Experimental Research on Recycled Aggregate Concrete for Highway Pavement

Abstract

The regeneration of concrete is a material-source cycle method which produces new concrete aggregate from waste concrete. This method is increasingly being used in practice. It can reduce the burden on the urban environment by recycling and utilizing otherwise abandoned concrete. It also one of the main measures of development of green concrete. Compared with natural aggregate (NA), recycled aggregate (RA) has its special physical and mechanical properties. This paper examines compressive strength of recycled aggregate concrete (RAC) manufactured using RA from a local recycling plant in Tianjin. Aggregate properties are tested and compared between RA and NA. The RA sample collected has a high water absorption rate of about 4.64%, while water absorption rate of NAis relatively low at about 0.89%. Due to weak mortar surrounding RA, its aggregate crushing value (ACV) is about 20.08% larger than that of NA. Compared with ordinary concrete, recycled aggregate concrete has characteristics like the better water retention, poor liquidity, lower compressive strength, and the same wear resistance. It is conclusive that the recycled coarse aggregate (RCA) replacement ratio has a remarkable influence on the compressive strength of RAC. Nevertheless, the compressive strength of recycled aggregate concrete can achieve the target compressive strength by choosing a correct replacement ratio of recycled aggregate. Recycled aggregate could be used to make recycled aggregate concrete for pavement if its technical specification conforms to the requirements of the standard of cement concrete pavement for highway (China) (JTGF30-2003). Consequently, recycled concrete aggregate is a good economic resource and great method for future development.