Monitoring of cement hydration reaction process based on ultrasonic technique of piezoelectric composite transducer

The piezoelectric composite transducers were fabricated by using different types of piezoelectric composites as core elements, and mixtures of cement, epoxy resin and hardener as packaging material. The performance testing results show that piezoelectric composite transducers have characteristics of broad band, high sensitivity and good matching ability with cement material, etc. Based on ultrasonic wave technique, the hydration reaction process of Portland cement was monitored by using the piezoelectric composite transducers as ultrasonic probes. Through analyzing the relationship between waveform and wave parameters of received ultrasonic wave and cement hydration reaction time, the cement hydration reaction rule is obtained. The cement hydration reaction process could be divided into about four periods, that is, induction period, acceleration period, attenuation period and steady period. Especially in initial 24 h of cement hydration reaction, the changes of wave velocity, head wave amplitude and dominant frequency value of received ultrasonic wave are very obvious.