Composite modified asphalt with anti-ultraviolet and anti-salt erosion aging and preparation method thereof

Abstract

The application provides a kind of composite modified asphalt with anti-ultraviolet and anti-salt corrosion aging and a preparation method thereof, and the preparation raw materials include base asphalt, linear SBS, GN, LDHs-PABA-CA, a compatibilizer and a stabilizer.The base asphalt is heated to a molten state to obtain molten asphalt.Under the condition of constant temperature heating and continuous stirring, linear SBS is added to the molten asphalt to make linear SBS swell in the molten asphalt, and then shear mixing is carried out to obtain SBS composite modified asphalt.GN and LDHs-PABA-CA are added to the SBS composite modified asphalt and stirred uniformly, and shear mixing is continued to obtain a composite modified asphalt base with anti-ultraviolet and anti-salt corrosion aging.A compatibilizer and a stabilizer are added to the composite modified asphalt base with anti-ultraviolet and anti-salt corrosion aging, and then the mixed system is stirred under constant temperature conditions to obtain a composite modified asphalt with anti-ultraviolet and anti-salt corrosion aging.

Description

Technical Field

[0001] This invention relates to the field of asphalt modification technology, specifically to a composite modified asphalt that combines resistance to ultraviolet radiation and salt erosion aging, and its preparation method. Background Technology

[0002] With the rapid development of transportation infrastructure construction, the surge in highway traffic volume, increased vehicle axle loads, and the impact of environmental factors, traditional asphalt pavement materials are facing severe challenges. Ordinary asphalt materials are prone to softening at high temperatures, leading to rutting and deformation; at low temperatures, their brittleness increases, causing cracking; and their aging resistance is insufficient, resulting in a shortened service life of asphalt pavements.

[0003] Generally, asphalt pavement aging can be classified into three categories: oxygen aging, thermal aging, and photoaging. During the construction phase, the high-temperature environment makes thermal aging dominant, leading to the volatilization of lightweight components in asphalt and the breakage and condensation of molecular chains; while during the service phase, the effect of thermal aging weakens. Oxygen aging accompanies the entire service life of asphalt, and its rate is positively correlated with temperature; the higher the temperature, the more intense the oxidation reaction. Photoaging (mainly ultraviolet light aging) also exists throughout the service life and is significantly affected by regional sunlight conditions. Ultraviolet light can promote the breakage of chemical bonds in asphalt and combine with oxygen to form oxygen-containing functional groups, forming a photo-oxygen coupled aging effect; the higher the radiation intensity, the faster the aging process.

[0004] Meanwhile, the nearshore salt-corrosion environment poses a significant threat to the road performance of asphalt and its mixtures. Under the coupled effects of salt solution, humidity, and ultraviolet radiation, asphalt hardens rapidly and develops microcracks. Salt solution intrusion into the asphalt-aggregate interface damages the adsorption layer and induces corrosion, leading to adhesion failure. The resulting microscopic damage manifests macroscopically as decreased water stability and fatigue resistance of the mixture, as well as exacerbated freeze-thaw damage. Simultaneously, salt concentration and crystallization on the pavement surface and within the pavement due to moisture evaporation further accelerate the aging of asphalt materials.

[0005] Currently, there are many types of modifiers and modification technologies for improving the resistance of asphalt to ultraviolet radiation and salt corrosion aging. However, the effect of a single anti-ultraviolet radiation and salt corrosion aging agent on the anti-aging of asphalt is limited. Moreover, commonly used anti-ultraviolet radiation and salt corrosion aging agents often have problems such as high cost and complex preparation process. Summary of the Invention

[0006] The purpose of this invention is to provide a composite modified asphalt that combines resistance to ultraviolet radiation and salt corrosion aging, and its preparation method, so as to solve the problems of existing road asphalt's performance easily deteriorating under strong ultraviolet radiation and high salt corrosion environment, high raw material cost, and complex preparation process.

