A composite modified asphalt and preparation method thereof

Abstract

The invention provides a composite modified asphalt and a preparation method thereof, belonging to the technical field of polymer materials, wherein the composite modified asphalt contains SBS modified asphalt, modified tire rubber powder, epoxy asphalt, SBR, high modulus anti-rutting agent, asphalt warm mix agent, maleic acid resin, rubber softening oil, ethylhexyl stearate, isopropyl stearate, etc.; SBS modified asphalt is modified by AH-110 asphalt, AH-90 asphalt and AH-70 asphalt through SBS modifier, and calcium stearate, isopropyl stearate, asphalt warm mix agent, etc. are also added; modified tire rubber powder is obtained by using waste tire rubber powder as raw material, and surface composite coating modification is performed by basalt fiber, silica ash and AH-130 asphalt powder. Various components are melted and prepared by blending, and the composite modified asphalt has good high temperature stability, low temperature crack resistance, fatigue resistance and water damage resistance, and better adapts to the use environment of viaducts.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a composite modified asphalt and a preparation method thereof. Background Art

[0002] In modern cities, viaducts usually bear the task of a large number of vehicles passing through. Due to the frequent travel of vehicles and the influence of heavy traffic, the viaduct pavement needs to have good load-bearing capacity, anti-rutting performance and anti-fatigue performance. At the same time, the environment in which the viaduct is located is relatively complex and may face different climatic conditions, such as high temperature, low temperature, rain, etc., which requires the pavement material to have good high temperature stability and low temperature crack resistance.

[0003] Traditional road asphalt can meet the use requirements of ordinary roads to a certain extent, but its performance has some shortcomings in special application scenarios such as viaducts. First of all, the height of the viaduct is high and the vehicle speed is relatively fast, which puts higher requirements on the flatness and anti-skid performance of the road surface. If the road surface is uneven or the anti-skid performance is poor, it is easy to cause unstable vehicle driving and increase the probability of traffic accidents. Secondly, viaducts are usually affected by the bridge structure, such as vibration and deformation of the bridge, which requires it to have better flexibility and fatigue resistance, and be able to adapt to the dynamic changes of the bridge without damage. Ordinary road asphalt is difficult to adapt to such dynamic changes and is prone to cracks, peeling and other damage. In addition, because the loads borne by the viaduct are more complex and the vibration is frequent, the requirements for anti-fatigue performance are higher, and it is necessary to have better resistance to fatigue damage to ensure the durability of the bridge deck pavement layer.

[0004] In order to meet the use requirements of viaducts, asphalt materials specially designed for viaducts came into being. This type of asphalt material is usually optimized and improved in terms of formula and performance, such as adding polymer modifiers, anti-rutting agents, anti-stripping agents, etc., in order to improve the corresponding use performance.

[0005] However, the current bridge asphalt still cannot meet the demand for durability and needs frequent maintenance and repair. It still needs to be improved in terms of high temperature stability, low temperature crack resistance, fatigue resistance and water damage resistance. It is necessary to continuously optimize the raw material formula and improve the preparation process to improve the various properties of asphalt materials, so that it can better adapt to the use environment of viaducts and provide guarantees for the safety and smoothness of urban traffic. Summary of the invention

[0006] In order to further improve the high temperature stability, low temperature crack resistance, fatigue resistance and water damage resistance of viaduct pavement asphalt, and better adapt to the use environment of the viaduct. The present invention provides a composite modified asphalt and a preparation method thereof. The composite modified asphalt contains SBS modified asphalt, modified tire rubber powder, epoxy asphalt, SBR, high modulus anti-rutting agent, asphalt warm mix agent, maleic acid resin, rubber softening oil, ethylhexyl stearate, isopropyl stearate, asphalt defoamer, etc. The composite modified asphalt prepared by melting and blending various components has good high temperature stability, low temperature crack resistance, fatigue resistance and water damage resistance, and better adapts to the use environment of the viaduct. The specific technical scheme is as follows:

[0007] A composite modified asphalt is prepared from the following raw materials in parts by mass: 70 to 80 parts of SBS modified asphalt, 15 to 25 parts of modified tire rubber powder, 5 to 10 parts of epoxy asphalt, 2 to 4 parts of SBR, 0.15 to 0.3 parts of high modulus anti-rutting agent, 2 to 3 parts of asphalt warm mix agent, 0.08 to 0.15 parts of maleic acid resin, 0.3 to 0.6 parts of rubber softening oil, 0.1 to 0.5 parts of ethylhexyl stearate, 0.1 to 0.5 parts of isopropyl stearate, and 0.01 to 0.03 parts of asphalt defoamer; the SBS modified asphalt is prepared by modifying AH-110 asphalt, AH-90 asphalt and AH-70 asphalt with an SBS modifier; the modified tire rubber powder is prepared by surface-modifying waste tire rubber powder with basalt fiber.

[0008] In the above-mentioned composite modified asphalt, the preparation method of the SBS modified asphalt comprises the following steps:

[0009] According to the mass ratio, AH-110 asphalt: AH-90 asphalt: AH-70 asphalt: SBS modifier: calcium stearate: isopropyl stearate: asphalt warm mix agent: asphalt defoamer = (15-25): (55-65): (10-15): (3-6): (0.1-0.3): (0.4-0.8): (1.5-2.5): (0.01-0.03); AH-110 asphalt, AH-90 asphalt, AH-70 asphalt and asphalt warm mix agent are melted at 140-160°C, and then isopropyl stearate and asphalt defoamer are added, stirred at low speed, and after mixing evenly, SBS modifier is added, stirred and sheared at high speed, and then developed at 130-150°C, and finally calcium stearate is added, stirred at low speed, and after mixing evenly, the temperature is lowered to obtain SBS modified asphalt.

