Influence of demolition waste used as recycled aggregate on performance of asphalt mixture

Abstract

The influence of demolition waste (DW) on the performance of asphalt mixture was investigated in this paper. DW was processed into recycled aggregate of different sizes which can be divided into recycled coarse aggregate (RCA, particle size of>4.75 mm) and recycled fine aggregate (RFA, particle size of≤4.75 mm). Three types of AC-25 asphalt mixture were prepared: RCA asphalt mixture prepared with RCA and limestone fine aggregate; RFA asphalt mixture prepared with RFA and limestone coarse aggregate; and the ordinary asphalt mixture prepared with natural limestone coarse and fine aggregate. A series of laboratory tests on recycled aggregate and asphalt mixture were carried out, including scanning electron microscopy test, immersion Marshall test, freeze–thaw split test, bending test at low temperature and rutting test at high temperature. Results showed that RCA asphalt mixture has higher optimal asphalt content and greater rutting resistance than the other two types. The cracking resistance of RCA asphalt mixture at low temperature is better than that of RFA asphalt mixture; while the water damage resistance of RFA asphalt mixture is better than that of RCA asphalt mixture. However, all these performances can meet the requirements of China's technical specifications. It can be seen that DW can be used in preparing asphalt mixture with satisfactory performance, especially for application in hot and dry environments. RCA asphalt mixture has lower temperature sensitivity while RFA asphalt mixture has lower water sensitivity.