[0007] This invention is achieved through the following technical solution: The composite modified asphalt, which combines resistance to ultraviolet radiation and salt corrosion aging, is prepared by means of the following raw materials by mass: base asphalt: 900-1100 parts, linear SBS: 46-54 parts, GN: 28-32 parts, LDHs-PABA-CA: 18-22 parts, compatibilizer: 28-32 parts, and stabilizer: 1-3 parts. Further, by mass fraction, the GN consists of 30% TR and 70% EVA40, where TR is a tackifying resin and EVA40 is an ethylene-vinyl acetate copolymer with a melt index of 40.

[0008] Furthermore, the preparation process of the LDHs-PABA-CA is as follows: using anion exchange method, p-aminobenzoic acid and cinnamic acid are inserted between the layers of Mg-Al LDHs to obtain organic intercalated LDHs-PABA-CA with excellent ultraviolet absorption function between the layers.

[0009] Furthermore, the compatibilizer is furfural extract oil.

[0010] Furthermore, the stabilizer is a sulfur-containing compound.

[0011] A method for preparing composite modified asphalt with both UV resistance and salt erosion aging resistance includes the following steps: 1) Heat the base asphalt to a molten state to obtain molten asphalt; 2) Under constant temperature heating and continuous stirring conditions, linear SBS is added to the molten asphalt to allow the linear SBS to fully swell in the molten asphalt, and then shear mixing is performed to obtain SBS composite modified asphalt. 3) Add GN, LDHs-PABA-CA together to SBS composite modified asphalt and stir evenly. Continue shearing and mixing to obtain a composite modified asphalt matrix that has both UV resistance and salt corrosion aging resistance. 4) Add compatibilizer and stabilizer to the composite modified asphalt matrix that has both UV resistance and salt erosion aging resistance; then stir the mixture under constant temperature conditions to obtain composite modified asphalt that has both UV resistance and salt erosion aging resistance.

[0012] Furthermore, the heating temperature in step 1) is 135°C.

[0013] Furthermore, in step 2), linear SBS is added to the molten asphalt under constant temperature heating conditions of 175°C and continuous stirring conditions. The feeding process lasts for 20 minutes, allowing the linear SBS to fully swell in the molten asphalt.

[0014] Furthermore, in steps 2) and 3), the shearing speed for shear mixing is 4000~4500 r / min, the shearing temperature is controlled at 170℃~175℃, the shearing time in step 2) is 40 min, and the shearing time in step 3) is 60 min.

[0015] Further, in step 4), the mixed system is stirred and developed at a constant temperature of 175°C and a rotation speed of 230~250 r / min for 240 min.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: (1) This invention utilizes the high-viscosity modifier GN and organic intercalated LDHs PABA The synergistic effect of CA and linear SBS allows linear SBS to swell in asphalt, forming a three-dimensional network structure that imparts high elasticity and resistance to deformation. The organically intercalated LDHs-PABA-CA utilizes its layered structure for UV shielding and the free radical scavenging function of organic anions to effectively slow down the UV aging of asphalt. Meanwhile, the high-viscosity modifier GN forms chemical bonds with asphalt components and linear SBS molecules through its active functional groups, enhancing the interfacial adhesion between asphalt and aggregates and promoting the uniform dispersion of LDHs within the SBS network. Together, these three components enhance the material's resistance to UV radiation and salt corrosion.

[0017] (2) In this invention, p-aminobenzoic acid (PABA) and cinnamic acid (CA) are inserted into the interlayer of Mg-AlLDHs by anion exchange method to prepare organic intercalated LDHs-PABA-CA materials. The benzene ring and conjugated double bond structure in PABA and CA molecules endow the material with excellent ultraviolet absorption capacity, and its anti-ultraviolet performance is significantly better than that of unmodified LDHs.

[0018] (3) The test results show that, compared with the base asphalt, the carbonyl index of the composite modified asphalt of the present invention is reduced by 57.9%, the sulfoxide index is reduced by 56.7%, the splitting strength is increased by 95.5%, the surface energy is increased by 45.1%, and the pull-out strength of asphalt and aggregate is increased by 188.4%.