[0010] In the above-mentioned preparation method of SBS modified asphalt, the rotation speed of the low-speed stirring is 200r / min~500r / min, and the time of low-speed stirring is 30min~60min; the rotation speed of the high-speed stirring and shearing is 3000r / min~5000r / min, and the time of high-speed stirring and shearing is 30min~60min; the stirring speed of the development is 300r / min~600r / min, and the time of development is 1h~3h; the stirring speed of the cooling is 30r / min~60r / min.

[0011] In the above-mentioned composite modified asphalt, the preparation method of the modified tire rubber powder comprises the following steps:

[0012] According to the mass ratio, waste tire rubber powder: basalt fiber: silica ash: AH-130 asphalt powder = (90-100): (5-10): (0.5-2): (2-4), firstly, the basalt fiber and silica ash are evenly mixed by air flow, and then the AH-130 asphalt powder is added and evenly mixed by air flow to obtain a mixture; the mixture is added into the waste tire rubber powder and evenly mixed, and then heated to 45°C-50°C for modification, cooled, and broken up to obtain a modified tire rubber powder.

[0013] In the preparation method of the modified tire rubber powder, the median particle size of the waste tire rubber powder is 700 μm to 800 μm; the diameter of the basalt fiber is 3 μm to 15 μm, and the length is 0.5 mm to 2.5 mm; the median particle size of the AH-130 asphalt powder is less than 5 μm.

[0014] In the above method for preparing modified tire rubber powder, the modification time is 30 minutes to 60 minutes.

[0015] In the above-mentioned composite modified asphalt, the SBR is styrene-butadiene rubber powder, and the particle size of the styrene-butadiene rubber powder is sieved through 40-80 meshes.

[0016] In the above-mentioned composite modified asphalt, the model of the high modulus anti-rutting agent is HFM-16K; the model of the maleic acid resin is WR5260; the model of the rubber softening oil is H302, and the rubber softening oil contains liquid chlorinated paraffin, which is a chlorinated derivative of paraffin hydrocarbons.

[0017] In the above technical solution, the model of the asphalt warm mix agent is WSG-H02; the model of the asphalt defoamer is W-735.

[0018] The above-mentioned method for preparing the composite modified asphalt comprises the following steps:

[0019] SBS modified asphalt, epoxy asphalt, asphalt warm mix agent, isopropyl stearate and defoamer are mixed and melted at 140°C to 150°C according to their mass proportions; then modified tire rubber powder, SBR, ethylhexyl stearate and rubber softening oil are added and mixed and melted continuously; finally, high modulus anti-rutting agent and maleic acid resin are added and mixed and melted continuously until uniform, thereby obtaining a composite modified asphalt.

[0020] The composite modified asphalt and the preparation method thereof provided by the present invention have the following beneficial effects compared with the prior art:

[0021] 1. The composite modified asphalt of the present invention contains SBS modified asphalt, modified tire rubber powder, epoxy asphalt, SBR, high modulus anti-rutting agent, asphalt warm mix agent, maleic acid resin, rubber softening oil, ethylhexyl stearate, isopropyl stearate, asphalt defoamer, etc. The various components are melted and blended to prepare the composite modified asphalt, which has good high temperature stability, low temperature crack resistance, fatigue resistance and water damage resistance, and is better adapted to the use environment of the viaduct.

[0022] 2. SBS modified asphalt is made of AH-110 asphalt, AH-90 asphalt and AH-70 asphalt in a certain proportion, and modified by SBS modifier, in which calcium stearate, isopropyl stearate, asphalt warm mix agent and asphalt defoamer are added. Among them, the use of AH-110 asphalt, AH-90 asphalt and AH-70 asphalt in a certain proportion can improve the 60℃ dynamic stability, tensile strength ratio, 25℃ elastic recovery rate, initial and molding strength of SBS modified asphalt, and make the high temperature stability, low temperature crack resistance, fatigue resistance and water damage resistance of the composite modified asphalt higher. Calcium stearate can stabilize SBS modified asphalt well to prevent denaturation. Isopropyl stearate can well fuse asphalts of various properties, and can promote the fusion of SBS modification, promote the improvement of modification effect and stability, and thus improve the performance of composite modified asphalt. Asphalt warm mix agent can reduce the temperature of asphalt modification and prevent aging.

[0023] The SBS modified asphalt of the present invention has good high temperature stability and can effectively resist the formation of rutting. Under high temperature conditions, the viscosity of the SBS modified asphalt increases and the elastic recovery performance is good, so that the road surface is not easy to deform under the vehicle load. In a low temperature environment, the SBS modified asphalt can still maintain a certain flexibility and can prevent the road surface from cracking due to temperature changes. It can withstand repeated vehicle loads, reduce the generation of road cracks, has good fatigue resistance, and prolongs the service life of the viaduct road surface.

