A waste asphalt mixture recycling micro-surfacing and a preparation method thereof

Abstract

The application belongs to the field of asphalt materials, and particularly relates to a waste asphalt mixture recycling micro-surfacing and a preparation method, which comprises the following steps: S1, collecting waste asphalt from pavement milling material and waste asphalt pavement, and screening the collected waste asphalt mixture using a drum screen to remove large impurities; S2, after preliminary screening, further fine separation is performed using a cyclone separator; S3, the fine separated waste asphalt is mixed with modified aggregate, Portland cement, admixture and water in a high-speed shearing machine to be uniformly mixed and sheared to develop and be subjected to regeneration treatment; and S4, the asphalt mixture after regeneration treatment is laid on the road surface using a paver and a road roller to form micro-surfacing. The application utilizes waste asphalt, lignin, polystyrene and calcium carbonate to reduce the raw material cost in the micro-surfacing construction process, reduce the dependence on traditional petroleum and sandstone resources and the influence on the environment, and conforms to the green development concept.

Description

Technical Field

[0001] This invention belongs to the field of asphalt materials, and specifically relates to a micro-surfacing treatment method for recycled waste asphalt mixtures. Background Technology

[0002] Asphalt is a dark brown mixture composed of hydrocarbons and non-metallic derivatives. It typically exists as a highly viscous liquid or semi-solid petroleum form and is widely used in industries such as coatings, plastics, and rubber, primarily for road paving. Waste asphalt is a common waste product in road construction. Due to its limited lifespan, large quantities of waste asphalt are discarded on roadsides or in landfills, causing serious environmental pollution. Micro-surfacing technology involves crushing, screening, and regenerating waste asphalt, and adding appropriate amounts of new materials and additives to prepare recycled micro-surfacing materials suitable for road surface layers. Micro-surfacing technology can improve the wear resistance of road surfaces by adding a wearing layer, making the road surface more durable and reducing wear. Furthermore, this technology can significantly improve the anti-skid performance of the road surface, increase the coefficient of friction, and improve driving safety, effectively extending the service life and safety of the road surface.

[0003] In the prior art, a search revealed Chinese patent publication number CN103669153A, which discloses a low-temperature micro-surfacing construction process. The raw materials include mineral aggregates, fillers, additives, and BCR-type emulsified asphalt. This micro-surfacing process addresses road maintenance under special conditions, meeting the requirements for micro-surfacing construction when the air temperature is above 5℃ and the surface temperature is above 10℃. However, in practical applications, the cost of raw materials such as mineral aggregates is relatively high, leading to an increase in overall construction costs. Furthermore, traditional raw material micro-surfacing technologies often result in poor quality and are prone to peeling. Summary of the Invention

[0004] The purpose of this invention is to provide a micro-surfacing treatment method for recycled waste asphalt mixtures.

[0005] The technical problem to be solved by this invention is: high raw material cost and poor quality of micro-surfacing.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A method for preparing recycled micro-surface treatment of waste asphalt mixture includes the following steps:

[0008] S1. Collect waste asphalt from road milling material and waste asphalt pavement, and use a drum screen to screen the collected waste asphalt mixture to remove large debris.

[0009] S2. After preliminary screening, a cyclone separator is used for further fine separation;

[0010] S3. The finely separated waste asphalt is mixed with modified aggregate, silicate cement, admixtures and water in a high-speed shear machine, and then sheared and developed for recycling.

[0011] S4. The recycled asphalt mixture is laid on the road surface using a paver and roller to form a micro-surfacing.

[0012] Furthermore, in step S1, the drum screen rotates at 10-16 rpm, the screen mesh size is 20-40 mm, and the drum screen inclination angle is 10-15°.

[0013] In step S2, the air velocity at the inlet of the cyclone separator is 20-30 m / s, and the diameter of the cyclone tube is 1-2 m.

[0014] The admixtures in step S3 include one or more of gypsum, fly ash, rubber powder, and limestone.

[0015] In step S3, the shearing development is carried out at 160-200℃ and 4000-4500 rpm for 30-60 minutes. After cooling to room temperature, the speed is adjusted to 2000-2500 rpm and the shearing development is carried out for 15-30 minutes.

[0016] According to another aspect of the present invention, a micro-surfacing treatment of waste asphalt mixture is provided, comprising the following raw materials by weight: 20-30 parts waste asphalt, 100-120 parts modified aggregate, 5-10 parts silicate cement, 1-5 parts admixture and 40-80 parts water.

[0017] Preferably, the raw materials include the following by weight: 22-24 parts waste asphalt, 100-110 parts modified aggregate, 5-7 parts silicate cement, 1-3 parts admixture and 40-60 parts water.

