Determination of volumetric water content of concrete using ground-penetrating radar

A large number of reinforced or prestressed concrete pathologies require the presence of water to develop. In this context, the quantification of water content is an important phase for the diagnosis of concrete. The propagation of electromagnetic waves is controlled by its electromagnetic properties, mainly influenced by the presence of water in the case of concrete. We propose to use the direct transmitter–receiver radar wave to determine the moisture of the cover concrete. The Wide Angle Reflection Refraction (WARR) measurement technique is used to obtain the speed of the direct wave. A method is used to extract the group and the phase velocity of this wave. We show that the speed is not dependent to the frequency between 300 MHz and 1.2 GHz in these testing conditions. By using two different concretes partially saturated, we show that there is a linear relation, independent of the concrete, between the volume water content and the propagation velocity of the direct wave on the one hand and its attenuation on the other hand.