Full-Scale Evaluation of Electrically Conductive Asphalt Pavements for Deicing Applications

Abstract

Electrically heated pavements are an emerging technology for deicing applications in cold regions. Such pavements usually contain a conductive layer (asphalt or concrete) and electrodes to transmit electricity through the pavement, thus heating it. The goal of this study was to evaluate the heating ability of electrically conductive pavement structures under cold weather conditions. To achieve this goal, three full-scale pavement strips were constructed at Rowan University. Test strip I was a conventional pavement strip without any heating elements, whereas test strips II and III had conductive asphalt layer sandwiched between base and asphalt surface courses. The conductive layer in test strip II consisted of a mixture of asphalt binder and conductive fibers, whereas test strip III contained a modified high-performance thin overlay (HPTO) mixture with graphite and carbon fibers. To provide electric potential across the conductive layers, steel electrodes with different spacings (6 in. and 12 in.) were installed at the bottom of the conductive layers of test strips II and III, and connected to a 24V AC power source. Electrical data showed that test strip II had a power consumption of 19.75 W/ft², which was nearly four times higher than test strip III. Thermal data showed that the surface temperature of test strip III with 6 in. electrode spacing increased above freezing point with nearly 50% less power consumption than test strip II. Further, electrodes with 6 in. spacing resulted in the highest increase of pavement surface temperature, which was 3°F higher than electrodes with 12 in. spacing.