Normal-temperature large-proportion recycled asphalt mixture preparation process

Abstract

The present application relates to the field of recycled asphalt preparation, and specifically discloses a normal-temperature large-proportion recycled asphalt mixture preparation process, comprising the following steps: step one: preparing raw materials, including 40-60% of total mass of waste asphalt mixture, 30-50% of new aggregate, 5-10% of mineral powder, and micro-nano reinforcing liquid and bio-based additive; step two: crushing the waste asphalt mixture to a particle size of less than or equal to 30mm, and screening and removing impurities to obtain the crushed and screened waste asphalt mixture; the present application significantly reduces the demand for new asphalt and new aggregate by using a high proportion of waste asphalt mixture, reduces the exploitation pressure on natural resources, reduces the accumulation and processing cost of waste asphalt mixture, realizes the reuse of resources, and has good environmental protection benefits; the introduction of micro-nano reinforcing liquid and bio-based additive significantly enhances the performance of the recycled asphalt mixture.

Description

Technical Field

[0001] This invention belongs to the field of recycled asphalt preparation, specifically a process for preparing a high-proportion recycled asphalt mixture at room temperature. Background Technology

[0002] With the rapid development of highway construction, asphalt pavements inevitably age and deteriorate during use, requiring regular maintenance and reconstruction. Traditional asphalt pavement repair methods primarily involve removing the old material and repaving with new material. This method not only wastes a large amount of waste asphalt mixture resources but also increases the cost of mining and transporting new materials, while exacerbating environmental pollution. Therefore, asphalt pavement recycling technology has gradually gained attention, with ambient temperature recycling technology attracting particular interest due to its advantages such as ease of operation, low energy consumption, and environmental friendliness.

[0003] However, the current process for preparing ambient temperature recycled asphalt mixtures still faces some technical challenges, such as low waste asphalt content, unsatisfactory recycling effect, and low performance of recycled mixtures. These problems limit the widespread application of ambient temperature recycling technology. Therefore, developing a process for preparing ambient temperature recycled asphalt mixtures with a high proportion to improve the waste asphalt content and recycling effect has significant practical implications and broad application prospects. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a process for preparing high-proportion recycled asphalt mixtures at room temperature, thereby solving the problems of low waste asphalt mixture content, unsatisfactory recycling effect, and low performance of recycled mixtures in the prior art.

[0005] A process for preparing a high-proportion recycled asphalt mixture at room temperature includes the following steps:

[0006] Step 1: Prepare raw materials, including waste asphalt mixture accounting for 30%-80% of the total mass, new aggregate accounting for 10%-65%, mineral powder accounting for 5%-10%, as well as micro-nano reinforcing liquid and bio-based additives.

[0007] Step 2: Crush the waste asphalt mixture to a particle size of less than or equal to 30mm, and screen to remove impurities, to obtain the crushed and screened waste asphalt mixture;

[0008] Step 3: Mix the crushed and screened waste asphalt mixture with new aggregates and mineral powder in the same proportion as in Step 1 to obtain the mixture;

[0009] Step 4: Prepare micro-nano strengthening liquid, wherein nano-sized silicates account for 0.1%-0.5% of the total mass of the strengthening liquid, dispersed in an environmentally friendly solvent, and surface modified by a silane coupling agent to obtain micro-nano strengthening liquid;

[0010] Step 5: At a temperature of 80°C to 140°C, spray the micro-nano reinforcing liquid obtained in Step 4 onto the surface of the mixture in Step 3 at a ratio of 0.5%-2% of the total mass of waste asphalt mixture and new aggregate, and mechanically stir for at least 10 minutes to ensure uniform distribution of micro-nano materials.

[0011] Step 6: Prepare bio-based additives, which are made by mixing natural plant oils and bio-enzymatically hydrolyzed lignin in a mass ratio of 1:1 and then obtaining bio-based additives through chemical modification.

