Experimental Investigation on Effects of Carbon and Nylon Fibers on Performance of Asphaltic Concrete

Reinforcement of asphalt concrete by fibers is one of the methods for improving concrete properties. In this research, the effects of two types of fibers on the properties of a common type of asphaltic concrete have been investigated. The fibers at different contents of 0.3, 0.4 and 0.5% and three different lengths of 10, 25 and 45 mm have been used, and the properties of the mixtures such as Marshal Stability, indirect tensile strength, moisture damage and static creep behavior have been studied. The results show that the Marshal stability of all the mixtures containing fiber is higher than that of the control mixture, with the highest stability for the mixture containing 0.3% of 25 mm carbon fiber. The indirect tensile strength tests show that, for the most cases of fiber contents and lengths, the indirect tensile strength of the fiber reinforced mixtures are lower than that of the control mixture without fiber. It is also found that, the permanent strain in creep tests decreases by using fibers, with the lowest permanent strain for the mixture containing 0.5% of 10mm carbon fiber. The moisture damage tests show that the carbon fiber has a better performance than the nylon fiber. The highest tensile strength ratio is found to be for the mixture containing o.4% of 10mm carbon fibers. The moisture damage increases with increasing the fiber content and length.