Automated shear-wave techniques to investigate the setting and hardening of concrete in through-transmission

Ultrasonic methods have been developed in the past few decades to study the properties of cement based materials in fresh and hardened state. However, most of the methods consider only a certain type of ultrasonic waves. To derive elastic parameters of fresh concrete like the Poisson's ratio and elastic modules it is required to measure shear waves as well as compression waves. It is relatively much more difficult to establish a setup to transmit and record shear waves in a way that the onset of these slower waves can be detected sufficiently clear to calculate the shear velocity with the required accuracy. In this paper, an experimental setup for testing concrete with different ultrasonic waves is presented and methods for automated onset determination of p- and s-waves are described.