Anti-aging UiO-66-COOH modified asphalt and preparation method thereof

Abstract

The invention provides anti-aging UiO-66-COOH modified asphalt and a preparation method thereof, and belongs to the technical field of asphalt processing. The anti-aging UiO-66-COOH modified asphalt is prepared from the following components in percentage by mass: 89.00 percent to 92.00 percent of asphalt, and 8.00 percent to 11.00 percent of a UiO-66-COOH modifier, the UiO-66-COOH modifier is obtained by enabling raw materials including zirconium chloride and 1, 2, 4-benzenetricarboxylic acid to react in N, N-dimethylformamide, and the UiO-66-COOH modifier is obtained by enabling raw materials including zirconium chloride and 1, 2, 4-benzenetricarboxylic acid to react in N, N-dimethylformamide. The anti-aging UiO-66-COOH modified asphalt prepared by adopting the preparation method disclosed by the invention has excellent anti-aging performance.

Description

Technical Field

[0002] The present invention belongs to the technical field of asphalt processing, and particularly relates to an aging-resistant UiO-66-COOH modified asphalt and a preparation method thereof. Background Art

[0004] Since the 21st century, highway construction has developed rapidly in China. Among them, asphalt pavements are widely used due to their excellent road performance. However, when asphalt is in long-term service, under the combined action of heat, light, oxygen and other factors in the natural climate environment, it is prone to complex aging reactions. After aging, the asphalt material becomes hard and brittle, and pavement cracking and other diseases gradually occur, thus affecting the durability, driving comfort and safety of asphalt pavements. Once the performance of asphalt deteriorates too severely, it is necessary to maintain and renovate it, which will in turn cause social problems such as environmental pollution and energy waste. To improve the anti-aging performance of asphalt, scholars at home and abroad have carried out a large number of research works. The main measures taken are to incorporate anti-aging materials such as antioxidants, ultraviolet absorbers, inorganic nanoparticles, layered materials, etc. into asphalt. Their action mechanisms are different and each has its own defects. With the higher requirements for the anti-aging performance of asphalt in the construction of long-life pavements, the lack of advanced and effective collaborative prevention and control technologies for road asphalt aging has become one of the most serious bottlenecks in this field.

[0005] MOF is a new type of porous material with a periodic network structure formed by the self-assembly of various organic ligands such as nitrogen and oxygen and metal ions. Based on the high specific surface area and adjustable pore size of MOF materials, they are suitable for storing and separating gases such as hydrogen, methane, and carbon dioxide. Therefore, the present invention proposes a new idea for exploring asphalt anti-aging, and designs to use a new type of metal-organic framework compound (Metal Organic Framework, MOF) material that stores aromatic components in asphalt to improve the aging resistance of asphalt. Summary of the Invention

[0007] In view of the above problems, the present invention provides an aging-resistant UiO-66-COOH modified asphalt and a preparation method thereof, wherein UiO-66-COOH improves the anti-aging performance of asphalt by adsorbing benzene series substances.

[0008] To achieve the above object, the present invention adopts the following technical scheme:

[0009] The present invention provides an aging-resistant UiO-66-COOH modified asphalt, which, by mass percentage, comprises 89.00% - 92.00% of asphalt and 8.00% - 11.00% of UiO-66-COOH modifier.

[0010] On the one hand, in the present invention, through the structural regulation of UiO-66-COOH, aromatic components can be stored efficiently and for a long time in asphalt, inhibiting the gelation of the asphalt structure; on the other hand, the introduced UiO-66-COOH has a benzene ring and thus has the ability to absorb ultraviolet light. Using the UiO-66-COOH modifier of the present invention to modify asphalt can effectively solve the problem of asphalt aging.

[0011] Furthermore, the above-mentioned UiO-66-COOH modifier is obtained by mixing and reacting raw materials including 49.00 - 64.00% zirconium chloride and 36.00 - 51.00% 1,2,4-benzenetricarboxylic acid by mass percentage.

[0012] Furthermore, the preparation method of the above-mentioned UiO-66-COOH modifier includes the following steps: dissolving zirconium tetrachloride and 1,2,4-benzenetricarboxylic acid in a solvent, reacting at a certain temperature, and centrifuging to collect the precipitate product; washing and drying the product to obtain metal-organic framework UiO-66-COOH crystals.

