Bio-based cold-laid asphalt thin overlay material and preparation method thereof

Abstract

The invention relates to the technical field of road materials, and particularly discloses a bio-based cold-laid asphalt thin overlay material and a preparation method thereof. The thin overlay material comprises the following components in percentage by mass: 85%-95% of asphalt pavement milling reclaimed material, 3%-10% of bio-based cold-mixed cementing fluid, 1%-4% of acrylic emulsion and 0.5%-1.5% of glycerin monostearate, the bio-based cold-mixed cementing fluid comprises the following components in percentage by mass: 5%-85% of asphalt, 5%-40% of vegetable oil, 5%-40% of oleic acid monoester and 3%-15% of terpene unsaturated compounds, the iodine value of the vegetable oil is greater than or equal to 100. All the components of the thin overlay material can be mixed under the normal temperature condition, the influence of the construction environment is small, the bio-based cold mixing cementing liquid can recover the performance of aged asphalt of the asphalt pavement and improve the overall performance of the road, and the acrylic emulsion and the glyceryl monostearate can improve the maintenance effect of the asphalt pavement.

Description

Technical Field

[0001] This application relates to the field of road materials technology, and in particular to a bio-based cold-laid asphalt thin-layer overlay material and its preparation method. Background Technology

[0002] With the rapid development of highway construction and the continuous increase in road maintenance mileage, maintenance funds are relatively scarce and maintenance levels are low. To change the current passive maintenance situation, the most effective method is to implement preventative maintenance. Preventative pavement maintenance aims to prevent premature and severe damage to the pavement, maintain or improve road traffic conditions, postpone the timing of highway repairs and reconstruction, extend the service life of the pavement, and take economical and effective measures at appropriate times and on suitable road sections. Preventative maintenance encompasses routine pavement maintenance, minor repairs, and the timely implementation of specific maintenance measures based on pavement performance. Therefore, a detailed study of the key technologies of preventative pavement maintenance, providing methods for determining the optimal timing of preventative maintenance, and developing preventative maintenance strategies are of great significance for extending pavement service life, maintaining good pavement performance, reducing pavement lifecycle costs, and saving maintenance and repair funds.

[0003] Currently, the commonly used preventive maintenance techniques for asphalt pavements typically employ hot-mix asphalt to ensure the pavement can resist the increased tensile stress at the bottom of the layer, fatigue damage rate of structural layers, and interlayer shear force caused by the reduction in thickness. However, hot-mix asphalt is easily affected by the ambient temperature during construction and has higher construction costs. Compared to hot-mix technology, cold-mix technology is less affected by the construction environment and has a shorter construction time. Commonly used cold-mix technologies include fog seal, slurry seal, micro-surfacing, synchronous chip seal, and ultra-thin overlay. However, pavements maintained using techniques such as slurry seal and micro-surfacing typically have a service life of only 2-3 years, and the resulting pavement surface has excessive roughness, poor smoothness, and low durability.

[0004] Therefore, there is an urgent need for an asphalt pavement maintenance technology that is less affected by the construction environment and has good maintenance effects. Summary of the Invention

[0005] To address the problems of existing road maintenance technologies being greatly affected by the construction environment or having poor maintenance effects, this application provides a bio-based cold-mix asphalt overlay material and its preparation method. This application uses a bio-based cold-mix binder composed of vegetable oil, oleic acid monoester, and terpene unsaturated compounds, mixed with recycled asphalt pavement milling material at room temperature. This fully restores the properties of aged asphalt in the recycled asphalt pavement milling material. Acrylic emulsion and glyceryl monostearate are also added, which work synergistically to enhance the water resistance, adhesion, and toughness of the overlay material, improving the maintenance effect of asphalt pavement and extending its service life by more than six years. Furthermore, the overlay material in this application can be constructed using existing paving equipment without the need for additional customized paving equipment, making it highly practical and possessing good market prospects.

[0006] In a first aspect, this application provides a bio-based cold-laid asphalt thin-layer overlay material, employing the following technical solution: A bio-based cold-laid asphalt thin-layer overlay material, comprising the following components by weight percentage: 85%-95% recycled asphalt pavement milling material, 3%-10% bio-based cold-mix binder, 1%-4% acrylic emulsion, and 0.5%-1.5% glyceryl monostearate; The bio-based cold mix binder comprises the following components by mass percentage: 5%-85% asphalt, 5%-40% vegetable oil, 5%-40% oleic acid monoester, and 3%-15% terpene unsaturated compounds; wherein the iodine value of the vegetable oil is ≥100.

