Collapsible Loess Region SMA Mixture Design Method Of Determining The Optimum Asphalt Content

According to the domestic and international research of SMA and the situation of early damage of asphalt pavements, the writer researched asphalt and modified asphalt in SMA, asphalt rubber solution, aggregate densities, the design of aggregate gradation and OAC in collapse loess region, and analyzed the advantage and disadvantage of SMA designing methods. Based on anti-crack technology in cold western regions , new aggregate gradation and new OAC designing methods were presented . Meanwhile , comparing volume parameter and OAC among experiments of Marshall ,small Marshall and rotating compression, the writer analyzed the relationship , advantages and disadvantages on defining OAC and the reasons of errors on different experiments. Finally more reliable parameters were presented .From checking a lot of domestic and international documentation, the writer presented the formula of calculation primal OAC from VMA of SMA, and verified that different cement content adapt to different kinds of asphalt firstly.When using acid stones or displace of mines, cement must be used for filler. So, the writer firstly presented three standards by researching three different experiments using for Gmm and gave suggestions on Gmm decision; and considering Va formula and the experimental datum of apparent density, bulk density and maximum loose density got before and after aging of mixture, obtained their influence on Va , suggested that Va should be used as Va ; and concluded that the densities of compressed and loose before and after aging are consistent ; and presented the evaluation method based on mechanical performance and concluded that coarse aggregate framework should be evaluated by dynamic stability .