Evaluation of the Effect of Different Factors on Pavement Roughness, Rutting and Cracking; A Case Study

A well-maintained transportation infrastructure system is an indicator of a well-functioning economy. Road degradation is often considered to be unpredictable due to the effect of various influential factors including environmental and geographical conditions. Even though, the real trends of the pavement deterioration under different combinations of environmental and geographic factors have not been much explored and they are not implemented in the optimum pavement designs. Therefore, this study examines the effect of different factors when considered individually and collectively on the performance of the flexible roads based on real field data of roughness based on International Roughness Index (IRI), rut depth and crack area measurements. The distribution of values of each distress in two road clusters; urban and rural is studied to identify the behavioural patterns with various external factors including rainfall, terrain type and drainage condition. The study is based on the monitoring data collected over 15 years across Australia. One-way analysis of variance (ANOVA) was performed to evaluate the significance of the selected external factors on road distress parameters. 60 unique combinations of factors including 5 different rainfall classes, 4 terrain types and 3 drainage conditions are analysed to identify the trends in the spatial distribution of each distress. The results reveal clear trends of IRI, rut depth and crack area values with rainfall, terrain type and drainage condition of the road when considered as individual factors while the combined effects of different factors show contradictory behaviours. The results can be used in the pavement maintenance decisions and also in the road pavement designs.