[0018] Furthermore, the modified aggregate is prepared by the following steps:

[0019] Lignin and polystyrene were added to an N-methylpyrrolidone solution and placed in a polytetrafluoroethylene-lined reactor. Benzoyl peroxide and stannous octoate were added, and the mixture was stirred. The reaction temperature was controlled at 60-70℃, and the reaction was carried out for 2-4 hours. While the mixture was still hot, 60-70 wt% calcium carbonate suspension was added, and the mixture was stirred. The reaction was continued for 3-5 hours. The mixture was cooled to room temperature, filtered, washed, and dried to obtain lignin-polystyrene copolymer supported nano-calcium carbonate.

[0020] The mass ratio of the lignin, polystyrene, benzoyl peroxide, stannous octoate and calcium carbonate suspension is (10-12):(20-25):(0.5-0.7):(0.01-0.03):(30-32).

[0021] The beneficial effects of this invention are:

[0022] 1. In the technical solution of this invention, polystyrene segments are introduced through copolymerization using lignin as the matrix, and nano-calcium carbonate is uniformly loaded into the copolymer structure to improve the adhesion between asphalt and coarse aggregate. This ensures that the waste asphalt mixture can better form a stable pavement structure during micro-surfacing. Simultaneously, it also enhances the flexibility of the waste asphalt mixture, enabling it to withstand greater stress and deformation.

[0023] 2. In the technical solution of this invention, the lignin-polystyrene copolymer loaded with nano-calcium carbonate effectively improves the thermal stability and aging resistance of waste asphalt mixtures, making them less prone to aging and damage, thus improving the stability of waste asphalt mixtures and extending their service life.

[0024] 3. In the technical solution of this invention, by utilizing waste asphalt, lignin, polystyrene and calcium carbonate, the raw material cost in the micro-surfacing construction process is reduced, the dependence on traditional petroleum and sand and gravel resources and the impact on the environment are reduced, which is in line with the concept of green development. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] The modified aggregate is prepared by the following steps:

[0028] 10g of lignin and 20g of polystyrene were added to an N-methylpyrrolidone solution and placed in a polytetrafluoroethylene-lined reactor. 0.5g of benzoyl peroxide and 0.01g of stannous octoate were added, and the mixture was stirred. The reaction temperature was controlled at 60℃ and the reaction was carried out for 2 hours. While the mixture was still hot, 30g of 60wt% calcium carbonate suspension was added, and the mixture was stirred and the reaction was continued for 3 hours. The mixture was then cooled to room temperature, filtered, washed, and dried to obtain lignin-polystyrene copolymer supported nano-calcium carbonate.

[0029] Example 2

[0030] The modified aggregate is prepared by the following steps:

[0031] 11g of lignin and 22.5g of polystyrene were added to an N-methylpyrrolidone solution and placed in a polytetrafluoroethylene-lined reactor. 0.6g of benzoyl peroxide and 0.02g of stannous octoate were added, and the mixture was stirred. The reaction temperature was controlled at 65℃ and the reaction was carried out for 3 hours. While the mixture was still hot, 31g of 65wt% calcium carbonate suspension was added, and the mixture was stirred and the reaction was continued for 4 hours. The mixture was then cooled to room temperature, filtered, washed, and dried to obtain lignin-polystyrene copolymer supported nano-calcium carbonate.

[0032] Example 3

[0033] The modified aggregate is prepared by the following steps:

[0034] 12g of lignin and 25g of polystyrene were added to an N-methylpyrrolidone solution and placed in a polytetrafluoroethylene-lined reactor. 0.7g of benzoyl peroxide and 0.02g of stannous octoate were added, and the mixture was stirred. The reaction temperature was controlled at 70℃ and the reaction was carried out for 4 hours. While the mixture was still hot, 32g of 70wt% calcium carbonate suspension was added, and the mixture was stirred and the reaction was continued for 5 hours. The mixture was then cooled to room temperature, filtered, washed, and dried to obtain lignin-polystyrene copolymer supported nano-calcium carbonate.

[0035] Example 4

[0036] A method for preparing recycled micro-surface treatment of waste asphalt mixture includes the following steps:

[0037] S1. Collect waste asphalt from road milling material and waste asphalt pavement, and use a drum screen to screen the collected waste asphalt mixture to remove large debris. The drum screen rotates at 10 rpm, the screen mesh size is 20 mm, and the drum screen inclination angle is 10°.

[0038] S2. After preliminary screening, a cyclone separator is used for further fine separation. The air velocity at the inlet of the cyclone separator is 20m / s, and the diameter of the cyclone tube is 1m.