[0024] 3. Modified tire rubber powder is made of waste tire rubber powder as raw material, and is obtained by surface composite coating modification with basalt fiber, silica ash and AH-130 asphalt powder. Among them, basalt fiber and silica ash are mixed in advance by air flow, and silica ash can improve the dispersion of basalt fiber, thereby improving the uniformity of coating; in addition, silica ash can increase the viscosity and stiffness modulus of asphalt, thereby improving the ability of asphalt mixture to resist deformation at high temperature and reduce the formation of rutting. Silica ash can improve the low-temperature performance of asphalt, reduce the brittle temperature of asphalt, improve its flexibility at low temperature, and reduce the low-temperature cracking of the road surface. Silica ash can effectively reduce the affinity of asphalt with water, improve the water damage resistance of asphalt mixture, and prevent the road surface from being damaged by water erosion. Silica ash forms a good combination with asphalt, which improves the overall strength of asphalt mixture, enables it to withstand greater traffic loads, and prolongs the service life of the road. Silica ash helps to improve the workability of asphalt mixture. AH-130 asphalt powder has low-temperature adhesion. Small-sized AH-130 asphalt powder can well achieve the surface coating of waste tire rubber powder particles by basalt fiber and silica fume, which is not easy to peel off. In the subsequent preparation of composite modified asphalt, modified tire rubber powder, as a carrier of basalt fiber and silica fume, can promote the dispersion of basalt fiber and silica fume, with uniform quality, not easy to stratify and settle, and effectively improve the overall high and low temperature mechanical properties of composite modified asphalt.

[0025] Waste tire rubber powder has a good noise reduction effect. When vehicles travel on rubber asphalt pavement, the impact on the surrounding environment is reduced. Waste tire rubber powder has high elasticity and toughness, which can adapt to the deformation and vibration of the bridge and reduce the occurrence of road cracks. Waste tire rubber powder can delay the aging process of asphalt and keep the road surface in good performance. It can also improve the anti-skid performance of the road surface and enhance driving safety.

[0026] 4. Epoxy asphalt has high strength and strong adhesion. It is very tightly bonded to the bridge structure and can effectively prevent the pavement from delamination. It has excellent high temperature stability and low temperature crack resistance, and can still maintain good performance under extreme temperature conditions. It has strong corrosion resistance. Epoxy asphalt has good resistance to water vapor, chemicals, etc., and is suitable for various harsh environments with strong corrosion resistance.

[0027] 5. Styrene-butadiene rubber (SBR) can increase the viscosity of asphalt, making it difficult to soften and flow at high temperatures, thereby improving the road's resistance to rutting and reducing road deformation in hot seasons. In low-temperature environments, styrene-butadiene rubber can improve the flexibility of asphalt, reduce its brittle temperature, prevent cracks in the road surface, and improve the durability of the road surface. It can also slow down the aging of asphalt under the influence of natural factors such as sunlight and air, and extend the service life of the road surface. Styrene-butadiene rubber can enhance the adhesion between asphalt and stone, making the road surface more solid, reducing the peeling of stone, and ensuring the flatness of the road surface and driving safety.

[0028] 6. According to the characteristics of the composite modified asphalt components, the use of specific high modulus anti-rutting agents can significantly improve the stiffness modulus of the asphalt mixture, making it more difficult to deform at high temperatures, effectively resisting the plastic flow caused by repeated rolling of vehicles, greatly reducing the depth and development speed of rutting, and ensuring the flatness of the road surface and driving safety. High modulus anti-rutting agents help to improve the fatigue life of asphalt pavements and reduce the risk of fatigue cracks due to repeated vehicle loads during long-term use. During the mixing, paving and compaction of asphalt mixtures, high modulus anti-rutting agents can improve the workability of the mixture, making it easier to construct and operate, and ensuring the construction quality of the road surface.

[0029] 7. Asphalt warm mix agent can reduce the construction temperature, mix and construct at a relatively low temperature, reduce fuel consumption, reduce energy costs, and also reduce the exhaust gas emissions caused by fuel combustion during construction, which is more environmentally friendly. In cold seasons, warm mix technology reduces the construction temperature requirements, so that highway construction can be carried out at a lower temperature, extending the construction season and facilitating the arrangement of project progress.

[0030] 8. Maleic acid resin can significantly enhance the bonding force between asphalt and aggregates such as stone, ensuring that under various environmental conditions, the aggregates in the asphalt mixture are not easily separated from the asphalt, thereby effectively preventing the road surface from becoming loose and peeling, and improving the integrity and durability of the road surface. It can increase the hardness and viscosity of asphalt, making the asphalt mixture more resistant to deformation at high temperatures. On highways, under the repeated action of vehicle loads, it can reduce the formation of rutting, maintain the flatness of the road surface, and improve driving safety and comfort. Maleic acid resin can, to a certain extent, slow down the aging speed of asphalt under the action of natural factors such as sunlight, air and moisture, and reduce the degree of aging of asphalt, thereby extending the service life of highway pavement and reducing the cost of repair and maintenance of the pavement.

[0031] 9. Rubber softening oil can serve as a medium to promote the full integration of rubber and asphalt. It can improve the dispersibility of rubber in asphalt, so that rubber and asphalt form a more stable system, thereby giving full play to the modification effect of rubber and improving the comprehensive performance of asphalt mixture. In low temperature environment, rubber softening oil can make asphalt softer, reduce the brittle temperature of asphalt, and improve the flexibility of asphalt mixture. This helps to reduce the possibility of cracks on highway pavement under low temperature conditions such as winter, enhance the low-temperature crack resistance of the pavement, and ensure the integrity of the pavement and driving safety. Rubber softening oil can adjust the viscosity of asphalt, making it easier to mix, spread and compact during construction. Appropriate viscosity helps to improve construction efficiency and ensure that the asphalt mixture can be evenly distributed on the road surface to form a flat and dense road surface structure.

