Laboratory Evaluation of the Electrical Resistivity and Mechanical Performance of Electrically Conductive Asphalt Mixtures

Abstract

This study aims to evaluate the electrical conductivity and mechanical performance of electrically conductive asphalt (ECA) mixtures to be used in cold regions for deicing applications. In this study, the ECA mixtures were prepared using a combination of two conductive additives (graphite and carbon fibers), three lengths of carbon fibers (3 mm, 6 mm, and 24 mm), and gneiss aggregates with two nominal maximum aggregate sizes (NMAS) (4.75 mm and 9.5 mm). For each mixture, different dosages of conductive additives were selected: (a) 5%, 10%, 15%, and 30% by asphalt volume for graphite, and (b) 0%, 1%, and 2% by asphalt volume for carbon fibers. A multimeter was then used to assess the electrical resistivity of each ECA mixture, while asphalt pavement analyzer and indirect tension cracking tests were performed to evaluate ECA rutting susceptibility and cracking resistance, respectively. The durability of ECA mixtures was also determined at intermediate temperatures using the Cantabro loss test to assess their integrity when carbon fibers are added. Results showed that aggregates with NMAS of 4.75 mm and carbon fibers with a length of 6 mm presented the most improvement in ECA mechanical performance. In addition, ECA mixtures with 30% graphite presented similar electrical resistivity to those prepared with 15% graphite and 2% carbon fiber (6 mm). In respect of mechanical performance, the addition of 2% carbon fiber improved the resistance of ECA mixtures at 15% graphite to both cracking and durability by at least 20%.