Defects in Flexible Pavements: A Relationship Assessment of the Defects of a Low-Cost Pavement Management System

Pavement maintenance is a key concern for pavement management authority. Countries (especially developing countries) are facing severe funding challenges regarding maintenance schemes. The existing pavement maintenance methods are goal-specific and lack integration of various indicators that are significant for low-cost PMSs. Thus, this paper investigates the possible defects that may occur in flexible pavements as well as the relationships between different defects. A detailed literature review was conducted to identify all possible defects in flexible pavements and key features considered PMSs. A questionnaire was designed to seek expert opinions on the defects and their possible relationships for a low-cost PMS. The data were collected from 283 experts currently working in pavement management authorities and pavement maintenance schemes. Aggregated mean score, box plotting, and the chi-square test were used to analyze the data. It is concluded that bumps/sags (3.17) are major defects reported by pavement experts in Pakistan, followed by fatigue cracks (3.07). Rutting (2.98) and rut depth (2.98) are the third-ranked key defects reported in this study. Depression (2.96), potholes (2.76), longitudinal crack (2.69), edge crack (2.55), roughness (2.51), and deflection (2.50) are also regular defects in pavement maintenance activities in Pakistan. The results are in an acceptable range of the three-mentioned validation methods. The correlation test results show that most of the defects in structural, functional, safety, and serviceability indicators reject the null hypothesis; thus, there are close relationships between these defects observed in flexible pavements. In the last stage, a PMS model is suggested to assist road management authorities in developing countries to make low-cost decisions for effective pavement rehabilitation.