An ultrasonic shear wave apparatus and its applications to rheology of hydraulic materials

In this paper a new ultrasonic shear wave apparatus is described. With the apparatus time dependent processes like hydration of hydraulic materials and reaction hardening can be studied. The sensitivity of the instrument to parameters (rheology, composition, water content, fineness, grain size distribution, addition of additives, ageing temperature) influencing these processes is eminent from the results obtained so far, offering several laboratory testing applications. The measurements are continuos, non-destructive and with no shearing applied. It is thus possible to obtain information on the growth of the physical strength of the fragile cement gel in the very early stage of hydration. The earliest usable time is limited by the time needed to prepare the sample and it extends to several days into hardened state. Application examples for cement pastes are presented.