| Asphalt aging can severely degrade the performance and the service life of pavement and ultraviolet aging is an important factor for asphalt aging. Different parts of the UV intensity difference is very big, the pavement of asphalt binder is also faced with different degrees of UV aging. It is necessary to investigate asphalt aging applicability for different UV intensity and anti-aging ability. This paper selects LDHs, montmorillonite, black three UV barrier material to modify asphalt and aging performance of three modified asphalt is analysis. According to different UV intensity levels, applicability of aged asphalt is studied.First of all, the anti-aging performance of asphalt were studied. The test results show that physical properties of three kinds of ultraviolet blocking material will make the physical performance of the asphalt decreased. But after UV aging, softening point increment decreases, residual penetration ratio increased, the ductility retention rate increased. Rheological properties test results show smaller composite modulus, increasing phase angle and smaller fatigue factor smaller. Chemical properties test results show that the ultraviolet blocking material incorporation, reduce carbonyl and sulfoxide and asphaltene formation rate during ultraviolet aging process. Aging resistant performance of asphalt results show that three kinds of materials are of asphalt resistant UV aging ability improved. The improving effect of LDHs is best, the effect of carbon black relatively poor.Then the performance of the asphalt was studied under different UV intensity. Using grey relational analysis compared the relationship between each properties and aging index. Results showed that 15 oC ductility and fatigue factor have closest correlation degree with asphalt ultraviolet aging index. The changes of asphalt properties under five typical grades is studied. The results indicated that under four and five UV intensity grades, asphalt properties changed little; from four to one UV intensity grades, aging resistance of asphalts gradually reduced with increasing UV intensity. So it is proposed that five and four districts were combined for a grade and the UV intensity is divided into four grades.Finally, aging asphalt applicability is studied for the different intensity of ultraviolet radiation. Results showed under grade I, three UV barrier materials can be used to improve anti-aging ablity and the suggested content is 1 wt%; under grade II, LDHs or montmorillonite are suggested, and dosage is less than 3 wt%; under grade III, LDHs is recommened, and content is 3 wt%; under grade IV, suggesting LDHs, and the content is higher than 3wt%. |
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