Asphalt overlay paving process

Abstract

A paving process for an asphalt overlay is characterized by comprising the following steps: step 1, forming a plurality of parallel grooves on the surface of a road base; step 2, filling the grooves with foamed asphalt; step 3, laying an intermediate reinforcing asphalt layer; and step 4, laying a surface strengthening layer.

Description

Technical Field

[0001] The invention belongs to the field of asphalt pavement, and in particular relates to a paving process for an asphalt overlay. Background Art

[0002] With the development of road construction, some older asphalt roads have developed various defects on their surfaces, which are detrimental to traffic safety. In the existing technology, asphalt overlay repair technology has emerged, which mainly removes the original asphalt surface and re-paves a thinner asphalt overlay to obtain a road surface with better performance.

[0003] However, the original road base often contains areas of stress concentration, such as fractures or protrusions. These stress concentrations can cause new stress damage to the newly laid asphalt overlay. Conventional technology typically employs methods such as placing a fabric mesh or bonding layer at the interface between the road base and the asphalt overlay to mitigate these stress concentrations. However, this approach increases construction costs, and the fabric mesh can easily become a starting point for asphalt delamination. Furthermore, the surface strength of the asphalt overlay needs to be further improved.

[0004] Therefore, it is necessary to provide an asphalt overlay paving process that can not only alleviate the stress damage at the stress concentration point of the original road base and improve the overall strength of the asphalt, but also improve the strength of the asphalt overlay surface. Summary of the Invention

[0005] The technical problem to be solved by this invention is that the original road base has some stress concentration areas, such as fractures or protrusions in the road base. These stress concentration areas can cause new stress damage to the newly laid asphalt overlay. Conventional technology typically uses a fabric mesh or bonding layer at the junction of the road base and the asphalt overlay to mitigate the damage to the asphalt overlay caused by these stress concentration areas. However, this method increases construction costs, and the fabric mesh can easily become the starting point for delamination between asphalt layers. Furthermore, the surface strength of the asphalt overlay needs to be further improved.

[0006] The technical solution adopted by the present invention to solve the technical problem is:

[0007] A paving process for an asphalt overlay comprises the following steps:

[0008] Step 1: After removing the existing asphalt surface layer on the road, clean the road base surface and use road trenching equipment to form multiple parallel grooves on the road base surface. The groove depth is 5-8 cm and the maximum width is 5-10 cm. The cross-section of the groove in the extension direction is triangular or inverted trapezoidal. For every 1 m width of the road base surface, 4-8 grooves are set. The grooves are continuous or discontinuous in their extension direction.

[0009] Step 2: Fill the groove with foamed asphalt

[0010] Before construction, the asphalt material is heated to a molten state of 180 degrees, and carbon fiber and SBS resin are added and stirred evenly. The mass ratio of asphalt material to carbon fiber is 100:15, and the mass ratio of asphalt material to SBS resin is 100:20. The stirred asphalt mixture is put into the foaming equipment and the asphalt mixture is contacted with atomized water and stirred for 5 hours. The mass ratio of asphalt mixture to atomized water is 100:7 to obtain foamed asphalt.

[0011] Spread the foamed asphalt on the surface of the road base with grooves, with a spreading amount of 1000-1200g / m 2 After paving is completed, the scraper is pulled by traction equipment to scrape off the excess foamed asphalt outside the groove above the road base surface;

[0012] Step 3: Lay out the middle reinforced asphalt layer

[0013] Laying a 2-4 cm thick asphalt mixture on the surface of the road base filled with foamed asphalt in the groove; the asphalt mixture at least includes: asphalt base material, SBS resin, sulfur powder and quartz sand powder;

[0014] Step 4: Lay out the surface strengthening layer

[0015] After the intermediate reinforced asphalt layer has cooled and solidified for 36 hours, a surface strengthening layer is laid on the surface of the intermediate reinforced asphalt layer. The surface strengthening layer is composed of a surface strengthening mixture. The surface strengthening mixture includes the following components in parts by mass:

[0016] 100 parts of solvent oil, 3-8 parts of aluminum oxide particles, 35-50 parts of SBS resin, 40-45 parts of high molecular weight polyethylene, 3-6 parts of tripropylene cyanurate, and 2 parts of benzophenone;

[0017] Use a spray truck to spray the surface strengthening mixture at a spraying rate of 600-750g / m 2 After spraying, dry it and expose it to sunlight for more than 10 hours to complete the paving.

