Monitoring Early Age Properties of Cementitious Material Using Ultrasonic Guided Waves in Embedded Rebar

摘要

The evaluation of early age properties of concrete is critical for ensuring construction quality. Using ultrasonic guided waves in a rebar for monitoring the early age properties of cementitious material is presented. The longitudinal L(0,1) mode guided wave in rebar is excited by an EMAT sensor and received by a P-wave ultrasonic transducer. Continuous measurements during cement hydration were used to monitor the longitudinal wave attenuation resulted from the leakage from the rebar to the surrounding concrete. The evolution of the shear wave velocity was also measured at the same time. Experiments were performed on four cement paste samples and three mortar samples. The results indicated that mechanical properties can be monitored by ultrasonic guided waves in the rebar.