Economical and environment-friendly soft pavement for urban slow system and preparation and construction method thereof

Abstract

The application discloses an economic and environment-friendly soft pavement for urban slow system and a preparation and construction method thereof, wherein components and mass percentages of raw materials are as follows: road petroleum asphalt 6-9%, tire rubber particles 10-20%, VE high-elastic anti-cracking particles 0.4-1%, gravel 60-75%, and mineral powder 5-10%. The economic and environment-friendly soft pavement for urban slow system has reasonable formula design, is paved on a slow walking path in a park, has soft pavement and good rebound performance, effectively reduces the impact force between the soles of human bodies and the ground during movement, improves the comfort degree of tourists during movement and fitness, and can also be paved on a park square, a walking path, a non-motor vehicle lane and the like, and is suitable for a wide range of applications.

Description

Technical Field

[0001] This invention belongs to the field of pavement technology, specifically relating to an economical and environmentally friendly soft pavement for urban slow-traffic systems, and its preparation and construction methods. Background Technology

[0002] Urban slow-traffic systems are slow-traffic systems that make walking, cycling, and other slow-moving modes of transportation the main modes of urban transportation, effectively solving problems such as conflicts between fast and slow traffic and difficulties for slow-traffic users.

[0003] The greenway surfaces of urban slow-traffic systems, especially park trails, mostly use economical and environmentally friendly soft pavement. As living standards improve, more and more people are exercising and want softer and more comfortable surfaces. However, many places have built a lot of colored plastic trails for this purpose, but plastic running tracks have low strength, poor durability, and high cost, making it difficult to promote them on a large scale in park trails.

[0004] Currently, there are records of using tire rubber for road paving both domestically and internationally, but this generally involves using finely ground tire rubber powder with a particle size of less than 1mm. In some cases, larger-diameter rubber particles are used, primarily to utilize the stress concentration effect of the rubber particles in the mixture to accelerate the melting of ice on the road surface. Furthermore, the addition amount is generally no more than 6% of the asphalt mixture, resulting in poor rebound performance. Ordinary asphalt has poor adhesion, and when the rubber particle content is high, the asphalt mixture performance is very poor, rendering it unusable. Modified asphalt has good adhesion, but the construction temperature is high, and the rubber particles release harmful gases at high temperatures, polluting the environment and posing a hazard to workers. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a technical solution with a reasonable formula that enables low-temperature construction and improves the adhesion between stone and rubber particles. This solution allows for increasing the amount of tire rubber particles added to the mixture to 10-20%, significantly enhancing the road surface's resilience. The resulting road surface is soft, has good resilience, and reduces the impact force between the feet and the ground during human movement, thereby meeting the requirements of urban slow-traffic systems.

[0006] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0007] An economical and environmentally friendly soft pavement for urban slow-traffic systems comprises the following components and their mass percentages: 6-9% road petroleum asphalt, 10-20% tire rubber granules, 0.4-1% VE high-elasticity crack-resistant particles, 60-75% crushed stone, and 5-10% mineral powder.

[0008] In a preferred embodiment of the present invention, the road petroleum asphalt is No. 90 heavy-duty road petroleum asphalt. The tire rubber granules are rubber granules with a particle size of 2-4 mm obtained by crushing and grinding waste automobile tires. The road petroleum asphalt is heavy-duty road petroleum asphalt, preferably No. 90 heavy-duty road petroleum asphalt. The crushed stone is basalt or limestone crushed stone. The mineral powder is obtained by grinding limestone to a particle size of less than 0.6 mm.

[0009] In a preferred embodiment of the present invention, the VE high-elasticity crack-resistant particles are thermoplastic elastic materials with high oil filling rate, mainly composed of linear triblock copolymers, which can significantly improve the bonding performance between asphalt and crushed stone, especially under conditions of reduced mixing temperature. The raw material components and their weight ratios of the VE high-elasticity crack-resistant particles are as follows: 60-80 parts of linear triblock copolymer (SEBS), 30-50 parts of white oil, 1-4 parts of polyethylene wax, and 3-8 parts of resin. The white oil is preferably 15# white oil, and the resin is preferably C5 resin.

[0010] A method for preparing an economical and environmentally friendly soft pavement for urban slow-traffic systems includes the following steps:

[0011] (1) Prepare the above-mentioned raw materials for economical and environmentally friendly soft pavement used in urban slow traffic systems;

[0012] (2) Heat the crushed stone to 160-170℃ and put it into the asphalt mixture mixing plant;

[0013] (3) Add the VE high-elasticity crack-resistant particles into the asphalt mixture mixer and stir for 5 to 30 seconds;

[0014] (4) Add the tire rubber granules at room temperature into the asphalt mixture mixer and stir for 5 to 30 seconds; since the tire rubber granules cannot be heated by open flame, it is preferred to add them at room temperature.

