Volumetric water content estimation of C-30 concrete using GPR

Abstract

In this research, we consider a laboratory specimen of C-30 concrete block using a geophysical technique called GPR (Ground-Penetrating Radar). The volumetric water content of the C-30 concrete block can be estimated using a central frequency of 2 GHz shielded GPR antenna in a non-destructive way. In this purpose, time-lapse GPR measurements were applied over the C-30 concrete block that took about 150 days. We estimated relative dielectric permittivity of concrete block from the scatters on GPR profiles that caused by an iron bar in the concrete block. Data were acquired consecutively 5 times in each day to calculate the arithmetic mean of relative dielectric permittivity. To estimate the volumetric water content of a sample, we used previously suggested formula for various concrete classes. Based on information from the factory, the volumetric water content of the sample was 7.31% according to its composition. However, based on our estimation by the formula, the volumetric water content was estimated 7.19% at the 3rd day after the concrete block was prepared in the factory. This experiment suggests that the water content variation of the corresponding concrete sample can be monitored using the GPR method in a non-destructive way. The result may be extended to other classes of concrete as well. The suggested method is a fast, economic and simple way to estimate the volumetric water content of a concrete sample. Our time-lapse measurements can be a guide to estimate volumetric water content of C-30 concrete class.