An interface-enhanced asphalt mixture

Abstract

The present invention relates to the technical field of road engineering, and specifically relates to an interface-enhanced asphalt mixture, which comprises the following raw materials in parts by weight: 57-72 parts of coarse aggregate, 20-32 parts of fine aggregate, 2-5 parts of filler, 4.5-5.5 parts of asphalt binder, and 0.5-1.0 part of interface enhancer, and is prepared by a step-by-step mixing method. The interface-enhanced asphalt mixture provided by the present invention, compared with traditional lime, cement or chemical anti-stripping agents, the provided interface enhancer can not only significantly improve the adhesion between asphalt and aggregate interfaces, but also maintain the adhesion improvement effect of the cross-section for a long time, effectively solving the technical problem that the adhesion effect between aggregate and asphalt is prone to failure, and enhancing the water damage resistance of the asphalt mixture; at the same time, by using the step-by-step mixing method for preparation, good contact can be formed between the interface enhancer and the aggregate, further ensuring the interface enhancement effect.

Description

Technical Field

[0001] The present invention relates to the technical field of road engineering, and specifically to an interface-enhanced asphalt mixture. Background Art

[0002] With the rapid development of the highway transportation industry, the requirements for the service performance of asphalt pavements are gradually increasing. As the raw material for asphalt pavement construction, the road performance of asphalt mixtures is one of the key factors affecting the construction quality of asphalt pavements. Asphalt mixture is a multiphase composite material composed of asphalt, aggregates, fillers and other substances. Among them, the interaction between the asphalt phase and the aggregate phase is the weak link affecting the road performance of asphalt mixtures. The detachment and cracking between asphalt and aggregates will directly lead to the attenuation of the mechanical properties of asphalt mixtures. Under the coupling action of external media (such as load, moisture and high temperature), a series of diseases such as spalling, loosening and potholes will occur on the asphalt pavement, seriously affecting driving safety and reducing the service life of the road. Therefore, it is of great practical significance to improve the adhesion between asphalt and aggregates and enhance the cohesion and strength of asphalt mixtures for improving the comprehensive road performance of asphalt mixtures.

[0003] To improve the adhesion strength between the asphalt phase and the aggregate phase interface in asphalt mixtures, currently, some admixtures (such as lime, cement or chemical anti-stripping agents) are mainly added to asphalt mixtures to improve the adhesion between asphalt and aggregates. Although the above methods have certain improvement effects, there are still some disadvantages in actual engineering applications. (1) Adding inorganic minerals such as lime and cement to asphalt mixtures mainly enhances the adhesion between acidic asphalt and aggregates by using the alkalinity of inorganic minerals and their cations. However, under the long-term presence of water, since water molecules are polar substances, it is easier for them to replace the combination of asphalt and aggregates, resulting in a decrease in the adhesion performance between asphalt and aggregates, that is, the long-term anti-stripping effect of lime and cement is limited; (2) Some liquid chemical anti-stripping agents will also be gradually dissolved under the long-term immersion of water, resulting in a decrease in their long-term anti-stripping effect. Therefore, it is urgent to provide an asphalt mixture with excellent interface adhesion effect from the perspective of improving the interface adhesion between asphalt and aggregates, so as to improve the adhesion strength between asphalt and aggregates and the water damage resistance of asphalt mixtures. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art, and provide an interface-enhanced asphalt mixture, providing an interface enhancer with excellent adhesion effect, and effectively enhancing the interfacial bond between aggregates and asphalt through a step-by-step mixing method.

[0005] To achieve the above technical effects, the present invention adopts the following technical solutions:

[0006] An interface-enhanced asphalt mixture, comprising the following raw materials in parts by weight:

[0007] 57 - 72 parts of coarse aggregate, 20 - 32 parts of fine aggregate, 2 - 5 parts of filler, 4.5 - 5.5 parts of asphalt binder, and 0.5 - 1.0 part of interface enhancer, and is prepared by a step-by-step mixing method.

[0008] Among them, the interface enhancer comprises the following raw materials in parts by weight:

[0009] 25 - 50 parts of polymer modifier, 15 - 35 parts of ethylene-vinyl acetate copolymer, 10 - 25 parts of co-solvent, 3 - 10 parts of cross-linking agent, 0.5 - 1 part of anti-aging agent.

