Correlation between damage evolution and resistivity reaction of concrete in-filled with graphene nanoplatelets

Pilot researches prove that graphene nanoplatelets (GNPs) are promising nano-sized additives to improve the smartness of cementitious materials. This work aims to reveal the explicit correlation between the damage development and the resistivity reaction of cementitious composites infilled with GNPs. A weight content of 4.5% (GNPs/cement) is used to cast two groups of concrete samples, named as C20 and 00 (according to their designed compressive strength), whose volume fractions of GNPs are 0.43% and 0.61%, respectively. Investigations shows different failure patterns during compression loading and their piezoresistive characteristics are probed systematically. Additionally, damages determined by strain-stress curves and ultrasonic pulse velocity penetrations in the middle section are also studied for comparing. The damage evolution process illustrated by resistivity reactions contains a slight decrease of resistivity within the elastic regime, a moderate damage developing stage before the peak force, an expeditive damage section just after the peak force and a relaxed damage expanding when the stress drops to less than 50% of the strength. At last, the damages obtained with resistivities increase to 0.8. This indicates that the piezoresistivity of smart concrete containing GNPs can be a promising tool to detect damages detailedly. (C) 2019 Elsevier Ltd. All rights reserved.