Tensile characterization of graphene nanoplatelets (GNP) mortar using acoustic emissions

Abstract

This study characterizes tensile behavior of graphene nanoplatelets (GNPs) reinforced cementitious composites using acoustic emissions (AE). Two acoustic sensors were attached to dog-bone specimens that were cast using GNP nano-reinforced mortar composites at concentration levels of 0% to 0.5 % by weight of cement. The specimens were tested under direct tensile loading and the average tensile strength was calculated. AE parameters such as average frequency (AF) and rise time over amplitude (RA) were used to analyze the cracking mode. Average RA was studied to investigate the effect of GNPs reinforcement. A correlation between average acoustic energy and the tensile strength was established. In addition, the acoustic emissions data was analyzed for the localization of cracks along the length of the specimens. Results indicated that the addition of GNPs increased the tensile strength of the cementitious composites by 8%–48%. In addition, the AE analysis revealed a delay in crack initiation shear stress transfer on the matrix -GNPs interface for mortar composites with GNPs and was able to localize cracks as they are initiated.