[0007] By adopting the above technical solutions, bio-based cold-mix binders can restore the properties of aged asphalt in milled recycled asphalt pavement. Acrylic emulsions have good adhesion, while glyceryl monostearate has good penetration and wetting properties. The combination of acrylic emulsions and glyceryl monostearate can improve the adhesion between the thin overlay material and the pavement base layer, increasing the bonding strength of the thin overlay material and making it less prone to peeling. In addition, after the acrylic emulsion is mixed with asphalt, the polymers in the acrylic emulsion interact with the colloids in the asphalt to form a cross-linked network structure, improving the toughness and durability of the asphalt pavement. This allows it to have better deformation capacity under stress caused by traffic loads and temperature changes, thereby reducing the risk of cracking and damage and improving pavement maintenance effectiveness.

[0008] In bio-based cold-mix binders, asphalt can compensate for the asphalt loss in milled and recycled asphalt pavement, increasing the bonding strength between particles. Vegetable oils contain a high amount of unsaturated acids, which can replenish the macaroni components lost during the aging process of asphalt, rebalance the component balance of aged asphalt, and restore its performance. In addition, vegetable oils with an iodine value ≥100 have strong diffusion ability in cold-mix binders, further enhancing the performance of aged asphalt. Oleic acid monoesters are small-molecule unsaturated higher fatty acid esters containing polar ester groups and non-polar straight-chain alkanes. The polar ester groups can adsorb asphaltenes in asphalt, while the non-polar straight-chain alkanes are compatible with macaroni in asphalt, thereby improving the compatibility between vegetable oils and aged asphalt, helping to restore the performance of aged asphalt. They can also act as plasticizers to enhance the strength of thin-layer overlay materials. Terpenoid unsaturated compounds have anti-corrosion properties, extending the storage time of bio-based cold-mix binders. They can also synergistically interact with oleic acid monoesters to further improve the compatibility of aged asphalt with other components, thereby enhancing the performance of aged asphalt. The terpene unsaturated compounds in this application are extracted or separated from fruits, pine trees or other agricultural wastes, and do not produce harmful or irritating odors when they volatilize, thus reducing harm to construction workers.

[0009] In addition, most of the thin-layer overlay material in this application is recycled material from milled asphalt pavement, realizing the recycling of solid waste, achieving cost savings and environmental protection while ensuring the maintenance effect of asphalt pavement.

[0010] In this application, the asphalt is selected from 50# asphalt, 70# asphalt, 90# asphalt, polymer-modified asphalt, or rubber-modified asphalt produced by straight distillation or cracking; the vegetable oil is a drying oil with an iodine value >140 or a semi-drying oil with an iodine value of 100-140, specifically selected from linseed oil, tung oil, walnut oil, soybean oil, corn oil, grape seed oil, sunflower seed oil, rapeseed oil, or cottonseed oil; the oleic acid monoester is selected from methyl oleate, methyl linoleate, ethyl oleate, propyl oleate, isopropyl oleate, butyl oleate, or isobutyl oleate; the terpene unsaturated compound is selected from one or more of acyclic monoterpenes, monocyclic monoterpenes, and bicyclic monoterpenes, such as limonene and α-pinene, with a 7-day reaction depth of 7.00 or higher to ensure its diffusion rate.

[0011] Preferably, the asphalt pavement milling recycled material comprises: 15%-25% asphalt pavement milling recycled material with a particle size of 0-3mm, 3%-11% asphalt pavement milling recycled material with a particle size of 3-5mm, and 65%-80% asphalt pavement milling recycled material with a particle size of 5-10mm.

[0012] By adopting the above technical solution and mixing asphalt pavement milling recycled materials with different particle sizes according to the above proportion, on the one hand, the small particle size asphalt pavement milling recycled materials can fill between the large particle size asphalt pavement milling recycled materials, improving the strength of the thin overlay material; on the other hand, the roughness of the road surface after maintenance can meet the anti-skid performance of the road, reduce the noise generated by the wheels, and improve the comfort and safety of driving.