[0010] The interface-enhanced asphalt mixture provided by the present invention, compared with traditional lime, cement or chemical anti-stripping agents, the provided interface enhancer can not only significantly improve the adhesion between asphalt and aggregate interface, but also maintain the cross-section adhesion improvement effect for a long time, effectively solving the technical problem that the adhesion effect between aggregate and asphalt is prone to failure, and enhancing the water damage resistance of the asphalt mixture; at the same time, by using the step-by-step mixing method for preparation, good contact can be formed between the interface enhancer and the aggregate, further ensuring the interface enhancement effect.

[0011] Preferably, the interface-enhanced asphalt mixture comprises the following raw materials in parts by weight:

[0012] 60 - 70 parts of coarse aggregate, 23 - 29 parts of fine aggregate, 3 - 5 parts of filler, 4.5 - 5.5 parts of asphalt binder, and 0.5 - 1.0 part of interface enhancer.

[0013] Preferably, the interface enhancer comprises the following raw materials in parts by weight:

[0014] 44 parts of polymer modifier, 28 parts of ethylene-vinyl acetate copolymer, 21 parts of co-solvent, 6.5 parts of cross-linking agent, 0.5 part of anti-aging agent.

[0015] Further preferably, the preparation method of the interface enhancer is as follows:

[0016] Mix the polymer modifier and ethylene-vinyl acetate copolymer particles and then crush them, then add the co-solvent, cross-linking agent and anti-aging agent to the mixture powder, stir to obtain a mixture, and then perform cold granulation in an extruder at a temperature below 80 °C to obtain the interface enhancer particles.

[0017] Preferably, the step-by-step mixing method specifically comprises the following steps:

[0018] At 190 - 200 °C, the coarse aggregate is mixed with the interface enhancer for 15 - 20 s, then the fine aggregate and the asphalt binder are added and mixing continues for 45 - 55 s, and then the filler is added and mixed for 35 - 45 s.

[0019] Further preferably, the rotation speed during mixing is 60 - 80 rpm; more preferably, the rotation speed is 75 rpm.

[0020] Preferably, the grading type of the interface - enhanced asphalt mixture is a framework - interlocked dense structure, and its maximum nominal size is 13.2 mm (type 13) or 19 mm (type 20).

[0021] Further preferably, the grading range of the type 13 mixture is: the passing rate of the standard sieve hole of 16 mm is in the range of 100%, the passing rate of the standard sieve hole of 13.2 mm is in the range of 90 - 100%, the passing rate of the standard sieve hole of 9.5 mm is in the range of 70 - 82%, the passing rate of the standard sieve hole of 4.75 mm is in the range of 39 - 53%, the passing rate of the standard sieve hole of 2.36 mm is in the range of 26 - 36%, the passing rate of the standard sieve hole of 1.18 mm is in the range of 18 - 26%, the passing rate of the standard sieve hole of 0.6 mm is in the range of 14 - 19%, the passing rate of the standard sieve hole of 0.3 mm is in the range of 9 - 13%, the passing rate of the standard sieve hole of 0.15 mm is in the range of 5 - 9%, and the passing rate of the standard sieve hole of 0.075 mm is in the range of 4 - 6%.

[0022] Further preferably, the grading range of the type 20 mixture is: the passing rate of the standard sieve hole of 26.5 mm is in the range of 100%, the passing rate of the standard sieve hole of 19 mm is in the range of 90 - 100%, the passing rate of the standard sieve hole of 16 mm is in the range of 81 - 92%, the passing rate of the standard sieve hole of 13.2 mm is in the range of 70 - 84%, the passing rate of the standard sieve hole of 9.5 mm is in the range of 54 - 68%, the passing rate of the standard sieve hole of 4.75 mm is in the range of 33 - 45%, the passing rate of the standard sieve hole of 2.36 mm is in the range of 21 - 32%, the passing rate of the standard sieve hole of 1.18 mm is in the range of 14 - 21%, the passing rate of the standard sieve hole of 0.6 mm is in the range of 9 - 15%, the passing rate of the standard sieve hole of 0.3 mm is in the range of 7 - 12%, the passing rate of the standard sieve hole of 0.15 mm is in the range of 5 - 9%, and the passing rate of the standard sieve hole of 0.075 mm is in the range of 4 - 6%.

[0023] Preferably, the asphalt binder is selected from SBS - modified asphalt or composite - modified rubber asphalt.

