Monitoring of the ultrasonic P-wave velocity in early-age concrete using Smart Aggregates

This paper deals with the use of embedded piezoelectric transducers to monitor the ultrasonic P-wave velocity evolution during the setting and hardening phases of concrete since casting time. The main advantage of the technique is the ability to overcome the limitations of traditional methods which do not allow to apply specific mechanical boundary conditions during the measurement. The embedded transducers are based on the “Smart Aggregates” concept previously developed at the University of Houston, Texas. Two piezoelectric transducers are embedded in a prismatic mold and the evolution of the P-wave velocity is recorded for the first 24 hours in concrete after casting time. The results are very promising and show a good agreement with classical ultrasonic tests using external transducers.