[0019] (4) This invention has the dual functions of resisting ultraviolet aging and resisting salt corrosion aging, which can effectively extend the service life of asphalt pavement. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. The following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is the ultraviolet-infrared spectrum of the composite modified asphalt in an embodiment of the present invention; Figure 2 The images shown are UV fluorescence images of composite modified asphalt in the embodiments of the present invention, where (a) is Example 1, (b) is Example 2, (c) is Example 3, (d) is Example 4, and (e) is Example 5. Detailed Implementation

[0022] The present invention will now be described in detail: This invention provides a composite modified asphalt with both UV resistance and salt corrosion aging resistance, comprising base asphalt, linear SBS, high viscosity modifier GN (by mass fraction, 30% TR + 70% EVA40), LDHs-PABA-CA, compatibilizer (furfural extract oil), and stabilizer (a sulfur-containing compound, specifically sulfur). The composition of the composite modified asphalt, by mass fraction, is as follows: base asphalt (900-1100 parts), linear SBS (46-54 parts), GN (30% TR + 70% EVA40) 28-32 parts, LDHs-PABA-CA (18-22 parts), compatibilizer (28-32 parts), and stabilizer (1-3 parts).

[0023] The high-viscosity modifier GN is composed of 30% TR and 70% EVA40, where TR is a tackifying resin and EVA40 is an ethylene-vinyl acetate copolymer with a melt index of 40.

[0024] The LDHs-PABA-CA method involves inserting p-aminobenzoic acid (PABA) and cinnamic acid (CA) into CO3 using an anion exchange process. 2- Organic intercalated LDHs-PABA-CA with excellent ultraviolet absorption function were prepared between the layers of magnesium-aluminum layered bimetallic hydroxides (Mg-Al LDHs).

[0025] The ion exchange method was used to exchange p-aminobenzoic acid (PABA) ions, cinnamic acid (CA) ions with carbonate ions to insert them into LDHs, forming functional organic intercalated LDHs. The specific experimental process is as follows: (1) Preparation of LDHs solution. 20g of LDHs were weighed and dissolved in 400mL of mixed solvent consisting of deionized water and anhydrous ethanol in a 1:1 volume ratio. The mixture was stirred at 65℃ for 1 hour to fully dissolve the LDHs and obtain an LDHs slurry. (2) Preparation of PABA-CA organic anionic solution. 5.6g of PABA and 6.1g of CA were added to 600mL of mixed solvent consisting of deionized water and anhydrous ethanol in a 1:1 volume ratio. The mixture was stirred continuously until it was completely dissolved to obtain the PABA-CA solution. (3) Intercalation reaction. Pour the obtained PABA-CA solution into the LDHs solution that is still being stirred. Use HCl to control the pH value of the entire solution in the range of 3-4, and let it be stirred and refluxed for 24 hours in a 50°C environment to allow CA ions to fully insert into LDHs and obtain PABA-CA-LDHs solution. The entire experimental process must be carried out under the protection of N2 environment. (4) Drying treatment. Use vacuum equipment to repeatedly filter and wash the PABA-CA-LDHs solution obtained in step (3), and finally filter to obtain PABA-CA LDHs filter cake. Put the filter cake into a vacuum drying oven at 60°C and continue to dry for 24 hours to allow the moisture to fully evaporate. After drying, crush, grind and sieve (200 mesh) the filter cake to obtain PABA-CA intercalated LDHs, denoted as PABA-CA-LDHs.

