Cold and hot mixed doping type warm mixing recycled asphalt mixture preparation process

Abstract

The invention relates to the technical field of asphalt mixture preparation, and particularly discloses a cold and hot mixed doping type warm mixing recycled asphalt mixture preparation process, which comprises the following steps: S1, raw material preparation, S2, asphalt mixture crushing, S2, temperature sensor installation, S4, cold and hot mixing, and S5, self-healing material addition. According to the invention, the regenerated asphalt is utilized to effectively reduce the demand of new materials and reduce the generation of building wastes, the temperature of the warm mixing process is low, the emission of volatile organic compounds and carbon dioxide of the asphalt in the construction process can be effectively reduced, and by adding the bio-based modifier and the nano-material and adopting the self-healing technology, the construction cost is reduced. According to the warm-mixed recycled asphalt mixture, the compressive strength, crack resistance and durability of the mixture are improved, the service life of the mixture is prolonged, the anti-skid performance of the mixture is improved by doping a nano material, the safety of a road is improved, and the warm-mixed recycled asphalt mixture shows good stability and higher adaptability under various weather conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of asphalt mixture preparation, and specifically relates to a cold-hot mixing and admixing type warm-mix recycled asphalt mixture preparation process. Background Art

[0002] In the current context of increasingly scarce global resources and increasing environmental awareness, the road construction industry is facing unprecedented challenges. The traditional asphalt mixture preparation process mainly relies on raw petroleum asphalt and mineral materials, which not only consumes a lot of resources, but also generates a large amount of construction waste during road maintenance and reconstruction, increasing the environmental burden. At the same time, hot-mix asphalt mixtures require high-temperature heating during the production process, resulting in high energy consumption, high asphalt volatile organic compounds (VOCs) and carbon dioxide emissions, and environmental pollution.

[0003] In response to the above problems, the industry has begun to explore the technical path of recycling recycled asphalt mixture (RAP) in order to reduce the demand for new materials and reduce the generation of construction waste. However, traditional RAP recycling technology mostly relies on simple mechanical crushing and remixing, and its regeneration efficiency and quality are often difficult to guarantee. In addition, the performance of recycled asphalt mixture is often lower than that of virgin asphalt mixture, which limits its scope of application.

[0004] In this regard, the inventors proposed a cold-hot mixing and admixing type warm-mix recycled asphalt mixture preparation process to solve the above-mentioned problems. Summary of the invention

[0005] The purpose of the present invention is to provide a cold-hot mixing and admixing type warm-mix recycled asphalt mixture preparation process to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A cold-hot mixing and admixing type warm-mix recycled asphalt mixture preparation process comprises the following steps:

[0008] S1. Raw material preparation: the recycled asphalt mixture includes 20% to 40% of waste asphalt, 20% to 40% of new asphalt, 1% to 2% of bio-based modifier, 1% to 2% of nanomaterials and 1% to 2% of microcapsules by mass, and the rest is aggregate;

[0009] S2, crushing the asphalt mixture, the recycled waste asphalt is initially screened with a coarse screen and then put into a crusher for crushing to a particle size of less than or equal to 25 mm, and then screened with a fine screen to remove impurities to obtain the crushed and screened waste asphalt mixture;

[0010] S3. Installing temperature sensors: Install temperature sensors in the mixing plant, electrically connect the controller in the mixing plant to the temperature sensor and the heating equipment, monitor the temperature of the new asphalt and nanomaterial mixture and the heating of the recycled asphalt in real time, and automatically adjust the heating equipment in the mixing plant through the electrical connection between the controller and the temperature sensor to keep the heating temperature within the set range;

[0011] S4, cold and hot mixing, the new asphalt and the bio-based modifier are put into the mixing plant in advance for mixing and mixing, and a new asphalt mixture is obtained, and then the new asphalt mixture is heated by the heating equipment in the mixing plant. After the new asphalt mixture is completely heated, the heating equipment is turned off, and nanomaterials are added to the mixing plant, and stirred evenly by the stirring device, and the new asphalt finished product is taken out;

[0012] 80% of the waste asphalt mixture obtained in step S2 is heated, and the remaining 20% ​​is not heated, and the new asphalt product, the heated waste asphalt mixture and the unheated waste asphalt mixture are put into a mixing plant together with aggregate and warm mix agent, and are mixed evenly together by a stirring device, and the heating device controls the temperature of the materials being stirred by a controller until they are stirred and mixed completely to obtain a mixed raw material;

[0013] S5. Adding self-healing materials: putting the mixed raw materials obtained in step S3 into the mixing plant, putting the microcapsules into the mixing plant and mixing them with the mixed raw materials obtained in step S3 through a stirring device, so that the self-healing materials are evenly dispersed in the mixed raw materials, and stirring and mixing are carried out through a stirring device. During this process, the heating equipment keeps the mixing plant warm at 120°C to 150°C, and the recycled asphalt mixture product is obtained after uniform mixing.

