Time-Dependent Water Infiltration Resistance of Thin-Lift Asphalt Overlay Longitudinal Joints

Abstract

In recent years, the Mississippi Department of Transportation (MDOT), among others, has begun considering thin-lift overlays (e.g., 2.5 cm or less) as a pavement preservation treatment; however, longer-term field performance has not been heavily evaluated despite concerns that sufficient density is more difficult to achieve and/or measure, particularly at longitudinal joints. The objective of this technical note is to evaluate thin-lift overlay longitudinal joints (both unsealed and sealed with RePLAY joint sealer) using water infiltration measurements over time as a mark of overall performance of the overlay. A total of 27 field measurements were obtained over a 4-year period on two MDOT thin-lift overlays near Baldwyn, Mississippi. Both sealed and unsealed locations exhibiting a range of initial joint qualities were tested. Water infiltration results correspond to joint deterioration and cracking over time, which appears to be heavily influenced by reflective cracking from underlying layers and less influenced by initial thin-lift overlay joint quality or treatment with the joint sealer. Overall, water infiltration measurements are useful in quantifying the severity of thin-lift overlay longitudinal joint cracking.