[0015] (5) Heat the road petroleum asphalt and mineral powder to 140-150°C, put them into an asphalt mixture mixer and stir for 20-60 seconds to obtain an economical and environmentally friendly soft pavement for urban slow traffic systems. The temperature of the asphalt mixture at the discharge point is 125-145°C.

[0016] A construction method for an economical and environmentally friendly soft pavement for urban slow-traffic systems includes the following steps:

[0017] (S1) The asphalt mixture obtained by the above-mentioned method for preparing economical and environmentally friendly soft pavement for urban slow traffic systems is transported to the construction site and spread on the base layer using an ordinary asphalt concrete paver to form a paving layer. The treatment requirements for the underlying layer before paving are the same as conventional requirements, and emulsified asphalt also needs to be sprayed. The temperature during paving is preferably controlled at 110-120℃; if the temperature of the asphalt mixture is too high, the asphalt mixture will be difficult to compact.

[0018] (S2) The pavement layer is compacted by a road roller, preferably a steel wheel road roller with a capacity of less than 13 tons. Vibration is not allowed during the compaction process, otherwise it will cause the road surface to shift and make compaction difficult.

[0019] (S3) Repeat step (S2) at least 2 times, preferably 4 to 6 times, to obtain an economical and environmentally friendly soft pavement for urban slow traffic systems. Spray the economical and environmentally friendly soft pavement for urban slow traffic systems with the required color paint to enhance the aesthetic effect.

[0020] The beneficial effects of this invention are as follows: This invention provides a rationally designed formula for an economical and environmentally friendly soft pavement for urban slow-traffic systems. When laid on park pedestrian paths, it can improve the comfort of visitors exercising. This economical and environmentally friendly soft pavement can also be laid in park squares, walkways, non-motorized vehicle lanes, and other areas. The pavement structure consists of a graded crushed stone base or a cement-stabilized crushed stone base, on which an economical and environmentally friendly soft pavement of approximately 4cm thickness is directly laid. Alternatively, a 3-4cm thick economical and environmentally friendly soft pavement can be directly laid on existing slow-traffic roads. In summary, this invention has the following advantages:

[0021] 1. The soft road surface is made with a high content of tire rubber particles, which has good resilience and reduces the impact force between the soles of the feet and the ground when the human body moves.

[0022] 2. Green and environmentally friendly. It utilizes a large amount of waste tire rubber granules, achieving resource utilization of waste tires. However, generally, adding tire rubber granules to asphalt mixtures requires a high heating temperature to ensure the mixture's bonding performance. When the mixture temperature exceeds 150℃, the tire rubber granules release a large amount of unpleasant, pungent odor. This invention uses VE high-elasticity crack-resistant particles, which have a low melting point and can rapidly melt at around 120℃, becoming a liquid. This liquid acts as a lubricant in the mixture, greatly improving its workability and achieving the purpose of cooling and mixing. Due to the addition of a large amount of tire rubber granules, it also has excellent noise reduction effects.

[0023] 3. Excellent durability. The added VE high-elasticity crack-resistant particles not only improve the workability of the mixture but also have excellent bonding properties. When the mixture temperature drops below 80 degrees Celsius, its superior bonding performance becomes apparent, enhancing the adhesion between aggregate and asphalt, between aggregate and tire rubber particles, and between tire rubber particles and asphalt, preventing particle scattering, especially during the rainy season. Simultaneously, this invention significantly improves the crack resistance of soft pavements, enhancing road fatigue durability.

[0024] 4. Reduced Costs. Currently, taking a 1.5cm thick synthetic running track as an example, the cost is generally between 200 and 300 yuan per square meter. The thicker the track, the higher the cost. However, the economical and environmentally friendly soft pavement constructed using this invention is only 3-4cm thick, with material costs of only 60-80 yuan (calculated based on market prices in January 2022). The construction process is simple, fully mechanized, and uses ordinary pavers and rollers. The cost depends only on the workload and shift rates. Preliminary estimates suggest that the final cost is only 50-60% of that of a synthetic running track, indicating a broad market prospect and facilitating widespread application.

[0025] The present invention will be further described below with reference to the embodiments. Detailed Implementation

[0026] The technical specifications of the raw materials prepared prior to implementation are shown in the table below. However, this does not constitute any limitation on the present invention. Those skilled in the art can also make changes and modifications using other materials with similar properties.

