An Experimental Study On Recycled Aggregate Asphalt Concrete

The comprehensive utilization of abandoned concrete is of great significance. This can not only solve the problem of environmental pollution, but also achieve a certain economic benefits by using the resources properly. At present, the study on recycled aggregate is mainly restricted to cement concrete and asphalt concrete pavement is seldom dealt with. In this thesis, some techniques of applying recycled aggregate to asphalt pavement are studied. By performing a series of experiments, the mixing proportion, strength and durability of recycled aggregate asphalt concrete are analyzed.First, whether the properties of recycled aggregate conform to the requirements of the current regulations is examined by experiment. Owing to the surface breakage of recycled aggregates during mixing, the variation of aggregate gradation is analyzed and an adjustment scheme of aggregate gradation is proposed. Second, asphalt concrete is cast by replacing natural aggregates with recycled aggregates in terms of the size and proportion. The Marshall stability and flow value are measured. The results show that asphalt concrete with natural aggregates replacing small size recycled aggregates in terms of the proportion can be used for asphalt pavement surface. In the durability study, the wheel tracking test, the immersed Marshall test and the freeze-thaw splitting test are conducted. An accelerating aging test is performed on asphalt concrete and the strength is then measured. It is found that application of recycled aggregates to asphalt concrete does not influence its durability and is beneficial to the anti-rutting property. Finally, some suggestions are proposed for the technical standards and application of recycled aggregate concrete.