Field Performance of Chat-Asphalt Test Road

Field performance of a chat-asphalt test road is pursued through non-destructive testing, field inspection and survey. Chat refers to mine tailings from the Tar Creek Superfund Site in Oklahoma. A 3150-ft. long Test Road was constructed near Cardin, Oklahoma using 80% raw chat in surface course and 50% raw chat in base course. Three non-destructive field tests, namely spectral analysis of surface waves (SASW), falling weight deflectometer (FWD) and ground penetrating radar (GPR) were conducted once immediately after construction and again after over two and a half years of service. The results show that the SASW moduli are approximately 5 times higher than the corresponding FWD moduli. The average modului were in the range of 841 MPa (122 ksi) to 1,751 MPa (254 ksi), which are lower than the traditional hot mix asphalt (HMA) moduli. The HMA layer thicknesses obtained from the GPR match closely with the design thicknesses. The distress survey showed relatively low level of rutting and a fairly high level of smoothness. Overall, chat-asphalt is found to be a good paving material.