[0032] 10. Ethylhexyl stearate is well compatible with asphalt and plays a role in stabilizing dispersion in asphalt. It can help other additives to be better dispersed in asphalt, improving the overall stability and performance uniformity of asphalt mixture. In particular, ethylhexyl stearate can promote the fusion of rubber and asphalt, is not easy to stratify and settle, has stable performance, does not produce weak parts, and can ensure overall performance improvement. It can adjust the viscosity of composite modified asphalt, making it easier to mix, spread and compact during construction. Appropriate viscosity is conducive to improving construction efficiency, ensuring uniform distribution of asphalt mixture, and forming a high-quality pavement structure.

[0033] 11. Under low temperature conditions, isopropyl stearate can make asphalt softer, reduce the brittle temperature of asphalt, and improve the flexibility of asphalt mixture. This helps to reduce the possibility of cracks on highway pavement in low temperature environments such as winter, enhance the low-temperature crack resistance of the pavement, and ensure the integrity of the pavement and the safety of driving. It can adjust the viscosity of asphalt, making it easier to mix, spread and compact asphalt during construction. Appropriate viscosity helps to improve construction efficiency, ensure the uniform distribution of asphalt mixture, and form a flat and dense pavement structure. Isopropyl stearate is well compatible with asphalt and plays a role in stabilizing dispersion in asphalt. It helps other additives to be evenly dispersed in asphalt, improving the overall stability of asphalt mixtures and the consistency of performance. The combination of ethylhexyl stearate and isopropyl stearate has a synergistic effect, can well blend the asphalt system, has good fusion, is not easy to stratify and settle, has stable performance, will not produce weak parts, and can ensure overall performance improvement. DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with specific implementation cases, but the present invention is not limited to these embodiments.

[0035] Example 1

[0036] A composite modified asphalt is prepared from the following raw materials in parts by mass: 75 parts of SBS modified asphalt, 205 parts of modified tire rubber powder, 8 parts of epoxy asphalt, 3 parts of SBR, 0.2 parts of high modulus anti-rutting agent, 2.5 parts of asphalt warm mix agent, 0.12 parts of maleic acid resin, 0.45 parts of rubber softening oil, 0.3 parts of ethylhexyl stearate, 0.3 parts of isopropyl stearate, and 0.02 parts of asphalt defoamer.

[0037] The preparation method of SBS modified asphalt comprises the following steps:

[0038] According to the mass ratio, AH-110 asphalt: AH-90 asphalt: AH-70 asphalt: SBS modifier: calcium stearate: isopropyl stearate: asphalt warm mix agent: asphalt defoamer = 20:60:12:4.5:0.2:0.6:2:0.02; AH-110 asphalt, AH-90 asphalt, AH-70 asphalt and asphalt warm mix agent were melted at 150°C, and then isopropyl stearate and asphalt defoamer were added, and the mixture was stirred at a low speed of 400r / min. After stirring for 45 minutes and mixing evenly, add SBS modifier and stir and shear at a high speed of 4000r / min for 45 minutes. Then develop at 140℃ with a stirring speed of 500r / min for 2 hours. Finally, add calcium stearate and stir at a low speed of 300r / min for 45 minutes. After mixing evenly, cool down. Stir at 50r / min during the cooling process until it becomes viscous and cannot be stirred. Cool to obtain SBS modified asphalt.

[0039] The preparation method of modified tire rubber powder comprises the following steps:

[0040] According to the mass ratio, waste tire rubber powder: basalt fiber: silica ash: AH-130 asphalt powder = 95:7:1.2:3. First, the basalt fiber and silica ash are evenly mixed by air flow, and then the AH-130 asphalt powder is added and evenly mixed by air flow to obtain a mixture; the mixture is added into the waste tire rubber powder and mixed evenly, and then heated to 46°C for modification for 45 minutes, cooled, and broken up to obtain modified tire rubber powder.

[0041] The above-mentioned method for preparing the composite modified asphalt comprises the following steps:

[0042] SBS modified asphalt, epoxy asphalt, asphalt warm mix agent, isopropyl stearate and defoamer were mixed and melted at 145°C according to their mass proportions; then modified tire rubber powder, SBR, ethylhexyl stearate and rubber softening oil were added and continued to be mixed and melted; finally, high modulus anti-rutting agent and maleic acid resin were added and continued to be mixed and melted until uniform, so as to obtain composite modified asphalt.

[0043] The median particle size of the waste tire rubber powder used in this embodiment is 754 μm; the diameter of the basalt fiber is 3 μm to 15 μm, and the length is 0.5 mm to 2.5 mm; the median particle size of the AH-130 asphalt powder is 3.6 μm; SBR is styrene butadiene rubber powder, and the particle size of the styrene butadiene rubber powder is sieved through a 60-mesh sieve.

[0044] Example 2

[0045] A composite modified asphalt is prepared from the following raw materials in parts by mass: 70 parts of SBS modified asphalt, 15 parts of modified tire rubber powder, 5 parts of epoxy asphalt, 2 parts of SBR, 0.15 parts of high modulus anti-rutting agent, 2 parts of asphalt warm mix agent, 0.08 parts of maleic acid resin, 0.3 parts of rubber softening oil, 0.1 parts of ethylhexyl stearate, 0.1 parts of isopropyl stearate, and 0.01 parts of asphalt defoamer.