[0013] Preferably, the above-mentioned solvent is N,N-dimethylformamide.

[0014] Preferably, the above-mentioned reaction temperature is 100 - 120 °C and the reaction time is 24 - 30 h.

[0015] Preferably, the above-mentioned washing liquid is N,N-dimethylformamide and methanol.

[0016] Preferably, the above-mentioned drying temperature is 100 - 120 °C and the drying time is 8 - 10 h.

[0017] Preferably, the above-mentioned asphalt is petroleum asphalt, with a penetration at 25 °C of 60 - 120 dmm, a softening point of 40 - 55 °C, and an elongation at 10 °C of 15 - 25 cm.

[0018] The present invention also provides a preparation method of the above-mentioned aging-resistant UiO-66-COOH modified asphalt, including the following steps: heating the asphalt to a flowing state, stirring at a speed of 530 rpm, while slowly adding the UiO-66-COOH modifier, maintaining the temperature at 165 °C, stirring at a speed of 4500 rpm for 1 h, and then continuing to stir at a speed of 550 rpm for 2 h to obtain the aging-resistant UiO-66-COOH modified asphalt.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] (1) In the present invention, UiO-66-COOH is designed to regulate pore characteristics and surface chemical characteristics by adjusting metal ions and organic ligands. When benzene series compounds volatilize during the aging process of asphalt, UiO-66-COOH can efficiently store them, achieving the purpose of storing aromatic components and inhibiting the gelation of the asphalt structure, that is, effectively improving the anti-aging performance of asphalt.

[0021] (2) In UiO-66-COOH of the present invention, the hydrogen atom of the carboxyl group can act as a hydrogen bond donor to form a hydrogen bond with the π electron cloud on the benzene ring, and the carboxyl group is a polar group. Therefore, carboxyl functionalization can, firstly, enhance the H-π interaction and improve the adsorption capacity for benzene series compounds; secondly, enhance the polarity of the modifier and improve the adsorption capacity for benzene series compounds.

[0022] (3) UiO-66-COOH in the present invention has a benzene ring, and together with the benzene ring in the stored aromatic components, it has excellent ultraviolet absorption ability, which can inhibit the influence of ultraviolet light on asphalt, that is, effectively improve the anti-aging performance of asphalt.

[0023] (4) UiO-66-COOH in the present invention is an organic-inorganic hybrid nanomaterial, which has some similarities with asphalt materials in terms of chemical bonding and microstructure. According to the principle of similar compatibility, the compatibility problem between the two is relatively easy to solve. Specific Embodiments

[0025] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope protected by the present invention. Any equivalent transformation or substitution made by those skilled in the art according to the following embodiments also belongs to the scope protected by the present invention.

[0026] A kind of anti-aging UiO-66-COOH modified asphalt provided by the present invention, by mass percentage, includes 89.00% - 92.00% of asphalt and 8.00% - 11.00% of UiO-66-COOH modifier.

[0027] In some examples, the UiO-66-COOH modifier is obtained by mixing and reacting raw materials including 49.00 - 64.00% of zirconium chloride and 36.00 - 51.00% of 1,2,4-benzenetricarboxylic acid by mass percentage.

[0028] In some examples, the preparation method of the UiO-66-COOH modifier includes the following steps: Dissolve zirconium tetrachloride and 1,2,4-benzenetricarboxylic acid in a solvent, react at a certain temperature, and centrifuge to collect the precipitate product; Wash and dry the product to obtain metal-organic framework UiO-66-COOH crystals. Among them, the reaction temperature is 100~120°C, the reaction time is 24~30h. The drying temperature for drying is 100~120°C, and the drying time is 8~10h.

[0029] In the following examples and comparative examples, zirconium chloride and N,N-dimethylformamide were both purchased from Shanghai Macklin Biochemical Co., Ltd., 1,2,4-benzenetricarboxylic acid was purchased from Shanghai Haohong Biopharmaceutical Technology Co., Ltd., and methanol was purchased from Shanghai Titan Technology Co., Ltd.; all raw materials are common raw materials on the market. Unless otherwise specified, the asphalt in the following examples and comparative examples is road petroleum asphalt, with a penetration at 25°C of 60~120 dmm, a softening point of 40~55°C, and an elongation at 10°C of 15~25 cm.