[0014] Preferably, the aggregate composition includes 70% to 80% coarse aggregate and 20% to 30% fine aggregate.

[0015] Preferably, the bio-based modifier is composed of linseed oil, palm oil and polylactic acid in a weight ratio of 2:2:1.

[0016] Preferably, the nanomaterial is one or more of nano-silicon and nano-clay.

[0017] Preferably, the inner core material of the microcapsule is made of a polymer material, the polymer material is polyurethane, the size is between 10 and 100 μm, and the warm-mixing agent is epoxy resin.

[0018] Preferably, the conditions for uniform stirring in step S3 are: the rotation speed of the stirring device is 30 to 50 rpm, and the stirring time is 5 to 10 minutes.

[0019] Preferably, the conditions for uniform mixing in step S3 are: the heating device is used to heat the mixing plant to maintain a temperature of 120-140° C. before stirring, and then the speed of the stirring device is 40-60 rpm, and the stirring time is 5-10 minutes.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The present invention utilizes recycled asphalt to effectively reduce the demand for new materials and the generation of construction waste. The temperature of the warm mix process is relatively low, which can effectively reduce the emission of volatile organic compounds and carbon dioxide from asphalt during construction. By adding bio-based modifiers, nanomaterials and self-healing technology, the compressive strength, crack resistance and durability of the mixture are improved, thereby extending its service life.

[0022] (2) The microcapsules in the mixture used in the present invention can automatically release the repair agent when microcracks are formed, effectively repairing the cracks and reducing maintenance costs. The warm mix process reduces the heating and construction temperature of the mixture, so that the construction can be completed in a shorter time, improving the construction efficiency. The plasticity of the mixture is enhanced, which is convenient for construction personnel to operate and reduces the requirements for construction equipment.

[0023] (3) The present invention uses recycled materials and bio-based modifiers to reduce the procurement cost of raw materials, while reducing transportation and energy consumption. The application of self-healing materials reduces the need for repairs due to cracks and reduces long-term maintenance costs. By doping with nanomaterials, the anti-skid performance of the mixture is improved, and the safety of the road is improved. The warm-mix recycled asphalt mixture shows good stability under various climatic conditions and has stronger adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a process flow chart for preparing a cold-hot mixing and admixing type warm-mix recycled asphalt mixture. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Embodiment 1:

[0027] See also Figure 1 As shown, a cold-hot mixing and admixing warm-mix recycled asphalt mixture preparation process comprises the following steps:

[0028] S1. Raw material preparation: the recycled asphalt mixture includes 30% waste asphalt, 20% new asphalt, 2% bio-based modifier, 1% nanomaterial, 1% microcapsule, and the rest is aggregate;

[0029] S2, crushing the asphalt mixture, the recycled waste asphalt is initially screened with a coarse screen and then put into a crusher for crushing to a particle size of less than or equal to 25 mm, and then screened with a fine screen to remove impurities to obtain the crushed and screened waste asphalt mixture;

[0030] S3. Installing temperature sensors: Install temperature sensors in the mixing plant, electrically connect the controller in the mixing plant to the temperature sensor and the heating equipment, monitor the temperature of the new asphalt and nanomaterial mixture and the heating of the recycled asphalt in real time, and automatically adjust the heating equipment in the mixing plant through the electrical connection between the controller and the temperature sensor to keep the heating temperature within the set range;

[0031] S4, cold and hot mixing, the new asphalt and the bio-based modifier are put into the mixing plant in advance for mixing and mixing, and a new asphalt mixture is obtained, and then the new asphalt mixture is heated by the heating equipment in the mixing plant. After the new asphalt mixture is completely heated, the heating equipment is turned off, and nanomaterials are added to the mixing plant, and stirred evenly by the stirring device, and the new asphalt finished product is taken out;