[0046] The preparation method of SBS modified asphalt comprises the following steps:

[0047] According to the mass ratio, AH-110 asphalt: AH-90 asphalt: AH-70 asphalt: SBS modifier: calcium stearate: isopropyl stearate: asphalt warm mix agent: asphalt defoamer = 15:55:10:3:0.1:0.4:1.5:0.01; AH-110 asphalt, AH-90 asphalt, AH-70 asphalt and asphalt warm mix agent were melted at 140°C, and then isopropyl stearate and asphalt defoamer were added, and the mixture was stirred at a low speed of 200r / min. After stirring for 30 minutes and mixing evenly, add SBS modifier and stir and shear at a high speed of 3000r / min for 30 minutes. Then develop at 130℃ with a stirring speed of 300r / min for 1h. Finally, add calcium stearate and stir at a low speed of 200r / min for 30min. After mixing evenly, cool down. Stir at 30r / min during the cooling process until it becomes viscous and cannot be stirred. Cool to obtain SBS modified asphalt.

[0048] The preparation method of modified tire rubber powder comprises the following steps:

[0049] According to the mass ratio, waste tire rubber powder: basalt fiber: silica ash: AH-130 asphalt powder = 90:5:0.5:2. First, the basalt fiber and silica ash are evenly mixed by air flow, and then the AH-130 asphalt powder is added and evenly mixed by air flow to obtain a mixture; the mixture is added into the waste tire rubber powder and mixed evenly, and then heated to 48°C for modification for 30 minutes, cooled, and broken up to obtain modified tire rubber powder.

[0050] The above-mentioned method for preparing the composite modified asphalt comprises the following steps:

[0051] SBS modified asphalt, epoxy asphalt, asphalt warm mix agent, isopropyl stearate and defoamer were mixed and melted at 140°C according to their mass proportions; then modified tire rubber powder, SBR, ethylhexyl stearate and rubber softening oil were added and continued to be mixed and melted; finally, high modulus anti-rutting agent and maleic acid resin were added and continued to be mixed and melted until uniform, so as to obtain composite modified asphalt.

[0052] The median particle size of the waste tire rubber powder used in this embodiment is 800 μm; the diameter of the basalt fiber is 3 μm to 15 μm, and the length is 0.5 mm to 2.5 mm; the median particle size of the AH-130 asphalt powder is 4.2 μm; SBR is styrene butadiene rubber powder, and the particle size of the styrene butadiene rubber powder is sieved through a 40-mesh sieve.

[0053] Example 3

[0054] A composite modified asphalt is prepared from the following raw materials in parts by mass: 70 parts of SBS modified asphalt, 25 parts of modified tire rubber powder, 5 parts of epoxy asphalt, 4 parts of SBR, 0.15 parts of high modulus anti-rutting agent, 3 parts of asphalt warm mix agent, 0.08 parts of maleic acid resin, 0.6 parts of rubber softening oil, 0.1 parts of ethylhexyl stearate, 0.5 parts of isopropyl stearate, and 0.01 parts of asphalt defoamer.

[0055] The preparation method of SBS modified asphalt comprises the following steps:

[0056] According to the mass ratio, AH-110 asphalt: AH-90 asphalt: AH-70 asphalt: SBS modifier: calcium stearate: isopropyl stearate: asphalt warm mix agent: asphalt defoamer = 25:55:15:3:0.3:0.4:2.5:0.01; AH-110 asphalt, AH-90 asphalt, AH-70 asphalt and asphalt warm mix agent were melted at 160°C, and then isopropyl stearate and asphalt defoamer were added, and the mixture was stirred at a low speed of 200r / min. After stirring for 60 minutes and mixing evenly, add SBS modifier and stir and shear at a high speed of 3000r / min for 60 minutes. Then develop at 130℃ with a stirring speed of 600r / min for 1h. Finally, add calcium stearate and stir at a low speed of 500r / min for 30min. After mixing evenly, cool down. Stir at 60r / min during the cooling process until it becomes viscous and cannot be stirred. Cool to obtain SBS modified asphalt.

[0057] The preparation method of modified tire rubber powder comprises the following steps:

[0058] According to the mass ratio, waste tire rubber powder: basalt fiber: silica ash: AH-130 asphalt powder = 90:10:0.5:4. First, the basalt fiber and silica ash are evenly mixed by air flow, and then the AH-130 asphalt powder is added and evenly mixed by air flow to obtain a mixture; the mixture is added into the waste tire rubber powder and mixed evenly, and then heated to 50°C for modification for 60 minutes, cooled, and broken up to obtain modified tire rubber powder.

[0059] The above-mentioned method for preparing the composite modified asphalt comprises the following steps:

[0060] SBS modified asphalt, epoxy asphalt, asphalt warm mix agent, isopropyl stearate and defoamer were mixed and melted at 140°C according to their mass proportions; then modified tire rubber powder, SBR, ethylhexyl stearate and rubber softening oil were added and continued to be mixed and melted; finally, high modulus anti-rutting agent and maleic acid resin were added and continued to be mixed and melted until uniform, so as to obtain composite modified asphalt.

[0061] The median particle size of the waste tire rubber powder used in this embodiment is 726 μm; the diameter of the basalt fiber is 3 μm to 15 μm, and the length is 0.5 mm to 2.5 mm; the median particle size of the AH-130 asphalt powder is less than 2.8 μm; SBR is styrene butadiene rubber powder, and the particle size of the styrene butadiene rubber powder is sieved through an 80-mesh sieve.

[0062] Example 4

[0063] A composite modified asphalt is prepared from the following raw materials in parts by mass: 80 parts of SBS modified asphalt, 25 parts of modified tire rubber powder, 10 parts of epoxy asphalt, 4 parts of SBR, 0.3 parts of high modulus anti-rutting agent, 3 parts of asphalt warm mix agent, 0.15 parts of maleic acid resin, 0.6 parts of rubber softening oil, 0.5 parts of ethylhexyl stearate, 0.5 parts of isopropyl stearate, and 0.03 parts of asphalt defoamer.

