Research On Dry Powder Asphalt Mixture Behaviour

The burning of tire crumb rubber produces black pollution,making the fragile environment worse and worse,therefore,it is particularly important to consume more crumb rubber by the dry process and change crumb rubber into things of valuein the construction of asphalt pavement.However,it was proved from the engineering practice that the volume deformationof the dry powder asphalt pavement becomes bigger and the durability of the dry powder asphalt pavement becomes more poor.Therefore,how to make design for asphalt mixture by the dry process and improve the road performance of asphalt pavement has become an important issue.According to it,this article makes a deep research on structure of dry powder asphalt mixture and the road performance of asphalt pavement,and this will provides reliable theoretical basis for practical engineering.This article got a set of key parameter combination which make the performance(road performance,work performance,etc.)of dry powder asphalt mixture get optimal by analysising the affect of key parameters(rubber powder dosage,powder fineness and mixture gradation)on the performance of dry powder asphalt mixture;The self-healing capability of dry powder and the aging properties of asphalt mixture were analyzed under the best parameter combination;Based on this,the road performance and construction workability the dry powder asphalt mixture were further enhanced by mixing with interface coupling agent and adjusting its dosage;According to the above research results,the modification mechanism of dry powder asphalt mixture was further explored;Finally,combining the economic benefits of dry powder asphalt mixture,the test road section was paved and the practical feasibility and manufacturability were analyzed.The results of wheel rutting test showed that the addition of rubber powder can significantly improve the high temperature performance of asphalt mixture;The results of low temperature bending test showed that the addition of rubber powder can make low temperature performance of asphalt mixture improved;The results of freeze-thaw splitting test showed that dry powder asphalt mixture has good performance in water resistance;The results of wheel rutting test showed that the effect of the time on the high temperature performance is mainly reflected in the deformation,which has little effect on the dynamic stability.The results of DSR verified that the rubber powder can improve the performance of asphalt mixture at high and medium temperature;The addition of coupling agent can greatly improve high temperature stability and water stability of the rubber powder asphalt mixture,the low temperature also has a certain degree of improvement;Based on this,the anti-rutting agent can greatly improve the high-temperature stability of asphalt mixture.Based on the test results,the gap grading and 10 ‰,40 mesh rubber powder in the dry powder asphalt mixture were proposed as the optimal combination of the key parameters in this article.20 times are recommended to be the forming plate number of the wheel grinding machine roller compacted dry powder asphalt mixture;96h was recommended to be the pacing time after forming dry powder asphalt mixture;At the same time adding 2%(mass fraction of rubber powder)coupling agent and 3 ‰ anti-rutting agent into dry powder in asphalt mixture were recommended;Solution concentration of optional coupling agent was that: m(optional coupling agent): m(distilled water): m(ethanol)= 1:1:9.