[0032] 80% of the waste asphalt mixture obtained in step S2 is heated, and the remaining 20% ​​is not heated, and the new asphalt product, the heated waste asphalt mixture and the unheated waste asphalt mixture are put into a mixing plant together with aggregate and warm mix agent, and are mixed evenly together by a stirring device, and the heating device controls the temperature of the materials being stirred by a controller until they are stirred and mixed completely to obtain a mixed raw material;

[0033] S5. Adding self-healing materials: putting the mixed raw materials obtained in step S3 into the mixing plant, putting the microcapsules into the mixing plant and mixing them with the mixed raw materials obtained in step S3 through a stirring device, so that the self-healing materials are evenly dispersed in the mixed raw materials, and stirring and mixing are carried out through a stirring device. During this process, the heating equipment keeps the mixing plant at 140° C., and the recycled asphalt mixture product is obtained after uniform mixing.

[0034] Specifically, the composition of the aggregate includes 75% coarse aggregate and 25% fine aggregate, the coarse aggregate is crushed stone, the fine aggregate is sand, the crushed stone (particle size 20-25mm) is a mixture of granite and limestone in equal proportions, and the sand (particle size 0.5-5mm) is machine-made sand.

[0035] Specifically, the bio-based modifier is composed of linseed oil, palm oil and polylactic acid in a ratio of 2:2:1.

[0036] Specifically, the nanomaterial is nanosilicon.

[0037] Specifically, the inner core material of the microcapsule is made of a polymer material, the polymer material is polyurethane, the size is between 10 and 100 μm, and the warm-mixing agent is epoxy resin.

[0038] Specifically, the conditions for uniform stirring in step S3 are: the rotation speed of the stirring device is 50 rpm, and the stirring time is 8 minutes.

[0039] Specifically, the conditions for uniform mixing in step S3 are: the heating device is used to heat and maintain the temperature of the mixing plant at 140° C. before stirring, and then the rotation speed of the stirring device is 50 rpm and the stirring time is 8 minutes.

[0040] From the above, we can see that the use of recycled asphalt (RAP) can effectively reduce the demand for new materials and reduce the generation of construction waste. The epoxy resin in the bio-based modifier can be used as a warm mix agent to reduce the mixing temperature of asphalt. The temperature of the warm mix process is relatively low, which can effectively reduce the volatile organic compounds (VOCs) and carbon dioxide emissions of asphalt during construction. By adding bio-based modifiers, nanomaterials and self-healing technology, the compressive strength, crack resistance and durability of the mixture can be improved, thereby extending its service life.

[0041] Embodiment 2:

[0042] A cold-hot mixing and admixing type warm-mix recycled asphalt mixture preparation process comprises the following steps:

[0043] S1. Raw material preparation: the recycled asphalt mixture includes 40% waste asphalt, 20% new asphalt, 2% nanomaterials, 2% microcapsules, and the rest is aggregate;

[0044] S2, crushing the asphalt mixture, the recycled waste asphalt is initially screened with a coarse screen and then put into a crusher for crushing to a particle size of less than or equal to 25 mm, and then screened with a fine screen to remove impurities to obtain the crushed and screened waste asphalt mixture;

[0045] S3. Installing temperature sensors: Install temperature sensors in the mixing plant, electrically connect the controller in the mixing plant to the temperature sensor and the heating equipment, monitor the temperature of the new asphalt and nanomaterial mixture and the heating of the recycled asphalt in real time, and automatically adjust the heating equipment in the mixing plant through the electrical connection between the controller and the temperature sensor to keep the heating temperature within the set range;

[0046] S4, cold and hot mixing, adding the new asphalt mixture to the mixing plant for heating, after the new asphalt mixture is completely heated, turning off the heating equipment, adding nanomaterials into the mixing plant, stirring evenly through the stirring device, taking out and obtaining the new asphalt finished product;

[0047] 80% of the waste asphalt mixture obtained in step S2 is heated, and the remaining 20% ​​is not heated, and the new asphalt product, the heated waste asphalt mixture and the unheated waste asphalt mixture are put into a mixing plant together with aggregate and warm mix agent, and are mixed evenly together by a stirring device, and the heating device controls the temperature of the materials being stirred by a controller until they are stirred and mixed completely to obtain a mixed raw material;

[0048] S5. Adding self-healing materials: putting the mixed raw materials obtained in step S3 into the mixing plant, putting the microcapsules into the mixing plant and mixing them with the mixed raw materials obtained in step S3 through a stirring device, so that the self-healing materials are evenly dispersed in the mixed raw materials, and stirring and mixing are carried out through a stirring device. During this process, the heating equipment keeps the mixing plant at 140° C., and the recycled asphalt mixture product is obtained after uniform mixing.

