Cold-mixed and cold-laid ultrathin overlay asphalt mixture and construction process thereof

Abstract

The invention discloses a cold-mixed and cold-laid ultrathin overlay asphalt mixture which is prepared from the following raw materials in parts by weight: 8-15 parts of rubber powder composite emulsified asphalt; 80 to 90 parts of aggregate; 0.3 to 0.5 part of polymer fiber; 0.5 to 1 part of an interface coupling agent; the invention also provides a construction process of the cold-mixed and cold-laid ultrathin overlay asphalt mixture. The rubber powder composite emulsified asphalt is obtained by emulsifying the composite modified asphalt prepared from the ground rubber powder of the waste tires and the SBS rubber, so that the performance index of the emulsified asphalt is greatly improved, and the bonding performance of a cold-mixed thin-layer asphalt mixture and an original pavement is ensured; in addition, by adding the polymer fibers, the structural strength and the crack resistance of the ultrathin overlay can be remarkably improved. The invention can significantly reduce energy consumption and environmental pollution, and has the advantages of noise reduction, environmental protection, low cost and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of road maintenance, and in particular relates to a cold-mixed and cold-paved ultra-thin overlay asphalt mixture and a construction process thereof. Background Art

[0002] As the overloading phenomenon becomes more and more serious, the various surface functions of the road surface decay quickly, and the decline in anti-skid, noise, flatness and other performances directly affects the safety and comfort of car driving. Therefore, the design of an effective overlay maintenance layer can greatly extend the service life of the built highway and improve driving comfort and safety, which is an important research content of road maintenance.

[0003] Thin-layer overlay is a relatively new technology in the preventive maintenance technology of road surface. This technology can be used on both asphalt and cement roads, and has many advantages such as noise reduction, anti-skid, rapid drainage, convenient construction, low cost, and fast traffic opening. While improving driving comfort and safety, thin-layer overlay can achieve energy conservation and emission reduction, low carbon and environmental protection during construction, and has gradually developed into a very promising form of high-grade highway maintenance.

[0004] At present, the domestic ultra-thin overlay technology mostly adopts hot-mixed and hot-laid high-viscosity modified asphalt technology, which usually has a very high dynamic viscosity (≥200,000 Pa•s, 60℃), and the construction temperature can reach 185℃. A large amount of smoke is released during the construction process. In addition, due to the thickness of 1.0~2.0cm, the temperature drops rapidly after paving, and the construction and workability are poor. In addition, the current cold-mixed and cold-laid thin-layer process is limited by the performance of emulsified asphalt, and its durability cannot meet the use requirements. Summary of the invention

[0005] In order to overcome the technical defects of the prior art, the technical problem to be solved by the present invention is to provide a cold-mixed and cold-laid ultra-thin overlay asphalt mixture. The present invention uses a composite modified asphalt prepared by grinding rubber powder from waste tires and SBS rubber, and obtains rubber powder composite emulsified asphalt after emulsification, which greatly improves the performance indicators of emulsified asphalt and ensures the bonding performance between the cold-mixed thin layer asphalt mixture and the original road surface. In addition, by adding polymer fibers, the crack resistance of the ultra-thin overlay can be significantly improved, thereby ensuring the durability of the road surface.

[0006] The present invention provides a cold-mixed and cold-laid ultra-thin overlay asphalt mixture, which is made from the following raw materials in parts by weight: 8-15 parts of rubber powder composite emulsified asphalt; Aggregate 80~90 parts; 0.3~0.5 parts of polymer fiber; Interface coupling agent 0.5~1 part; The rubber powder composite emulsified asphalt is prepared by composite modification of petroleum asphalt with waste tire rubber powder and thermoplastic rubber SBS, and then emulsified by colloid mill; the softening point of the evaporation residue of the rubber powder composite emulsified asphalt is ≥75°C, the dynamic viscosity at 60°C is ≥100,000 Pa·s, and the tensile strength at 20°C is ≥1.0MPa; the mineral gradation of the aggregate is as shown in the following table: Screen size / mm 9.5 8 4.75 2.36 1.18 0.6 0.3 0.15 0.075 Pass rate / % 100 90~100 28~50 20~32 15~25 12~22 10~18 9~16 8~13

[0007] Preferably, the solid content of the rubber powder composite emulsified asphalt is ≥65%.

[0008] Preferably, the aggregate is one of basalt, diabase and diorite.

[0009] Preferably, the polymer fiber is one or more of polyester fiber, polyacrylonitrile fiber and polyamide fiber.

[0010] Preferably, the interfacial crosslinking agent is fatty alcohol polyoxyethylene ether.

[0011] Preferably, the grinding disc gap of the colloid mill is 1.5-3 mm.