[0039] S3. By weight, 22 parts of the finely separated waste asphalt, 100 parts of the modified aggregate prepared in Example 1, 5 parts of silicate cement, 1 part of admixture and 40 parts of water are put into a high-speed shear machine and mixed evenly. The mixture is sheared and developed for recycling. Preferably, the admixture is rubber powder.

[0040] S4. The recycled asphalt mixture is laid on the road surface using a paver and roller to form a micro-surfacing.

[0041] Example 5

[0042] A method for preparing recycled micro-surface treatment of waste asphalt mixture includes the following steps:

[0043] S1. Collect waste asphalt from road milling material and waste asphalt pavement, and use a drum screen to screen the collected waste asphalt mixture to remove large debris. The drum screen rotates at 13 rpm, the screen mesh size is 30 mm, and the drum screen inclination angle is 12.5°.

[0044] S2. After preliminary screening, a cyclone separator is used for further fine separation. The air velocity at the inlet of the cyclone separator is 25m / s, and the diameter of the cyclone tube is 1.5m.

[0045] S3. By weight, 23 parts of the finely separated waste asphalt, 105 parts of the modified aggregate prepared in Example 2, 6 parts of silicate cement, 2 parts of admixture and 50 parts of water are put into a high-speed shear machine and mixed evenly. The mixture is sheared and developed for recycling. Preferably, the admixture is rubber powder.

[0046] S4. The recycled asphalt mixture is laid on the road surface using a paver and roller to form a micro-surfacing.

[0047] Example 6

[0048] A method for preparing recycled micro-surface treatment of waste asphalt mixture includes the following steps:

[0049] S1. Collect waste asphalt from road milling material and waste asphalt pavement, and use a drum screen to screen the collected waste asphalt mixture to remove large debris. The drum screen rotates at 16 rpm, the screen mesh size is 40 mm, and the drum screen inclination angle is 15°.

[0050] S2. After preliminary screening, a cyclone separator is used for further fine separation. The air velocity at the inlet of the cyclone separator is 30m / s, and the diameter of the cyclone tube is 2m.

[0051] S3. By weight, 24 parts of the finely separated waste asphalt, 110 parts of the modified aggregate prepared in Example 3, 7 parts of silicate cement, 3 parts of admixture and 60 parts of water are put into a high-speed shear machine and mixed evenly. The mixture is sheared and developed for recycling. Preferably, the admixture is rubber powder.

[0052] S4. The recycled asphalt mixture is laid on the road surface using a paver and roller to form a micro-surfacing.

[0053] Comparative Example 1

[0054] In this comparative example, commercially available sand and gravel aggregates were used, and the remaining steps were the same as in Example 4, namely:

[0055] A method for preparing recycled micro-surface treatment of waste asphalt mixture includes the following steps:

[0056] S1. Collect waste asphalt from road milling material and waste asphalt pavement, and use a drum screen to screen the collected waste asphalt mixture to remove large debris. The drum screen rotates at 10 rpm, the screen mesh size is 20 mm, and the drum screen inclination angle is 10°.

[0057] S2. After preliminary screening, a cyclone separator is used for further fine separation. The air velocity at the inlet of the cyclone separator is 20m / s, and the diameter of the cyclone tube is 1m.

[0058] S3. By weight, 22 parts of the finely separated waste asphalt, 100 parts of sand and gravel aggregate, 5 parts of silicate cement, 1 part of admixture and 40 parts of water are put into a high-speed shear machine and mixed evenly. The mixture is sheared and developed for recycling. Preferably, the admixture is rubber powder.

[0059] S4. The recycled asphalt mixture is laid on the road surface using a paver and roller to form a micro-surfacing.

[0060] The recycled micro-surfaced samples of waste asphalt mixtures prepared in Examples 4-6 and Comparative Example 1 were subjected to physical property tests, high temperature resistance tests, viscosity tests, and surface texture tests. The performance indicators of each sample were measured, and the results are shown in Table 1.

[0061] Table 1. Test results of Examples 4-6 and Comparative Example 1

[0062]

[0063]

[0064] As shown in Table 1, the average compressive strength of Examples 4-6 was 9.53 MPa, the average flexural strength was 5.36 MPa, and the average tensile strength was 4.72 MPa, significantly higher than that of Comparative Example 1. This indicates that the physical properties were significantly improved through the preparation method of the recycled asphalt mixture micro-surfacing. Regarding the softening point, the average softening point of the examples was 87.3℃, indicating a significant improvement in the high-temperature resistance of the micro-surfacing. The average viscosity of the examples was 0.88 Pa·s, higher than that of Comparative Example 1 (0.65 Pa·s). Adding polystyrene increases the viscosity of the mixture to a certain extent, but does not affect the performance of the micro-surfacing. The average texture depth of the examples was 1.42 mm, indicating a significant improvement in the anti-skid performance of the micro-surfacing.