[0030] Example 1

[0031] The UiO-66-COOH modifier provided in this example is composed of the following raw materials in mass percentage: 53.00% zirconium tetrachloride, 47.00% 1,2,4-benzenetricarboxylic acid; The preparation method of the UiO-66-COOH includes the following steps:

[0032] S1. Mix zirconium tetrachloride, 1,2,4-benzenetricarboxylic acid, and N,N-dimethylformamide, ultrasonically dissolve them, and then load them into a polytetrafluoroethylene reaction kettle; among them, the mass ratio of 1,2,4-benzenetricarboxylic acid to N,N-dimethylformamide is 1:260;

[0033] S2. React in an oven at 120°C for 24h, and centrifuge to collect the precipitate;

[0034] S3. Wash the product 3 times with N,N-dimethylformamide and methanol respectively and centrifuge to collect;

[0035] S4. Place the product in an oven at 120°C and dry for 8h to obtain metal-organic framework UiO-66-COOH crystals.

[0036] Use the above UiO-66-COOH modifier to prepare aging-resistant UiO-66-COOH modified asphalt. The aging-resistant UiO-66-COOH modified asphalt is composed of the following raw materials in mass percentage: 91.00% asphalt, 9.00% UiO-66-COOH modifier;

[0037] The preparation method of the aging-resistant UiO-66-COOH modified asphalt is as follows:

[0038] Heat the asphalt to a flowing state, stir at a rotation speed of 530 rpm, and slowly add the UiO-66-COOH while maintaining the temperature at 165 °C. Start the high-speed shearer and stir at a rotation speed of 4500 rpm for 1 h; continue to maintain 165 °C, and then continue to stir at a rotation speed of 550 rpm for 2 h to obtain the aging-resistant UiO-66-COOH modified asphalt.

[0039] Example 2

[0040] The UiO-66-COOH modifier provided in this example is composed of the following raw materials in mass percentage: 49.00% zirconium tetrachloride and 51.00% 1,2,4-benzenetricarboxylic acid; the preparation method of the UiO-66-COOH includes the following steps:

[0041] S1. Mix zirconium tetrachloride, 1,2,4-benzenetricarboxylic acid, and N,N-dimethylformamide, and after ultrasonic dissolution, load them into a polytetrafluoroethylene reaction kettle; among them, the mass ratio of 1,2,4-benzenetricarboxylic acid to N,N-dimethylformamide is 1:260;

[0042] S2. React in an oven at 120 °C for 24 h, and centrifuge to collect the precipitate;

[0043] S3. Wash the product 3 times with N,N-dimethylformamide and methanol respectively and centrifuge to collect;

[0044] S4. Place the product in an oven at 120 °C and dry for 8 h to obtain metal-organic framework UiO-66-COOH crystals.

[0045] Use the above UiO-66-COOH modifier to prepare aging-resistant UiO-66-COOH modified asphalt. The aging-resistant UiO-66-COOH modified asphalt is composed of the following raw materials in mass percentage: 89.00% asphalt and 11.00% UiO-66-COOH modifier;

[0046] The preparation method of the aging-resistant UiO-66-COOH modified asphalt is as follows:

[0047] Heat the asphalt to a flowing state, stir at a rotation speed of 530 rpm, and slowly add the UiO-66-COOH while maintaining the temperature at 165 °C. Start the high-speed shearer and stir at a rotation speed of 4500 rpm for 1 h; continue to maintain 165 °C, and then continue to stir at a rotation speed of 550 rpm for 2 h to obtain the aging-resistant UiO-66-COOH modified asphalt.

[0048] Example 3

[0049] The UiO-66-COOH modifier provided in this example is composed of the following raw materials in mass percentage: 58.00% zirconium tetrachloride and 42.00% 1,2,4-benzenetricarboxylic acid; the preparation method of the UiO-66-COOH includes the following steps:

[0050] S1. Mix zirconium tetrachloride, 1,2,4-benzenetricarboxylic acid, and N,N-dimethylformamide, and after ultrasonic dissolution, load them into a polytetrafluoroethylene reaction kettle; among them, the mass ratio of 1,2,4-benzenetricarboxylic acid to N,N-dimethylformamide is 1:260;

[0051] S2. React in an oven at 120 °C for 24 h, and centrifuge to collect the precipitate;

[0052] S3. Wash the product 3 times with N,N-dimethylformamide and methanol respectively and centrifuge to collect;

[0053] S4. Place the product in an oven at 100-120 °C and dry it for 8-10 h to obtain metal-organic framework UiO-66-COOH crystals.

