Compatibility Between Pavement Surface Condition and Structural Capacity: A Case Study

Abstract: The common practice of a Pavement Management System (PMS) is to collect the pavement surface condition and generate an optimized work plan based on the age, surface condition, and function of each road segment within the network. Rarely, the pavement structural capacity is taken into consideration for work plan establishment. This common practice is assuming that the surface and structural condition are compatible and do not contradict each other. This study is putting this theory to the test on approximately 90 miles pavement network in the Chicago Metropolitan Area. A surface condition survey using a Laser Crack Measurement System (LCMS-2) was conducted, generating a Pavement Condition Index (PCI) for each road segment. In parallel, a network structural testing was conducted using a Falling Weight Deflectometer (FWD) with a frequency of one test per 0.05 miles. The structural testing was evaluated using two parameters: Remaining Life (RL) and Overlay Thickness (OT). By comparing the PCI to the RL and OT, it was observed that weak correlation was observed between the surface condition and structural capacity. Therefore, a PMS work plan that is solely optimized based on surface condition, might not provide the most economical/optimal solution. This shows the importance of considering the structural evaluation parameters to better determine appropriate treatment types. Additionally, even though the correlation between RL and OT is strong, both RL and OT parameters are suggested to be used for structural evaluation and work plan optimization as each parameter provides different type of information.