Reserch Of Asphalt Treated Base Mixture Performance

Many diseases appear during asphalt pavement operation period of expressway, just as reflection crack and water damage, and asphalt treated base (ATB) have received more attention for its advantage in settling the diseases. According to the less use condition, it have great sense to research the key technique character of ATB for optimizing road structure,improving road employment level and extending road service period.Aggregate gradation of ATB is researched firstly. It is brought forward of new kettle specification for coarse aggregate through aggregate loose,dry-rod compact and libration density tests. The effect of different size aggregate on volume character is tested based uniformity design method. It is concluded form rutting test that gradation have great influence on mixture high-temperature performance, and the anti-distortion performance of coarse mixture is not better than fine mixture. Regression analysis proves that there have good pertinence between SSC,VCADRC and mixture dynamic stability. Finally it is putted forward new ATB mixture gradation design method basing on coarse aggregate dry-rod compact test.It is found that gradation curve shape index can distinguish effectively different mixture gradation, and have good relation with dynamic stability. ATB mixture's dynamic stability augments with mixture board thickness increasing, and the thickness do not bigger than 2.5 times of nominal maximum particle size. There have good correlation between Marshall immersion test and freeze thaw split test, and void is the key factor determining the mixture water stability. The anti-crack function is studied though theory analysis and laboratory test, then data proves that VFA can forecast the mixture anti-crack performance preferably. Wheel press have great influence on asphalt layer performance. Final crack time, using as the index of mixture impact tenacity test, can distinguish different mixture efficiently, and establish good correlation with APA test result.New mixture segregation test instrument is developed, which can simulate the actual segregation situation. Trough burning test of aggregate and asphalt mixture, it is proved that burning method can testing asphalt content exactly, but gradation result have big error. Test result show that gradation is the key influence factor of mixture segregation, in which the aggregate that is small than 9.5mm have the main effect, and asphalt content have some effect, finally the asphalt grade have little effect.