Clogging evaluation of porous asphalt pavement using ground-penetrating radar

Clogging reduces the porosity of porous asphalt (PA) pavement, which would jeopardize its permeability, noise absorption, and skid resistance. Existing evaluating methods use in-situ cores that damage the pavement with limited coverage. This study explored the feasibility of evaluating PA pavement clogging using ground-penetrating radar (GPR). Laboratory tests were performed on porous asphalt (PA) slabs under various clogging degrees. The effect of antenna type and moisture on clogging evaluation were investigated. The performances of two clogging indicators were examined, including the bulk dielectric constant obtained using the time-of-flight method and time–frequency spectrograms using the short-time Fourier transform (STFT). Effectiveness of GPR-based clogging evaluation was validated by permeability tests. Results show that both indicators could effectively evaluate clogging in PA pavement. The effectivenesses of proposed indicators were verified through permeability tests. GPR surveys are suggested 72 h after rainfall in sunny days using 2 GHz air-coupled antennas.