[0054] The above UiO-66-COOH modifier is used to prepare aging-resistant UiO-66-COOH modified asphalt. The aging-resistant UiO-66-COOH modified asphalt is composed of the following raw materials in mass percentage: 90.00% asphalt and 10.00% UiO-66-COOH modifier;

[0055] The preparation method of the aging-resistant UiO-66-COOH modified asphalt is as follows:

[0056] Heat the asphalt to a flowing state, stir at a speed of 530 rpm, and slowly add the UiO-66-COOH while maintaining the temperature at 165 °C. Start a high-speed shearer and stir at a speed of 4500 rpm for 1 h; continue to maintain 165 °C, and then continue to stir at a speed of 550 rpm for 2 h to obtain the aging-resistant UiO-66-COOH modified asphalt.

[0057] Example 4

[0058] The UiO-66-COOH modifier provided in this example is composed of the following raw materials in mass percentage: 64.00% zirconium tetrachloride and 36.00% 1,2,4-benzenetricarboxylic acid; the preparation method of the UiO-66-COOH includes the following steps:

[0059] S1. Mix zirconium tetrachloride, 1,2,4-benzenetricarboxylic acid, and N,N-dimethylformamide, and after ultrasonic dissolution, load them into a polytetrafluoroethylene reaction kettle; among them, the mass ratio of 1,2,4-benzenetricarboxylic acid to N,N-dimethylformamide is 1:260;

[0060] S2. React at 120 °C in an oven for 24 h, and centrifuge to collect the precipitate;

[0061] S3. Wash the product three times with N,N-dimethylformamide and methanol respectively and centrifuge to collect;

[0062] S4. Dry the product in an oven at 120 °C for 8 h to obtain metal-organic framework UiO-66-COOH crystals.

[0063] Use the above UiO-66-COOH modifier to prepare aging-resistant UiO-66-COOH modified asphalt. The aging-resistant UiO-66-COOH modified asphalt is composed of the following raw materials by mass percentage: 92% asphalt, 8.00% UiO-66-COOH modifier;

[0064] The preparation method of the aging-resistant UiO-66-COOH modified asphalt is as follows:

[0065] Heat the asphalt to a flowing state, stir at a speed of 530 rpm, and slowly add the UiO-66-COOH while maintaining the temperature at 165 °C. Start a high-speed shearer and stir at a speed of 4500 rpm for 1 h; continue to maintain 165 °C, and then continue to stir at a speed of 550 rpm for 2 h to obtain the aging-resistant UiO-66-COOH modified asphalt.

[0066] Comparative Example 1

[0067] The modified asphalt provided in this comparative example is prepared according to the following method:

[0068] Heat 91.00 wt% of asphalt to a flowing state, stir at a speed of 530 rpm, and slowly add 9.00 wt% zirconium chloride while maintaining the temperature at 165 °C. Start a high-speed shearer and stir at a speed of 4500 rpm for 1 h; continue to maintain 165 °C, and then continue to stir at a speed of 550 rpm for 2 h to obtain zirconium chloride modified asphalt. That is, compared with Example 1, zirconium chloride is directly used to modify asphalt in this comparative example.

[0069] Comparative Example 2

[0070] The modified asphalt provided in this comparative example is prepared according to the following method:

[0071] Heat 91.00 wt% of asphalt to a flowing state, stir at a rotation speed of 530 rpm, and slowly add 9.00 wt% of 1,2,4-benzenetricarboxylic acid while maintaining the temperature at 165 °C. Start the high-speed shear mixer and stir at a rotation speed of 4500 rpm for 1 h; continue to maintain 165 °C, and then continue to stir at a rotation speed of 550 rpm for 2 h to obtain 1,2,4-benzenetricarboxylic acid modified asphalt. That is, compared with Example 1, in this comparative example, 1,2,4-benzenetricarboxylic acid material is directly used to modify asphalt.