[0012] Step 7: Add the bio-based additive obtained in Step 6 to the mixture at 1%-3% of the total mass of waste asphalt mixture and new aggregate, and continue stirring for at least 5 minutes until the additive is completely incorporated.

[0013] Step 8: The recycled asphalt mixture obtained in Step 7 is subjected to ultrasonic treatment for 3-10 minutes to further enhance the dispersion effect of micro-nano materials and bio-based additives.

[0014] Step 9: Perform preliminary compaction on the ultrasonically treated mixture;

[0015] Step 10: Further compact the initially compacted mixture until it reaches the required density and stability as designed.

[0016] Preferably, the environmentally friendly solvent in step four is water, and the particle size of the nano-sized silicate is less than 100 nm.

[0017] Preferably, the chemical modification treatment in step six includes heating to 60-80°C and adding an appropriate amount of acid catalyst to react, so as to improve the activity of the bio-based additive.

[0018] Preferably, the mechanical stirring in step five uses a twin-shaft mixer with a stirring speed of 50-100 revolutions per minute.

[0019] Preferably, the ultrasonic treatment in step eight uses an ultrasonic device with a frequency of 20-40kHz.

[0020] Preferably, the preliminary compaction in step nine is carried out using a vibratory roller, with 2-3 compaction passes.

[0021] Preferably, the further compaction in step ten is carried out using a static roller until the Marshall stability required by the design is achieved.

[0022] Preferably, the micro / nano strengthening liquid comprises nano-sized silicates, silane coupling agents, and environmentally friendly solvents, wherein the nano-sized silicates account for 0.1%-0.5% of the total mass of the strengthening liquid, and the silane coupling agent accounts for 1%-5% of the mass of the nano-sized silicates.

[0023] Preferably, the bio-based additive is obtained by mixing natural plant oil and bio-enzymatically hydrolyzed lignin in a mass ratio of 1:1, and then chemically modifying it by heating it to 60-80°C and adding an acid catalyst.

[0024] Compared with existing technologies, this invention has the following beneficial effects: By using a high proportion of waste asphalt mixtures, the demand for new asphalt and new aggregates is significantly reduced, lowering the pressure on the extraction of natural resources. At the same time, it reduces the accumulation and processing costs of waste asphalt mixtures, realizing resource reuse and having good environmental benefits. By introducing micro-nano reinforcing liquids and bio-based additives, the performance of recycled asphalt mixtures is significantly enhanced. Micro-nano materials can improve the microstructure of asphalt, improving its durability, anti-aging properties, and high-temperature stability. Bio-based additives, through their natural components and chemical modification treatment, improve the adhesion and road performance of the mixture. Detailed Implementation

[0025] Example 1:

[0026] This invention provides a process for preparing a high-proportion recycled asphalt mixture at room temperature, comprising the following steps:

[0027] Step 1: Prepare the raw materials

[0028] Waste asphalt mixture: accounting for 50% of the total mass, ensuring its stable source and reliable quality.

[0029] New aggregates: accounting for 42%, selected from high-quality aggregates that meet the requirements.

[0030] Mineral powder: accounting for 8%, ensuring that the quality and particle size of the mineral powder meet the requirements.

[0031] Micro / nano-reinforced liquid and bio-based additives: Prepare according to the requirements of subsequent steps.

[0032] Step 2: Crushing and Screening of Waste Asphalt Mixture

[0033] Waste asphalt mixture is fed into a crusher for crushing until the particle size is less than or equal to 30mm.

[0034] Impurities such as mud and stones are removed from the crushed material by screening equipment to obtain a pure crushed and screened waste asphalt mixture.

[0035] Step 3: Preparation of the mixture

[0036] According to the proportions in step one, put the crushed and screened waste asphalt mixture, new aggregate, and mineral powder into the mixer.

[0037] Turn on the mixer and mix thoroughly until all the raw materials are evenly distributed to obtain a mixture.

