Durable drainage asphalt mixture and method for preparing the same

Abstract

The application discloses a durable drainage asphalt mixture and a preparation method thereof, and relates to the technical field of road engineering. The durable drainage asphalt mixture comprises, in mass parts, 3.8-5.0 parts of high-performance asphalt binder, 100 parts of aggregate, 1.0-4.0 parts of mineral powder and 0.2-0.4 parts of fiber stabilizer. The raw material of the high-performance asphalt binder comprises, in mass parts, 100 parts of base asphalt, 6-10 parts of high-vinyl styrene-butadiene-styrene block copolymer, 0.1-0.5 parts of crosslinking agent and 0.1-1.0 parts of stabilizer, and the high-vinyl styrene-butadiene-styrene block copolymer is a stable network structure with SBS as a continuous phase and asphalt as a dispersed phase. The application further provides a preparation method of the durable drainage asphalt mixture. The prepared durable drainage asphalt mixture effectively solves the defects of poor durability, poor anti-scattering and anti-fatigue performance of the existing drainage asphalt mixture, and significantly improves the road performance and long-term durability of the drainage asphalt mixture.

Description

Technical Field

[0001] This invention relates to the field of road engineering technology, specifically to a durable drainage asphalt mixture and its preparation method. Background Technology

[0002] Open-graded anti-skid wear course or porous asphalt concrete is a functional pavement structure widely used due to its excellent drainage, noise reduction and anti-skid performance. This type of mixture, by adopting open gradation with high coarse aggregate content and low fine aggregate content, forms a skeleton-void structure with a connected porosity of up to 18%~25%, which can quickly drain surface water and significantly improve driving safety in rainy weather.

[0003] However, it is precisely this high porosity that leads to a serious defect in the durability of drainage asphalt pavements. This is mainly manifested in the following ways: fewer contact points between the asphalt binder and aggregates; under the repeated shearing of vehicle loads and the pressure of dynamic water, coarse aggregates are easily detached from the pavement surface, causing potholes and loosening of the pavement rapidly; high porosity makes it easier for moisture to penetrate the asphalt-aggregate interface, causing asphalt film peeling and exacerbating water damage; a larger area of ​​the asphalt film is exposed to air and sunlight, resulting in a faster aging rate; and due to its weak structure, it is more prone to fatigue cracking under repeated loading.

[0004] To improve the durability of drainage asphalt mixtures, high-viscosity modified asphalt is often used, such as by adding TPS (TAFPACK-Super, a high-viscosity thermoplastic composite modifier), rubber powder, or high-dose SBS (Styrene-Butadiene-Styrene Block Copolymer). However, conventional high-viscosity asphalt generally suffers from problems such as difficulty in balancing viscosity and workability, poor thermal storage stability, and insufficient low-temperature crack resistance. These problems are particularly pronounced when the SBS content exceeds 6%, severely limiting the further improvement of the service life of drainage asphalt pavements.

[0005] Therefore, there is an urgent need to propose a durable drainage asphalt mixture and its preparation method, which has excellent drainage and noise reduction functions, and improves the anti-scattering, anti-water loss, anti-fatigue and anti-aging properties of drainage asphalt mixture. Summary of the Invention

[0006] This invention aims to solve the above-mentioned problems and proposes a durable drainage asphalt mixture and its preparation method. The durable drainage asphalt mixture is prepared by using a high-performance asphalt binder with an SBS continuous phase structure, which effectively solves the defects of insufficient durability, poor anti-scattering and anti-fatigue performance of existing drainage asphalt mixtures, and significantly improves the road performance and long-term durability of drainage asphalt mixtures.

[0007] The present invention adopts the following technical solution: A durable drainage asphalt mixture, comprising the following components by weight: High-performance asphalt binder: 3.8~5.0 parts; Materials: 100 portions; Mineral powder: 1.0~4.0 parts; Fiber stabilizer: 0.2~0.4 parts; The raw materials for high-performance asphalt binder, by mass parts, include the following components: Base bitumen: 100 parts; High vinyl styrene-butadiene-styrene block copolymer: 6-10 parts; Crosslinking agent: 0.1~0.5 parts; Stabilizer: 0.1~1.0 parts.

[0008] Preferably, the high-performance asphalt binder is a stable network structure with SBS as the continuous phase and asphalt as the dispersed phase.

