Automated detection of cracks in roads using ground penetrating radar

Abstract A critical assessment criterion for road condition assessment is the amount and severity of cracking. Cracking causes a loss of structural capacity (i.e. strength and stiffness) and if severe can cause water infiltration into the subbase and subgrade, potentially leading to more serious structural failure. The onset of cracking therefore accelerates the processes of deterioration of the road. To date the accurate and reliable automated detection of road surface cracking is still problematic. Ground Penetrating Radar (GPR) has the potential to detect cracks in materials as they cause changes in electromagnetic reflection. This paper proposes a method of automatic detection of road surface cracks using GPR and establishes the limits of its potential regarding the detectable crack size. Tests were conducted on asphalt pavement samples in a controlled laboratory environment. Significant changes in diffracted signal levels were observed in the GPR image when the image was analysed using a Singular Value Decomposition (SVD) algorithm for clutter reduction and a median filter to reduce noise. Moreover, a manifestly enhanced performance was achieved using a novel post-processing technique, which enabled the detection of cracks larger than 1.3 mm in width. The detected cracks were detectable irrespectively of the simulated physical conditions suggesting that the developed methodology is robust for use in practice. The experimental results indicate that the GPR system can be applied to automatically detect road cracking reliably in practice.