Wheel tracker testing of recycled concrete and tyre aggregates in Australia

Due to the ever-increasing abundance of discarded by-products, it is imperative to develop innovative engineering applications of waste materials, to manage the capacity of landfills. The disposal and landfilling issues associated with tyre waste have necessitated Australian authorities to find innovative applications of tyre waste in pavement construction. In this research, to examine the efficiency of tyre-derived aggregates (TDAs) as a replacement material for quarry aggregates in pavement subbase applications, a series of repeated load triaxial (RLT) tests and wheel-tracker (WT) tests were undertaken on specimens made of proportioned recycled concrete aggregate (RCA) blended with small-sized TDA (TDA-S) and medium-sized TDA (TDA-M), thus merging these two waste materials into a valued pavement-construction material. The results from the RLT and WT tests confirmed that TDA–RCA blends are a suitable alternative for pavement base/subbase materials. Compared with TDA-S, TDA-M resulted in a lower rutting deformation and permanent deformation in WT and RLT tests, respectively. The resilient modulus (M r) of the RCA + TDA-M mix was also found to be higher than that of the RCA + TDA-S mix, and it was almost comparable with the M r of the control RCA.