Highway subsurface assessment using pavement surface distress and roughness data

In this paper, pavement sections of the highway connecting Jeddah to Jazan were selected and analyzed to investigate the relationship between International Roughness Index (IRI) and pavement damage including cracking, rutting, and raveling. The Ministry of Transport (MOT) of Saudi Arabia has been collecting pavement condition data using the Road Surface Tester (RST) vehicle. The MOT measures roughness (ROU), rutting (RUT), cracking (CRA), and raveling (RAV). Roughness measurements are calculated in terms of the International Roughness Index (IRI). In the present three relationships, including CRA versus IRI, RUT versus IRI, and RAV versus IRI have been developed. The models relating to three types of distresses under study, and model relating IRI to ride quality have been studied in the present work. The results of the analysis indicate that a significant relationship exists between IRI and cracking, and IRI and raveling at 95% confidence level. The results also show that the rutting did not show a significant relationship to IRI values. It can be concluded from the results that cracking and raveling may possibly be described as ride quality distresses, whereas the rutting distress may be described as non-ride quality distress. The results indicate that while statistically significant relationships exist between IRI and both cracking and rutting, these relationships are not strong enough for IRI to be used as a surrogate measure for pavement condition.