[0009] Preferably, in the high-performance asphalt binder, the base asphalt is 70# petroleum base asphalt or 90# petroleum base asphalt; The styrene to butadiene block copolymer has a styrene to butadiene block ratio of 15 / 85 to 25 / 85 and a molecular weight of 50,000 to 120,000. The crosslinking agent is sulfur or a sulfur-containing compound; The stabilizer is a styrene-maleic anhydride copolymer.

[0010] Preferably, the recovery rate R of the high-performance asphalt binder under multi-stress creep recovery test conditions of 64℃ and 3.2kPa shear stress is [value missing]. 3.2 Not less than 90%, irreversible creep compliance J nr,3.2 The elastic recovery at 25℃ is not less than 95%, and the dynamic shear complex modulus G* at 64℃ is not less than 12.0 kPa; the softening point difference after being stored in a 163℃ oven for 48 hours is not greater than 2.5℃.

[0011] Preferably, the aggregate is basalt with a nominal maximum particle size of 10mm, 13.2mm or 16mm, and the gradation adopts open gradation; The mineral powder is limestone mineral powder; The fiber stabilizer is basalt fiber.

[0012] Preferably, the target porosity of the durable drainage asphalt mixture is 18% to 23%, and the interconnected porosity is not less than 14%.

[0013] A method for preparing a durable drainage asphalt mixture, comprising the following steps: Step 1, raw material pretreatment; High-performance asphalt binder, aggregates and mineral powder are preheated separately, and then the fiber stabilizer is dried for later use. Step 2, dry mix; The preheated aggregate and fiber stabilizer are put into a mixing pot and dry-mixed to obtain a dry-mixed mixture. Step 3, wet mixing; Preheated high-performance asphalt binder is added to the dry mixture for wet mixing to obtain a wet mixture. Step 4: Add mineral powder and mix. Preheated mineral powder is added to the wet mixture and stirred continuously to obtain a durable drainage asphalt mixture.

[0014] Preferably, in step 1, the high-performance asphalt binder is heated to 160~175℃ for later use, and the aggregate and mineral powder are heated to 180~195℃ for later use.

[0015] Preferably, the dry mixing time is set to 5-10 seconds; the wet mixing time is set to 60-100 seconds; and the mixing time is set to 60-90 seconds. The mixing temperature is set to 175~185℃, and the discharge temperature of the durable drainage asphalt mixture is controlled at 170~185℃.

[0016] Preferably, the Kentenberg scattering loss of the durable drainage asphalt mixture is no more than 8%; the freeze-thaw splitting strength ratio is no less than 90%; and the rutting dynamic stability under the conditions of 60℃ and 0.7MPa is no less than 6000 times / mm.

[0017] The present invention has the following beneficial effects: This invention proposes a durable drainage asphalt mixture and its preparation method. The durable drainage asphalt mixture is prepared using a high-performance asphalt binder with a stable network structure consisting of SBS as the continuous phase and asphalt as the dispersed phase. This results in a drainage asphalt mixture with ultra-high elasticity (i.e., elastic recovery greater than 95%) and extremely strong cohesion. During application, the drainage asphalt mixture prepared by this invention can form a high-toughness, high-strength asphalt film on the aggregate surface and a strong elastic connection at the aggregate contact points. This significantly enhances the pavement structure's resistance to vehicle load shear and dynamic water pressure erosion, effectively solving the problems of pavement structure looseness and potholes.

[0018] Meanwhile, the durable drainage asphalt mixture prepared by this invention possesses extremely strong high-temperature deformation resistance due to the continuous SBS network in the high-performance asphalt binder. Furthermore, the rutting dynamic stability of this durable drainage asphalt mixture exceeds 6000 cycles / mm under 60℃ and 0.7MPa conditions, meeting the requirements of heavy traffic levels and effectively solving the problem of rutting easily caused by the unstable skeleton structure of traditional drainage pavements. Moreover, the presence of the continuous SBS phase fundamentally improves the adhesion between asphalt and aggregates, significantly enhancing the durability of the mixture in a water environment, with the freeze-thaw splitting strength ratio (TSR) remaining stable above 90%. Simultaneously, the high viscosity and high elasticity characteristics endow the durable drainage asphalt mixture of this invention with excellent flexibility and fatigue crack resistance. The fatigue life in the four-point bending fatigue test is several times higher than that of traditional drainage asphalt mixtures, significantly extending the service life of the pavement structure. Combined with excellent storage stability, this effectively ensures the stable and controllable quality of the project.

