Unveiling the dielectric property change of concrete during hardening process by ground penetrating radar with the antenna frequency of 1.6 GHz and 2.6 GHz

With the extensively application of electronics at information age, the dielectric property of concrete is one of the worthiest study topics for enhancing the development of smart infrastructure and enabling efficient nondestructive testing and monitoring of concrete structures. In this work, concrete samples with the water-tocement (w/c) ratios of 0.4 and 0.5 were prepared and cured in saturated lime water, by curing compound and directly exposed in air. The dielectric properties of concrete samples during hardening process were investigated by a ground penetrating radar (GPR) system with the frequency of 1.6 GHz and 2.6 GHz. Moreover, the compressive strength and free water content were determined to interpretate the dielectric property change of concrete. The pore structure of concrete was examined by mercury intrusion porosimetry (MIP) method to reveal its influence on dielectric property change. The hydration kinetics of concrete was measured by thermogravimetric analysis (TGA) to understand the underlying mechanism of dielectric property change. The research findings from this work have the potential to be used for non-destructively assessing the quality and uniformity of concrete hydration in field.