[0038] Step 4: Preparation of micro / nano-reinforced liquid

[0039] Environmentally friendly water solution was selected, and the required amount of nano-sized silicate was calculated to account for 0.3% of the total mass of the strengthening solution.

[0040] Nanoscale silicates were dispersed in water and then surface-modified using a silane coupling agent to obtain a micro / nano-reinforced liquid. The amount of silane coupling agent used was 3% of the mass of the nanoscale silicates.

[0041] Step 5: Spraying and stirring of the micro / nano-enhanced liquid

[0042] At a temperature of 110°C, the micro-nano reinforcing liquid obtained in step four is sprayed onto the surface of the mixture from step three at a rate of 1% of the total mass of waste asphalt mixture and new aggregate.

[0043] A twin-shaft mixer is used to stir the mixture at a speed of 75 revolutions per minute for at least 10 minutes to ensure that the micro- and nano-materials are evenly distributed in the mixture.

[0044] Step Six: Preparation of Bio-based Additives

[0045] Natural plant oil and bio-enzymatically hydrolyzed lignin are mixed in a 1:1 mass ratio.

[0046] The mixture was heated to 70°C, and an appropriate amount of acid catalyst was added to enhance the activity of the bio-based additive. After the reaction was complete, the bio-based additive was obtained.

[0047] Step 7: Adding and mixing the bio-based additives

[0048] Add the bio-based additive obtained in step six to the mixture at 2% of the total mass of waste asphalt mixture and new aggregate.

[0049] Continue mixing using a twin-shaft mixer at a constant speed for at least 5 minutes, until the additives are fully incorporated into the mixture.

[0050] Step 8: Ultrasonic Treatment

[0051] The recycled asphalt mixture obtained in step seven is placed in an ultrasonic treatment device and treated with ultrasound at a frequency of 30 kHz for 5 minutes to further enhance the dispersion effect of micro-nano materials and bio-based additives.

[0052] Step 9: Initial compaction

[0053] A vibratory roller is used to perform preliminary compaction on the ultrasonically treated mixture, with two compaction passes to ensure the mixture is initially formed.

[0054] Step 10: Further compaction

[0055] The pre-compacted mixture is then moved to a static roller for further compaction until the required Marshall stability and density are achieved.

[0056] Note: In this invention, room temperature refers to a mixing temperature 20 to 40 degrees lower than that of traditional warm mixing agents. The mixing temperature of traditional warm mixing agents in this invention is between 120°C and 160°C. Therefore, in this invention, room temperature refers to a temperature between 80°C and 140°C.

[0057] Example 2:

[0058] This invention provides a process for preparing a high-proportion recycled asphalt mixture at room temperature, comprising the following steps:

[0059] Step 1: Prepare the raw materials

[0060] Waste asphalt mixture: accounting for 30% of the total mass, ensuring its stable source and reliable quality.

[0061] New aggregates: accounting for 65%, selected from high-quality aggregates that meet the requirements.

[0062] Mineral powder: 5%, ensuring that the quality and particle size of the mineral powder meet the requirements.

[0063] Micro / nano-reinforced liquid and bio-based additives: Prepare according to the requirements of subsequent steps.

[0064] Step 2: Crushing and Screening of Waste Asphalt Mixture

[0065] Waste asphalt mixture is fed into a crusher for crushing until the particle size is less than or equal to 30mm.

[0066] Impurities such as mud and stones are removed from the crushed material by screening equipment to obtain a pure crushed and screened waste asphalt mixture.

[0067] Step 3: Preparation of the mixture

[0068] According to the proportions in step one, put the crushed and screened waste asphalt mixture, new aggregate, and mineral powder into the mixer.

[0069] Turn on the mixer and mix thoroughly until all the raw materials are evenly distributed to obtain a mixture.

[0070] Step 4: Preparation of micro / nano-reinforced liquid

[0071] Environmentally friendly water solution was selected, and the required amount of nano-sized silicate was calculated to account for 0.1% of the total mass of the strengthening solution.