[0027] The road petroleum asphalt is selected as the base asphalt, and the road petroleum asphalt is preferably No. 90 heavy-duty road petroleum asphalt. Its technical indicators are shown in Table 1 below:

[0028] Table 1

[0029]

[0030] The tire rubber granules are rubber granules with a particle size of 2-4 mm obtained by crushing and grinding waste automobile tires. The waste automobile tires are preferably waste truck tires, and their physicochemical properties are shown in Table 2 below.

[0031] Table 2

[0032]

[0033] The VE high-elasticity crack-resistant particles are thermoplastic elastic materials with high oil filling rate, mainly composed of linear triblock copolymers.

[0034] The raw materials and their weight ratios for the VE high-elasticity crack-resistant particles are as follows: 60-80 parts linear triblock copolymer (SEBS), 30-50 parts white oil, 1-4 parts polyethylene wax, and 3-8 parts resin. The white oil is preferably 15# white oil, and the resin is preferably C5 resin.

[0035] The VE high-elasticity crack-resistant particles can significantly improve the bonding performance between asphalt and crushed stone, especially under conditions of reduced mixing temperature.

[0036] The technical specifications of the VE high-elasticity crack-resistant particles are shown in Table 3 below.

[0037] Table 3

[0038] project unit Technical Requirements Experimental methods Appearance - Granular, uniform, and plump - Single particle mass g ≤0.015 - density g / cm3 0.85～0.99 GT / T1033 Melt flow index (135℃, 2.16kg) g / 10min ≥3 GT / T3682 Ash ％ ≤1 T0614

[0039] The crushed stone is preferably basalt or limestone crushed stone. Its technical specifications are shown in Table 4 below:

[0040] Table 4

[0041] Testing items unit Technical Requirements Test methods Stone crushing value ％ ≤20 T 0316 Polishing value - ≥42 T 0321 Los Angeles wear loss ％ ≤28 T 0317 Apparent relative density - ≥2.60 T 0304 Water absorption rate ％ ≤2.0 T 0304 sturdiness ％ ≤12 T 0314 Needle-like and flaky content (in the mixture) ％ ≤12 T 0312 Water washing method <0.075mm particle content ％ ≤0.8 T 0310 Soft stone content ％ ≤3 T 0320

[0042] The mineral powder is obtained by grinding limestone, and its technical specifications are shown in Table 5 below:

[0043] Table 5

[0044]

[0045] The aggregate mixture consisting of crushed stone and mineral powder meets the gradation requirements in Table 6.

[0046] Table 6

[0047]

[0048]

[0049] Example 1: This example provides an economical and environmentally friendly soft pavement for urban slow traffic systems, as well as its preparation and construction method. The components and their mass percentages are as follows: road petroleum asphalt 6%, tire rubber granules 14%, VE high-elasticity crack-resistant particles 0.5%, crushed stone 71.5%, and mineral powder 8%.

[0050] The raw materials and their weight ratios for the VE high-elasticity crack-resistant particles are as follows: 60 parts linear triblock copolymer (SEBS), 40 parts white oil, 3 parts polyethylene wax, and 5 parts resin.

[0051] During preparation, crushed stone is heated to 160-170°C and added to an asphalt mixture mixing plant; the VE high-elasticity crack-resistant particles are added to the asphalt mixture mixing plant and stirred for 5-30 seconds; the tire rubber granules at room temperature are added to the asphalt mixture mixing plant and stirred for 5-30 seconds; road petroleum asphalt and mineral powder are heated to 140-150°C and added to the asphalt mixture mixing plant and stirred for 20-60 seconds to obtain an economical and environmentally friendly soft pavement for urban slow-traffic systems. The preferred temperature of the asphalt mixture at discharge is 125-145°C.

[0052] During construction, the asphalt mixture is transported to the construction site and spread on the base layer using a regular asphalt concrete paver to form a paving layer. The treatment requirements for the underlying layer before paving are the same as conventional requirements, and emulsified asphalt also needs to be sprayed. The temperature during paving is preferably controlled at 110-120℃; if the temperature of the asphalt mixture is too high, it will be difficult to compact. It is preferable to use a steel wheel roller of less than 13 tons to compact the paving layer. Vibration is not used during the compaction process. Compaction is carried out 4-6 times to obtain an economical and environmentally friendly soft pavement for urban slow traffic systems. Finally, the desired color of paint is sprayed on for an aesthetically pleasing appearance.