[0013] In some specific embodiments, the asphalt pavement milling recycled material is specifically composed of: 18%-22% asphalt pavement milling recycled material with a particle size of 0-3mm, 5%-9% asphalt pavement milling recycled material with a particle size of 3-5mm, and 70%-77% asphalt pavement milling recycled material with a particle size of 5-10mm.

[0014] Preferably, the mass ratio of the acrylic emulsion to the glyceryl monostearate is (2-5):1.

[0015] By adopting the above technical solution, the mass ratio of acrylic emulsion and glyceryl monostearate is controlled within the above range, resulting in a better synergistic effect between the two. This helps to improve the adhesion between the thin overlay material and the road base layer, increase the bonding strength of the thin overlay material, and make it less prone to peeling.

[0016] In some preferred embodiments, the mass ratio of the acrylic emulsion to the glyceryl monostearate can be 3:1, 4:1, or 5:1, etc.

[0017] Preferably, the thickness of the thin-layer cover material is 15-25 mm.

[0018] If the thickness of the thin overlay material is too thick, it may cause uneven road surface, increase internal stress, and increase construction costs. If the thickness of the thin overlay material is too thin, it may not provide sufficient strength and durability, making it difficult for the road surface to withstand the expected traffic load and stress, which may easily lead to road surface damage. Moreover, it may not be able to effectively prevent water penetration, causing serious water seepage problems and accelerating the formation of cracks.

[0019] In some preferred embodiments, the thickness of the thin-layer cover material is 18 mm.

[0020] Preferably, the vegetable oil has a viscosity of 200-500 mPa·s at 25°C and a flash point higher than 200°C; the oleic acid monoester has a viscosity of 1-50 mPa·s at 25°C and a flash point higher than 110°C.

[0021] By adopting the above technical solutions, the bio-based cold mix binder is guaranteed to have good fluidity, mixing workability and molding strength at room temperature. The selection of vegetable oils and oleic acid monoesters with high flash points can improve the safety of the bio-based cold mix binder during transportation and use.

[0022] Preferably, the mass ratio of the oleic acid monoester to the terpene unsaturated compound is (1-3):1.

[0023] By adopting the above technical solution and further adjusting the mass ratio of oleic acid monoester to terpene unsaturated compounds, it is helpful to improve the compatibility between aged asphalt and vegetable oil, and to more fully restore the performance of aged asphalt.

[0024] In some preferred embodiments, the mass ratio of the oleic acid monoester to the terpene unsaturated compound can be 1:1, 2:1, or 3:1, etc.

[0025] Preferably, the bio-based cold-mix cementitious solution is obtained through the following steps: S1. Heat the asphalt to a fluid state and then add the vegetable oil to it and stir evenly to obtain a primary premixed liquid. S2. Add the oleic acid monoester to the primary premix and stir until homogeneous to obtain the secondary premix. S3. After the secondary premix has cooled to below 50°C, add the terpene unsaturated compound and stir until homogeneous to obtain the bio-based cold-mix cementitious liquid.

[0026] By adopting the above technical solution, since terpene unsaturated compounds are easily volatilized under high temperature conditions, affecting their performance, it is necessary to wait until the secondary premix cools down before adding terpene unsaturated compounds to ensure the effect of the bio-based cold-mixed cementitious liquid.

[0027] In some specific embodiments, the stirring conditions in the above steps are all 50-2500 rad / min, the stirring time in steps S1 and S2 is 5 min, and the stirring time in step S3 is 15 min.

[0028] Preferably, in step S1, the asphalt is heated to 90°C-190°C.

[0029] Secondly, this application provides a method for preparing a bio-based cold-laid asphalt thin-layer overlay material, employing the following technical solution: A method for preparing a bio-based cold-laid asphalt thin-layer overlay material includes the following steps: T1. The milled material from the recycled asphalt pavement is screened, and milled materials with different particle sizes are mixed in proportion to obtain the recycled asphalt pavement milled material. T2. Mix the acrylic emulsion and glyceryl monostearate evenly to obtain a mixed additive solution; T3. Mix the asphalt pavement milling recycled material with the bio-based cold mix binder to obtain recycled milling material; T4. Add the mixed additive liquid to the recycled milling material and mix evenly to obtain the thin-layer coating material.

[0030] In some specific embodiments, in step T4, the recycled milling material can be added to the mixing additive in multiple batches so that the two are mixed more evenly, which helps to improve the performance of the thin-layer cover material.

