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.

Field Performance and Cost-Effectiveness of Chip Seals and Asphalt Concrete Overlays with and without Asphalt Concrete Stripping Damage

“…Similarly, the treatment PSL (PSL T ) was computed by extrapolating the performance curve after the treatment until it reached the same cutoff value. Finally, ΔPSL was calculated by subtracting PSL R from PSL T considering a PCI threshold value of 60 as suggested by LaDOTD PMS ( 18 , 19 ).…”

Machine-Learning-Based Framework for Prediction of the Long-Term Field Performance of Asphalt Concrete Overlays in a Hot and Humid Climate

“…Pavement performance data were obtained from the LaDOTD Pavement Management System (PMS) database. In the LaDOTD PMS, pavement condition measurements from 1996 to 2019, collected biennially using the Automatic Road Analyzer (ARAN), are available ( 15 ). Pavement condition values are reported every 1/10th of a mile (a log mile) and are analyzed to calculate distress indices such as the PCI, alligator cracking index (ALCR), rutting index (RUT), RCI (RNDM), roughness index (RUFF), and patch index (PTCH), on a scale of 0–100 (100 indicating a perfect condition).…”

Impact of the Great Flood of 2016 on the Asphaltic Concrete Road Infrastructure in Louisiana

“…In the LaDOTD PMS, pavement performance data are reported for the period ranging from 1996 to 2019. These data are based on pavement condition measurements that are collected biennially using the automatic road analyzer (ARAN) system that provides a continuous assessment of the road network ( 16 ).…”

“…These indices include the pavement condition index (PCI), alligator cracking index (ALCR), rutting index (RUT), random cracking index (RNDM), roughness index (RUFF), and patch index (PTCH). For flexible pavements, PCI is calculated as follows ( 16 ):…”

“…RUFF reflects the irregularities in the pavement surface and is expressed on a scale from zero to 100, with 100 representing the case of a smooth pavement. It is related to IRI using the following empirical equation ( 16 ):…”