Study On The Material And Structure Of Asphalt Pavement With Asphalt Treated Base

Comparing with the semi-rigid base materials, asphalt treated base that is used as base material performs higher shear strength and well anti-fatigue properties and it can restrain and reduce the cracks of asphalt pavement reflection effectively, which has a good application prospect. However, asphalt treated base is rarely used at home and related research about it has just started now. In order to find a better mix proportion design method for asphalt treated mixture, choosing3different gradations of ATB-25mixture, the essay compared the test method of big Marshall with standard Marshall’s by indoor experiments. Then the essay did tests and comparability analyzed the pavement performances of3gradations mixture under optimum asphalt content. At last, aiming at the problem that there was no mature method for structural design of flexible base asphalt pavement,the essay analyzed the effects of four factors that are modulus, thickness of asphalt-treated upper base and thickness of semi-rigid base and sub-grade modulus on the three indicators that are the deflection on the surface, the asphalt layer bottom stretching strain and semi-rigid base bottom tensile stress. The results showed that there was well consistency on the optimum proportion obtained through two methods. However, the aggregate was crushed seriously by standard Marshall Test method, and there were not many differences in volume index. The density of big Marshall Specimens was larger than standard Marshall Specimens0.03-0.04g/cm3, but the void content of the former was lower about0.2%. Not only the structure of asphalt treated base showed excellent advantages on mechanical property, low-temperature cracking resistance, high temperature stability and water stability, but also the compressive resilient modulus of it was lower than the semi-rigid base materials. Being used as upper base of asphalt-treated material, it made for reducing the modulus ratio. Sub-grade modulus is the most significant factor on the deflection on the surface, and the thickness of asphalt treated base and semi-rigid base have a marked impact on the asphalt layer bottom stretching strain and semi-rigid base bottom tensile stress. Comprehensively considering technical and economic factors, the essay suggested that the thickness of asphalt treated base should be controlled between10cm to15cm, the thickness of semi-rigid base30cm at least.