[0024] Further preferably,

[0025] The parameters of SBS modified asphalt are as follows: penetration at 25°C is 35 - 55 (0.1 mm), ductility at 5°C ≥ 20 cm, softening point ≥ 65°C, kinematic viscosity at 135°C is 1.2 - 3.0 Pa·s, flash point ≥ 230°C, elastic recovery at 25°C ≥ 75%; the mass change after thin film oven aging ≤ ±0.5%, penetration ratio at 25°C ≥ 65%, residual ductility at 5°C ≥ 15 cm;

[0026] The parameters of composite modified rubber asphalt are as follows: penetration at 25°C is 50 - 70 (0.1 mm), ductility at 5°C ≥ 20 cm, softening point ≥ 70°C, kinematic viscosity at 180°C is 1.0 - 4.0 Pa·s, elastic recovery at 25°C ≥ 75%; the mass change after thin film oven aging ≤ ±0.5%, penetration ratio at 25°C ≥ 60%, residual ductility at 5°C ≥ 12 cm.

[0027] Preferably, the coarse and fine aggregates and fine aggregate are selected from steel slag, basalt or limestone.

[0028] Basalt or limestone is a common aggregate for asphalt mixtures. Engineering practice has proved that the overall performance of asphalt mixtures prepared from basalt and limestone is relatively excellent; steel slag aggregate is an alkaline material, and at the same time it has characteristics such as porous and rich in edges and corners, which can significantly improve the adhesion performance between the aggregate and asphalt while improving the mechanical strength of the asphalt mixture.

[0029] Preferably, the filler consists of mineral powder and steel slag powder. Further preferably, in the filler, the weight ratio of mineral powder to steel slag powder is 2:1.

[0030] Among them, steel slag powder is an alkaline material, which can improve the adhesion performance between the aggregate and asphalt, and can improve the toughness of the asphalt mortar after being mixed with the modified asphalt, thereby improving the strength and crack resistance of the asphalt mixture. After mixing the steel slag powder and mineral powder evenly, grind them to 100 - 300 meshes to obtain the filler.

[0031] Preferably, in the interface enhancer, the polymer modifier is selected from one of SBS or SBR; the co - solvent is selected from one or a combination of aromatic solvents, amide compounds, ketones or esters, the cross - linker is selected from one or a combination of polyisocyanates, polyols, acrylate esters or amines, and the anti - aging agent is selected from one of asphaltene solubilizers or phosphite esters.

[0032] Preferably, the residual strength ratio (TSR) of the interface-enhanced asphalt mixture in the freeze-thaw splitting test is greater than 90%, the dynamic stability at 60°C is greater than 5000 times / mm, the low-temperature bending failure strain at -10°C is greater than 3500 με, the maximum deformation in the Hamburg wheel tracking test at 50°C and 20000 times is less than 5.0 mm, and the fatigue life in the four-point bending fatigue test under the control strain conditions of 15°C, 10 Hz, and 230 με is greater than 1.5 million times. The above parameters are measured according to the test methods provided in JTG E20-2011 "Test Procedures for Bitumen and Bituminous Mixtures in Highway Engineering".

[0033] Preferably, the Marshall test conditions and data of the interface-enhanced asphalt mixture are as follows:

[0034] It is formed by the Marshall compaction method, the compaction times are 75 times on both sides, the void ratio is 3.0 - 5.0%, the voids in mineral aggregate of type 13 mixture are 13.5 - 15.5%, the voids in mineral aggregate of type 20 mixture are 12.5 - 14.5%, the asphalt saturation is 65.0 - 75.0%, the stability is greater than 10 kN, and the flow value is 1.5 - 3.5 mm.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The interface-enhanced asphalt mixture provided by the present invention, compared with traditional lime, cement or chemical anti-stripping agents, can not only significantly improve the adhesion between asphalt and aggregate interface, but also maintain the interface adhesion improvement effect for a long time, effectively solve the technical problem that the adhesion between aggregate and asphalt is prone to failure, and enhance the water damage resistance of asphalt mixture.

[0037] 2. Compared with traditional asphalt mixtures, the interface-enhanced asphalt mixture provided by the present invention uses a mixture of mineral powder and steel slag fine powder as filler. Steel slag fine powder is an alkaline material. When it is applied to asphalt mixtures, while improving the adhesion performance between aggregate and asphalt, it can improve the toughness of asphalt mortar after being mixed with the modified asphalt, thereby enhancing the strength and crack resistance of asphalt mixtures.