[0018] Specifically, the asphalt mixture of the middle reinforced asphalt layer includes the following components in parts by mass: 100 parts of base asphalt, 15-18 parts of SBS resin, 20-25 parts of solvent oil, 5-10 parts of quartz sand powder, and 30-33 parts of modified particles; the single particle structure of the modified particles includes: hollow thermosetting polyimide tubular particles, a mixture of paraffin and sulfur particles filling the hollow part inside the tubular particles, and an external paraffin spray layer covering the tubular particles. The average length of the modified particles is between 15-20 mm, the average outer diameter is between 10 mm and 12 mm, and the average inner diameter of the tubular particles is 5 mm.

[0019] The present invention has the following beneficial effects:

[0020] 1. Since foamed asphalt has relatively high elasticity, the road base is grooved and filled with foamed asphalt. On the one hand, the grooves can release the stress of the road base. On the other hand, when the foamed asphalt is filled in the grooves, it can release part of the stress through elastic deformation without transferring the stress to the middle layer.

[0021] 2. The reinforcing particles in the asphalt mixture not only enhance the mechanical properties of the asphalt matrix, but the paraffin solution coated on their surface acts as a strong oil-phase surface fusing agent, improving the wettability of the tubular particles with the asphalt. Furthermore, the paraffin wax and sulfur particles within the tubular particles melt during the warm mixing process, flowing out of the tubular particles and mixing with the asphalt matrix. The sulfur particles act as a bridging agent for the polymer components, causing cross-linking reactions and improving the compatibility between the polymer and asphalt components. Furthermore, the sulfur particles are gradually released from the tubular particles into the asphalt matrix during stirring, providing a slow-release effect. This achieves simultaneous homogenization and cross-linking of the material, avoiding the problem of uneven material structure caused by excessive cross-linking reactions.

[0022] 3. The surface strengthening layer contains aluminum oxide particles to improve the mechanical strength and wear resistance of the layer, and 40-45 parts of high molecular weight polyethylene can be cross-linked under the joint action of 3-6 parts of tripropylene cyanurate (cross-linking agent) and 2 parts of benzophenone (photoinitiator) under visible light irradiation, thereby improving the heat resistance and impact resistance of the overall surface layer.

[0023] 4. At the same time, the bottom foamed asphalt, the middle reinforced asphalt layer and the surface reinforced layer all contain SBS resin, and the middle reinforced asphalt layer contains sulfur particles, which can be used as a cross-linking agent, so that the SBS resins in the bottom foamed asphalt, the middle reinforced asphalt layer and the surface reinforced layer can be cross-linked to a certain extent, thereby improving the fusion of the three-layer structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention provides a flow chart of the asphalt overlay paving process. DETAILED DESCRIPTION

[0025] The present invention will be described in more detail below with reference to the accompanying drawings, in which preferred embodiments of the present invention are shown. It should be understood that those skilled in the art may modify the present invention described herein while still achieving the beneficial effects of the present invention. Therefore, the following description should be understood as a general guide for those skilled in the art and not as a limitation of the present invention.

[0026] For the sake of clarity, not all features of the actual embodiments are described. In the following description, well-known functions and structures are not described in detail because they would obscure the present invention with unnecessary detail. It should be understood that in the development of any actual embodiment, numerous implementation details must be made to achieve the developer's specific goals.

[0027] In order to make the purpose and features of the present invention more obvious and easy to understand, the specific embodiments of the present invention are further described below with reference to the accompanying drawings. It should be noted that the drawings are all in a very simplified form and use non-precise ratios, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0028] The present invention provides a paving process for an asphalt overlay, comprising the following steps:

[0029] Step 1: forming a plurality of grooves on the surface of the road base, specifically comprising:

[0030] After removing the original asphalt surface layer on the road, clean the road base surface and use road trenching equipment to form multiple parallel grooves on the road base surface. The groove depth is 5-8 cm, the maximum width is 5-10 cm, and the cross-section of the groove in the extension direction is triangular or inverted trapezoidal. For every 1 m width of the road base surface, 4-8 grooves are set. The above-mentioned grooves are continuous or discontinuous in their extension direction.

[0031] Step 2: Filling the trench with foamed asphalt, specifically including:

[0032] Before construction, the asphalt material is heated to a molten state at 180 degrees. The asphalt material can be the original asphalt surface layer removed in step 1; or other asphalt materials.