[0049] Specifically, the aggregate comprises 70% crushed stone and 30% sand, wherein the crushed stone (particle size 20-25 mm) is granite, and the sand (particle size 0.5-5 mm) is machine-made sand.

[0050] Specifically, the nanomaterial is nanoclay.

[0051] Specifically, the inner core material of the microcapsule is made of a polymer material, the polymer material is polyurethane, the size is between 10 and 100 μm, and the warm-mixing agent is epoxy resin.

[0052] Specifically, the conditions for uniform stirring in step S3 are: the rotation speed of the stirring device is 50 rpm, and the stirring time is 10 minutes.

[0053] Specifically, the conditions for uniform mixing in step S3 are: the heating device is used to heat and maintain the temperature of the mixing plant at 120° C. before stirring, and then the speed of the stirring device is 50 rpm and the stirring time is 10 minutes.

[0054] From the above, it can be seen that the microcapsules in the mixture can automatically release the repair agent when microcracks are formed, effectively repair the cracks and reduce maintenance costs. The warm mix process reduces the heating and construction temperature of the mixture, so that the construction can be completed in a shorter time, improving construction efficiency. The plasticity of the mixture is enhanced, which is convenient for construction personnel to operate and reduces the requirements for construction equipment.

[0055] Embodiment three:

[0056] A cold-hot mixing and admixing type warm-mix recycled asphalt mixture preparation process comprises the following steps:

[0057] S1. Raw material preparation: the recycled asphalt mixture includes 20% waste asphalt, 40% new asphalt, 2% bio-based modifier, 2% microcapsule, and the rest is aggregate;

[0058] S2, crushing the asphalt mixture, the recycled waste asphalt is initially screened with a coarse screen and then put into a crusher for crushing to a particle size of less than or equal to 25 mm, and then screened with a fine screen to remove impurities to obtain the crushed and screened waste asphalt mixture;

[0059] S3. Installing temperature sensors: Install temperature sensors in the mixing plant, electrically connect the controller in the mixing plant to the temperature sensor and the heating equipment, monitor the temperature of the new asphalt and nanomaterial mixture and the heating of the recycled asphalt in real time, and automatically adjust the heating equipment in the mixing plant through the electrical connection between the controller and the temperature sensor to keep the heating temperature within the set range;

[0060] S4, cold and hot mixing, the new asphalt and the bio-based modifier are put into the mixing plant in advance for mixing and mixing, and a new asphalt mixture is obtained, and then the new asphalt mixture is heated by the heating equipment in the mixing plant, and is stirred evenly by the stirring device, and taken out to obtain the new asphalt finished product;

[0061] 80% of the waste asphalt mixture obtained in step S2 is heated, and the remaining 20% ​​is not heated, and the new asphalt product, the heated waste asphalt mixture and the unheated waste asphalt mixture are put into a mixing plant together with aggregate and warm mix agent, and are mixed evenly together by a stirring device, and the heating device controls the temperature of the materials being stirred by a controller until they are stirred and mixed completely to obtain a mixed raw material;

[0062] S5. Adding self-healing materials: putting the mixed raw materials obtained in step S3 into the mixing plant, putting the microcapsules into the mixing plant and mixing them with the mixed raw materials obtained in step S3 through a stirring device, so that the self-healing materials are evenly dispersed in the mixed raw materials, and stirring and mixing are carried out through a stirring device. During this process, the heating equipment keeps the mixing plant at 140° C., and the recycled asphalt mixture product is obtained after uniform mixing.

[0063] Specifically, the aggregate comprises 77% crushed stone and 23% sand, wherein the crushed stone (particle size 20-25 mm) is granite, and the sand (particle size 0.5-5 mm) is machine-made sand.

[0064] Specifically, the bio-based modifier is composed of linseed oil, palm oil and polylactic acid in a ratio of 2:2:1.

[0065] Specifically, the inner core material of the microcapsule is made of a polymer material, the polymer material is polyurethane, the size is between 10 and 100 μm, and the warm-mixing agent is epoxy resin.

[0066] Specifically, the conditions for uniform stirring in step S3 are: the rotation speed of the stirring device is 50 rpm, and the stirring time is 10 minutes.

