| WMA is widely used because of its advantages of energy saving and environmental protection.In view of the shortcomings of poor water stability,based on the laboratory simulation of the presence of residual moisture in the process of aggregate mixing,with the help of industrial CT technology and finite element method,mesoscopic research for water stability of WMA with organic wax additive was carried out.The critical moisture content of aggregates was determined,which provided the theoretical basis for the effective control of water damage of asphalt pavement with organic wax additive.In this paper,RH was used as organic wax additive and limestone was selected.Firstly,RH-WMA was subjected to freeze-thaw splitting by using the modified Lottman test(AASHTO T283),the microstructure and void ratio variation of RH-WMA was observed by industrial CT technique before and after freeze-thaw splitting test.Then the relationship between the void ratio and moisture content of RH-WMA would be established.Through the visual modeling and calculation of RH-WMA,it was found that the voids were the most sensitive to water in the 5-10mm3 volume interval.When the moisture content of the aggregates was 3%,the void volume changed the most.With the increase of the moisture content of the aggregates,the void ratio of RH-WMA was increased.Secondly,the correlation between the void ratio variation,moisture content and water stability was established by analyzing the correlation between the void ratio,ITS and TSR of RH-WMA before and after freeze-thaw splitting test.The results showed that the moisture content and void ratio of RH-WMA were related to their ITS and TSR.With the increase of the moisture content of the aggregates,the void ratio of RH-WMA was increased,the value of ITS and TSR were linearly decreased and the decreasing rate was faster,indicating that the presence of moisture lead to larger void ratio of RH-WMA after freeze-thaw cycle and water stability became worse.Finally,based on the digital image processing and finite element method,the 3D numerical model of RH-WMA sample was established,and the virtual splitting test of 3D numerical model was simulated.By analyzing the correlation between the internal stress,fracture development of RH-WMA and moisture content of the aggregate,it was found that the existence of voids would have a great influence on the stress distribution and the development location of the asphalt mixture,and the internal force distribution was not uniform,most of the cracks along the gap at the development.And the greater the moisture content of the aggregate,the more cracks generated by the gap,the faster the development,resulting in worse water stability of RH-WMA.It was suggested that the critical moisture content of aggregates of WMA with organic wax additive was no more than 2% by analyzing the correlation between its void ratio,ITS,TSR,stress distribution,fracture development and moisture content of aggregates. |
PDF Full Text Request