| In the moist heat areas of Fujian,asphalt pavements are prone to early disease due to long-term exposure to harsh environments with high temperatures,strong ultraviolet radiation,and frequent rainfall,resulting in insufficient road durability and a low service life.At present,there are few studies on the aging characteristics and mechanism of asphalt in Fujian,and there is a lack of research on effectively improving the anti-aging properties of asphalt in moist heat areas.In view of this,this article uses the indoor accelerated aging test and the actual pavement aging test to study the aging characteristics and mechanism of the asphalt in Fujian.According to the aging characteristics of asphalt,the improving technology of asphalt anti-aging performance is proposed.The specific work and achievements are as follows:Firstly,in order to study the aging characteristics of the asphalt in Fujian,the aging conditions of the asphalt pavement in the four regions of Fuzhou,Chongqing,Harbin and Lhasa were statistically analyzed,and based on this,the indoor aging test conditions in four regions were established.Studies have shown that the aging of the asphalt in the four regions,the softening point,viscosity increased,while the ductility and penetration significantly reduced.The relationship between asphalt aging degree in four regions is:Lhasa>Fuzhou>Harbin>Chongqing;Asphalt aging in Lhasa is mainly caused by its strong UV radiation(lower temperature and less rainfall).The aging of asphalt in Fuzhou is ultraviolet radiation and high temperature.The result of a combination of harsh environmental effects such as water.In the Fujian area,the effect of ultraviolet aging on asphalt is far greater than that of thermal aging.The aging rate at 10 days before aging is about 1.7 times that of the latter 5 days.That is,the rate at the early stage of aging of asphalt is greater than that at the later stage of aging,and the effect of water will make the asphalt surface appear.Microcracks and ductility are significantly attenuated.By comparing the aging effect of the asphalt in the four regions,it was found that the aging degree of the SBS modified asphalt used in Fuzhou for 2 years was equivalent to the ageing rate of 2.98 years in Chongqing,2.18 in Harbin,and 1.43 in Lhasa.In order to further study the aging characteristics of the asphalt in Fujian,the core pavement was drilled and the old asphalt was recovered by centrifugal extraction and distillation to study the actual aging of the asphalt pavement.Research shows that the aging degree of asphalt increases with the increase of service life and decreases with the increase of the vertical depth of the road;the aging of non-motor vehicle asphalt is greater than that of motor vehic:le lanes.The effect of UV radiation,temperature,and load on the aging of the asphalt is approximately in the range of 0 to 9 cm on the road surface,and the depth beyond 9 cm can ignore the influence of these factors.The reason is that the nature of asphalt aging is the occurrence of oxidation reaction,and the difference between heat aging and UV aging is the difference in aging rate.For the problems of water and ultraviolet light in the hot and humid areas,such as the influence of water and ultraviolet light on the asphalt,and the rapid decay of the ductility,it is proposed that the use of nano-ZnO can reduce the hardness of the ultraviolet radiation to the asphalt.Studies have shown that the nano-ZnO can effectively improve the anti-aging properties of the asphalt.Since the effect of ultraviolet radiation on the aging of asphalt is inversely proportional to the depth of the pavement,and when the depth is>9 cm,the effect of ultraviolet radiation on the asphalt is negligible.Therefore,it is recommended that the asphalt with different aging resistance be used in layers to approach the horizon of the road surface.Use asphalt that has better aging resistance.Based on the above studies,the effect of UV aging on asphalt is greater than that of thermal aging in Fujian,and water will accelerate the decay rate of asphalt ductility.The rate in the early aging period is greater than that in the late aging period.In view of the above problems,the use of nano-ZnO improves the ductility retention of asphalt.,Studies have shown that nano-ZnO can block UV and inhibit asphalt oxidation reaction,improve the anti-aging properties of asphalt.According to ultraviolet radiation and other factors on asphalt aging and inversely proportional to the depth of the road surface,it is recommended to use different layers of asphalt aging resistance,the closer to the horizon of the road,the priority is to use good anti-aging asphalt.In order to reduce the effect of water on the aging of the asphalt,it is recommended that the road surface be densely mixed and the seal be added. |
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