[0072] Comparative Example 3

[0073] The modified asphalt provided in this comparative example is prepared according to the following method:

[0074] Heat 91.00 wt% of asphalt to a flowing state, stir at a rotation speed of 530 rpm, and slowly add 9.00 wt% of UiO-66 while maintaining the temperature at 165 °C. Start the high-speed shear mixer and stir at a rotation speed of 4500 rpm for 1 h; continue to maintain 165 °C, and then continue to stir at a rotation speed of 550 rpm for 2 h to obtain UiO-66 modified asphalt. That is, compared with Example 1, in this comparative example, UiO-66 is directly used to modify asphalt. Among them, UiO-66 is obtained by reacting zirconium tetrachloride and terephthalic acid in a mass ratio of 1.4:1 in DMF solvent at 120 °C. The specific preparation method of UiO-66 is as follows:

[0075] Mix zirconium tetrachloride, terephthalic acid, and N,N-dimethylformamide in a mass ratio of 23:16:900, ultrasonically dissolve and then load into a polytetrafluoroethylene reaction kettle; react in an oven at 120 °C for 24 h, centrifuge to collect the precipitate; wash the product 3 times with N,N-dimethylformamide and methanol respectively and centrifuge to collect; place the product in an oven at 120 °C and dry for 8 h to obtain metal-organic framework UiO-66 crystals.

[0076] Comparative Example 4

[0077] The UiO-66-COOH modifier provided in this example is composed of the following raw materials in mass percentage: 53.00% zirconium tetrachloride, 47.00% 1,2,4-benzenetricarboxylic acid; the preparation method of the UiO-66-COOH modifier is the same as that of Example 1.

[0078] Use the above UiO-66-COOH modifier to prepare aging-resistant UiO-66-COOH modified asphalt. The aging-resistant UiO-66-COOH modified asphalt is composed of the following raw materials in mass percentage: 99.00% asphalt, 1.00% UiO-66-COOH modifier;

[0079] The preparation method of the aging-resistant UiO-66-COOH modified asphalt is the same as that in Example 1.

[0080] Comparative Example 5

[0081] In this example, the UiO-66-COOH modifier provided is composed of the following raw materials in terms of mass percentage: 53.00% zirconium tetrachloride and 47.00% 1,2,4-benzenetricarboxylic acid; the preparation method of the UiO-66-COOH modifier is the same as that in Example 1.

[0082] The above UiO-66-COOH modifier is used to prepare aging-resistant UiO-66-COOH modified asphalt, which is composed of the following raw materials in terms of mass percentage: 80.00% asphalt and 20.00% UiO-66-COOH modifier;

[0083] The preparation method of the aging-resistant UiO-66-COOH modified asphalt is the same as that in Example 1.

[0084] Test on the anti-aging performance of modified asphalt

[0085] The modified asphalt prepared in the above examples and comparative examples was respectively subjected to short-term thermal-oxidative aging (RTFOT, temperature 163 °C, aging time 5 hours) and ultraviolet accelerated aging test (UV, ultraviolet light intensity 1200 μW / cm 2 , temperature 60 °C, aging time 9 days); then the properties of each sample before and after aging were tested, and the residue penetration (residue penetration = penetration after aging / penetration before aging × 100%), softening point increment (softening point increment = softening point after aging - softening point before aging) and ductility retention rate (ductility retention rate = ductility after aging / ductility before aging × 100%) were calculated. The test results are listed in Table 1.

[0086] Table 1 Test results of the anti-aging performance of the modified asphalt prepared in each example and comparative example

[0087]

