Effects of Electrically Conductive Additives on Laboratory-Measured Properties of Asphalt Mixtures

Abstract

An asphalt mixture generally behaves as an insulator. The addition of electrically conductive additives may produce conductive asphalt mixtures. The present study investigated the effectiveness of several commonly used conductive additives to produce electrically conductive hot-mix asphalt (HMA). The effects of three conductive additives, a micron-scale steel fiber, a carbon fiber, and graphite, on some laboratory-measured properties of HMA mixtures were investigated through mixture performance testing. The results from this study indicated that the micron-scale steel fiber was the most effective additive to produce conductive HMA. The inclusion of steel and carbon fibers improved permanent deformation properties, maintained the indirect tensile cracking resistance, and slightly reduced the dynamic modulus of the conductive HMA. The inclusion of graphite as an electrically conductive additive significantly improved the rut resistance, increased the dynamic modulus, and significantly reduced the indirect tensile cracking resistance of the conductive HMA mixtures.