[0064] The preparation method of SBS modified asphalt comprises the following steps:

[0065] According to the mass ratio, AH-110 asphalt: AH-90 asphalt: AH-70 asphalt: SBS modifier: calcium stearate: isopropyl stearate: asphalt warm mix agent: asphalt defoamer = 25:65:15:6:0.3:0.8:2.5:0.03; AH-110 asphalt, AH-90 asphalt, AH-70 asphalt and asphalt warm mix agent were melted at 160°C, and then isopropyl stearate and asphalt defoamer were added, and the mixture was stirred at a low speed of 500r / min. After stirring for 60 minutes and mixing evenly, add SBS modifier and stir and shear at a high speed of 5000r / min for 60 minutes. Then develop at 150℃ with a stirring speed of 600r / min for 3 hours. Finally, add calcium stearate and stir at a low speed of 500r / min for 60 minutes. After mixing evenly, cool down. Stir at 60r / min during the cooling process until it becomes viscous and cannot be stirred. Cool to obtain SBS modified asphalt.

[0066] The preparation method of modified tire rubber powder comprises the following steps:

[0067] According to the mass ratio, waste tire rubber powder: basalt fiber: silica ash: AH-130 asphalt powder = 100:10:2:4. First, the basalt fiber and silica ash are evenly mixed by air flow, and then the AH-130 asphalt powder is added and evenly mixed by air flow to obtain a mixture; the mixture is added into the waste tire rubber powder and mixed evenly, and then heated to 45°C for modification for 60 minutes, cooled, and broken up to obtain modified tire rubber powder.

[0068] The above-mentioned method for preparing the composite modified asphalt comprises the following steps:

[0069] SBS modified asphalt, epoxy asphalt, asphalt warm mix agent, isopropyl stearate and defoamer were mixed and melted at 150°C according to their mass proportions; then modified tire rubber powder, SBR, ethylhexyl stearate and rubber softening oil were added and continued to be mixed and melted; finally, high modulus anti-rutting agent and maleic acid resin were added and continued to be mixed and melted until uniform, so as to obtain composite modified asphalt.

[0070] The median particle size of the waste tire rubber powder used in this embodiment is 783 μm; the diameter of the basalt fiber is 3 μm to 15 μm, and the length is 0.5 mm to 2.5 mm; the median particle size of the AH-130 asphalt powder is 1.6 μm; SBR is styrene butadiene rubber powder, and the particle size of the styrene butadiene rubber powder is sieved through a 40-mesh sieve.

[0071] Example 5

[0072] A composite modified asphalt is prepared from the following raw materials in parts by mass: 80 parts of SBS modified asphalt, 15 parts of modified tire rubber powder, 10 parts of epoxy asphalt, 2 parts of SBR, 0.3 parts of high modulus anti-rutting agent, 2 parts of asphalt warm mix agent, 0.15 parts of maleic acid resin, 0.3 parts of rubber softening oil, 0.5 parts of ethylhexyl stearate, 0.1 parts of isopropyl stearate, and 0.03 parts of asphalt defoamer.

[0073] The preparation method of SBS modified asphalt comprises the following steps:

[0074] According to the mass ratio, AH-110 asphalt: AH-90 asphalt: AH-70 asphalt: SBS modifier: calcium stearate: isopropyl stearate: asphalt warm mix agent: asphalt defoamer = 15:65:10:6:0.1:0.8:1.5:0.03; AH-110 asphalt, AH-90 asphalt, AH-70 asphalt and asphalt warm mix agent were melted at 140°C, and then isopropyl stearate and asphalt defoamer were added, and the mixture was stirred at a low speed of 500r / min. After stirring for 30 minutes and mixing evenly, add SBS modifier and stir and shear at a high speed of 5000r / min for 30 minutes. Then develop at 150℃ with a stirring speed of 300r / min for 3 hours. Finally, add calcium stearate and stir at a low speed of 200r / min for 60 minutes. After mixing evenly, cool down. Stir at 30r / min during the cooling process until it becomes viscous and cannot be stirred. Cool to obtain SBS modified asphalt.

[0075] The preparation method of modified tire rubber powder comprises the following steps:

[0076] According to the mass ratio, waste tire rubber powder: basalt fiber: silica ash: AH-130 asphalt powder = 100:5:2:2. First, the basalt fiber and silica ash are evenly mixed by air flow, and then the AH-130 asphalt powder is added and evenly mixed by air flow to obtain a mixture; the mixture is added into the waste tire rubber powder and mixed evenly, and then heated to 47°C for modification for 30 minutes, cooled, and broken up to obtain modified tire rubber powder.

[0077] The above-mentioned method for preparing the composite modified asphalt comprises the following steps:

[0078] SBS modified asphalt, epoxy asphalt, asphalt warm mix agent, isopropyl stearate and defoamer were mixed and melted at 150°C according to their mass proportions; then modified tire rubber powder, SBR, ethylhexyl stearate and rubber softening oil were added and continued to be mixed and melted; finally, high modulus anti-rutting agent and maleic acid resin were added and continued to be mixed and melted until uniform, so as to obtain composite modified asphalt.

[0079] The median particle size of the waste tire rubber powder used in this embodiment is 700 μm; the diameter of the basalt fiber is 3 μm to 15 μm, and the length is 0.5 mm to 2.5 mm; the median particle size of the AH-130 asphalt powder is 2.4 μm; SBR is styrene butadiene rubber powder, and the particle size of the styrene butadiene rubber powder is sieved through 80 mesh.