[0026] This invention also provides a method for preparing composite modified asphalt that combines resistance to ultraviolet radiation and salt erosion aging, comprising the following steps: 1) First, heat the base asphalt (900-1100 parts) in an oven at 135℃ until it melts; then transfer the molten asphalt to a constant temperature electric heating jacket and control the temperature at 175±5℃; then slowly add linear SBS (46-54 parts) under continuous stirring. The feeding process takes about 20 minutes to ensure that the linear SBS is fully swollen in the molten asphalt. 2) Use a high-speed shearing machine to shear and mix, control the shearing speed at 4000~4500 r / min, control the shearing temperature at 170℃~175℃, and perform high-speed shearing for 40 min to initially obtain SBS composite modified asphalt; 3) Add 28-32 parts of GN (30% TR + 70% EVA40) and 18-22 parts of LDHs-PABA-CA to the SBS composite modified asphalt in step 2) and stir evenly. Continue high-speed shearing at 170℃~175℃ for 60 minutes, with a shearing speed of 4000~4500 r / min to obtain a composite modified asphalt matrix that has both UV resistance and salt corrosion resistance. 4) Add compatibilizer (28-32 parts) and stabilizer (1-3 parts) to the composite modified asphalt matrix with both UV resistance and salt erosion aging resistance in step 3); then place the mixture in a constant temperature heating jacket at 175℃ and use an electric stirrer to stir and develop at a low speed of 230~250 r / min for 240 min; the continuous stirring during this development stage not only ensures the full reaction and structural stability between the components, but also effectively removes air bubbles from the modified asphalt, finally obtaining a uniform and stable composite modified asphalt with both UV resistance and salt erosion aging resistance.

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise specified, the methods and experimental equipment used in the following embodiments are conventional methods and instruments.

[0028] Example 1 1000 parts of base asphalt were weighed and heated in an oven at 135℃ until completely melted. Then, 50 parts of linear SBS were added, and the mixture was sheared at 4500 r / min for 40 min at 175℃. Next, 30 parts of GN (30% TR + 70% EVA40) and 20 parts of LDHs-PABA-CA were added sequentially, and the mixture was stirred evenly. Afterward, it was sheared at 4500 r / min for 60 min at the same temperature. Finally, 30 parts of compatibilizer and 2 parts of stabilizer were added, and the mixture was stirred at 240 r / min using an electric mixer for 240 min under constant temperature of 175℃ to obtain a composite modified asphalt with both UV resistance and salt erosion resistance. The performance results of the obtained composite modified asphalt are shown in Table 1.

[0029] Example 2 900 parts of base asphalt were weighed and heated in an oven at 135℃ until completely melted. Then, 46 parts of linear SBS were added, and the mixture was sheared at 4500 r / min for 40 min at 175℃. Next, 28 parts of GN (30% TR + 70% EVA40) and 18 parts of LDHs-PABA-CA were added sequentially, and the mixture was stirred evenly. Afterward, it was sheared at 4500 r / min for 60 min at the same temperature. Finally, 28 parts of compatibilizer and 1 part of stabilizer were added, and the mixture was stirred at 240 r / min using an electric mixer for 240 min under constant temperature of 175℃ to obtain a composite modified asphalt with both UV resistance and salt erosion resistance. The performance results of the obtained composite modified asphalt are shown in Table 1.

[0030] Example 3 950 parts of base asphalt were weighed and heated in an oven at 135℃ until completely melted. Then, 48 parts of linear SBS were added, and the mixture was sheared at 4500 r / min for 40 min at 175℃. Next, 29 parts of GN (30% TR + 70% EVA40) and 19 parts of LDHs-PABA-CA were added sequentially, and after thorough mixing, the mixture was sheared at 4500 r / min for another 60 min at the same temperature. Finally, 29 parts of compatibilizer and 1.5 parts of stabilizer were added, and the mixture was stirred at 240 r / min using an electric mixer for 240 min under constant temperature of 175℃ to obtain a composite modified asphalt with both UV resistance and salt erosion resistance. The performance results of the obtained composite modified asphalt are shown in Table 1.

[0031] Example 4 1050 parts of base asphalt were weighed and heated in an oven at 135℃ until completely melted. Then, 52 parts of linear SBS were added, and the mixture was sheared at 4500 r / min for 40 min at 175℃. Next, 31 parts of GN (30% TR + 70% EVA40) and 21 parts of LDHs-PABA-CA were added sequentially, and after thorough mixing, the mixture was sheared at 4500 r / min for another 60 min at the same temperature. Finally, 31 parts of compatibilizer and 2.5 parts of stabilizer were added, and the mixture was stirred at 240 r / min using an electric mixer for 240 min under constant temperature of 175℃ to obtain a composite modified asphalt with both UV resistance and salt erosion resistance. The performance results of the obtained composite modified asphalt are shown in Table 1.

