Study to evaluation position and size of voids in concrete by backscattered gamma technique

Abstract: In this study, the scattering gamma method used radioactive sources of 137Cs (5mCi) and NaI (Tl) detector with 1200 scattering angles to determine the position and size of voids in concrete. Concrete samples having the density of 2.3g / cm3 thickness of 10 cm with voids diameter varying from 1cm to 3cm in the measurement plane have been made for experimental measurements. The obtained results indicate that the position of the voids has been determined relatively accurately, while the size of the voids is different from the actual value. This result shows that backscatter gamma technique can be applied to determine the position and size of defects inside concrete materials after optimizing investigating conditions.
Keywords: Gamma backscattering, Compton scattering.