[0080] The model of the high modulus anti-rutting agent used in the above embodiments is HFM-16K, Beijing Huajian Shenghe Technology Development Co., Ltd.; the model of the maleic acid resin is WR5260, Shanghai Shuixing Industrial Co., Ltd.; the model of the rubber softening oil is H302, and the rubber softening oil contains liquid chlorinated paraffin, which is a chlorinated derivative of paraffin hydrocarbons, Maoming Hongtai Petrochemical Co., Ltd.; the model of the asphalt warm mix agent is WSG-H02, Shanghai Wanzhao Fine Chemical Co., Ltd.; the model of the asphalt defoamer is W-735, Guangzhou Zhongwan New Materials Co., Ltd.

[0081] The asphalt raw materials used in the above embodiments are from the same batch of raw materials, and the specific indicators are shown in Table 1 below.

[0082] Table 1 Asphalt raw material indicators

[0083]

[0084] The allowable index range of each batch of asphalt raw materials after mass production refers to the standard range of "Heavy Traffic Road Petroleum Asphalt" GB / T15180. Among them, the softening point index of AH-130 asphalt is required to be below 45℃.

[0085] Comparative Example 1

[0086] In the preparation method of SBS modified asphalt, isopropyl stearate is not added, and the content of isopropyl stearate is replaced by AH-90 asphalt; other parameters and methods are the same as in Example 1.

[0087] Comparative Example 2

[0088] In the preparation method of SBS modified asphalt, AH-110 asphalt, AH-70 asphalt and isopropyl stearate are not added, and the contents of AH-110 asphalt, AH-70 asphalt and isopropyl stearate are replaced by AH-90 asphalt; other parameters and methods are the same as in Example 1.

[0089] Comparative Example 3

[0090] The preparation method of the modified tire rubber powder is to directly mix 99.2 parts of waste tire rubber powder and 7 parts of basalt fiber at room temperature to obtain the modified tire rubber powder; other parameters and methods are the same as in Example 1.

[0091] Comparative Example 4

[0092] In the preparation method of the modified tire rubber powder, no silica fume is added, and the content of silica fume is replaced by waste tire rubber powder; other parameters and methods are the same as in Example 1.

[0093] Comparative Example 5

[0094] In the composite modified asphalt, modified tire rubber powder and SBR are not added, and the content of modified tire rubber powder and SBR is replaced by SBS modified asphalt; other parameters and methods are the same as in Example 1.

[0095] Comparative Example 6

[0096] In the composite modified asphalt, ethylhexyl stearate is not added, and the content of ethylhexyl stearate is replaced by SBS modified asphalt; other parameters and methods are the same as in Example 1.

[0097] Comparative Example 7

[0098] In the composite modified asphalt, isopropyl stearate is not added, and the content of isopropyl stearate is replaced by SBS modified asphalt; other parameters and methods are the same as in Example 1.

[0099] Comparative Example 8

[0100] In the composite modified asphalt, ethylhexyl stearate and isopropyl stearate are not added, and the content of ethylhexyl stearate and isopropyl stearate is replaced by SBS modified asphalt; other parameters and methods are the same as in Example 1.

[0101] According to the test methods of "Testing Procedures for Asphalt and Asphalt Mixtures for Highway Engineering" JTG E20-2011 and "Construction and Acceptance Procedures for Finished and Semi-finished Products of Roads and Drainage Pipelines" DG / TJ 08-87-2016, the above-mentioned composite modified asphalts were tested for indicators. Among them: the mass loss rate was tested by the cohesiveness test method; the residual stability was tested by the immersion Marshall test method; the 60°C dynamic stability was tested by the high temperature stability test method, and the asphalt (5wt% addition) was mixed with the C50 concrete sample to simulate the pavement; the tensile strength ratio was tested by the freeze-thaw splitting test method; the elastic recovery rate was tested by the ductility test machine, and the middle part of the test mold was replaced with a straight side mold; the initial strength and molding strength were tested by the Marshall strength test method, and the asphalt (5wt% addition) was mixed with the C50 concrete sample to prepare the test piece. The results are shown in Table 2 below:

[0102] Table 2 Performance index test results

[0103]

[0104] Among them, the asphalt prepared in Comparative Examples 1, 3 and 4 began to show stratification and sedimentation after being kept at a constant temperature for 16 hours in a molten state; the asphalt prepared in Comparative Examples 6, 7 and 8 began to show stratification and sedimentation after being kept at a constant temperature for 10 hours in a molten state; the asphalt prepared in other embodiments and comparative examples did not show stratification or sedimentation after being kept at a constant temperature for 24 hours in a molten state.