[0019] In summary, the drainage asphalt mixture provided by this invention combines drainage function with structural durability, providing strong technical support for promoting the long-term application of drainage pavements. Attached Figure Description

[0020] Figure 1 The image shows a fluorescence microscope photograph of the high-performance asphalt binder used in Example 1.

[0021] Figure 2 This is a flowchart of the method for preparing the durable drainage asphalt mixture of the present invention.

[0022] Figure 3 This is a flowchart of the high-performance asphalt binder preparation method of the present invention. Detailed Implementation

[0023] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0024] This invention proposes a method for calculating the adsorbed gas content in core samples from deep shale gas reservoirs based on molecular simulation, such as... Figure 1 As shown, the steps for obtaining the adsorbed gas content in a core sample from a deep shale gas reservoir include: Example 1 This embodiment proposes a durable drainage asphalt mixture, which, by weight, comprises 4.2 parts high-performance asphalt binder, 100 parts aggregate, 3.0 parts mineral powder, and 0.3 parts fiber stabilizer. Further, the raw materials of the high-performance asphalt binder in this embodiment, by weight, comprise 100 parts base asphalt, 7.5 parts high-vinylstyrene-butadiene-styrene block copolymer, 0.2 parts crosslinking agent, and 0.5 parts stabilizer.

[0025] Specifically, the high-performance asphalt binder has a stable network structure with SBS as the continuous phase and asphalt as the dispersed phase, such as... Figure 1 As shown. In the high-performance asphalt binder, the base asphalt is 70# petroleum base asphalt, the crosslinking agent is sulfur, the stabilizer is styrene-maleic anhydride copolymer, and the block ratio of styrene to butadiene in the high vinyl styrene-butadiene-styrene block copolymer is 23 / 77, with a molecular weight of approximately 100,000. The aggregate is basalt, and the basalt gradation is open gradation, wherein the ratio between 10-15mm particle size, 5-10mm particle size and 0-3mm particle size is 40:45:15, the mineral powder is limestone mineral powder, and the fiber stabilizer is basalt fiber.

[0026] The preparation method of the durable drainage asphalt mixture in this embodiment is as follows: Figure 2 As shown, the specific process is as follows: High-performance asphalt binder is heated to 170°C for later use, and aggregates and mineral powder are heated to 190°C for later use. The preheated aggregates and fiber stabilizers are added to a mixing pot and dry-mixed for 8 seconds to obtain a dry-mixed mixture. The preheated high-performance asphalt binder is then added to the dry-mixed mixture, and wet-mixed at 180°C for 90 seconds. After that, mineral powder is added and mixing is continued for 60 seconds. The material is then discharged to obtain a durable drainage asphalt mixture.

[0027] Specifically, the preparation method of the high-performance asphalt binder in this embodiment is as follows: Figure 3 As shown, the specific process is as follows: After heating the base asphalt to 170-175℃, a high-vinyl styrene-butadiene-styrene block copolymer was added. The mixture was stirred and swollen at 500 rpm for 60 minutes. The temperature was then raised to 175-180℃, and the mixture was sheared at 5000 rpm for 40 minutes using a high-speed shearing machine to form a continuous SBS phase skeleton and achieve phase inversion. The system temperature was then raised to 180-185℃, and a crosslinking agent was added. The mixture was stirred and developed at 1000 rpm for 120 minutes to achieve moderate crosslinking and lock the phase inversion structure. A stabilizer was then added to stabilize the polymer interface, and the mixture was stirred and developed at 500 rpm for 60 minutes at 175℃ to obtain a high-performance asphalt binder.

[0028] Furthermore, the material properties of the high-performance asphalt binder were tested, and the recovery rate R of the high-performance asphalt binder prepared in this embodiment was obtained during a multi-stress creep recovery test under the conditions of 64℃ temperature and 3.2kPa test shear stress. 3.2 The non-recoverable creep compliance is 92.5% J. nr,3.2The elastic recovery is 97% at 25℃, and the dynamic shear complex modulus G* is 13.5kPa at 64℃. The softening point difference after being stored in a 163℃ oven for 48 hours is no greater than 2.5℃.

