Laboratory evaluation of hot-mix asphalt containing petroleum-contaminated soil as a surface mix for low-volume roads

Petroleum-contaminated soil (PCS) is typically a mixture of sand, silt, clay, and petroleum products. In Oman, Petroleum Development Oman generates approximately 53,000 tons/year of PCS. The amount raises a significant disposal problem. Results are presented on the use of PCS in hot asphalt mixes as potential surface mixes for low-volume roads. The mixes were designed with the Marshall mix design method. The dynamic modulus |E*| test, as a primary material property input in the Mechanistic-Empirical Pavement Design Guide (MEPDG), was conducted at different frequencies (0.1 to 16 Hz) and temperatures (25°C to 60°C). |E*| master curves and shift factors were developed for the control and PCS mixes and compared with Witczak's predictive models. Environmental assessment of PCS indicated that it posed no threat to the environment. The mix design results indicated that mixes containing up to 15% PCS met the specification limits set for high-volume surface mixes except for voids in mineral aggregate (VMA), which was lower than the specification limits. Mixes containing up to 30% and 40% PCS met the low-volume surface or base mix specifications set by the Asphalt Institute with the exception of air voids or VMA for some mixes. The |E*| and indirect tensile strength results were consistent with Marshall stability. Witczak's predictive model for |E*| agreed well with the laboratory-fitted results for 0% and 5% PCS mix up to a 10-Hz frequency. This paper contributes to MEPDG implementation by developing the necessary parameters and optimizing the mix design of the PCS mixes.