Nondestructive evaluation of concrete infrastructure with ground penetrating radar

In recent years the use of ground penetrating radar (GPR) at frequencies from 500 MHz to 2.5 GHz has yielded very good results for inspection of concrete structures. The possibility of performing nondestructive measurements quickly and with convenient recording of the measurement results is particularly beneficial. The technique is well-suited for locating tendon ducts at depths down to 50 cm, detecting voids and detachments, and measuring thickness of structures that are only accessible from one side. This paper presents the basics of GPR, its limits, and the results of laboratory investigations and case studies. It also shows that GPR can be used for regular inspection, searching for the cause of damage, and quality assessment of civil engineering structures.