[0029] Example 2 This embodiment proposes a durable drainage asphalt mixture, which, by weight, comprises 4.2 parts high-performance asphalt binder, 100 parts aggregate, 3.0 parts mineral powder, and 0.3 parts fiber stabilizer. Further, the raw materials of the high-performance asphalt binder in this embodiment, by weight, comprise 100 parts base asphalt, 9.0 parts high-vinylstyrene-butadiene-styrene block copolymer, 0.3 parts crosslinking agent, and 0.7 parts stabilizer.

[0030] Specifically, the high-performance asphalt binder is a stable network structure with SBS as the continuous phase and asphalt as the dispersed phase. In the high-performance asphalt binder, the base asphalt is 70# petroleum base asphalt, the crosslinking agent is sulfur, and the stabilizer is a styrene-maleic anhydride copolymer. The high-vinyl styrene-butadiene-styrene block copolymer has a styrene to butadiene block ratio of 23 / 77 and a molecular weight of approximately 100,000. The aggregate is basalt, and the basalt gradation is open gradation, wherein the ratio of 10-15mm particle size, 5-10mm particle size, and 0-3mm particle size is 40:45:15. The mineral powder is limestone mineral powder, and the fiber stabilizer is basalt fiber.

[0031] The preparation method of the durable drainage asphalt mixture in this embodiment is as follows: High-performance asphalt binder is heated to 170°C for later use, and aggregates and mineral powder are heated to 195°C for later use. The preheated aggregates and fiber stabilizers are added to a mixing pot and dry-mixed for 8 seconds to obtain a dry-mixed mixture. The preheated high-performance asphalt binder is then added to the dry-mixed mixture, and wet-mixed at 185°C for 90 seconds. After that, mineral powder is added and mixing is continued for 80 seconds. The material is then discharged to obtain a durable drainage asphalt mixture.

[0032] Specifically, the preparation process of the high-performance asphalt binder in this embodiment is as follows: After heating the base asphalt to 170-175℃, a high-vinyl styrene-butadiene-styrene block copolymer was added. The mixture was stirred and swollen at 500 rpm for 60 minutes. The temperature was then raised to 175-180℃, and the mixture was sheared at 5000 rpm for 40 minutes using a high-speed shearing machine to form a continuous SBS phase skeleton and achieve phase inversion. The system temperature was then raised to 180-185℃, and a crosslinking agent was added. The mixture was stirred and developed at 1000 rpm for 120 minutes to achieve moderate crosslinking and lock the phase inversion structure. A stabilizer was then added to stabilize the polymer interface, and the mixture was stirred and developed at 500 rpm for 60 minutes at 175℃ to obtain a high-performance asphalt binder.

[0033] Furthermore, the material properties of the high-performance asphalt binder were tested, and the recovery rate R of the high-performance asphalt binder prepared in this embodiment was obtained during a multi-stress creep recovery test under the conditions of 64℃ temperature and 3.2kPa test shear stress. 3.2 The irreversible creep compliance is 94.1% J. nr,3.2 The elastic recovery is 98% at 25℃, and the dynamic shear complex modulus G* is 15.8 kPa at 64℃. The softening point difference after being stored in a 163℃ oven for 48 hours is no greater than 2.5℃.

[0034] Comparative Example 1 In this embodiment, commercially available high-viscoelastic modified asphalt is used to replace the high-performance asphalt binder in Example 1 to prepare drainage asphalt mixture. The remaining materials, proportions and preparation processes are the same as those in the durable drainage asphalt mixture in Example 1.

[0035] Comparative Example 2 In this embodiment, conventional ID-grade SBS modified asphalt is used to replace the high-performance asphalt binder in Example 1 to prepare drainage asphalt mixture. The remaining materials, proportions and preparation processes are the same as those in the durable drainage asphalt mixture in Example 1.

[0036] Furthermore, the performance of the drainage asphalt mixtures prepared in the above embodiments and comparative examples was tested, and the performance test results of each drainage asphalt mixture were obtained, as shown in Table 1.

