Investigating the rutting and moisture damage properties of nylon fiber reinforced asphaltic concrete

In order to investigate the effect of nylon fibers on the performance of asphaltic mixtures, 12mm long nylon fibers in different contents of 0.1, 0.2 and 0.3% (by the weight of total mixture) were added to a typical asphaltic concrete. After determination of the optimum binder content of the mixtures, the volumetric properties of the mixtures containing different percentages of nylon fibers were analyzed. Then, the fiber reinforced mixtures were subjected to Marshall Stability, flow an indirect tensile strength tests. In addition, in order to evaluate the permanent deformation behavior of the mixtures, using UTM-10, dynamic creep tests were conducted under different stress levels of 200 and 400kPa, and at different temperatures of 40, 50 and 60°C. Dynamic creep curve, flow number and the creep strain slope (CSS) were used for analysis of the results. Then, the creep behavior of the mixtures was modeled using the three-stage model developed by Zhou et al. The resistance against moisture damage of the mixtures were also evaluated using the tensile strength ratio (TSR) and Marshall Stability ratio (MSR). The results showed that the mechanical properties of the mixture such as the Marshall stability, Marshall Quotient and the indirect tensile strength of the mixture can be improved by modifying with 0.1% of nylon fiber. Also, the moisture sensitivity of the mixtures decreases with increasing fiber content, up to the fiber content of 0.1%, after which, increases with increasing fiber content. The results of dynamic creep tests and modelling the creep curve using the three=stage model showed that the mixture containing 0.1% of nylon fiber has the highest length of primary creep region and flow number and the lowest creep stain slope, indicating that its resistance against the permanent deformation is the highest.