Short and Long-Term Field Performances and Optimal Timing of Chip Seal in Hot and Humid Climates

Abstract

Chip seal is a preventive maintenance technique typically applied on relatively low traffic roads to reduce pavement deterioration rate and to defer the need for costly rehabilitation activities. This study aims to address the common challenges with chip seal application in hot and humid climates such as Louisiana to ensure the maximum benefits are achieved. Specifically, this study evaluated the short and long-term field performances and optimal timing of chip seal by analyzing the cracking, roughness, and overall pavement conditions of 47 flexible and composite pavement sections in Louisiana. Furthermore, potential moisture damage in asphalt concrete after chip seal application was assessed. Results indicated that chip seal extended pavement service life by 4–17 years based on the pre-treatment pavement conditions and pavement type (flexible or composite). Based on the cost benefit analysis, it is recommended to use alternating cycles of asphalt overlay and chip seal on low volume roads (less than 5,300 vehicles per day) with chip seal applied when the pavement condition index (PCI) of the pavement drops to a value between 70 and 74. In this case, significant monetary savings could be achieved when compared with adding chip seals at different time periods (outside the recommended range of PCI between 70 and 74). Results also showed that the application of chip seal does not seem to contribute to moisture damage. Instead, shallow groundwater conditions present in the State seem to contribute to moisture damage in asphalt pavements owing to moisture entrapment underneath the asphalt layer.