[0033] Subsequently, carbon fiber and styrene-butadiene-styrene block copolymer (SBS resin) were added to the melted asphalt material and stirred for 5 h to fully mix and evenly distribute the mixture.

[0034] Among them, the mass ratio of asphalt material to carbon fiber is 100:15, and the mass ratio of asphalt material to SBS resin is 100:20. The stirred asphalt mixture is put into the foaming equipment, and the asphalt mixture is contacted with atomized water and stirred for 5 hours. The mass ratio of the asphalt mixture and atomized water is 100:7 to obtain foamed asphalt.

[0035] Spread the foamed asphalt on the surface of the road base with grooves, with a spreading amount of 1000-1200g / m 2 After paving is completed, the scraper is pulled by traction equipment to scrape off the excess foamed asphalt outside the groove above the surface of the road base.

[0036] After scraping off, most of the foamed asphalt is only located in the groove, not above the road base surface. Then, a larger elastic bubble asphalt layer is formed inside the road base groove.

[0037] Since foamed asphalt has relatively high elasticity, the road base is grooved and filled with foamed asphalt. On the one hand, the grooves can release the stress of the road base. On the other hand, when the foamed asphalt is filled in the grooves, it can release part of the stress through elastic deformation without transferring the stress to the middle layer.

[0038] Step 3: Laying the middle reinforcing asphalt layer, specifically including:

[0039] Use a paver to lay a 2-4 cm thick asphalt mixture on the road base surface filled with foamed asphalt in the groove;

[0040] The asphalt mixture includes the following components in parts by mass: the asphalt mixture of the middle reinforcing asphalt layer includes the following components in parts by mass: 100 parts of base asphalt, 15-18 parts of SBS resin, 20-25 parts of solvent oil, 5-10 parts of quartz sand powder, and 30-33 parts of modified particles; the single particle structure of the modified particles includes: hollow thermosetting polyimide tubular particles, a mixture of paraffin and sulfur particles filling the hollow part inside the tubular particles, and an external paraffin spray layer covering the tubular particles. The average length of the modified particles is between 15-20 mm, the average outer diameter is between 10 mm and 12 mm, and the average inner diameter of the tubular particles is 5 mm.

[0041] The method for preparing the asphalt mixture is as follows:

[0042] Step A prepares modified particles, specifically comprising:

[0043] 1) Make a paraffin wax and sulfur mixture

[0044] After ball milling sulfur to form sulfur powder, paraffin wax is added to a container and heated to 160 degrees to melt. The paraffin wax is kept warm and 1.5g of calcium stearate is added to every 100g of paraffin wax and stirred thoroughly for 20 minutes to mix evenly. The sulfur powder is added to the melted paraffin wax and calcium stearate mixture at a ratio of 17g of sulfur powder to every 100g of paraffin wax and stirred thoroughly to mix evenly.

[0045] 2) Preparation of thermosetting polyimide tubular particles

[0046] Thermosetting polyimide is formed into a hollow tube by heat molding, and the tube is cut into hollow tubular particles with a length of 15-20 mm;

[0047] 3) Filled with paraffin and sulfur mixture

[0048] After placing the hollow tubular particles in a molten paraffin and sulfur mixture, the weight ratio of the paraffin and sulfur mixture to the hollow tubular particles is 1.5:1, and vibrating the particles with an ultrasonic vibration device for 15 minutes to expel the air inside the hollow tubular particles so that the hollow part is completely filled with the paraffin and sulfur mixture. The heat preservation is stopped, and then the excess paraffin and sulfur mixture is removed. The tubular particles are cooled and air-dried to solidify the paraffin wax.

[0049] 4) Spray paraffin surface coating

[0050] Melt paraffin at 70 degrees to form a paraffin melt, and spray it onto the surface of tubular particles filled with a mixture of paraffin and sulfur through a spray gun, spraying 20 grams of the paraffin melt per 100 grams of tubular particles. After spraying, cool and air-dry to obtain modified particles;

[0051] Step B, mixing, specifically comprises:

[0052] After adding diluent to the matrix asphalt material, add SBS resin and solvent oil, stir for 30 minutes, and keep the temperature at 160±5℃ during mixing; then add quartz sand powder, stir for 2 hours, 160±5℃; finally add modified particles, stir for 8 hours, and keep the temperature at 160±5℃ during mixing to obtain asphalt mixture.

