The Research of Bituminous Mixture Water Stability Based on Aggregate Cleanness

Water stability of bituminous mixture, whose sediment concentration of coarse and fine aggregate are respectively in 1%, 2%, 3%, 4%, is tested and analyzed; meanwhile, under the condition of vacuum saturation, the water uptake and the residual water of bituminous mixture, whose sediment concentration of coarse and fine aggregate are respectively in 0%, 2%, 4%, are also tested. Based on the test, the tensile splitting strengths are analyzed, in correspondence to different water rates. Results show that the water stability of bituminous mixture reduces as the aggregate sediment concentration increases, and its influence on the cleanness to the fine aggregate is more sensitive than on the coarse aggregate; the ability of water uptake increases as the aggregate sediment concentration increases; residual water approaches to stability with the extension of time. However, the higher the sediment concentration is, the higher residual water ratio will be as at approaching to stability. For clean aggregate, when the ratio of the residual water reaches 50%, its splitting strength appears to be the lowest; but for the unclean aggregate, when its splitting strength is in the lowest, the rate of residual water would rise to above 75%.