Study On Key Technologies Of Construction Control Of Expressway Asphalt Pavement

In recent years the expressway construction in China has developed rapidly.Thevast majority of the construction of expressway pavement is asphalt pavement.As forthe substantial increase of the number of vehicles and overloading,the expresswayasphalt pavement has more early failure. Therefore, in order to improve the quality ofthe asphalt pavement construction and extend the pavement life, it is very necessaryto carry out in-depth study on construction control of asphalt pavement.This study is based on DaoHe Expressway with a large number of experimentaldatas and theoretical analysis, starting with the research of the impact of aggregatewater absorption in optimum bitumen-aggregate ratio in mixture design.It analyzedthe impact of different water absorption in the performance of asphalt mixture; addinglignin fibers could effectively reduce the effect of water absorption variability inasphalt mixture design;as well as the impact of adding fiber in the performance ofasphalt mixture.Then seven different degrees of aggregate gradation segregation withlimestone aggregate and 70# modified asphalt binder were chosen to study the impactof aggregate segregation in the performance of asphalt mixture. it puts up with thecontrol standards of aggregate segregation of DaoHe Expressway.Afterwards, thespecimens with different thickness from the bottom layer,middle layer and upper layerwere contucted rutting test,in order to study the impact of the specimen thickness inthe dynamic stability,and estable the relationship between the 5cm standard specimenthickness and the actual design thickness dynamic stability.Finally the construction quality control of DaoHe Expressway pavement wasevaluated from three factors: bitumen-aggregate ratio, aggregate gradationfluctuations and high temperature stability. The results show that, little change inbitumen-aggregate ratio，only 1.08% coefficient of variation; aggregate gradationfluctuations within control standards limits; the road high temperature stabilitymeeting the technical requirements.At the same time, it is recommended to use thespecimens immediately cut from construction site to contuct the rutting test toevaluate the high temperature stability of pavement mixture.