for 5 minutes. The mixing resistance is monitored by a torque sensor.

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