[0032] Example 5 1100 parts of base asphalt were weighed and heated in an oven at 135℃ until completely melted. Then, 54 parts of linear SBS were added, and the mixture was sheared at 4500 r / min for 40 min at 175℃. Next, 32 parts of GN (30% TR + 70% EVA40) and 22 parts of LDHs-PABA-CA were added sequentially, and after thorough mixing, the mixture was sheared at 4500 r / min for another 60 min at the same temperature. Finally, 32 parts of compatibilizer and 3 parts of stabilizer were added, and the mixture was stirred at 240 r / min using an electric mixer for 240 min under constant temperature of 175℃ to obtain a composite modified asphalt with both UV resistance and salt erosion resistance. The performance results of the obtained composite modified asphalt are shown in Table 1.

[0033] Comparative Example 1 The difference between this comparative example and Example 1 is that the raw materials used in the preparation of this comparative example do not contain stabilizers.

[0034] Comparative Example 2 The difference between this comparative example and Example 1 is that the raw materials used in the preparation of this comparative example 2 do not contain a compatibilizer.

[0035] Comparative Example 3 The difference between this comparative example and Example 1 is that the raw materials used in this comparative example 3 replace the SBS (linear) in Example 1 with an equal amount of SBS (star-shaped).

[0036] Comparative Example 4 The difference between this comparative example and Example 1 is that the raw materials used in the preparation of this comparative example 4 replace LDHs-PABA-CA in Example 1 with an equal amount of LDHs-PABA.

[0037] Comparative Example 5 The difference between this comparative example and Example 1 is that the raw materials used in the preparation of this comparative example 5 are replaced with an equal amount of LDHs-CA, which was used in Example 1.

[0038] Comparative Example 6 The difference between this comparative example and Example 1 is that the raw materials used in the preparation of this comparative example 6 are LDHs-PABA-CA from Example 1, which are replaced by an equal amount of LDHs.

[0039] Comparative Example 7 The difference between this comparative example and Example 1 is that the raw materials used in the preparation of this comparative example 7 are replaced with an equal amount of GN (40%TR+60%EVA40) instead of GN (30%TR+70%EVA40) in Example 1.

[0040] Comparative Example 8 The difference between this comparative example and Example 1 is that the raw materials used in the preparation of this comparative example 8 are made by replacing GN (30% TR + 70% EVA40) in Example 1 with an equal amount of EVA40.

[0041] Comparative Example 9 The difference between this comparative example and Example 1 is that the raw materials used in the preparation of this comparative example 9 replace GN (30% TR + 70% EVA40) in Example 1 with an equal amount of TR.

[0042] The surface free energy, tensile strength, splitting tensile strength, carbonyl index, and sulfoxide index of the composite modified asphalts prepared in Examples 1-5 and Comparative Examples 1-9 were tested. Surface free energy, tensile strength, and splitting tensile strength were mainly used to evaluate the asphalt's resistance to salt corrosion, while the carbonyl index and sulfoxide index were used to evaluate its UV resistance. The test results are shown in Table 1.

[0043] Table 1 Performance Test Results

[0044] As shown in Table 1, Examples 1-5 all exhibited excellent UV resistance and salt corrosion resistance. Comparing Comparative Example 1 with Example 1, it is evident that the addition of the stabilizer improved the UV resistance and salt corrosion resistance of the composite modified asphalt. Compared to the absence of a stabilizer, the improved UV resistance and salt corrosion resistance of the composite modified asphalt is fundamentally due to the fact that the addition of the stabilizer enables moderate chemical cross-linking of SBS, transforming the physical blending system into a chemically cross-linked network, significantly enhancing the thermal storage stability and elastic recovery performance of the modified asphalt.

[0045] Comparing Comparative Example 2 with Example 1, it is evident that the addition of a compatibilizer significantly impacts the performance of the composite modified asphalt. Compared to the system without a compatibilizer, the composite modified asphalt in Example 1 exhibits superior UV resistance and salt corrosion resistance. The fundamental reason for this is that the compatibilizer effectively balances the interfacial compatibility of the modified asphalt system, reducing the interfacial tension between the base asphalt and the polar components (SBS, GN, LDHs-PABA-CA). This promotes the uniform dispersion of modifiers (such as LDHs), enabling them to form a continuous, dense three-dimensional network structure and significantly inhibiting the aggregation of modifiers.