[0038] 3. The interface-enhanced asphalt mixture provided by the present invention can not only effectively solve the problem that the adhesion between asphalt and aggregate interface is prone to failure, but also significantly improve the comprehensive performance of asphalt mixtures such as high-temperature rutting resistance, low-temperature cracking resistance, and medium-temperature fatigue resistance. When it is applied to asphalt pavement paving projects, it can effectively extend the service life of roads and has good promotion and application value. Detailed Embodiments

[0039] The present invention will be further described below in conjunction with examples and comparative examples.

[0040] Unless otherwise specified, the raw materials used in each example and comparative example are common commercially available raw materials in the industry, and their specific sources will not be elaborated.

[0041] Example 1:

[0042] An interface-enhanced asphalt mixture comprises raw materials in the following weight parts:

[0043] 63 parts of coarse aggregate, 27 parts of fine aggregate, 4 parts of filler, 5.2 parts of asphalt binder, and 0.8 part of interface enhancer.

[0044] Among them, the interface enhancer comprises raw materials in the following weight parts: 44 parts of polymer modifier, 28 parts of ethylene-vinyl acetate copolymer, 21 parts of co-solvent, 6.5 parts of cross-linking agent, and 0.5 part of anti-aging agent. In this example, the polymer modifier is SBS, the co-solvent is acetamide, the cross-linking agent is diacetone acrylamide, and the anti-aging agent is dipentaerythritol diisodecyl diphosphite;

[0045] The preparation method of the interface enhancer is as follows:

[0046] Mix the polymer modifier and ethylene-vinyl acetate copolymer particles and then crush them. Then add the liquid co-solvent, cross-linking agent, and anti-aging agent to the mixture powder, stir to obtain a mixture, and then perform cold granulation at 75°C in an extruder to obtain the interface enhancer particles.

[0047] In this example, the asphalt binder used in the interface-enhanced asphalt mixture is SBS modified asphalt, with a penetration at 25°C of 49.1 (0.1 mm), a ductility at 5°C of 25.2 cm, a softening point of 76.5°C, a kinematic viscosity at 135°C of 1.8 Pa·s, a flash point of 270°C, and an elastic recovery at 25°C of 95%; the mass change after thin film oven aging is -0.069%, the penetration ratio at 25°C is 81%, and the residual ductility at 5°C is 16.6 cm;

[0048] The coarse aggregate is steel slag aggregate, with a Los Angeles abrasion loss of 11.6%, a crushing value of 9.8%, a water absorption of 2.61%, an apparent density of 3.512, a soundness of 0.2%, a polishing value of 63, a content of flaky and elongated particles of 4.5%, a content of soft stones of 0.1%, a swelling rate in water of 1.4%, and a swelling rate of the asphalt mixture in water of 0.5%;

[0049] The fine aggregate is limestone manufactured sand, with an apparent density of 2.712, a soundness of 0.3%, a sand equivalent of 72%, a methylene blue of 0.3 g / kg, and an angularity of 34 s;

[0050] The filler is a mixture of mineral powder and steel slag fine powder, with a weight ratio of mineral powder to steel slag fine powder of 2:1 and a mesh number of 100 - 200 meshes.

[0051] In this embodiment, the mixing method of the interface-enhanced asphalt mixture adopts the step-by-step mixing method, which includes the following steps: at 190 °C, the coarse aggregate is mixed with the interface enhancer for 15 s, then the fine aggregate and the asphalt binder are added and mixed for another 50 s, and then the filler is added and mixed for 45 s. The rotation speed during mixing is kept at 75 rpm.

[0052] In this embodiment, the grading type of the interface-enhanced asphalt mixture is the framework interlocking dense structure, and specifically the No. 13 grading is adopted. The grading of the No. 13 mixture is as follows: the passing rate of the standard sieve hole of 16 mm is 100%, the passing rate of the standard sieve hole of 13.2 mm is 95.6%, the passing rate of the standard sieve hole of 9.5 mm is 76.3%, the passing rate of the standard sieve hole of 4.75 mm is 44.5%, the passing rate of the standard sieve hole of 2.36 mm is 30.8%, the passing rate of the standard sieve hole of 1.18 mm is 21.0%, the passing rate of the standard sieve hole of 0.6 mm is 16.7%, the passing rate of the standard sieve hole of 0.3 mm is 11.1%, the passing rate of the standard sieve hole of 0.15 mm is 7.2%, and the passing rate of the standard sieve hole of 0.075 mm is 5.1%.