[0088] As can be seen from Table 1, compared with Example 1, in Comparative Example 1, zirconium chloride was directly used to modify asphalt. After the modified asphalt underwent thermal-oxidative aging and ultraviolet aging, its residual penetration and ductility retention rates were both lower than those of the modified asphalt prepared with the UiO-66-COOH modifier prepared in the present invention, while the softening point increment was greater than that of the modified asphalt prepared in the present invention; compared with Example 1, in Comparative Example 2, 1,2,4-benzenetricarboxylic acid was directly used to modify asphalt. After the modified asphalt underwent thermal-oxidative aging and ultraviolet aging, its residual penetration and ductility retention rates were both lower than those of the modified asphalt prepared in the present invention, while the softening point increment was greater than that of the modified asphalt prepared in the present invention; compared with Example 1, in Comparative Example 3, UiO-66 was directly used to modify asphalt. After the modified asphalt underwent thermal-oxidative aging and ultraviolet aging, its residual penetration and ductility retention rates were both lower than those of the modified asphalt prepared in the present invention, while the softening point increment was greater than that of the modified asphalt prepared in the present invention; this indicates that the modified asphalt prepared with the UiO-66-COOH modifier has more excellent thermal-oxidative aging and ultraviolet aging resistance compared with the asphalt modified directly with zirconium chloride or directly with 1,2,4-benzenetricarboxylic acid or directly with UiO-66; compared with Example 1, in Comparative Example 4, a very small amount of UiO-66-COOH modifier was used to modify asphalt. After the modified asphalt underwent thermal-oxidative aging and ultraviolet aging, its residual penetration and ductility retention rates were both lower than those of the modified asphalt prepared in the present invention, while the softening point increment was greater than that of the modified asphalt prepared in the present invention; compared with Example 1, in Comparative Example 5, a large amount of UiO-66-COOH modifier was used to modify asphalt. After the modified asphalt underwent thermal-oxidative aging and ultraviolet aging, its residual penetration and ductility retention rates were both lower than those of the modified asphalt prepared in the present invention, while the softening point increment was greater than that of the modified asphalt prepared in the present invention; this indicates that the effect of the modified asphalt prepared with too little or too much UiO-66-COOH modifier is not good, and the UiO-66-COOH modifier should be used appropriately.

[0089] The above are only the preferred embodiments of the present invention and are not used to limit the protection scope of the present invention. For any person skilled in the art, various changes and modifications can be made to the present invention. Any simple equivalent changes and modifications made according to the protection scope of the present invention application and the content of the specification should be included in the protection scope of the present invention.

Claims

1. An aging-resistant UiO-66-COOH modified asphalt, characterized in that: Calculated by mass percentage, it includes 89.00%~92.00% of asphalt and 8.00%~11.00% of UiO-66-COOH modifier.

2. The aging-resistant UiO-66-COOH modified asphalt according to claim 1, characterized in that: The UiO-66-COOH modifier is obtained by mixing raw materials including 49.00-64.00% by mass of zirconium chloride and 36.00-51.00% by mass of 1,2,4-benzenetricarboxylic acid.

3. The aging-resistant UiO-66-COOH modified asphalt according to claim 2, characterized in that: The preparation method of the UiO-66-COOH modifier comprises the following steps: dissolving zirconium tetrachloride and 1,2,4-benzenetricarboxylic acid in a solvent, reacting at a certain temperature, and collecting the precipitated product by centrifugation; and washing and drying the product to obtain a metal organic framework UiO-66-COOH crystal.

4. The aging-resistant UiO-66-COOH modified asphalt according to claim 3, characterized in that: The solvent is N,N-dimethylformamide.

5. The aging-resistant UiO-66-COOH modified asphalt according to claim 3, characterized in that: The reaction temperature is 100-120° C., and the reaction time is 24-30 h.

6. The aging-resistant UiO-66-COOH modified asphalt according to claim 3, characterized in that: The washing liquid is N,N-dimethylformamide and methanol.

7. The aging-resistant UiO-66-COOH modified asphalt according to claim 3, characterized in that: The drying temperature is 100-120°C and the drying time is 8-10h.

8. The aging-resistant UiO-66-COOH modified asphalt according to claim 1, characterized in that: The asphalt is petroleum asphalt, with a needle penetration of 60-120 dmm at 25°C, a softening point of 40-55°C, and an elongation of 15-25 cm at 10°C.

9. The method for preparing the aging-resistant UiO-66-COOH modified asphalt according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: heating the asphalt to a fluid state, stirring at a rotation speed of 530 rpm, slowly adding the UiO-66-COOH modifier, maintaining the temperature at 165°C, stirring at a rotation speed of 4500 rpm for 1 hour, and then continuing to stir at a rotation speed of 550 rpm for 2 hours to obtain the aging-resistant UiO-66-COOH modified asphalt.

Images