[0053] The reinforcing particles in the asphalt mixture not only enhance the mechanical properties of the asphalt matrix, but the paraffin solution coated on their surface acts as a strong oil-phase surface fusion agent, improving the wettability of the tubular particles with the asphalt. Furthermore, the paraffin wax and sulfur particles within the tubular particles melt during the warm mixing process, flowing out of the tubular particles and mixing with the asphalt matrix. The sulfur particles act as a bridging agent for the polymer components, causing cross-linking reactions and improving compatibility between the polymer and asphalt components. Furthermore, the sulfur particles are gradually released from the tubular particles into the asphalt matrix during stirring, providing a slow-release effect. This achieves simultaneous homogenization and cross-linking of the material, avoiding the problem of uneven material structure caused by excessively concentrated cross-linking reactions.

[0054] Step 4: Laying the surface strengthening layer, specifically including:

[0055] After the middle reinforced asphalt layer is cooled and solidified for 36 hours, a surface strengthening layer is laid on the surface of the middle reinforced asphalt layer. The surface strengthening layer is composed of a surface strengthening mixture, which includes the following components in parts by mass: 100 parts of solvent oil, 3-8 parts of aluminum oxide particles, 35-50 parts of SBS resin, 40-45 parts of high molecular weight polyethylene, 3-6 parts of tripropylene cyanurate, and 2 parts of benzophenone.

[0056] Use a spray truck to spray the surface strengthening mixture at a spraying rate of 600-750g / m 2 After spraying, dry it and expose it to sunlight for more than 10 hours to complete the paving.

[0057] The surface strengthening layer contains aluminum oxide particles to improve the mechanical strength and wear resistance of the layer, and 40-45 parts of high molecular weight polyethylene can be cross-linked under the joint action of 3-6 parts of tripropylene cyanurate (cross-linking agent) and 2 parts of benzophenone (photoinitiator) under visible light irradiation, thereby improving the heat resistance and impact resistance of the overall surface layer.

[0058] At the same time, the bottom foamed asphalt, the middle reinforced asphalt layer and the surface reinforced layer all contain SBS resin, and the middle reinforced asphalt layer contains sulfur particles, which can serve as a cross-linking agent, so that the SBS resins in the bottom foamed asphalt, the middle reinforced asphalt layer and the surface reinforced layer can be cross-linked to a certain extent, thereby improving the fusion of the three-layer structure.

[0059] Comparative test

[0060] Example 1:

[0061] Three layers of asphalt overlay were laid on a 1m*1m cement substrate with a thickness of 50mm according to the process of the above embodiment.

[0062] Comparative Example 1:

[0063] Compared with the paving process of Example 1, the steps of digging grooves and filling with foamed asphalt in step 1 are basically omitted, and the asphalt overlay is paved.

[0064] Comparative Example 2:

[0065] Compared with the paving process of Example 1, the middle reinforced asphalt layer only uses the asphalt mixture whose components are: 100 parts of base asphalt, 20-25 parts of solvent oil, 5-10 parts of quartz sand powder, and the asphalt overlay is paved.

[0066] Comparative Example 3:

[0067] Compared with the paving process of Example 1, the process without laying the surface strengthening layer is to lay the asphalt overlay.

[0068] The comparative experiments are as follows:

[0069] Twenty 1m*1m cement substrates with a thickness of 50mm were fixed on a test road. Twenty test samples using different processes were laid four times in the order of Example 1 and Comparative Examples 1-3. After laying, the cement substrates together with the asphalt layer above were cut out and tested, and the average value of the 20 samples was taken. The specific test is as follows:

[0070] 1) Marshall compaction test, used to test the volume parameters of the specimen;

[0071] 2) Compression modulus test: the compression modulus test temperature is 20℃, the low temperature bending tensile failure strain test temperature is -15℃,

[0072] 3) Rutting test: rolling test samples to test the fatigue performance of the specimens, the test temperature is 25℃.

[0073] The test results are as follows:

[0074]

[0075] It can be seen that the improvements of this application have significantly improved the compression resistance and fatigue performance of the asphalt overlay.

[0076] This application has the following beneficial effects:

[0077] 1. Since foamed asphalt has relatively high elasticity, the road base is grooved and filled with foamed asphalt. On the one hand, the grooves can release the stress of the road base. On the other hand, when the foamed asphalt is filled in the grooves, it can release part of the stress through elastic deformation without transferring the stress to the middle layer.

