Early-age strength monitoring of the recycled aggregate concrete using the EMI method

Abstract

Abstract At present, the recycled aggregate concrete (RAC) technology has served as an environment-friendly means to dispose the waste concrete. This paper mainly investigates the feasibility of the early-age strength monitoring of the RAC using the electro-mechanical impedance (EMI) method. Both the compressive test and EMI test utilizing the embedded piezoelectric smart aggregate (SA) transducers were conducted on the specimens with different recycled coarse aggregate (RCA) replacement ratios and loading ages. The compressive test results show the early-age strength of the RAC develops more slowly on the whole as the RCA replacement ratio increases. In addition, the EMI test results as well as the theoretical analysis show that the conductance resonant frequency (CRF) of the SA generally rises as the age goes on. By regression analysis, the linear relationship between the early-age strength of the RAC and the CRF increment was established. It validates the applicability of using the EMI method to monitor the early-age strength of the RAC in engineering practice.