[0053] After the interface-enhanced asphalt mixture is mixed, the Marshall test is carried out. The mixture is formed by the Marshall compaction method. The compaction times are 75 times on both sides. The void ratio is 4.1%, the voids in mineral aggregate is 14.6%, the asphalt saturation is 71.9%, the stability is 13.7 kN, and the flow value is 2.9 mm.

[0054] After the interface-enhanced asphalt mixture is formed, the test methods in JTG E20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" are used to check its various road performance indicators. The residual strength ratio (TSR) of the freeze-thaw splitting test is 95.5%, the dynamic stability (60 °C) is 6800 times / mm, the low-temperature bending failure strain (-10 °C) is 3856 με, the maximum deformation of the Hamburg wheel rut test (50 °C, 20000 times) is 2.9 mm, and the fatigue life of the four-point bending fatigue test (15 °C, 10 Hz, under the condition of 230 με controlled strain) is 1.96 million times.

[0055] Example 2:

[0056] An interface-enhanced asphalt mixture, comprising the following raw materials in parts by weight:

[0057] 67 parts of coarse aggregate, 24 parts of fine aggregate, 3.4 parts of filler, 5.0 parts of asphalt binder, and 0.6 part of interface enhancer.

[0058] Among them, the interface improver includes the following raw materials in parts by weight: 25 parts of polymer modifier, 34 parts of ethylene-vinyl acetate copolymer, 12 parts of cosolvent, 9 parts of crosslinking agent, and 0.8 part of anti-aging agent. In this embodiment, SBR is selected as the polymer modifier, N-methylpyrrolidone is selected as the cosolvent, hydroxypropyl methacrylate is selected as the crosslinking agent, and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite is selected as the anti-aging agent;

[0059] The preparation method of the interface improver is as follows:

[0060] Mix the polymer modifier and ethylene-vinyl acetate copolymer particles and then crush them. Then, add the liquid cosolvent, crosslinking agent, and anti-aging agent to the mixture powder, stir to obtain a mixture, and then perform cold granulation at 75°C in an extruder to obtain the interface improver particles.

[0061] In this embodiment, the asphalt binder for the interface-enhanced asphalt mixture is a composite modified rubber asphalt, with a penetration at 25°C of 57.3 (0.1 mm), an elongation at 5°C of 26.7 cm, a softening point of 85.6°C, a kinematic viscosity at 180°C of 3.2 Pa·s, and an elastic recovery at 25°C of 95%; the mass change after thin film oven aging is 0.098%, the penetration ratio at 25°C is 72%, and the residual elongation at 5°C is 13.8 cm.

[0062] The selection of coarse aggregate, fine aggregate, and filler is the same as that in Example 1.

[0063] In this embodiment, the mixing method of the interface-enhanced asphalt mixture adopts a step-by-step mixing method, including the following steps: mix the coarse aggregate and the interface improver at 200°C for 20 s, add the fine aggregate and the asphalt binder and continue mixing for 45 s, add the filler and mix for 40 s, and keep the rotation speed at 75 rpm during mixing.

[0064] In this embodiment, the grading type of the interface-enhanced asphalt mixture is a framework interlocking dense structure, specifically adopting a No. 20 grading. The grading of the No. 20 mixture is as follows: the passing rate of the standard sieve hole of 26.5 mm is 100%, the passing rate of the standard sieve hole of 19 mm is 96.8%, the passing rate of the standard sieve hole of 16 mm is 85.0%, the passing rate of the standard sieve hole of 13.2 mm is 77.1%, the passing rate of the standard sieve hole of 9.5 mm is 61.2%, the passing rate of the standard sieve hole of 4.75 mm is 39.3%, the passing rate of the standard sieve hole of 2.36 mm is 26.9%, the passing rate of the standard sieve hole of 1.18 mm is 18.8%, the passing rate of the standard sieve hole of 0.6 mm is 13.4%, the passing rate of the standard sieve hole of 0.3 mm is 10.6%, the passing rate of the standard sieve hole of 0.15 mm is 6.8%, and the passing rate of the standard sieve hole of 0.075 mm is 4.9%.

[0065] After the interface-enhanced asphalt mixture is mixed, the Marshall test is carried out. The mixture is formed by the Marshall compaction method, with the compaction times being 75 times on both sides, the void ratio being 4.3%, the voids in mineral aggregate being 13.7%, the asphalt saturation being 68.6%, the stability being 15.2 kN, and the flow value being 2.6 mm.