[0078] 2. The reinforcing particles in the asphalt mixture not only enhance the mechanical properties of the asphalt matrix, but the paraffin solution coated on their surface acts as a strong oil-phase surface fusing agent, improving the wettability of the tubular particles with the asphalt. Furthermore, the paraffin wax and sulfur particles within the tubular particles melt during the warm mixing process, flowing out of the tubular particles and mixing with the asphalt matrix. The sulfur particles act as a bridging agent for the polymer components, causing cross-linking reactions and improving the compatibility between the polymer and asphalt components. Furthermore, the sulfur particles are gradually released from the tubular particles into the asphalt matrix during stirring, providing a slow-release effect. This achieves simultaneous homogenization and cross-linking of the material, avoiding the problem of uneven material structure caused by excessive cross-linking reactions.

[0079] 3. The surface strengthening layer contains aluminum oxide particles to improve the mechanical strength and wear resistance of the layer, and 40-45 parts of high molecular weight polyethylene can be cross-linked under the joint action of 3-6 parts of tripropylene cyanurate (cross-linking agent) and 2 parts of benzophenone (photoinitiator) under visible light irradiation, thereby improving the heat resistance and impact resistance of the overall surface layer.

[0080] 4. At the same time, the bottom foamed asphalt, the middle reinforced asphalt layer and the surface reinforced layer all contain SBS resin, and the middle reinforced asphalt layer contains sulfur particles, which can be used as a cross-linking agent, so that the SBS resins in the bottom foamed asphalt, the middle reinforced asphalt layer and the surface reinforced layer can be cross-linked to a certain extent, thereby improving the fusion of the three-layer structure.

[0081] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A paving process for an asphalt overlay, characterized by: The steps include: Step 1: After removing the existing asphalt surface layer on the road, clean the road base surface and use road trenching equipment to form multiple parallel grooves on the road base surface. The groove depth is 5-8 cm and the maximum width is 5-10 cm. The cross-section of the groove in the extension direction is triangular or inverted trapezoidal. For every 1 m width of the road base surface, 4-8 grooves are set. The grooves are continuous or discontinuous in their extension direction. Step 2: Fill the groove with foamed asphalt Before construction, the asphalt material is heated to a molten state of 180 degrees, and carbon fiber and SBS resin are added and stirred evenly. The mass ratio of asphalt material to carbon fiber is 100:15, and the mass ratio of asphalt material to SBS resin is 100:

20. The stirred asphalt mixture is put into the foaming equipment and the asphalt mixture is contacted with atomized water and stirred for 5 hours. The mass ratio of asphalt mixture to atomized water is 100:7 to obtain foamed asphalt. Spread the foamed asphalt on the grooves formed on the road base surface, with a spreading amount of 1000-1200g / m 2 After paving is completed, the scraper is pulled by traction equipment to scrape off the excess foamed asphalt outside the groove above the road base surface; Step 3: Lay out the middle reinforced asphalt layer Laying a 2-4 cm thick asphalt mixture on the surface of the road base filled with foamed asphalt in the groove; the asphalt mixture at least includes: asphalt base material, SBS resin, sulfur powder and quartz sand powder; Step 4: Lay out the surface strengthening layer After the intermediate reinforced asphalt layer has cooled and solidified for 36 hours, a surface strengthening layer is laid on the surface of the intermediate reinforced asphalt layer. The surface strengthening layer is composed of a surface strengthening mixture. The surface strengthening mixture includes the following components in parts by mass: 100 parts of solvent oil, 3-8 parts of aluminum oxide particles, 35-50 parts of SBS resin, 40-45 parts of high molecular weight polyethylene, 3-6 parts of tripropylene cyanurate, and 2 parts of benzophenone; Use a spray truck to spray the surface strengthening mixture at a spraying rate of 600-750g / m 2 After spraying, dry it and expose it to sunlight for more than 10 hours to complete the paving.

2. The asphalt overlay paving process according to claim 1, characterized in that: The asphalt mixture of the middle reinforcing asphalt layer includes the following components in parts by mass: 100 parts of base asphalt, 15-18 parts of SBS resin, 20-25 parts of solvent oil, 5-10 parts of quartz sand powder, and 30-33 parts of modified particles. The single particle structure of the modified particles includes: hollow thermosetting polyimide tubular particles, a mixture of paraffin and sulfur particles filling the hollow part inside the tubular particles, and an external paraffin spray layer covering the tubular particles. The average length of the modified particles is between 15-20 mm, the average outer diameter is between 10 mm and 12 mm, and the average inner diameter of the tubular particles is 5 mm.

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