[0031] By adopting the above technical solution, all components of the thin-layer cover material can be mixed at room temperature, which is less affected by the construction environment and makes storage and construction more convenient.

[0032] In summary, this application includes at least one of the following beneficial technical effects: 1. In the bio-based cold mix binder of this application, vegetable oil can rebalance the component balance of aged asphalt in the milled recycled material of asphalt pavement and restore the performance of aged asphalt, while oleic acid monoester can synergistically improve the compatibility between vegetable oil and aged asphalt with terpene unsaturated compounds, thereby fully restoring the performance of aged asphalt. 2. In the thin-layer overlay material of this application, the bio-based cold-mix binder can restore the performance of aged asphalt in the milled recycled asphalt pavement material. The acrylic emulsion and glyceryl monostearate compound can improve the adhesion between the thin-layer overlay material and the pavement base layer, increase the adhesion strength of the thin-layer overlay material, and make it less prone to peeling. In addition, the polymer in the acrylic emulsion can also interact with the colloids in the asphalt, improve the toughness and durability of the asphalt pavement, thereby extending the service life of the pavement and improving the pavement maintenance effect. Moreover, the components can be mixed at room temperature and are less affected by the construction environment. 3. The raw materials used in the preparation of the thin-layer overlay material of this application are mostly recycled asphalt pavement milling material, which can recycle solid waste, reduce maintenance costs, and ensure the maintenance effect of the pavement by using appropriate gradation. This ensures that the roughness of the pavement after maintenance meets the anti-skid performance of the road, reduces the noise generated by the wheels, and improves the comfort and safety of driving. Attached Figure Description

[0033] Figure 1 This is a flowchart illustrating the preparation method of the bio-based cold-mix cementitious liquid of this application; Figure 2 This is a flowchart illustrating the preparation method of the bio-based cold-laid asphalt thin-layer overlay material of this application. Detailed Implementation

[0034] To make this application easier to understand, the following detailed description will be provided with reference to embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of application of this application. Unless otherwise specified, the raw materials or components used in this application can be obtained commercially or by conventional methods.

[0035] Source of raw materials The asphalt used in the following examples was 70# asphalt from Shandong Jingbo Petrochemical Co., Ltd.; the vegetable oil was rapeseed oil from Shandong Sihecheng Oil Co., Ltd.; the oleic acid monoester was methyl linoleate from Wuhan Kemike Biomedical Technology Co., Ltd.; the terpene unsaturated compound was α-pinene from Jishui Yikang Natural Fragrance Oil Refinery; the acrylic emulsion was purchased from Shandong Mingyue Chemical Co., Ltd.; and the glyceryl monostearate was purchased from Shaanxi Chenming Biotechnology Co., Ltd.

[0036] Preparation Example 1: Preparation of Asphalt Pavement Milling Recycled Material The recycled asphalt pavement milling material is composed of particles of different sizes, specifically: 19 kg of recycled asphalt pavement milling material with a particle size of 0-3 mm, 7 kg of recycled asphalt pavement milling material with a particle size of 3-5 mm, and 74 kg of recycled asphalt pavement milling material with a particle size of 5-10 mm. Its preparation method is as follows: the recycled asphalt pavement milling material is collected and sieved. The milling materials of different particle sizes are then mixed according to the above-mentioned proportions to obtain the recycled asphalt pavement milling material.

[0037] Preparation Example 2: Preparation of Asphalt Pavement Milling Recycled Material The difference between Preparation Example 2 and Preparation Example 1 is that the dosage of asphalt pavement milling recycled material with different particle sizes is different. Specifically, it is 15 kg of asphalt pavement milling recycled material with a particle size of 0-3 mm, 5 kg of asphalt pavement milling recycled material with a particle size of 3-5 mm, and 80 kg of asphalt pavement milling recycled material with a particle size of 5-10 mm. The rest is the same as Preparation Example 1.

[0038] Preparation Example 3: Preparation of Asphalt Pavement Milling Recycled Material The difference between Preparation Example 3 and Preparation Example 1 is that the dosage of asphalt pavement milling recycled material with different particle sizes is different. Specifically, it is 25 kg of asphalt pavement milling recycled material with a particle size of 0-3 mm, 10 kg of asphalt pavement milling recycled material with a particle size of 3-5 mm, and 65 kg of asphalt pavement milling recycled material with a particle size of 5-10 mm. The rest is the same as Preparation Example 1.