[0053] Example 2 provides an economical and environmentally friendly soft pavement for urban slow-traffic systems, along with its preparation and construction methods. It is essentially the same as Example 1, except for the different proportions of the raw materials in the economical and environmentally friendly soft pavement for urban slow-traffic systems and the VE high-elasticity crack-resistant particles. The component proportions of the economical and environmentally friendly soft pavement for urban slow-traffic systems are: 8% road petroleum asphalt, 10% tire rubber granules, 0.6% VE high-elasticity crack-resistant particles, 75% crushed stone, and 6.4% mineral powder. The components and their weight ratios of the VE high-elasticity crack-resistant particles are: 80 parts linear triblock copolymer (SEBS), 50 parts white oil, 4 parts polyethylene wax, and 8 parts resin.

[0054] Example 3 provides an economical and environmentally friendly soft pavement for urban slow-traffic systems, along with its preparation and construction methods. It is essentially the same as Example 1, except that the proportions of the raw materials for the economical and environmentally friendly soft pavement for urban slow-traffic systems and the VE high-elasticity crack-resistant particles are different. The proportions of the economical and environmentally friendly soft pavement for urban slow-traffic systems are: 9% road petroleum asphalt, 20% tire rubber granules, 0.4% VE high-elasticity crack-resistant particles, 60.6% crushed stone, and 10% mineral powder. The components and their weight ratios of the VE high-elasticity crack-resistant particles are: 70 parts linear triblock copolymer (SEBS), 35 parts white oil, 1 part polyethylene wax, and 1 part resin.

[0055] Example 4 provides an economical and environmentally friendly soft pavement for urban slow-traffic systems, along with its preparation and construction methods. It is essentially the same as Example 1, except for the different proportions of the raw materials in the economical and environmentally friendly soft pavement for urban slow-traffic systems and the VE high-elasticity crack-resistant particles. The component proportions for the economical and environmentally friendly soft pavement for urban slow-traffic systems are: 9% road petroleum asphalt, 20% tire rubber granules, 1% VE high-elasticity crack-resistant particles, 60% crushed stone, and 10% mineral powder. The components and their weight ratios of the VE high-elasticity crack-resistant particles are: 72 parts linear triblock copolymer (SEBS), 30 parts white oil, 2 parts polyethylene wax, and 3 parts resin.

[0056] Example 5 provides an economical and environmentally friendly soft pavement for urban slow-traffic systems, along with its preparation and construction method. 7560g of crushed stone is heated to 160-170℃ and added to an asphalt mixing plant. 40g of high-elasticity, crack-resistant particles are added and stirred for 10-15 seconds. 1000g of tire rubber granules are then added. Subsequently, 600g of base asphalt at 140-150℃ and 800g of mineral powder at room temperature are added to the mixing plant and stirred for 35-45 seconds. The discharge temperature is 125-135℃, yielding a soft pavement-specific asphalt mixture. The asphalt mixture is then subjected to mixture index testing, and the soft pavement mixture is compacted using a test mold of an asphalt mixture rutting tester.

[0057] Example 6 provides an economical and environmentally friendly soft pavement for urban slow-traffic systems, along with its preparation and construction method. 6790g of crushed stone is heated to 160-170℃ and added to an asphalt mixing plant. 50g of high-elasticity, crack-resistant particles are added and stirred for 10-15 seconds. 1500g of tire rubber granules are then added. Subsequently, 760g of base asphalt at 140-150℃ and 900g of mineral powder at room temperature are added to the mixing plant and stirred for 35-45 seconds. The discharge temperature is 125-135℃, yielding a soft pavement-specific asphalt mixture. The asphalt mixture is then subjected to mixture index testing, and the soft pavement mixture is compacted using a test mold of an asphalt mixture rutting tester.

[0058] Example 7 provides an economical and environmentally friendly soft pavement for urban slow-traffic systems, along with its preparation and construction method. 6040g of crushed stone is heated to 160-170℃ and added to an asphalt mixing plant. 60g of high-elasticity, crack-resistant particles are added and stirred for 10-15 seconds. 2000g of tire rubber granules are then added. Subsequently, 900g of base asphalt at 140-150℃ and 1000g of mineral powder at room temperature are added to the mixing plant and stirred for 35-45 seconds. The discharge temperature is 125-135℃, yielding a soft pavement-specific asphalt mixture. The asphalt mixture is then subjected to mixture index testing, and the soft pavement mixture is compacted using a test mold of an asphalt mixture rutting tester.

