Study On Application Technology Of Electrically Conductive Asphalt Concrete

Snow and ice on the pavement surface will seriously affect the trafic smooth and driving safity. It is always one of the most important subjects that how to keep highway and runway from influence of snow and ice. In this paper, we mostly discuss and analyze the structure of Electrically Conductive Asphalt Concrete(ECAC), proposed by using composite technology and synergistic effect for ECAC preparation methods, design a new type of bituminous cover course contain with snow-melting agent, and construct a thermal insulation bonding layer of asphalt pavement. This research not only has important practical significance for the runway, roads and bridge but also plays a guiding role on the structural design of asphalt pavement conductivity.First of all, consulting about relevant regulations, preparation and actual situation of ECAC, we made the structure and the technical requirements. Using Superpave-12.5 as gradation, Mafilon(MFL) snow-melting agent instead of powder to design bituminous cover. Marshall conventional performance, moisture stability and other tests show that the performance of pavement with incorporation of MFL snow-melting agent could meet regulatory requirements. In addition, through comparative analysis of the mechanism of melting and freezing point test shows that MFL snow-melting agent greatly improve snowmelt efficiency than ordinary ice-melting salt, and almost has no effect on the environment.Electrically conductive layer mixture uses AC-20C as gradation, compound with steel slag, graphite and carbon fiber. It has greately pavement performance and function of snow-melting. The electrical resistivity of mixture, of which aggregate gradation has been optimized reduces and is below 1Ω·m. According to Calculation, when the electrode spacing is 0.7m and external voltage surpasses 54V, the asphalt pavement can satisfy the requirement of snow melting. Resistance test shows the resistivity of electrically conductive layer increases with increasing temperature, but the increase was small, at less than 10℃, the resistivities of electrically conductive layer are less than 1Ω·m. Four bend fatigue test shows the maximal fatigue live of electrically conductive layer can reach 2 times the normal asphalt concrete.In order to reduce loss of heat conducted to sublayer, heat insulation bonding layer is set between them. We have compared with several common heat insulation materials and finally choose polyurethane rigid foam to made heat insulation bonding layer. The low thermal conductivity, easy construction and a certainty intensity of polyurethane rigid foam satisfy the requirement of insulation bonding layer and increase the melting efficiency.Lastly, based on the indoor experiment (laboratory), the big plates of conductive course were carried on, on the conditions of the distance between electrodes 0.7m and direct voltage 60V, the curves of plates increasing temperature are obtained, the temperature goes up approximately 13℃after 3 hours electric circuit of electrically conductive asphalt course. Temperature of bottom is only about half of the surface because of heat insulation bonding layer.