[0066] After the interface-enhanced asphalt mixture is formed, the test methods in JTG E20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" are used to check its various pavement performance indicators. The residual strength ratio (TSR) of the freeze-thaw splitting test is 93.7%, the dynamic stability (60 °C) is 7350 times / mm, the low-temperature bending failure strain (-10 °C) is 3782 με, the maximum deformation of the Hamburg wheel rut test (50 °C, 20000 times) is 2.7 mm, and the fatigue life of the four-point bending fatigue test (15 °C, 10 Hz, under the condition of 230 με controlled strain) is 1.87 million times.

[0067] Comparative Example 1:

[0068] An asphalt mixture has the same composition as that in Example 1, except that in the preparation process, a conventional mixing method is adopted, that is, at 190 °C, the coarse aggregate, fine aggregate and interface enhancer are mixed for 20 s, and then the filler and asphalt binder are added and mixed for another 90 s.

[0069] Using the test method of Example 1, the Marshall test and pavement performance indicators of the asphalt mixture are as follows:

[0070] The void ratio is 4.2%, the voids in mineral aggregate are 14.7%, the asphalt saturation is 71.4%, the stability is 12.9 kN, and the flow value is 3.0 mm.

[0071] The residual strength ratio (TSR) of the freeze-thaw splitting test is 90.7%, the dynamic stability (60 °C) is 5120 times / mm, the low-temperature bending failure strain (-10 °C) is 3218 με, the maximum deformation of the Hamburg wheel rut test (50 °C, 20000 times) is 4.5 mm, and the fatigue life of the four-point bending fatigue test (15 °C, 10 Hz, under the condition of 230 με controlled strain) is 1.39 million times.

[0072] It can be seen from the data that since the composition raw materials used in Comparative Example 1 are the same as those in Example 1, the Marshall test data are not very different, but its pavement performance indicators are quite different from those in Example 1. This is because the step-by-step mixing method enables the interface enhancer to fully wrap on the surface of the coarse aggregate, greatly improving the interfacial adhesion between the aggregate and the asphalt, while the conventional mixing method cannot achieve the above effect.

[0073] Comparative Example 2:

[0074] An asphalt mixture, the preparation method of which is the same as that of Example 1, except that instead of using the interface enhancer provided in Example 1, conventional lime powder is used as an anti-stripping agent.

[0075] Marshall tests and road performance indicators were conducted on the asphalt mixture, and the data are as follows:

[0076] The void ratio is 4.0%, the voids in mineral aggregate (VMA) is 14.5%, the asphalt saturation is 72.4%, the stability is 12.5 kN, and the flow value is 3.0 mm.

[0077] The residual strength ratio (TSR) of the freeze-thaw splitting test is 89.6%, the dynamic stability (at 60 °C) is 4538 times / mm, the low-temperature bending failure strain (-10 °C) is 3127 με, the maximum deformation of the Hamburg wheel rut test (at 50 °C, 20000 times) is 5.5 mm, and the fatigue life of the four-point bending fatigue test (at 15 °C, 10 Hz, under the condition of 230 με controlled strain) is 1.28 million times.

[0078] It can be seen from the data that since the composition raw materials used in Comparative Example 2 are the same as those in Example 1 except for the interface enhancer, the Marshall test data are not much different, but the road performance indicators are far from those in Example 1, indicating that the interface enhancer provided by the present invention effectively ensures the various indicators of the prepared asphalt mixture.

[0079] Comparative Example 3:

[0080] An asphalt mixture, the preparation method of which is the same as that of Example 1, except that instead of using the interface enhancer provided in Example 1, conventional cement is used as an anti-stripping agent.

[0081] Marshall tests and road performance indicators were conducted on the asphalt mixture, and the data are as follows:

[0082] The void ratio is 4.1%, the voids in mineral aggregate (VMA) is 14.5%, the asphalt saturation is 71.7%, the stability is 12.7 kN, and the flow value is 2.9 mm.

[0083] The residual strength ratio (TSR) of the freeze-thaw splitting test is 88.1%, the dynamic stability (at 60 °C) is 4875 times / mm, the low-temperature bending failure strain (-10 °C) is 3051 με, the maximum deformation of the Hamburg wheel rut test (at 50 °C, 20000 times) is 5.3 mm, and the fatigue life of the four-point bending fatigue test (at 15 °C, 10 Hz, under the condition of 230 με controlled strain) is 1.16 million times.

[0084] As can be seen from the data, since the constituent materials used in Comparative Example 3 are the same as those in Example 1, the Marshall test data are not much different, but the pavement performance indicators are far from those in Example 1, indicating that the interface enhancer provided by the present invention effectively ensures various indicators of the prepared asphalt mixture.