[0059] Currently, there is a lack of simple and reliable methods for evaluating the flexibility of sports surfaces such as synthetic running tracks. This invention uses a lightweight falling weight impact tester to evaluate the flexibility of paved surfaces and proposes an index for absorbing impact energy. The falling weight impact tester consists of a testing section and a data output section, connected by a data cable. During the test, a weight falls freely from a fixed height, impacting the sensor at the bottom. The sensor measures the maximum impact force and surface deformation, and the resilience modulus of the surface can be calculated. However, for the flexible surface of this invention, the ability to absorb impact energy is more important. Therefore, we directly multiply the maximum impact force by the surface deformation to obtain a concept of impact energy absorption. Although this concept is not rigorous from a mechanical perspective, it can objectively evaluate the flexibility of the surface from a practical perspective, and the calculation is simple. The falling weight impact tester was used to evaluate the flexibility of the finished products prepared in Examples 5-7, and the test results are shown in Table 7.

[0060] Table 7

[0061] conventional asphalt pavement badminton court Example 5 Example 6 Example 7 Scattered loss, % - - 15 18 23 Residual freeze-thaw splitting strength ratio, % - - 82 71 65 Elastic modulus, MPa 2353 471 647 522 381 Absorbing impact energy, J 0.22 2.62 2.05 2.43 4.51

[0062] The results show that flexible asphalt mixtures exhibit slightly lower losses from dispersion and water stability compared to conventional asphalt mixtures. However, considering the significantly lower road load compared to conventional pavements, this flexible pavement fully meets the needs of urban slow-traffic systems such as fitness trails and non-motorized vehicle lanes. Furthermore, this flexible pavement has a significantly lower modulus of elasticity than conventional asphalt pavements, resulting in a substantial increase in the absorption of impact energy, even exceeding that of a badminton court. This can significantly improve the comfort of residents' daily fitness activities and demonstrates its excellent application value.

[0063] Based on the disclosure and teachings of the above specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention. As described in the above embodiments of the present invention, other pavements and their preparation and construction methods obtained using the same or similar methods and components are all within the protection scope of the present invention.

Claims

1. An economical and environmentally friendly soft pavement for urban slow traffic system, characterized in that, The raw materials and their mass percentages are as follows: Road petroleum asphalt 6-9%, Tire rubber particles 10-20%, VE high-elastic anti-cracking particles 0.4-1%, Gravel 60-75%, Mineral powder 5-10%; The road petroleum asphalt is heavy-interchange road petroleum asphalt; The tire rubber particles are rubber particles with a particle size of 2-4 mm obtained by crushing and grinding waste automobile tires; The raw materials of the VE high-elastic anti-cracking particles and their weight ratio are as follows: linear triblock copolymer SEBS 60-80 parts, white oil 30-50 parts, polyethylene wax 1-4 parts, and resin 3-8 parts; It comprises the following steps: (1) preparing the raw materials of the economic and environmentally friendly soft pavement for urban slow traffic system; (2) heating the gravel to 160-170℃ and feeding into the asphalt mixture mixing machine; (3) feeding the VE high-elastic anti-cracking particles into the asphalt mixture mixing machine for stirring; (4) feeding the tire rubber particles at room temperature into the asphalt mixture mixing machine for stirring; (5) heating the road petroleum asphalt and mineral powder to 140-150℃ and feeding into the asphalt mixture mixing machine for stirring to obtain the asphalt mixture of the economic and environmentally friendly soft pavement for urban slow traffic system, and the temperature of the asphalt mixture when discharged is 125-145℃.

2. The economical and environment-friendly soft pavement for urban slow traffic system according to claim 1, characterized in that, The gravel is basalt or limestone gravel.

3. The economical and environment-friendly soft pavement for urban slow traffic system according to claim 1, characterized in that, The mineral powder is obtained by grinding limestone to a particle size of less than 0.6 mm.

4. The economical and environment-friendly soft pavement for urban slow traffic system according to claim 1, characterized in that, The white oil is 15# white oil, and the resin is C5 resin.

5. An economical and environmentally friendly soft pavement construction method for urban slow traffic systems, characterized by, It comprises the following steps: (S1) transporting the asphalt mixture obtained in the preparation method of the economic and environmentally friendly soft pavement for urban slow traffic system to the construction site and paving on the base layer to form a paving layer, and the temperature during paving is controlled at 110-120℃; (S2) using a road roller to roll the paving layer, and not vibrating during the rolling process; (S3) repeating step (S2) at least 2 times to obtain the economic and environmentally friendly soft pavement for urban slow traffic system.

6. The construction method according to claim 5, characterized in that, Spraying the economic and environmentally friendly soft pavement for urban slow traffic system with the color paint required.

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