[0046] A comparison of Comparative Example 3 and Example 1 shows that star-shaped SBS, due to its complex molecular structure and uneven dispersion, is prone to defects at the interface during aging, leading to a faster increase in the carbonyl index and sulfoxide index, and relatively weaker UV resistance. Linear SBS, on the other hand, forms a more uniform and continuous network structure, resulting in a more even stress distribution during aging. Therefore, linear SBS composite modified asphalt exhibits excellent UV and salt corrosion resistance.

[0047] Comparing Comparative Examples 4, 5, and 6 with Example 1, it is evident that the organically modified LDHs-PABA-CA, LDHs-PABA, and LDHs-CA exhibit superior UV resistance compared to unmodified LDHs. The order of UV resistance strength is: LDHs-PABA-CA > LDHs-PABA > LDHs-CA > LDHs, indicating that the modified organic modifier can be more uniformly and stably integrated into the asphalt and exert its effect. Comparing Comparative Example 7 with Example 1, it was found that a 40% EV content is more beneficial for improving the adhesion properties of asphalt than a 20% EV content. This indicates that a 40% EV content can more effectively improve the polar component of the surface free energy of the composite modified asphalt, making it easier for the asphalt to wet the aggregate surface, thus resulting in better performance in indicators such as tensile strength and splitting strength. Comparing Comparative Examples 8 and 9 with Example 1, it is evident that changing the composition of GN affects the adhesion properties between the composite modified asphalt and the aggregate. In Comparative Example 8, the high viscosity modifier was completely replaced by EVA, and in Comparative Example 9, the high viscosity modifier was completely replaced by TR. Compared with Example 1, the adhesion performance of Comparative Example 8 and Comparative Example 9 to the aggregate was weakened, and the UV aging resistance was also reduced.

[0048] Comparing Examples 1 to 5, it can be seen that the surface free energy, tensile strength, and splitting strength of Example 1 are all higher than those of the other examples, indicating that it has excellent salt corrosion resistance; at the same time, its sulfoxide index and carbonyl index are lower than those of the other examples, proving that it has excellent UV resistance. Combined with... Figure 1 UV spectrum of composite modified asphalt and Figure 2 The UV fluorescence image of the composite modified bitumen shows that Example 1 showed a fluorescence intensity of 1030 cm⁻¹. -1 and 1700 cm -1 The smaller peak area indicates lower carbonyl and sulfoxide indices, resulting in superior UV resistance. UV fluorescence analysis shows that the internal network structure of Example 1 remains well-preserved after UV aging, indicating excellent UV resistance under the same aging conditions. Comparing Examples 2 and 5 with Example 1 reveals that the changes in UV resistance and salt corrosion resistance of the composite modified asphalt are minimal at both the minimum and maximum dosages designed for the component. Figure 1 and Figure 2 Microscopic characterization also shows that after UV aging, both the carbonyl index and sulfoxide index remain at a low level, and the three-dimensional network structure is still relatively intact, further verifying the superiority of the composition design and preparation method of this invention.

[0049] Example 1 was ultimately determined to be the optimal composition design. Under this composition design, the composite modified asphalt exhibits excellent resistance to salt corrosion and UV radiation, demonstrating good road durability. This invention successfully prepared a composite modified asphalt with both salt corrosion and UV resistance through a multi-component synergistic design of base asphalt, linear SBS, GN (30% TR + 70% EVA40), LDHs-PABA-CA, compatibilizer, and stabilizer. Specifically, linear SBS swells in the asphalt to form a three-dimensional network structure, endowing the material with excellent high-temperature deformation resistance and low-temperature crack resistance. The TR component in the high-viscosity modifier GN enhances the system's cohesion and adhesion through active functional groups, while the EVA40 component forms a dense physical barrier to block chloride ion penetration, thereby achieving salt corrosion resistance. Organic intercalated LDHs-PABA-CA utilizes the UV reflection effect of LDHs layers and the strong UV absorption and free radical scavenging ability of intercalated organic anions (PABA, CA) to endow the material with excellent UV resistance. Compatibilizers and stabilizers improve the interfacial compatibility of each component and promote moderate cross-linking of SBS, ensuring the uniform and stable dispersion of functional components in the asphalt matrix. Together, they achieve a comprehensive improvement in UV resistance and salt corrosion resistance, forming a multi-protection mechanism that can effectively cope with the harsh environment of strong UV radiation and high salt corrosion aging in coastal areas, and significantly extend the service life of asphalt pavement.