[0072] Nanoscale silicates were dispersed in water and then surface-modified using a silane coupling agent to obtain a micro / nano-reinforced liquid. The amount of silane coupling agent used was 1% of the mass of the nanoscale silicates.

[0073] Step 5: Spraying and stirring of the micro / nano-enhanced liquid

[0074] At a temperature of 80°C, the micro-nano reinforcing liquid obtained in step four is sprayed onto the surface of the mixture in step three at a rate of 0.5% of the total mass of waste asphalt mixture and new aggregate.

[0075] A twin-shaft mixer is used to stir the mixture at a speed of 50 revolutions per minute for at least 10 minutes to ensure that the micro- and nano-materials are evenly distributed in the mixture.

[0076] Step Six: Preparation of Bio-based Additives

[0077] Natural plant oil and bio-enzymatically hydrolyzed lignin are mixed in a 1:1 mass ratio.

[0078] The mixture was heated to 60°C, and an appropriate amount of acid catalyst was added to enhance the activity of the bio-based additive. After the reaction was complete, the bio-based additive was obtained.

[0079] Step 7: Adding and mixing the bio-based additives

[0080] Add the bio-based additive obtained in step six to the mixture at 1% of the total mass of waste asphalt mixture and new aggregate.

[0081] Continue mixing using a twin-shaft mixer at a constant speed for at least 5 minutes, until the additives are fully incorporated into the mixture.

[0082] Step 8: Ultrasonic Treatment

[0083] The recycled asphalt mixture obtained in step seven is placed in an ultrasonic treatment device and treated with ultrasound at a frequency of 20kHz for 3 minutes to further enhance the dispersion effect of micro-nano materials and bio-based additives.

[0084] Step 9: Initial compaction

[0085] A vibratory roller is used to perform preliminary compaction on the ultrasonically treated mixture, with two compaction passes to ensure the mixture is initially formed.

[0086] Step 10: Further compaction

[0087] The pre-compacted mixture is then moved to a static roller for further compaction until the required Marshall stability and density are achieved.

[0088] Example 3

[0089] This invention provides a process for preparing a high-proportion recycled asphalt mixture at room temperature, comprising the following steps:

[0090] Step 1: Prepare the raw materials

[0091] Waste asphalt mixture: accounting for 80% of the total mass, ensuring its stable source and reliable quality.

[0092] New aggregates: accounting for 10%, selected from high-quality aggregates that meet the requirements.

[0093] Mineral powder: accounting for 10%, ensuring that the quality and particle size of the mineral powder meet the requirements.

[0094] Micro / nano-reinforced liquid and bio-based additives: Prepare according to the requirements of subsequent steps.

[0095] Step 2: Crushing and Screening of Waste Asphalt Mixture

[0096] Waste asphalt mixture is fed into a crusher for crushing until the particle size is less than or equal to 30mm.

[0097] Impurities such as mud and stones are removed from the crushed material by screening equipment to obtain a pure crushed and screened waste asphalt mixture.

[0098] Step 3: Preparation of the mixture

[0099] According to the proportions in step one, put the crushed and screened waste asphalt mixture, new aggregate, and mineral powder into the mixer.

[0100] Turn on the mixer and mix thoroughly until all the raw materials are evenly distributed to obtain a mixture.

[0101] Step 4: Preparation of micro / nano-reinforced liquid

[0102] Environmentally friendly water solution was selected, and the required amount of nano-sized silicate was calculated to account for 0.5% of the total mass of the strengthening solution.

[0103] Nanoscale silicates were dispersed in water and then surface-modified using a silane coupling agent to obtain a micro / nano-reinforced liquid. The amount of silane coupling agent used was 5% of the mass of the nanoscale silicates.