[0039] Preparation Example 4: Preparation of Bio-based Cold Mixing Cementitious Solution Preparation Example 4: The raw materials and their dosages for the preparation of the bio-based cold-mix cementitious liquid are shown in Table 1. The mass ratio of methyl linoleate to α-pinene is 2:1. Rapeseed oil has a viscosity of 325 mPa·s and a flash point of 280°C at 25°C. Methyl linoleate has a viscosity of 5.5 mPa·s and a flash point of 110°C at 25°C. The preparation method of the bio-based cold-mix cementitious liquid is as follows: Refer to... Figure 1 70# asphalt was heated to 90℃ to make it fluid. Rapeseed oil was added to it and stirred at 500 rad / min for 5 min to obtain a primary premix. Then, methyl linoleate was added to the primary premix and stirred again at 500 rad / min for 5 min to obtain a secondary premix. The secondary premix was set aside to cool. When its temperature dropped to 40℃, α-pinene was added to it and stirred at 500 rad / min for 15 min to obtain a bio-based cold-mix cementitious liquid.

[0040] Preparation Examples 5-6: Preparation of Bio-based Cold Mixing Cementitious Compounds The difference between Preparation Examples 5-6 and Preparation Example 4 lies in the different amounts of each raw material used in the preparation of the cold-mixed cementitious liquid, as shown in Table 1. The rest is the same as Preparation Example 4.

[0041] Preparation Examples 7-8: Preparation of Bio-based Cold Mixing Cementitious Compounds The difference between Preparation Examples 7-8 and Preparation Example 4 lies in the different amounts of each raw material used in the preparation of the cold-mixed cementitious liquid, as shown in Table 1. The mass ratios of methyl linoleate to α-pinene are 1:1 and 3:1, respectively, while the rest are the same as in Preparation Example 4.

[0042] Table 1. Raw materials (kg) for the preparation of bio-based cold-mix cementitious solutions in Examples 4-8 Preparation Example 4 Preparation Example 5 Preparation Example 6 Preparation Example 7 Preparation Example 8 70# asphalt 66.67 83.2 59.8 71.5 71.5 rapeseed oil 11.11 6.9 17.1 11.7 11.7 Methyl linoleate 11.11 6.2 15.4 8.4 12.6 α-pinene 11.11 3.7 7.8 8.4 4.2 Comparative Preparation Example 1: Preparation of Bio-based Cold Mixing Cementitious Solution The difference between Preparation Example 1 and Preparation Example 4 is that diesel oil (purchased from Guangdong Huanyang Petrochemical Co., Ltd.) was used to replace α-pinene in an equal amount in the raw materials for preparing the cold-mixed cementitious liquid, while the rest was the same as in Preparation Example 4.

[0043] Examples 1-3: Preparation of thin-layer cover materials The raw materials for preparing the thin overlay material are shown in Table 2. The mass ratio of acrylic emulsion to glyceryl monostearate is 3:1. The asphalt pavement milling recycled material is the asphalt pavement milling recycled material obtained in Preparation Example 1, and the bio-based cold mix binder is the bio-based cold mix binder obtained in Preparation Example 4. The preparation steps for the thin overlay material are as follows: Refer to... Figure 2Acrylic emulsion and glyceryl monostearate were mixed and stirred at 800 rad / min for 10 min to obtain a mixed additive. Separately, asphalt pavement milling recycled material and bio-based cold mix binder were mixed and stirred at 500 rad / min for 3 min to obtain recycled milling material. Finally, the mixed additive was added to the recycled milling material and stirred at 500 rad / min for 10 min at 20°C to obtain a thin-layer overlay material.

[0044] Examples 4-5: Preparation of Thin-Layer Covering Materials The difference between Examples 4-5 and Example 1 lies in the different amounts of raw materials used in the preparation of the thin-layer coating material, as shown in Table 2. The mass ratios of acrylic emulsion and glyceryl monostearate are 4:1 and 5:1, respectively, while the rest are the same as in Example 1.

