Evaluation of Moisture Damage under Crack-Sealed Asphalt Pavements in Louisiana

Crack sealing prevents the ingress of water in the pavement structure, thus preventing the weakening of the pavement and delaying its deterioration. Earlier studies indicate that sealing pavements in areas with a high ground water table (GWT) may prevent moisture from escaping upwards through cracks in asphalt pavements, therefore, accelerating stripping. The objective of this study was to provide guidelines for using crack sealing to minimize moisture entrapment under cracks, thus reducing stripping on low volume roadways. To achieve this, a calibrated Finite Element (FE) model was used to model a field experiment consisting of cracked and crack-sealed asphalt pavement sections. Sensitivity analysis was then conducted to compare crack-sealed and unsealed sections under different GWT levels, air relative humidity, air temperatures, rain intensities, and asphalt hydraulic conductivities. Results indicate that crack sealing could be applied under common rain intensities in Louisiana and any GWT depth without potential for stripping because of moisture entrapment if the hydraulic conductivity of the original pavement does not exceed 2 X 10(-6) m/s. Yet, crack sealing should be applied after a dry period to ensure that the existing moisture in the original pavement is minimal. A non-linear regression model was developed for use in the Southern United States to help determine whether crack sealing should be used to avoid moisture damage in a cracked pavement at a given site based on the GWT and air relative humidity without the need for FE simulations. This can be a useful tool when planning maintenance activities.