Preparation And Properties Investigation Of Multiplex Electrically Conductive Asphalt Concrete

Snow cover and ice over on road has brought bad effect on expedite and secure traffic. Asphalt pavement has become the dominant type of motorway in China. Electrically conductive asphalt concrete (ECAC) is a newly developed bituminous composite that contains certain amount of electronically conductive components to attain relatively high electrical conductivity. Due to its electrical resistance, a thin layer of electrically conductive asphalt concrete can generate enough heat to prevent ice formation and snow cover on pavement when energized by a power source. ECAC may be used in snow melting and deicing for motorway because of its special advantages, such as function timely, no traffic interruption and environmental friendly. So ECAC has the potential to become a very cost-effective pavement snow melting and deicing method when compared with other technologies.In this paper, multiplex electrically conductive asphalt concrete has been prepared by adding certain amounts of electrically conductive aggregates, fiber and power. The proportions of electrically conductive components have been designed using composite technology and synergy effect. The pavement performance and electrical properties have been investigated, and the results indicate that multiplex electrically conductive asphalt concrete is competent for snow melting and deicing of motorway.Multiplex materials used as electrically conductive components are graphite, carbon fiber and electrically conductive steel slag. Superpave volumetric mix design procedures have been used for the selection of design aggregate structure and determination of optimum asphalt content. Mix procedures have been modified due to the special material characteristics of multiplex materials. The results of electrical conductivity test show that the addition of graphite improves electrical conductivity of asphalt mixture much more than addition of carbon fiber, and steel slag appears to be the worst. But steel slag combined with graphite and carbon fiber can improve electrical conductivity remarkably, while combination effect of carbon fiber and graphite is not adequate. Electrical conductivity of multiplex electrically conductive asphalt concrete could reach to 10 S/m.The Dynamic Shear Rheometers test has been used to characterize master curve and rutting parameter of graphite modified bitumen by measuring the complex shear modulus and phase angle. Pavement performance of multiplex electrically conductive asphalt concrete has been tested and analyzed, comparing with traditional asphalt concrete and unitary electrically conductive asphalt concrete. The used tests include the Marshall Stability test and Indirect Tensile Strength test for determining resistance to moisture damage of electrically conductive asphalt concrete, the Cyclic Uniaxial Compression test for permanent deformation prediction, the Indirect Tensile Fatigue test for the fatigue properties.Laboratory-scale samples of multiplex electrically conductive asphalt concrete have been prepared for snow melting and deicing test. The relationships between electrical conductivity with temperature and voltage have been investigated respectively. Then, the rising rule of inner temperature of multiplex electrically conductive asphalt concrete has been researched when it was energized by a power source in laboratory. Finally, the test of snow melting has been conducted outside laboratory. The electrothermal effect and snow melting efficiency of multiplex electrically conductive asphalt concrete have been investigated.