[0104] Step 5: Spraying and stirring of the micro / nano-enhanced liquid

[0105] At a temperature of 140°C, the micro-nano reinforcing liquid obtained in step four is sprayed onto the surface of the mixture from step three at a rate of 2% of the total mass of waste asphalt mixture and new aggregate.

[0106] A twin-shaft mixer is used to stir the mixture at a speed of 100 revolutions per minute for at least 10 minutes to ensure that the micro- and nano-materials are evenly distributed in the mixture.

[0107] Step Six: Preparation of Bio-based Additives

[0108] Natural plant oil and bio-enzymatically hydrolyzed lignin are mixed in a 1:1 mass ratio.

[0109] The mixture was heated to 80°C, and an appropriate amount of acid catalyst was added to enhance the activity of the bio-based additive. After the reaction was complete, the bio-based additive was obtained.

[0110] Step 7: Adding and mixing the bio-based additives

[0111] Add the bio-based additive obtained in step six to the mixture at 3% of the total mass of waste asphalt mixture and new aggregate.

[0112] Continue mixing using a twin-shaft mixer at a constant speed for at least 5 minutes, until the additives are fully incorporated into the mixture.

[0113] Step 8: Ultrasonic Treatment

[0114] The recycled asphalt mixture obtained in step seven is placed in an ultrasonic treatment device and treated with ultrasound at a frequency of 40 kHz for 10 minutes to further enhance the dispersion effect of micro-nano materials and bio-based additives.

[0115] Step 9: Initial compaction

[0116] A vibratory roller is used to perform preliminary compaction on the ultrasonically treated mixture, with two compaction passes to ensure the mixture is initially formed.

[0117] Step 10: Further compaction

[0118] The pre-compacted mixture is then moved to a static roller for further compaction until the required Marshall stability and density are achieved.

[0119] Example 4

[0120] This invention provides a process for preparing a high-proportion recycled asphalt mixture at room temperature, comprising the following steps:

[0121] Step 1: Prepare the raw materials

[0122] Waste asphalt mixture: accounting for 47% of the total mass, ensuring its stable source and reliable quality.

[0123] New aggregates: accounting for 47%, selected from high-quality aggregates that meet the requirements.

[0124] Mineral powder: accounting for 6%, ensuring that the quality and particle size of the mineral powder meet the requirements.

[0125] Micro / nano-reinforced liquid and bio-based additives: Prepare according to the requirements of subsequent steps.

[0126] Step 2: Crushing and Screening of Waste Asphalt Mixture

[0127] Waste asphalt mixture is fed into a crusher for crushing until the particle size is less than or equal to 30mm.

[0128] Impurities such as mud and stones are removed from the crushed material by screening equipment to obtain a pure crushed and screened waste asphalt mixture.

[0129] Step 3: Preparation of the mixture

[0130] According to the proportions in step one, put the crushed and screened waste asphalt mixture, new aggregate, and mineral powder into the mixer.

[0131] Turn on the mixer and mix thoroughly until all the raw materials are evenly distributed to obtain a mixture.

[0132] Step 4: Preparation of micro / nano-reinforced liquid

[0133] Environmentally friendly water solution was selected, and the required amount of nano-sized silicate was calculated to account for 0.4% of the total mass of the strengthening solution.

[0134] Nanoscale silicates were dispersed in water and then surface-modified using a silane coupling agent to obtain a micro / nano-reinforced liquid. The amount of silane coupling agent used was 4% of the mass of the nanoscale silicates.

[0135] Step 5: Spraying and stirring of the micro / nano-enhanced liquid

[0136] At a temperature of 140°C, the micro-nano reinforcing liquid obtained in step four is sprayed onto the surface of the mixture from step three at a rate of 2% of the total mass of waste asphalt mixture and new aggregate.

[0137] A twin-shaft mixer is used to stir the mixture at a speed of 80 revolutions per minute for at least 10 minutes to ensure that the micro- and nano-materials are evenly distributed in the mixture.