[0045] Table 2. Raw materials (kg) for the preparation of thin-layer cover materials in Examples 1-5 Example 1 Example 2 Example 3 Example 4 Example 5 Asphalt pavement milling recycled material 90.5 85.7 94.6 90.5 90.5 Bio-based cold mix cementitious liquid 5.9 9.1 3.4 5.9 5.9 acrylic emulsion 2.7 3.9 1.5 2.88 3 Glyceryl monostearate 0.9 1.3 0.5 0.72 0.6 Examples 6-7: Preparation of Thin-Layer Covering Material The difference between Examples 6-7 and Example 4 is that the asphalt pavement milling recycled material from Preparation Examples 2-3 is used to replace the asphalt pavement milling recycled material from Preparation Example 1 in equal amounts; otherwise, they are the same as in Example 4.

[0046] Examples 8-11: Preparation of Thin-Layer Covering Materials The difference between Examples 8-11 and Example 4 is that the bio-based cold mix cementitious liquid of Preparation Examples 5-8 is used to replace the bio-based cold mix cementitious liquid of Preparation Example 4 in equal amounts; otherwise, they are the same as in Example 4.

[0047] Comparative Example 1: Preparation of Thin-Layer Coating Material The difference between Comparative Example 1 and Example 1 lies in the raw materials and dosage of the thin overlay material. Specifically, Comparative Example 1 uses 94.7 kg of recycled asphalt pavement milling material and 5.3 kg of bio-based cold mix binder, while the rest is the same as in Example 1.

[0048] Comparative Example 2: Preparation of Thin-Layer Coating Material The difference between Comparative Example 2 and Example 1 lies in the raw materials and dosage of the thin overlay material. Specifically, Comparative Example 2 uses 90.5 kg of recycled asphalt pavement milling material, 5.9 kg of bio-based cold mix binder, and 3.6 kg of acrylic emulsion. The rest is the same as in Example 1.

[0049] Comparative Example 3: Preparation of Thin-Layer Coating Material The difference between Comparative Example 3 and Example 1 is that the bio-based cold mix cementitious liquid of Comparative Preparation Example 1 is used to replace the bio-based cold mix cementitious liquid of Preparation Example 4 in an equal amount, and the rest is the same as Example 4.

[0050] Test example: The performance of the thin-layer overlay materials of Examples 1-11 and Comparative Examples 1-3 was tested, specifically including the coefficient of friction, stability, texture depth, permeability coefficient, and freeze-thaw splitting residual strength ratio. The coefficient of friction was tested according to the "Field Test Procedures for Highway Subgrade and Pavement" (JTG E60-2008) T0964-2008; the stability was tested according to the industry standard JTJ052 "Tests on Asphalt and Asphalt Mixtures for Kilometer Engineering" T0709 "Marshall Stability Test of Asphalt Mixtures"; the texture depth was tested according to the "Field Test Procedures for Highway Subgrade and Pavement" (JTG E60-2008) T0961-1995; and the permeability coefficient was tested according to the "Field Test Procedures for Highway Subgrade and Pavement" (JTG E60-2008) T0961-1995. The test was conducted according to E60-2008)T0971-2008, and the freeze-thaw splitting residual strength ratio was tested according to the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2011)T0729-2000. The test results are shown in Table 3.

[0051] Table 3 According to the test data in Table 3, the friction coefficient of Examples 1-11 and Comparative Examples 1-3 is 41-74, the stability is 4.7-16.8kN, the structural depth is 0.52-1.10mm, the water permeability coefficient is 9-126mL / min, and the freeze-thaw splitting residual strength ratio is 61%-97%.

[0052] The test results from Examples 1-5 and Comparative Examples 1-2 show that the addition of acrylic emulsion and glyceryl monostearate to the thin-layer overlay material results in a synergistic effect, jointly improving the adhesion between the thin-layer overlay material and the road base layer, and enhancing the toughness and durability of the asphalt pavement. The synergistic effect is particularly pronounced when the mass ratio of acrylic emulsion to glyceryl monostearate is 3:1, further improving the maintenance effect of the asphalt pavement.

[0053] The test results of Examples 4 and 6-7 show that the asphalt pavement milling recycled material prepared according to the proportion of Preparation Example 1 is better. After curing, the pavement roughness is more suitable, the anti-skid performance of the road is better, the strength is greater, and the driving comfort and safety are improved.