[0037] Table 1 Performance test results of various drainage asphalt mixtures As shown in Table 1, the durable drainage asphalt mixtures prepared in Examples 1 and 2 not only possess excellent drainage performance, but their key durability indicators (i.e., resistance to scattering, resistance to water damage, and resistance to rutting at high temperatures) are also significantly superior to those of the drainage asphalt mixture prepared using conventional high-viscosity asphalt in Comparative Example 1 and the drainage asphalt mixture prepared using traditional SBS modified asphalt in Comparative Example 2. This demonstrates that the high-performance asphalt binder used in this invention can fundamentally improve the structural strength and bonding toughness of the prepared drainage asphalt mixture, significantly extending the service life of the pavement structure.

[0038] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A durable drainage asphalt mixture, characterized in that, Based on parts by mass, it includes the following components: High-performance asphalt binder: 3.8~5.0 parts; Materials: 100 portions; Mineral powder: 1.0~4.0 parts; Fiber stabilizer: 0.2~0.4 parts; The raw materials for high-performance asphalt binder, by mass parts, include the following components: Base bitumen: 100 parts; High vinyl styrene-butadiene-styrene block copolymer: 6-10 parts; Crosslinking agent: 0.1~0.5 parts; Stabilizer: 0.1~1.0 parts.

2. The durable drainage asphalt mixture according to claim 1, characterized in that, The high-performance asphalt binder has a stable network structure with SBS as the continuous phase and asphalt as the dispersed phase.

3. The durable drainage asphalt mixture according to claim 1, characterized in that, In the high-performance asphalt binder, the base asphalt is 70# petroleum base asphalt or 90# petroleum base asphalt. The styrene to butadiene block copolymer has a styrene to butadiene block ratio of 15 / 85 to 25 / 85 and a molecular weight of 50,000 to 120,000. The crosslinking agent is sulfur or a sulfur-containing compound; The stabilizer is a styrene-maleic anhydride copolymer.

4. The durable drainage asphalt mixture according to claim 3, characterized in that, The recovery rate R of the high-performance asphalt binder under multi-stress creep recovery test at a temperature of 64℃ and a test shear stress of 3.2kPa was... 3.2 Not less than 90%, irreversible creep compliance J nr,3.2 The elastic recovery at 25℃ is not less than 95%, and the dynamic shear complex modulus G* at 64℃ is not less than 12.0 kPa; the softening point difference after being stored in a 163℃ oven for 48 hours is not greater than 2.5℃.

5. The durable drainage asphalt mixture according to claim 1, characterized in that, The aggregate is basalt with a nominal maximum particle size of 10mm, 13.2mm or 16mm, and the gradation adopts open gradation. The mineral powder is limestone mineral powder; The fiber stabilizer is basalt fiber.

6. The durable drainage asphalt mixture according to claim 1, characterized in that, The target porosity of the durable drainage asphalt mixture is 18% to 23%, and the interconnected porosity is not less than 14%.

7. A method for preparing a durable drainage asphalt mixture, characterized in that, The preparation of the durable drainage asphalt mixture as described in any one of claims 1 to 6 includes the following steps: Step 1, raw material pretreatment; High-performance asphalt binder, aggregates and mineral powder are preheated separately, and then the fiber stabilizer is dried for later use. Step 2, dry mix; The preheated aggregate and fiber stabilizer are put into a mixing pot and dry-mixed to obtain a dry-mixed mixture. Step 3, wet mixing; Preheated high-performance asphalt binder is added to the dry mixture for wet mixing to obtain a wet mixture. Step 4: Add mineral powder and mix. Preheated mineral powder is added to the wet mixture and stirred continuously to obtain a durable drainage asphalt mixture.

8. The method for preparing durable drainage asphalt mixture according to claim 7, characterized in that, In step 1, the high-performance asphalt binder is heated to 160~175℃ for later use, and the aggregate and mineral powder are heated to 180~195℃ for later use.

9. The method for preparing durable drainage asphalt mixture according to claim 7, characterized in that, The dry mixing time is set to 5-10 seconds; the wet mixing time is set to 60-100 seconds; and the mixing time is set to 60-90 seconds. The mixing temperature is set to 175~185℃, and the discharge temperature of the durable drainage asphalt mixture is controlled at 170~185℃.

10. The method for preparing durable drainage asphalt mixture according to claim 7, characterized in that, The durable drainage asphalt mixture shall have a Kentenberg scattering loss of no more than 8%; a freeze-thaw splitting strength ratio of no less than 90%; and a rutting dynamic stability of no less than 6000 cycles / mm under the conditions of 60℃ and 0.7MPa.

Images