[0050] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A composite modified asphalt possessing both UV resistance and salt erosion aging resistance, characterized in that, By mass, the raw materials for its preparation include: base bitumen: 900-1100 parts, linear SBS: 46-54 parts, GN: 28-32 parts, LDHs-PABA-CA: 18-22 parts, compatibilizer: 28-32 parts, and stabilizer: 1-3 parts.

2. The composite modified asphalt with both UV resistance and salt erosion aging resistance according to claim 1, characterized in that, By mass fraction, the GN consists of 30% TR and 70% EVA40, where TR is a tackifying resin and EVA40 is an ethylene-vinyl acetate copolymer with a melt index of 40.

3. The composite modified asphalt with both UV resistance and salt erosion aging resistance according to claim 1, characterized in that, The preparation process of LDHs-PABA-CA is as follows: p-aminobenzoic acid and cinnamic acid are inserted into the interlayer of Mg-AlLDHs using anion exchange method to obtain organic intercalated LDHs-PABA-CA with excellent ultraviolet absorption function between the layers.

4. The composite modified asphalt with both UV resistance and salt erosion aging resistance according to claim 1, characterized in that, The compatibilizer is furfural extract oil.

5. The composite modified asphalt with both UV resistance and salt erosion aging resistance according to claim 1, characterized in that, The stabilizer is a sulfur-containing compound.

6. The method for preparing the composite modified asphalt with both UV resistance and salt erosion resistance as described in any one of claims 1-5, characterized in that, Includes the following steps: 1) Heat the base asphalt to a molten state to obtain molten asphalt; 2) Under constant temperature heating and continuous stirring conditions, linear SBS is added to the molten asphalt to allow the linear SBS to fully swell in the molten asphalt, and then shear mixing is performed to obtain SBS composite modified asphalt. 3) Add GN, LDHs-PABA-CA together to SBS composite modified asphalt and stir evenly. Continue shearing and mixing to obtain a composite modified asphalt matrix that has both UV resistance and salt corrosion aging resistance. 4) Add compatibilizer and stabilizer to the composite modified asphalt matrix that has both UV resistance and salt erosion aging resistance; then stir the mixture under constant temperature conditions to obtain composite modified asphalt that has both UV resistance and salt erosion aging resistance.

7. The method for preparing composite modified asphalt with both UV resistance and salt erosion aging resistance according to claim 6, characterized in that, The heating temperature in step 1) is 135℃.

8. The method for preparing composite modified asphalt with both UV resistance and salt erosion aging resistance according to claim 6, characterized in that, In step 2), linear SBS is added to the molten asphalt under constant temperature heating conditions of 175℃ and continuous stirring. The feeding process lasts for 20 minutes, allowing the linear SBS to fully swell in the molten asphalt.

9. The method for preparing composite modified asphalt with both UV resistance and salt erosion aging resistance according to claim 6, characterized in that, In steps 2) and 3), the shearing speed for shearing and mixing is 4000~4500 r / min, and the shearing temperature is controlled at 170℃~175℃. The shearing and mixing time in step 2) is 40 min, and the shearing and mixing time in step 3) is 60 min.

10. The method for preparing composite modified asphalt with both UV resistance and salt erosion aging resistance according to claim 6, characterized in that, In step 4), the mixture is stirred and developed at a constant temperature of 175℃ and a rotation speed of 230~250 r / min for 240 min.

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