Evaluation of pavement distress on forest road curves (Case study: Shanderman ‎‎watershed)‎

This study aimed to evaluate of unsurfaced forest road distresses on the existing curves. Numbers of 30 selective plots on the center of curves were measured. A paired sample plot beside of each curve was measured. In each plot, seven indices of unsurfaced road distress including improper cross section, inadequate roadside drainage, corrugation, dust, potholes, ruts and loose aggregate of soil were measured. Paired samples t-test and Wilcoxon test were used to analysis of data. Result showed that there were improper cross section and dust distresses factors in all plots on the curves, while 3.3 % of paired plots had none of these distresses. Also, distress intensity causing by improper cross section and inadequate roadside drainage factors were more in the curves than to paired plots and significant difference between the curves and paired plots was observed. The results of corrugation indicated that 70 and 66.7 % of sampled plots in the curves points and side plots lacked this type of distress, respectively. Results showed that the depth and area of potholes and ruts, and loose of soil aggregate in the curves points were greater than the paired plots but there was no significant difference between the curves and paired plots. Results of this study shows importance of regular maintenance activities and application of evaluation indices at the network level of pavement.