[0012] The present invention also provides a construction process for cold-mixed and cold-laid ultra-thin overlay asphalt mixture, the specific steps of which are: A. Cleaning or milling of the original road surface; B. Add rubber powder composite emulsified asphalt, aggregate, polymer fiber and interface coupling agent in the mixing box of the slurry sealer in parts by weight, and stir for 60 to 90 seconds to obtain a direct-injection modified ultra-thin wearing layer asphalt mixture; C. Spread the above asphalt mixture by a slurry sealer; D. Use a rubber-wheel roller to roll the road 3 to 4 times and then open it to traffic after 30 minutes.

[0013] Preferably, a vibrating scraper is provided at the rear of the slurry sealing vehicle.

[0014] Preferably, the stirring speed of the stirring box in step B is 100-150 r / min.

[0015] Compared with the prior art, the present invention has the following advantages and effects: The present invention utilizes rubber powder and SBS after grinding waste tires to compositely modify petroleum asphalt, and then obtains rubber powder composite emulsified asphalt through colloid mill emulsification. In the present invention, the gap between the grinding discs of the colloid mill is higher than to ensure that the rubber powder and SBS composite emulsified asphalt can not only ensure storage stability, but also ensure the production continuity of the high-viscosity rubber powder composite emulsified asphalt during the colloid mill emulsification process. Compared with conventional modified emulsified asphalt, the high-temperature performance, viscoelastic properties and bonding properties of the rubber powder composite emulsified asphalt are significantly improved; in addition, through the interface effect of the interface coupling agent, on the one hand, the bonding force between the asphalt mixture and the original pavement is promoted; on the other hand, the adhesion between the emulsified asphalt and the aggregate is enhanced; finally, polymer fibers are added to further improve the structural strength and crack resistance of the thin layer overlay. The cold-mixed cold-laid ultra-thin overlay asphalt mixture provided by the present invention solves the problems of poor construction and workability of hot ultra-thin overlay asphalt in the prior art, high construction temperature, and serious on-site pollution, improves the material durability of the cold-mixed asphalt mixture, and through the recycling of waste rubber powder solid waste, has the advantages of low cost, reduced road noise, convenient construction, and low-carbon environmental protection. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is further elaborated and illustrated in conjunction with specific embodiments below.

[0017] The present invention provides a cold-mixed cold-laid ultra-thin overlay asphalt mixture, which is prepared from the following raw materials in parts by weight: 8-15 parts of rubber powder composite emulsified asphalt; 80-90 parts of aggregate; 0.3-0.5 parts of polymer fiber; 0.5-1 parts of interface coupling agent; The rubber powder composite emulsified asphalt is prepared by composite modification of petroleum asphalt with waste tire rubber powder and thermoplastic rubber SBS, and then emulsified by colloid mill; the softening point of the evaporation residue of the rubber powder composite emulsified asphalt is ≥75°C, the dynamic viscosity at 60°C is ≥100,000 Pa·s, and the tensile strength at 20°C is ≥1.0MPa; the mineral gradation of the aggregate is as shown in the following table: Table 1 Mineral gradation Screen size / mm 9.5 8 4.75 2.36 1.18 0.6 0.3 0.15 0.075 Pass rate / % 100 90~100 28~50 20~32 15~25 12~22 10~18 9~16 8~13

[0018] Embodiment 1: Cold-mixed and cold-laid ultra-thin overlay asphalt mixture is made of the following raw materials in parts by weight: 8 parts of rubber powder composite emulsified asphalt; 90 parts of aggregate; 0.3 parts of polyester fiber; 0.8 parts of fatty alcohol polyoxyethylene ether; the softening point of the evaporation residue of the rubber powder composite emulsified asphalt is 78°C, the dynamic viscosity at 60°C is 120,000 Pa·s, and the tensile strength at 20°C is ≥1.15MPa; the aggregate meets the grading range of Table 1.

[0019] The performance indicators of cold-mixed and cold-laid ultra-thin overlay asphalt mixture after curing and molding are shown in Table 2.

[0020] Embodiment 2: Cold-mixed and cold-laid ultra-thin overlay asphalt mixture is made of the following raw materials in parts by weight: 12 parts of rubber powder composite emulsified asphalt; 85 parts of aggregate; 0.5 parts of polyamide fiber; 0.5 parts of fatty alcohol polyoxyethylene ether; the softening point of the evaporation residue of the rubber powder composite emulsified asphalt is 76°C, the dynamic viscosity at 60°C is 113,000 Pa·s, and the tensile strength at 20°C is ≥1.07MPa; the aggregate meets the grading range of Table 1.

[0021] The performance indicators of cold-mixed and cold-laid ultra-thin overlay asphalt mixture after curing and molding are shown in Table 2.

[0022] Embodiment 3: Cold-mixed and cold-laid ultra-thin overlay asphalt mixture is made of the following raw materials in parts by weight: 10 parts of rubber powder composite emulsified asphalt; 90 parts of aggregate; 0.4 parts of polyacrylonitrile fiber; 1 part of fatty alcohol polyoxyethylene ether; the softening point of the evaporation residue of the rubber powder composite emulsified asphalt is 78°C, the dynamic viscosity at 60°C is 132,000 Pa·s, and the tensile strength at 20°C is ≥1.28MPa; the aggregate meets the grading range of Table 1.