[0067] Specifically, the conditions for uniform mixing in step S3 are: the heating device is used to heat and maintain the temperature of the mixing plant at 120° C. before stirring, and then the speed of the stirring device is 50 rpm and the stirring time is 10 minutes.

[0068] From the above, we can see that by using recycled materials and bio-based modifiers, the procurement cost of raw materials is reduced, while transportation and energy consumption are reduced.

[0069] Embodiment 4:

[0070] This design is specifically applied to the field of road construction. With the continuous expansion of urban transportation networks, the demand for infrastructure maintenance and reconstruction has increased. Warm-mix recycled asphalt mixture can be used as an economical and efficient solution to meet the requirements of road construction. The production and construction of traditional asphalt mixtures have a significant negative impact on the environment. Asphalt materials used in road construction often lead to greenhouse gas emissions and energy consumption. At the same time, the production process of asphalt requires high-temperature heating, which increases the difficulty and risk of construction. In order to solve these problems, in recent years, the research and application of warm-mix recycled asphalt mixtures have gradually received attention. By using recycled materials and modifiers, it can not only effectively reduce dependence on new resources, but also improve the performance and durability of road materials.

[0071] Furthermore, a cold-hot mixing and admixing warm-mix recycled asphalt mixture preparation process comprises the following steps:

[0072] S1. Raw material preparation: the recycled asphalt mixture includes 30% waste asphalt, 40% new asphalt, 2% bio-based modifier, 2% nanomaterial, and the rest is aggregate;

[0073] S2, crushing the asphalt mixture, the recycled waste asphalt is initially screened with a coarse screen and then put into a crusher for crushing to a particle size of less than or equal to 25 mm, and then screened with a fine screen to remove impurities to obtain the crushed and screened waste asphalt mixture;

[0074] S3. Installing temperature sensors: Install the temperature sensors in the mixing plant, and electrically connect the controller in the mixing plant to the temperature sensor and the heating equipment, respectively, to monitor the temperature of the new asphalt and nanomaterials mixed and the heating temperature of the recycled asphalt in real time. Through the electrical connection between the controller and the temperature sensor, the heating equipment in the mixing plant is automatically adjusted to keep the heating temperature within the set range, and the recycled asphalt mixture is obtained after uniform mixing;

[0075] S4, cold and hot mixing, the new asphalt and the bio-based modifier are put into the mixing plant in advance for mixing and mixing, and a new asphalt mixture is obtained, and then the new asphalt mixture is heated by the heating equipment in the mixing plant. After the new asphalt mixture is completely heated, the heating equipment is turned off, and nanomaterials are added to the mixing plant, and stirred evenly by the stirring device, and the new asphalt finished product is taken out;

[0076] 80% of the waste asphalt mixture obtained in step S2 is heated, and the remaining 20% ​​is not heated, and the new asphalt product, the heated waste asphalt mixture and the unheated waste asphalt mixture are put into a mixing plant together with aggregate and warm mix agent, and are mixed evenly together through a stirring device. The heating equipment controls the temperature of the materials being stirred through a controller until they are stirred and mixed completely to obtain a mixed raw material.

[0077] Specifically, the aggregate comprises 75% crushed stone and 25% sand, wherein the crushed stone (particle size 20-25 mm) is limestone, and the sand (particle size 0.5-5 mm) is machine-made sand.

[0078] Specifically, the bio-based modifier is composed of linseed oil, palm oil and polylactic acid in a ratio of 2:2:1.

[0079] Specifically, the nanomaterial is nanoclay.

[0080] Specifically, the warm mix agent is epoxy resin.

[0081] Specifically, the conditions for uniform stirring in step S3 are: the rotation speed of the stirring device is 50 rpm, and the stirring time is 10 minutes.

[0082] Specifically, the conditions for uniform mixing in step S3 are: the heating device is used to heat and maintain the temperature of the mixing plant at 120° C. before stirring, and then the speed of the stirring device is 50 rpm and the stirring time is 10 minutes.

[0083] The mixed materials obtained in the above-mentioned Examples 1 to 4 were tested, specifically:

[0084] 1. Marshall stability test:

[0085] Equipment and Materials:

[0086] Equipment: Marshall testing machine, heating furnace, electronic scale, test mold, hammer.

[0087] Materials: Asphalt mixture samples prepared in Examples 1 to 4.