[0138] Step Six: Preparation of Bio-based Additives

[0139] Natural plant oil and bio-enzymatically hydrolyzed lignin are mixed in a 1:1 mass ratio.

[0140] The mixture was heated to 80°C, and an appropriate amount of acid catalyst was added to enhance the activity of the bio-based additive. After the reaction was complete, the bio-based additive was obtained.

[0141] Step 7: Adding and mixing the bio-based additives

[0142] Add the bio-based additive obtained in step six to the mixture at 3% of the total mass of waste asphalt mixture and new aggregate.

[0143] Continue mixing using a twin-shaft mixer at a constant speed for at least 5 minutes, until the additives are fully incorporated into the mixture.

[0144] Step 8: Ultrasonic Treatment

[0145] The recycled asphalt mixture obtained in step seven is placed in an ultrasonic treatment device and treated with ultrasound at a frequency of 40kHz for 3-10 minutes to further enhance the dispersion effect of micro-nano materials and bio-based additives.

[0146] Step 9: Initial compaction

[0147] A vibratory roller is used to perform preliminary compaction on the ultrasonically treated mixture, with two compaction passes to ensure the mixture is initially formed.

[0148] Step 10: Further compaction

[0149] The pre-compacted mixture is then moved to a static roller for further compaction until the required Marshall stability and density are achieved.

[0150] The following experimental table is obtained according to different ultrasonic treatment times:

[0151] Experimental group Ultrasonic treatment time (min) Marshall stability (kN) Rutting depth (mm) Resistance to moisture damage (residual stability, %) A 3 11.2 2.2 89 B 5 11.8 2.0 91 C 7 (reference group) 12.5 1.8 92 D 10 12.3 1.9 91.5 Control group 0 (untreated) 10.8 2.4 88

[0152] Experimental Analysis:

[0153] The effect of ultrasonic treatment time on Marshall stability:

[0154] The experimental data show that the Marshall stability initially increases and then tends to stabilize as the ultrasonic treatment time increases. The Marshall stability of experimental groups B, C, and D are all higher than that of the control group, indicating that ultrasonic treatment does indeed help improve the cohesion and stability of the mixture.

[0155] The Marshall stability of experimental group C (7-minute treatment time) reached the highest value, while the stability of experimental group D (10-minute treatment time) decreased slightly, but was still higher than that of the control group. This may indicate that increasing the ultrasonic treatment time within a certain range can significantly improve the performance of the mixture, but excessively long treatment times may no longer produce additional positive effects, and may even slightly reduce performance due to overtreatment.

[0156] The effect of ultrasonic treatment time on rut depth:

[0157] Rut depth data showed that rut depth gradually decreased with increasing ultrasonic treatment time, but the decrease became insignificant after the treatment time exceeded a certain value (e.g., from experimental group C to D). This further supports the view that ultrasonic treatment helps improve the mixture's resistance to permanent deformation.

[0158] The rutting depths of experimental groups C and D were similar and lower than those of the control group, indicating that the rutting resistance of the mixture was effectively improved under both treatment times.

[0159] The effect of ultrasonic treatment time on water damage resistance:

[0160] Water damage resistance (expressed as residual stability) increased with increasing ultrasonic treatment time, but the difference was not significant between experimental groups C and D. This indicates that ultrasonic treatment can enhance the water damage resistance of the mixture, but the effect of improving water damage resistance may tend to saturate after the treatment time exceeds a certain value (e.g., 7 minutes).

[0161] The residual stability of experimental groups C and D was higher than that of the control group, and was close to or exceeded 90%, indicating that ultrasonic treatment is of great significance for improving the durability of the mixture.

[0162] In summary, ultrasonic treatment time has a significant impact on the performance of high-proportion recycled asphalt mixtures at room temperature. Within a certain range, increasing the ultrasonic treatment time can significantly improve the Marshall stability of the mixture, reduce rutting depth, and enhance resistance to water damage. However, when the treatment time exceeds a certain value (such as 7 minutes in this experiment), the performance improvement may tend to saturate or slightly decrease. Therefore, in practical applications, an appropriate ultrasonic treatment time should be selected based on the specific material composition and performance requirements.

