Effect of Basalt Fiber on the Asphalt Binder and Mastic at Low Temperature

Abstract

The effect of basalt fiber on asphalt binder and mastic at low temperatures is investigated in this study. Basalt fibers are dispersed into the asphalt binder and mastic specimens to prepare the fiber-reinforced binding materials. The fiber-reinforced specimens are tested using the direct tension test and a newly developed fatigue test procedure, which is able to directly apply cyclic tensile loading to the asphalt binder and mastic specimens. The reinforcement effects of basalt fiber to the fatigue resistance of asphalt binding materials are evaluated. The direct tension test results show that with an appropriate content, the tensile strength of the asphalt binder is improved with the use of basalt fiber. The basalt fiber also restrains the axial strain and increases the stiffness of both the asphalt binder and mastic specimens. The fatigue test results indicate that the fatigue life of both asphalt binder and mastic specimens is significantly improved by the basalt fibers. The effect of basalt fibers is also analyzed using numerical simulations of direct tension and fatigue tests based on the finite-element method. The internal structure of the fiber-reinforced mastic is considered with the assistance of X-ray tomography technology. The fiber-reinforced mastic model is a heterogeneous composite in which the asphalt binder, fillers, and basalt fibers are treated as different materials. The axial stress and strain of the model are analyzed under unidirectional tensile loading and cyclic tensile loading. The results show that the fiber added between fillers releases the stress concentration of the critical area and diminishes the fatigue damage caused by cyclic loading.