[0054] The test results from Examples 4, 8-11, and Comparative Example 3 show that the performance of the thin-layer overlay material obtained by adding diesel oil in the preparation of bio-based cold-mix binder is significantly worse than that obtained by adding α-pinene. This may be due to the synergistic effect between α-pinene and methyl linoleate, which jointly promotes the compatibility of rapeseed oil with aged asphalt in the milled and recycled asphalt pavement material, readjusts the composition of the aged asphalt, and fully restores its performance, thereby improving the maintenance effect of the thin-layer overlay material on asphalt pavement. When the mass ratio of methyl linoleate to α-pinene is 2:1, the synergistic effect is even better, further restoring the performance of aged asphalt, recycling solid waste, reducing maintenance costs, and improving the maintenance effect of asphalt pavement.

[0055] It should be noted that the embodiments described above are only for explaining this application and do not constitute any limitation on this application. This application has been described with reference to typical embodiments, but it should be understood that the terms used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to this application within the scope of the claims, and revisions can be made to the invention without departing from the scope and spirit of this application. Although the application described herein relates to specific methods, materials, and embodiments, it does not mean that this application is limited to the specific examples disclosed herein; on the contrary, this application can be extended to all other methods and applications with the same function.

Claims

1. A bio-based cold-laid asphalt thin-layer overlay material, characterized in that: The thin overlay material comprises the following components by weight percentage: 85%-95% recycled asphalt pavement milling material, 3%-10% bio-based cold mix binder, 1%-4% acrylic emulsion, and 0.5%-1.5% glyceryl monostearate; The bio-based cold mix binder comprises the following components by mass percentage: 5%-85% asphalt, 5%-40% vegetable oil, 5%-40% monooleic oleic acid ester, and 3%-15% terpene unsaturated compounds; wherein the iodine value of the vegetable oil is ≥100.

2. The bio-based cold-laid asphalt thin-layer overlay material according to claim 1, characterized in that: The asphalt pavement milling recycled material specifically comprises: 15%-25% asphalt pavement milling recycled material with a particle size of 0-3mm, 3%-11% asphalt pavement milling recycled material with a particle size of 3-5mm, and 65%-80% asphalt pavement milling recycled material with a particle size of 5-10mm.

3. The bio-based cold-laid asphalt thin-layer overlay material according to claim 1, characterized in that: The mass ratio of the acrylic emulsion to the glyceryl monostearate is (2-5):

1.

4. The bio-based cold-laid asphalt thin-layer overlay material according to any one of claims 1-3, characterized in that: The thickness of the thin-layer cover material is 15-25mm.

5. The bio-based cold-laid asphalt thin-layer overlay material according to any one of claims 1-3, characterized in that: The vegetable oil has a viscosity of 200-500 mpa·s at 25°C and a flash point higher than 200°C; the oleic acid monoester has a viscosity of 1-50 mpa·s at 25°C and a flash point higher than 110°C.

6. The bio-based cold-laid asphalt thin-layer overlay material according to claim 4, characterized in that: The mass ratio of the oleic acid monoester to the terpene unsaturated compound is (1-3):

1.

7. The bio-based cold-laid asphalt thin-layer overlay material according to claim 6, characterized in that: The bio-based cold-mix cementitious solution is obtained through the following steps: S1. Heat the asphalt to a fluid state and then add the vegetable oil to it and stir evenly to obtain a primary premixed liquid. S2. Add the oleic acid monoester to the primary premix and stir until homogeneous to obtain the secondary premix. S3. After the secondary premix has cooled to below 50°C, add the terpene unsaturated compound and stir until homogeneous to obtain the bio-based cold-mix cementitious liquid.

8. The bio-based cold-laid asphalt thin-layer overlay material according to claim 7, characterized in that: In step S1, the asphalt is heated to 90℃-190℃.

9. A method for preparing a bio-based cold-laid asphalt thin-layer overlay material as described in any one of claims 1-8, characterized in that: Includes the following steps: T1. The milled material from the recycled asphalt pavement is screened, and milled materials with different particle sizes are mixed in proportion to obtain the recycled asphalt pavement milled material. T2. Mix the acrylic emulsion and glyceryl monostearate evenly to obtain a mixed additive solution; T3. Mix the asphalt pavement milling recycled material with the bio-based cold mix binder to obtain recycled milling material; T4. Add the mixed additive liquid to the recycled milling material and mix evenly to obtain the thin-layer coating material.

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