[0163] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. "A plurality of" means two or more, unless otherwise explicitly specified.

[0164] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0165] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0166] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0167] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for preparing a high-proportion recycled asphalt mixture at room temperature, characterized in that, Includes the following steps: Step 1: Prepare raw materials, including waste asphalt mixture accounting for 30%-80% of the total mass, new aggregate accounting for 10%-65%, mineral powder accounting for 5%-10%, as well as micro-nano reinforcing liquid and bio-based additives. Step 2: Crush the waste asphalt mixture to a particle size of less than or equal to 30mm, and screen to remove impurities, to obtain the crushed and screened waste asphalt mixture; Step 3: Mix the crushed and screened waste asphalt mixture with new aggregates and mineral powder in the same proportion as in Step 1 to obtain the mixture; Step 4: Prepare micro-nano strengthening liquid, wherein nano-sized silicates account for 0.1%-0.5% of the total mass of the strengthening liquid, dispersed in an environmentally friendly solvent, and surface modified by a silane coupling agent to obtain micro-nano strengthening liquid; Step 5: At a temperature of 80°C to 140°C, spray the micro-nano reinforcing liquid obtained in Step 4 onto the surface of the mixture in Step 3 at a ratio of 0.5%-2% of the total mass of waste asphalt mixture and new aggregate, and mechanically stir for at least 10 minutes to ensure uniform distribution of micro-nano materials. Step 6: Prepare bio-based additives, which are made by mixing natural plant oils and bio-enzymatically hydrolyzed lignin in a mass ratio of 1:1 and then obtaining bio-based additives through chemical modification. Step 7: Add the bio-based additive obtained in Step 6 to the mixture at 1%-3% of the total mass of waste asphalt mixture and new aggregate, and continue stirring for at least 5 minutes until the additive is completely incorporated. Step 8: The recycled asphalt mixture obtained in Step 7 is subjected to ultrasonic treatment for 3-10 minutes to further enhance the dispersion effect of micro-nano materials and bio-based additives. Step 9: Perform preliminary compaction on the ultrasonically treated mixture; Step 10: Further compact the initially compacted mixture until it reaches the required density and stability as designed. The chemical modification process in step six involves heating to 60-80°C and adding an appropriate amount of acid catalyst to enhance the activity of the bio-based additive.

2. The process for preparing a high-proportion recycled asphalt mixture at room temperature as described in claim 1, characterized in that, The environmentally friendly solvent in step four is water, and the particle size of the nano-sized silicate is less than 100 nm.

3. The process for preparing a high-proportion recycled asphalt mixture at room temperature as described in claim 2, characterized in that, The mechanical mixing in step five uses a twin-shaft mixer with a mixing speed of 50-100 revolutions per minute.

4. The process for preparing a high-proportion recycled asphalt mixture at room temperature as described in claim 3, characterized in that, The ultrasonic treatment in step eight uses an ultrasonic device with a frequency of 20-40kHz.

5. The process for preparing a high-proportion recycled asphalt mixture at room temperature as described in claim 4, characterized in that, The initial compaction in step nine is carried out using a vibratory roller, with 2-3 compaction passes.

6. The process for preparing a high-proportion recycled asphalt mixture at room temperature as described in claim 1, characterized in that, Further compaction in step ten is carried out using a static roller until the Marshall stability required by the design is achieved.

7. The process for preparing a high-proportion recycled asphalt mixture at room temperature as described in claim 6, characterized in that, The micro / nano strengthening liquid contains nano-sized silicates, silane coupling agents, and environmentally friendly solvents, wherein the nano-sized silicates account for 0.1%-0.5% of the total mass of the strengthening liquid, and the silane coupling agents account for 1%-5% of the mass of the nano-sized silicates.