Laboratory Evaluation of Hot-Mix Asphalt Concrete Containing Copper Slag Aggregate

This paper reports a laboratory study investigating the use of granulated copper slag as a fine aggregate in hot-mix asphalt concrete. Marshall-mix design was performed on different blends of aggregate containing up to 40% copper slag. The dynamic modulus $|E^{*}|$ test, as a primary material property input in the Mechanistic-Empirical Pavement Design Guide (ME-PDG), was conducted at different frequencies (0.1 to 16 Hz) and temperatures (25 to 60°C). $|E^{*}|$ master curves and shift factors were developed for the control and slag mixes. The developed curves were compared with the Witczak predictive $|E^{*}|$ model for Levels 2 and 3 of the ME-PDG. The results indicated strength reduction as slag content increases in the mixes compared to the control mix. The developed master curves and shift factors were compared with the Witczak predictive model. The results of stripping potential evaluated by the indirect tensile strength indicated a reduction in strength, but the tensile-strength ratio was superior to that of the control mix. The results indicated a good potential for using copper slag as an aggregate in asphalt mixes and provided the essential material characterization for using the material in the ME-PDG method.