Experimental study on the effect of basalt and glass fibers on behavior of open-graded friction course asphalt modified with nano-silica

Abstract

• The sample which has the largest permeability, had the minimum value of draindown. • The effect of glass fiber in reducing the permeability is far greater than that of the basalt. • The tensile strength of asphalt mixtures increases by adding fiber. • The effect of nano-silica in reducing abrasion and reduction of sensitivity to oxidation is considerable. Open-graded friction course (OGFC) is a mixture having gap graded aggregate which is used in pavement surfacing. Asphalt mixtures were modified by Nano silica, polymer, basalt fiber and glass fiber. A draindown test, Cantabro test, permeability test and an indirect tensile strength test and moisture susceptibility were used to evaluate the performance of OGFC mixtures. Test results revealed optimum compounds for 0.2% basalt fiber with 2% nano-silica and 4.5% Styrene-Butadiene Styrene (SBS) Polymer. The minimum air voids content of fiber-reinforced OGFC mixtures modified with nanomaterial should be 13% for 6% bitumen. The results showed the effect of nano-silica in reducing abrasion and reduction of sensitivity to oxidation is considerable and the effect of basalt fiber per 0.2% in the asphalt mixture to be greater than that of glass fiber in reducing the draindown phenomenon; and for controlling the level of draindown phenomenon, nano-silica compound should also be used with basalt fiber. It was also found that although the use of basalt fiber is more effective in decreasing draindown in comparison with glass fiber, the effect of glass fiber in reducing the permeability of the asphalt mixture is far greater than basalt fiber.