Quantification of Surface Crack depth in Concrete Panels using 1.6 GHz GPR Images

摘要

Cracking of concrete structures such as highway bridges is commonly observed in the U.S. and around the world, which can be attributed to one or many damage mechanisms. The inability of visual inspection for determining crack depth has a detrimental effect on its reliability. With the use of nondestructive evaluation (XDE) techniques such as microwave and radar sensors, subsurface sensing can be achieved in concrete structures. The objective of this paper is to investigate the performance of a commercially available ground penetrating radar (GPR) sensor on artificially-cracked concrete specimens in the laboratory and real concrete structures with cracks in the field. Three artificially-cracked concrete specimens (30x30x4 cm~3) with different crack dimensions were manufactured with one pristine concrete panel without any crack as the control sample. Three different crack dimensions were introduced in concrete panel specimens, including specimen CNC with a 10x0.5x0.5 cm~3 crack, specimen CNCD with a 10x0.5x1.5 cm~3 crack, specimen CNCW with a 10x2x0.5 cm~3 crack. An L-band GPR sensor (carrier frequency = 1.6GHz) was used in all experimental measurements. From our result, it was found that the use of a 1.6 GHz GPR sensor can detect the presence of an artificial crack, as well as detecting crack dimension (e.g., depth). Empirical models were developed from the B-scan GPR images for crack quantification.