Study on electrical conductivity of hot mix asphalt with copper slag and carbon fiber

Abstract

One of the effective measures to remove snow and ice accumulated on roads is to construct pavements using conductive asphalt mixture. In order to enhance the electrical conductivity of hot mix asphalt (HMA), copper slag (CS) was used to replace basaltic fine aggregates with same volume and particle size, and short-cut carbon fiber (CF) with high carbon content was added. Eighteen types of mixtures were prepared with 6 copper slag substitution ratios increasing from 0% to 100% by step of 20% and 3 fiber content of 0.2%, 0.3% and 0.4%. A series of laboratory experiments were performed to evaluate the effects of factors such as content of CS and CF, voltage level, aging and freeze–thaw cycles on the electrical resistivity, heating rate and deicing efficiency of asphalt mixture respectively. The test results show that the resistivity of the mixture decreases with the increase of CS and CF content. After aging and freeze–thaw cycles, the HMA specimen resistivity increases slightly while heating rate decreases non-significantly. Voltage level have remarkable effect on temperature rise rate and deicing efficiency. The higher the voltage, the greater the improvement. Specimen thickness affects the temperature distribution. The time required to raise the temperature (to 0 °C) at the same measuring point shows a linear increase with the increases of the specimen thickness. Besides, HMA with CS and CF shows better road performance, especially in high temperature stability.