[0105] It can be seen from the above results that the components in the composite modified asphalt of Examples 1 to 5 have good compatibility, uniform and stable quality, and are not prone to melting stratification and sedimentation problems; their 60°C dynamic stability, tensile strength ratio, 25°C elastic recovery rate, initial and molding strength indicators are significantly improved, achieving high performance. From the comparison of the results of Comparative Example 1, it can be seen that the addition of isopropyl stearate in the preparation of SBS modified asphalt can well fuse asphalts of various properties, and can promote the fusion of SBS modification, promote the improvement of the modification effect, and thus improve the performance of the composite modified asphalt. From the comparison of the results of Comparative Example 2, it can be seen that without adding AH-110 asphalt, AH-70 asphalt and isopropyl stearate, the properties of SBS modified asphalt are seriously affected, and the comprehensive performance is reduced; it shows that AH-110 asphalt, AH-70 asphalt and AH-90 asphalt are compounded and modified in a certain proportion, which can improve the comprehensive performance effect of SBS modified asphalt. From the comparison of the results of comparative example 3, it can be seen that the waste tire rubber powder is not modified and is directly mixed with basalt fiber at room temperature. When the basalt fiber is added to the melt, it is unevenly dispersed, which will affect the overall performance of the composite modified asphalt, such as 60°C dynamic stability, tensile strength ratio, 25°C elastic recovery rate, initial and molding strength. From the comparison of the results of comparative example 4, it can be seen that not adding silica fume will affect the uneven dispersion and coating of basalt fiber, and then affect the distribution of basalt fiber in the composite modified asphalt, affecting the decline of various mechanical properties of the composite modified asphalt; in addition, the role of silica fume in the asphalt system is also lacking. From the comparison of the results of comparative example 5, it can be seen that not adding modified tire rubber powder and SBR significantly reduces the 60°C dynamic stability, tensile strength ratio, 25°C elastic recovery rate, initial and molding strength indicators of the composite modified asphalt. From the comparison of the results of Comparative Examples 6 to 8, it can be seen that the combination of ethylhexyl stearate and isopropyl stearate has a synergistic effect, can well blend the asphalt system, has good fusion, is not easy to stratify and settle, has stable performance, does not produce weak spots, and can ensure overall performance improvement.

Claims

1. A composite modified asphalt, characterized in that: It is made of the following raw materials in parts by mass: 70 to 80 parts of SBS modified asphalt, 15 to 25 parts of modified tire rubber powder, 5 to 10 parts of epoxy asphalt, 2 to 4 parts of SBR, 0.15 to 0.3 parts of high modulus anti-rutting agent, 2 to 3 parts of asphalt warm mix agent, 0.08 to 0.15 parts of maleic acid resin, 0.3 to 0.6 parts of rubber softening oil, 0.1 to 0.5 parts of ethylhexyl stearate, 0.1 to 0.5 parts of isopropyl stearate, and 0.01 to 0.03 parts of asphalt defoamer; The SBS modified asphalt is prepared by modifying AH-110 asphalt, AH-90 asphalt and AH-70 asphalt with an SBS modifier. The mass ratio of the components of the SBS modified asphalt is AH-110 asphalt: AH-90 asphalt: AH-70 asphalt: SBS modifier: calcium stearate: isopropyl stearate: asphalt warm mix agent: asphalt defoamer = (15-25): (55-65): (10-15): (3-6): (0.1-0.3): (0.4-0.8): (1.5-2.5): (0.01-0.03); The modified tire rubber powder is obtained by surface-modifying waste tire rubber powder with basalt fiber. The method comprises the following steps: according to the mass ratio, waste tire rubber powder: basalt fiber: silica ash: AH-130 asphalt powder = (90-100): (5-10): (0.5-2): (2-4), firstly, the basalt fiber and silica ash are evenly mixed by air flow, and then the AH-130 asphalt powder is added and evenly mixed by air flow to obtain a mixture; the mixture is added into the waste tire rubber powder and evenly mixed, and then the mixture is heated to 45°C-50°C for modification, cooled, and dispersed to obtain the modified tire rubber powder.

2. A composite modified asphalt according to claim 1, characterized in that: The preparation method of the SBS modified asphalt comprises the following steps: According to the mass ratio, AH-110 asphalt: AH-90 asphalt: AH-70 asphalt: SBS modifier: calcium stearate: isopropyl stearate: asphalt warm mix agent: asphalt defoamer = (15-25): (55-65): (10-15): (3-6): (0.1-0.3): (0.4-0.8): (1.5-2.5): (0.01-0.03); AH-110 asphalt, AH-90 asphalt, AH-70 asphalt and asphalt warm mix agent are melted at 140-160°C, and then isopropyl stearate and asphalt defoamer are added, stirred at low speed, and after mixing evenly, SBS modifier is added, stirred and sheared at high speed, and then developed at 130-150°C, and finally calcium stearate is added, stirred at low speed, and after mixing evenly, the temperature is lowered to obtain SBS modified asphalt.

3. A composite modified asphalt according to claim 2, characterized in that: The rotation speed of the low-speed stirring is 200r / min~500r / min, and the time of low-speed stirring is 30min~60min; the rotation speed of the high-speed stirring and shearing is 3000r / min~5000r / min, and the time of high-speed stirring and shearing is 30min~60min; the stirring speed of the development is 300r / min~600r / min, and the time of development is 1h~3h; the stirring speed of the cooling is 30r / min~60r / min.

4. The composite modified asphalt according to claim 1, characterized in that: The median particle size of the waste tire rubber powder is 700 μm to 800 μm; the diameter of the basalt fiber is 3 μm to 15 μm, and the length is 0.5 mm to 2.5 mm; the median particle size of the AH-130 asphalt powder is less than 5 μm.

5. The composite modified asphalt according to claim 1, characterized in that: The time for heating to 45°C to 50°C for modification is 30min to 60min.

6. The composite modified asphalt according to claim 1, characterized in that: The SBR is styrene butadiene rubber powder, and the particle size of the styrene butadiene rubber powder is sieved through 40-80 meshes.

7. The method for preparing a composite modified asphalt according to claim 1, characterized in that: The preparation method comprises the following steps: SBS modified asphalt, epoxy asphalt, asphalt warm mix agent, isopropyl stearate and defoamer are mixed and melted at 140°C to 150°C according to their mass proportions; then modified tire rubber powder, SBR, ethylhexyl stearate and rubber softening oil are added and mixed and melted continuously; finally, high modulus anti-rutting agent and maleic acid resin are added and mixed and melted continuously until uniform, thereby obtaining a composite modified asphalt.

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