[0088] Test steps:

[0089] Sample preparation: Heat the mixture in a furnace to 150°C to ensure homogeneity.

[0090] Use a hammer to compact the mixture in the test mold, compacting it layer by layer to the specified height.

[0091] Cooling and demoulding: Cool the sample to room temperature and gently demould to obtain the test specimen.

[0092] Stability test: Place the sample in a Marshall testing machine and apply vertical load.

[0093] The maximum load (kN) at which the sample failed was recorded.

[0094] 2. Flow value test

[0095] Equipment and Materials:

[0096] Equipment: Asphalt flow meter, heating furnace, electronic scale.

[0097] Materials: Asphalt mixture samples prepared in Examples 1 to 4.

[0098] Test steps: Heat the sample in a heating furnace to 140°C to ensure uniformity.

[0099] Flow value test: Pour the heated sample into the flow value meter, record the outflow height (mm) and time, and calculate the flow value.

[0100] 3. Peel strength test

[0101] Equipment and Materials:

[0102] Equipment: Peel strength tester, steam bath.

[0103] Materials: Asphalt mixture samples prepared in Examples 1 to 4.

[0104] Test procedure: The sample was immersed in water for 24 hours and then subjected to freeze-thaw cycles (freeze for 24 hours, thaw for 24 hours).

[0105] Strength test: Measure the strength of asphalt after peeling off from aggregate, record the data and calculate the peeling strength.

[0106] 4. Compressive strength test:

[0107] Equipment and Materials:

[0108] Equipment: Compression testing machine.

[0109] Materials: Asphalt mixture samples prepared in Examples 1 to 4.

[0110] Test steps: Place the sample into the compression testing machine and apply load.

[0111] The maximum load when the sample failed was recorded and the compressive strength (MPa) was calculated.

[0112] 5. Self-healing performance test:

[0113] Equipment and Materials:

[0114] Equipment: Universal materials testing machine.

[0115] Materials: Asphalt mixture samples prepared in Examples 1 to 4.

[0116] Test procedure: Prepare mixed material samples of the same size (10cm×15cm×5cm).

[0117] Crack simulation: Stress is applied to the sample surface to form microcracks.

[0118] Self-healing test: Place at room temperature for 12 hours, observe whether the cracks are healed, and record the self-healing efficiency.

[0119] 6. Anti-slip test:

[0120] Equipment and Materials:

[0121] Equipment: Friction coefficient tester.

[0122] Materials: Asphalt mixture samples prepared in Examples 1 to 4.

[0123] Test steps: Use a friction coefficient tester to test and record the friction coefficient value.

[0124] 7. Durability test:

[0125] Equipment and Materials:

[0126] Equipment: Freeze-thaw test machine.

[0127] Materials: Asphalt mixture samples prepared in Examples 1 to 4.

[0128] Test steps:

[0129] Freeze-thaw cycle: Place the sample in a freeze-thaw testing machine and perform the specified freeze-thaw cycle (freeze for 24 hours and thaw for 24 hours).

[0130] Strength loss test: Test the strength of the sample after freeze-thaw cycles and calculate the percentage of strength loss.

[0131] The data of the test on the mixtures obtained in the above-mentioned embodiments 1 to 4 are shown in the following Table 1:

[0132]

[0133] Table 1

[0134] The above data table and test results show that the various properties of the hot and cold mixed warm mix recycled asphalt mixture in Example 1 meet the requirements of the corresponding standards and have good performance. The service life of the mixture is extended by improving the self-healing ability, and the environmental protection and comprehensive performance of the material are improved by combining the use of bio-based modifiers and nanomaterials.

[0135] As can be seen from the above, the use of recycled asphalt (RAP) can effectively reduce the demand for new materials and the generation of construction waste. The temperature of the warm mix process is relatively low, which can effectively reduce the emission of volatile organic compounds (VOCs) and carbon dioxide from asphalt during construction. By adding bio-based modifiers, nanomaterials and self-healing technology, the compressive strength, crack resistance and durability of the mixture can be improved, thus extending its service life.

[0136] The microcapsules in the mixture can automatically release the repair agent when microcracks are formed, effectively repairing the cracks and reducing maintenance costs. The warm mix process reduces the heating and construction temperature of the mixture, allowing the construction to be completed in a shorter time, improving construction efficiency. The plasticity of the mixture is enhanced, which is convenient for construction personnel to operate and reduces the requirements for construction equipment.