[0065] Referring to the standard JTG D50-2006 "Specifications for Design of Highway Asphalt Pavement", the recycled micro-surfaced samples of waste asphalt mixtures prepared in Examples 4-6 and Comparative Example 1 were subjected to Marshall stability tests to determine the stability and flow value of each sample. The results are shown in Table 2.

[0066] Table 2. Test results of Examples 4-6 and Comparative Example 1

[0067] Marshall stability (kN) 12.56 12.39 12.89 9.61 Flow value (0.1mm) 2.28 2.23 2.14 3.82

[0068] As shown in Table 2, the average Marshall stability of Examples 4-6 is 12.61 kN, which is higher than that of Comparative Example 1, indicating that the micro-surfaces prepared in these examples have higher structural strength and stability. The average flow value of Examples 4-6 is 2.22 mm, which is lower than that of Comparative Example 1, indicating that the micro-surfaces prepared in these examples have better resistance to deformation.

[0069] In summary, the effectiveness and superiority of the waste asphalt mixture recycling micro-surfacing preparation methods provided in Examples 4-6 contribute to service life and safety.

[0070] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," 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.

[0071] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for preparing recycled micro-surface treatment of waste asphalt mixture, characterized in that, The recycled micro-surfacing material of the waste asphalt mixture comprises the following raw materials by weight: 20-30 parts waste asphalt, 100-120 parts modified aggregate, 5-10 parts silicate cement, 1-5 parts admixture and 40-80 parts water. Modified aggregates are prepared through the following steps: Lignin and polystyrene were added to an N-methylpyrrolidone solution and placed in a polytetrafluoroethylene-lined reactor. Benzoyl peroxide and stannous octoate were added, and the mixture was stirred. The reaction temperature was controlled at 60-70℃ and the reaction was carried out for 2-4 hours. While the mixture was still hot, 60-70 wt% calcium carbonate suspension was added, and the mixture was stirred. The reaction was continued for 3-5 hours. The mixture was cooled to room temperature, filtered, washed, and dried to obtain lignin-polystyrene copolymer supported nano-calcium carbonate. The mass ratio of lignin, polystyrene, benzoyl peroxide, stannous octoate, and calcium carbonate suspension is (10-12):(20-25):(0.5-0.7):(0.01-0.03):(30-32); The preparation method of recycled micro-surface treatment for waste asphalt mixture includes the following steps: S1. Collect waste asphalt from road milling material and waste asphalt pavement, and use a drum screen to screen the collected waste asphalt mixture to remove large debris. S2. After preliminary screening, a cyclone separator is used for further fine separation; S3. The finely separated waste asphalt is mixed with modified aggregate, silicate cement, admixtures and water in a high-speed shear machine, and then sheared and developed for recycling. S4. The recycled asphalt mixture is laid on the road surface using a paver and roller to form a micro-surfacing.

2. The method for preparing a recycled micro-surface treatment of waste asphalt mixture according to claim 1, characterized in that, In step S1, the drum screen rotates at 10-16 rpm, the screen mesh size is 20-40 mm, and the drum screen inclination angle is 10-15°.

3. The method for preparing a recycled micro-surface treatment of waste asphalt mixture according to claim 1, characterized in that, In step S2, the air velocity at the inlet of the cyclone separator is 20-30 m / s, and the diameter of the cyclone tube is 1-2 m.

4. The method for preparing a recycled micro-surface treatment of waste asphalt mixture according to claim 1, characterized in that, The admixtures in step S3 include one or more of gypsum, fly ash, rubber powder, and limestone.

5. The method for preparing a recycled micro-surface treatment of waste asphalt mixture according to claim 1, characterized in that, In step S3, the shearing development is carried out at 160-200℃ and 4000-4500 rpm for 30-60 minutes. After cooling to room temperature, the rotation speed is adjusted to 2000-2500 rpm for 15-30 minutes.

6. The method for preparing a recycled micro-surface treatment of waste asphalt mixture according to claim 1, characterized in that, The recycled micro-surfacing of the waste asphalt mixture comprises the following raw materials by weight: 22-24 parts waste asphalt, 100-110 parts modified aggregate, 5-7 parts silicate cement, 1-3 parts admixture, and 40-60 parts water.

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