Recommendation of RILEM TC 218-SFC: Sonic methods for quality control of fresh cementitious materials* Testing of fresh concrete by ultrasound transmission

摘要

This recommendation deals with the determination of the stiffening and hardening of fresh cementitious materials, mainly mortar and concrete. The method uses an ultrasonic pulse which is transmitted through a sample of fresh material. The transit time is measured which leads with the known travelling distance to the velocity of the longitudinal wave (simply called pulse velocity) in the material. The pulse velocity correlates with the elastic properties. By taking measurements on a regular basis during the first hours of hydration the transition from the fresh state to the hardening state can be clearly detected.