Abstract:

Conductive components were prepared by carbon fiber and graphite powders, and the relationships between different dosage of carbon fiber, graphite powders and asphalt mortar resistivity were investigated by aboratory test. The material pressure sensitivity and pressure-sensitive reversibility were analyzed by cyclic compressive loading test. The change rate of electrical volume resistivity Fn and the fractional change in resistivity per unit stress Kn were analyzed. The regularity and trend of variations of Fn and Kn under different loading circles were discussed by the mathematical statistics method. The results showed that the carbon fiber and graphite powders could reduce the resistivity of the asphalt mortar effectively. The conductivity increased with the compression stress and decreased with the compression stress increasing unloading, which showed good pressure sensitivity. There was a good correlation between Fn, Kn and numbers of cyclic compressive loading. With the loading cycles increasing, the change in resistivity per unit stress decreased, demonstrating that the reversibility of material tend to be stable. Reducing plastic deformation is very important to the reliability of initial detection results.

Key words: asphalt mortar, conductivity, pressure sensitivity, resistivity