[0137] By using recycled materials and bio-based modifiers, the procurement cost of raw materials is reduced, while transportation and energy consumption are reduced. The application of self-healing materials reduces the need for repairs due to cracks and reduces long-term maintenance costs. By doping with nanomaterials, the anti-skid performance of the mixture is improved, which improves road safety. Warm-mix recycled asphalt mixtures show good stability and greater adaptability under various climatic conditions.

[0138] The preparation process of hot and cold mixing warm mix recycled asphalt mixture not only achieves the effective utilization of resources and environmental protection goals, but also significantly improves the performance and construction efficiency of the mixture, with significant economic and social benefits.

[0139] Although 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 the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for preparing warm-mix recycled asphalt mixture by cold and hot mixing, characterized in that: The following steps are involved: S1. Raw material preparation: The modified asphalt binder includes, by mass percentage, 20% to 40% of waste asphalt, 20% to 40% of new asphalt, 1% to 2% of bio-based modifier, 1% to 2% of nanomaterials and 1% to 2% of microcapsules, and the rest is aggregate; S2. Crushing of asphalt mixture: The recycled waste asphalt is initially screened with a coarse screen and then put into a crusher for crushing until the particle size is less than or equal to 25 mm, and impurities are removed by screening with a fine screen to obtain the crushed and screened waste asphalt mixture; S3. Installing the temperature sensor: installing the temperature sensor in the mixing plant, electrically connecting the controller in the mixing plant to the temperature sensor and the heating device respectively, and automatically adjusting the heating device in the mixing plant through the electrical connection between the controller and the temperature sensor to keep the heating temperature within the set range; S4, hot and cold mixing: the new asphalt and the bio-based modifier are put into the mixing plant in advance for mixing and mixing, and a new asphalt mixture is obtained, and then the new asphalt mixture is heated by the heating equipment in the mixing plant. After the new asphalt mixture is completely heated, the heating equipment is turned off, and nanomaterials are added to the mixing plant, and the mixture is stirred evenly by the stirring device, and the new asphalt finished product is taken out; 80% of the waste asphalt mixture obtained in step S2 is heated, and the remaining 20% ​​is not heated, and the new asphalt product, the heated waste asphalt mixture and the unheated waste asphalt mixture are put into a mixing plant together with aggregate and warm mix agent, and are mixed evenly together by a stirring device, and the heating device controls the temperature of the materials being stirred by a controller until they are stirred and mixed completely to obtain a mixed raw material; S5. Adding self-healing materials: putting microcapsules into a mixing plant and mixing them with the mixed raw materials obtained in step S3 through a stirring device, so that the self-healing materials are evenly dispersed in the mixed raw materials, and stirring and mixing are carried out through a stirring device. During this process, a heating device is used to keep the mixing plant warm at 120°C to 150°C, and after uniform mixing, a recycled asphalt mixture product is obtained.

2. A cold-hot mixing and admixing warm-mix recycled asphalt mixture preparation process according to claim 1, characterized in that: The aggregate comprises 70% to 80% of coarse aggregate and 20% to 30% of fine aggregate.

3. The cold-hot mixing and admixing warm-mix recycled asphalt mixture preparation process according to claim 1 is characterized in that: The bio-based modifier is composed of linseed oil, palm oil and polylactic acid in a weight ratio of 2:2:

1.

4. The cold-hot mixing and admixing warm-mix recycled asphalt mixture preparation process according to claim 1 is characterized in that: The nano material is one or more of nano silicon and nano clay.

5. The cold-hot mixing and admixing warm-mix recycled asphalt mixture preparation process according to claim 1 is characterized in that: The inner core material of the microcapsule is made of polymer material, the polymer material is polyurethane, the size is between 10 and 100 μm, and the warm mixing agent is epoxy resin.

6. The cold-hot mixing and admixing warm-mix recycled asphalt mixture preparation process according to claim 1 is characterized in that: The conditions for uniform stirring in step S3 are: the rotation speed of the stirring device is 30 to 50 rpm, and the stirring time is 5 to 10 minutes.

7. The cold-hot mixing and admixing warm-mix recycled asphalt mixture preparation process according to claim 1 is characterized in that: The conditions for uniform mixing in step S3 are: the heating device is used to heat the mixing plant to maintain a temperature of 120-140° C. before stirring, the rotation speed of the stirring device is 40-60 rpm, and the stirring time is 5-10 minutes.

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