GPR Application for Moisture Content Prediction of Cold In-Place Recycling

Cold in-place recycling (CIR) of asphalt concrete pavement is a rehabilitation technique that is widely applied by many states. The CIR rehabilitation process is thought to be economical and sustainable. One of the limitations of this technique is identifying the moisture content of the pavement layer to allow for traffic opening and placing overlay. In this paper, the feasibility of monitoring moisture content of CIR mixtures during curing using ground-penetrating radar (GPR) was investigated. Several tests, including GPR surveys, lightweight deflectometer, dynamic cone penetrometer, and sand cone tests, were performed to track both the dielectric properties' and mechanical properties' progression during curing. The relationship between the dielectric constant and the moisture content of cold in-place recycled asphalt pavements was built using a preliminary mixture theory model. Results show that the dielectric constant is strongly correlated to moisture content and GPR has the potential to monitor moisture content in future research.