[0023] The performance indicators of cold-mixed and cold-laid ultra-thin overlay asphalt mixture after curing and molding are shown in Table 2.

[0024] Embodiment 4: Cold-mixed and cold-laid ultra-thin overlay asphalt mixture is made of the following raw materials in parts by weight: 15 parts of rubber powder composite emulsified asphalt; 90 parts of aggregate; 0.4 parts of polyacrylonitrile fiber; 0.7 parts of fatty alcohol polyoxyethylene ether; the softening point of the evaporation residue of the rubber powder composite emulsified asphalt is 78°C, the dynamic viscosity at 60°C is 126,000 Pa·s, and the tensile strength at 20°C is ≥1.28MPa; the aggregate meets the grading range of Table 1.

[0025] The performance indicators of cold-mixed and cold-laid ultra-thin overlay asphalt mixture after curing and molding are shown in Table 2.

[0026] The construction process of the cold-mixed and cold-laid ultra-thin overlay asphalt mixture of the present invention comprises the following specific steps: A. Cleaning or milling of the original road surface; B. Add rubber powder composite emulsified asphalt, aggregate, polymer fiber and interface coupling agent in the mixing box of the slurry sealer in parts by weight, and stir for 60 to 90 seconds to obtain a direct-injection modified ultra-thin wearing layer asphalt mixture; C. Spread the above asphalt mixture by a slurry sealer; D. Use a rubber-wheel roller to roll the road 3 to 4 times and then open it to traffic after 30 minutes.

[0027] The performance indicators of the ultra-thin wearing layer asphalt mixtures of Examples 1 to 4 are shown in Table 2 below.

[0028] Table 2 Performance indexes of asphalt mixture It can be seen from Table 2 above that the stability in Examples 1 to 4, the cold-mixed and cold-paved asphalt mixtures after curing have excellent anti-scattering and anti-reflective cracking capabilities. In addition, the friction coefficient of the asphalt mixture meets the requirements of the specification and has a good noise reduction effect.

[0029] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the specification of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A cold-mixed and cold-laid ultra-thin overlay asphalt mixture, characterized in that: Made from the following raw materials in parts by weight: 8-15 parts of rubber powder composite emulsified asphalt; Aggregate 80~90 parts; Polymer fiber 0.3~0.5 parts; Interface coupling agent 0.5~1 part; The rubber powder composite emulsified asphalt is prepared by composite modification of petroleum asphalt with waste tire rubber powder and thermoplastic rubber SBS, and then emulsified by colloid mill; the softening point of the evaporation residue of the rubber powder composite emulsified asphalt is ≥75°C, the dynamic viscosity at 60°C is ≥100,000 Pa·s, and the tensile strength at 20°C is ≥1.0MPa; the mineral gradation of the aggregate is as shown in the following table: 。 2. The cold-mixed and cold-laid ultra-thin overlay asphalt mixture according to claim 1 is characterized in that: The solid content of the rubber powder composite emulsified asphalt is ≥65%.

3. The cold-mixed and cold-laid ultra-thin overlay asphalt mixture according to claim 1, characterized in that: The aggregate is one of basalt, diabase and diorite.

4. The cold-mixed and cold-laid ultra-thin overlay asphalt mixture according to claim 1, characterized in that: The polymer fiber is one or more of polyester fiber, polyacrylonitrile fiber and polyamide fiber.

5. The cold-mixed and cold-laid ultra-thin overlay asphalt mixture according to claim 1, characterized in that: The interfacial crosslinking agent is fatty alcohol polyoxyethylene ether.

6. The cold-mixed and cold-laid ultra-thin overlay asphalt mixture according to claim 1, characterized in that: The grinding disc gap of the colloid mill is 1.5-3 mm.

7. The construction process of cold-mixed and cold-laid ultra-thin asphalt mixture according to any one of claims 1 to 6, characterized in that: The specific steps are: Sweeping or milling of original road surface; Add rubber powder composite emulsified asphalt, aggregate, polymer fiber and interface coupling agent in the mixing box of the slurry sealer in parts by weight, and stir for 60 to 90 seconds to obtain a direct-injection modified ultra-thin wearing layer asphalt mixture; Spreading the above asphalt mixture by a slurry sealing vehicle; Use a rubber-wheel roller to roll the road 3 to 4 times and then open it to traffic after 30 minutes.

8. The construction process of cold-mixed and cold-laid ultra-thin asphalt mixture according to claim 7 is characterized in that: A vibrating scraper is arranged at the rear of the slurry sealing vehicle.

9. The construction process of cold-mixed and cold-laid ultra-thin overlay asphalt mixture according to claim 7 is characterized in that: The stirring speed of the stirring box in step B is 100-150 r / min.

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