[0085] Comparative Example 4:

[0086] An asphalt mixture, the preparation method is the same as that in Example 1, the difference is that the interface enhancer does not contain ethylene-vinyl acetate copolymer.

[0087] The Marshall test and pavement performance indicators of the asphalt mixture were carried out, and the data are as follows:

[0088] The void ratio is 4.0%, the void in mineral aggregate is 14.4%, the asphalt saturation is 72.2%, the stability is 13.0 kN, and the flow value is 2.8 mm.

[0089] The residual strength ratio (TSR) of the freeze-thaw splitting test is 91.6%, the dynamic stability (60 °C) is 5285 times / mm, the low-temperature bending failure strain (-10 °C) is 3220 με, the maximum deformation of the Hamburg wheel rutting test (50 °C, 20000 times) is 3.9 mm, and the fatigue life of the four-point bending fatigue test (15 °C, 10 Hz, 230 με controlled strain condition) is 1.42 million times.

[0090] As can be seen from the data, since the constituent materials used in Comparative Example 4 are the same as those in Example 1, the Marshall test data are not much different, but the pavement performance indicators are quite different from those in Example 1. The use of ethylene-vinyl acetate copolymer in the interface enhancer improves the adhesiveness of the asphalt mixture.

Claims

1. An interface-enhanced asphalt mixture, characterized in that, it comprises the following raw materials in parts by weight: 57 - 72 parts of coarse aggregate, 20 - 32 parts of fine aggregate, 2 - 5 parts of filler, 4.5 - 5.5 parts of asphalt binder, and 0.5 - 1.0 part of interface enhancer, and is prepared by a step-by-step mixing method; The coarse and fine aggregates and the fine aggregate are selected from steel slag, basalt or limestone; Among them, the interface enhancer comprises the following raw materials in parts by weight: 25 - 50 parts of polymer modifier, 15 - 35 parts of ethylene-vinyl acetate copolymer, 10 - 25 parts of co-solvent, 3 - 10 parts of cross-linking agent, 0.5 - 1 part of anti-aging agent; The step-by-step mixing method specifically comprises the following steps: At 190 - 200 °C, the coarse aggregate is mixed with the interface enhancer for 15 - 20 s, then the fine aggregate and the asphalt binder are added and mixing continues for 45 - 55 s, and then the filler is added and mixed for 35 - 45 s; In the interface enhancer, the polymer modifier is selected from one of SBS or SBR; The co-solvent is selected from one or a combination of aromatic solvents, amide compounds, ketones or esters, The cross-linking agent is selected from one or a combination of polyisocyanates, polyols, acrylate esters or amines, The anti-aging agent is selected from one of asphaltene gum solvents or phosphite esters; The preparation method of the interface enhancer is as follows: The polymer modifier and the ethylene-vinyl acetate copolymer particles are mixed and then pulverized, then the co-solvent, the cross-linking agent and the anti-aging agent are added to the mixture powder, stirred to obtain a mixture, and then cold granulated in an extruder at a temperature below 80 °C to obtain the interface enhancer particles.

2. The interface-enhanced asphalt mixture according to claim 1, characterized in that, the interface-enhanced asphalt mixture comprises the following raw materials in parts by weight: 60 - 70 parts of coarse aggregate, 23 - 29 parts of fine aggregate, 3 - 5 parts of filler, 4.5 - 5.5 parts of asphalt binder, and 0.5 - 1.0 part of interface enhancer.

3. The interface-enhanced asphalt mixture according to claim 2, characterized in that, the interface enhancer comprises the following raw materials in parts by weight: 44 parts of polymer modifier, 28 parts of ethylene-vinyl acetate copolymer, 21 parts of co-solvent, 6.5 parts of cross-linking agent, 0.5 part of anti-aging agent.

4. The interface-enhanced asphalt mixture according to claim 1, characterized in that, the rotation speed during mixing is 60 - 80 rpm.

5. The interface-enhanced asphalt mixture according to claim 4, characterized in that, the rotation speed is 75 rpm.

6. The interface-enhanced asphalt mixture according to claim 1, characterized in that, the grading type of the interface-enhanced asphalt mixture is a framework interlocked dense structure, and its maximum nominal size is 13.2 mm or 19 mm.

7. The interface-enhanced asphalt mixture according to claim 6, characterized in that, When the maximum engineering particle size of the interface-enhanced asphalt mixture gradation type is 13.2 mm, the gradation range is as follows: the passing rate range of the standard sieve hole of 16 mm is 100%, the passing rate range of the standard sieve hole of 13.2 mm is 90 - 100%, the passing rate range of the standard sieve hole of 9.5 mm is 70 - 82%, the passing rate range of the standard sieve hole of 4.75 mm is 39 - 53%, the passing rate range of the standard sieve hole of 2.36 mm is 26 - 36%, the passing rate range of the standard sieve hole of 1.18 mm is 18 - 26%, the passing rate range of the standard sieve hole of 0.6 mm is 14 - 19%, the passing rate range of the standard sieve hole of 0.3 mm is 9 - 13%, the passing rate range of the standard sieve hole of 0.15 mm is 5 - 9%, and the passing rate range of the standard sieve hole of 0.075 mm is 4 - 6%. When the maximum engineering particle size of the interface-enhanced asphalt mixture gradation type is 19 mm, the passing rate range of the standard sieve hole of 26.5 mm is 100%, the passing rate range of the standard sieve hole of 19 mm is 90 - 100%, the passing rate range of the standard sieve hole of 16 mm is 81 - 92%, the passing rate range of the standard sieve hole of 13.2 mm is 70 - 84%, the passing rate range of the standard sieve hole of 9.5 mm is 54 - 68%, the passing rate range of the standard sieve hole of 4.75 mm is 33 - 45%, the passing rate range of the standard sieve hole of 2.36 mm is 21 - 32%, the passing rate range of the standard sieve hole of 1.18 mm is 14 - 21%, the passing rate range of the standard sieve hole of 0.6 mm is 9 - 15%, the passing rate range of the standard sieve hole of 0.3 mm is 7 - 12%, the passing rate range of the standard sieve hole of 0.15 mm is 5 - 9%, and the passing rate range of the standard sieve hole of 0.075 mm is 4 - 6%.

8. The interface-enhanced asphalt mixture according to claim 1, characterized in that, the asphalt binder is selected from SBS modified asphalt or composite modified rubber asphalt; The parameters of SBS modified asphalt are as follows: the penetration at 25 °C is 35 - 55 (0.1 mm), the ductility at 5 °C ≥ 20 cm, the softening point ≥ 65 °C, the kinematic viscosity at 135 °C is 1.2 - 3.0 Pa·s, the flash point ≥ 230 °C, the elastic recovery at 25 °C ≥ 75%; the mass change after thin film oven aging ≤ ±0.5%, the penetration ratio at 25 °C ≥ 65%, and the residual ductility at 5 °C ≥ 15 cm; The parameters of the composite modified rubber asphalt are as follows: the penetration at 25 °C is 50 - 70 (0.1 mm), the ductility at 5 °C ≥ 20 cm, the softening point ≥ 70 °C, the kinematic viscosity at 180 °C is 1.0 - 4.0 Pa·s, the elastic recovery at 25 °C ≥ 75%; the mass change after thin film oven aging ≤ ±0.5%, the penetration ratio at 25 °C ≥ 60%, and the residual ductility at 5 °C ≥ 12 cm.

9. The interface-enhanced asphalt mixture according to claim 1, characterized in that, the filler is composed of mineral powder and steel slag fine powder.

10. The interface-enhanced asphalt mixture according to claim 9, characterized in that, in the filler, the weight ratio of the mineral powder to the steel slag fine powder is 2:

1.

11. The interface-enhanced asphalt mixture according to claim 1, characterized in that, The residual strength ratio of the interface-enhanced asphalt mixture in the freeze-thaw splitting test is greater than 90%, the dynamic stability at 60°C is greater than 5000 times / mm, the low-temperature bending failure strain at -10°C is greater than 3500 με, the maximum deformation in the Hamburg wheel tracking test at 50°C and 20000 times is less than 5.0 mm, and the fatigue life in the four-point bending fatigue test under the control strain conditions of 15°C, 10 Hz, and 230 με is greater than 1.5 million times; The interface-enhanced asphalt mixture is formed by the Marshall compaction method. The compaction times are 75 times on both sides, the void ratio is 3.0 - 5.0%, the voids in mineral aggregate of type 13 mixture are 13.5 - 15.5%, the voids in mineral aggregate of type 20 mixture are 12.5 - 14.5%, the asphalt saturation is 65.0 - 75.0%, the stability is greater than 10 kN, and the flow value is 1.5 - 3.5 mm.