Abstract
This paper describes the relationship between the setting/hardening properties of cement paste and ultrasonic propagation characteristics from both a macroscopic and a microscopic point of view. The first experimental series was aimed at evaluating changes in the physical properties of high-early-strength cement paste. In the experiment, a single cylinder rotational viscometer was used for viscosity measurement. The second series of experiments was aimed at evaluating changes in the chemical properties of ultra-rapid-hardening cement paste. In the experiment, scanning electron microscopy (SEM) and powder X-ray diffraction analysis were done to investigate the generation of hydration products.
As a result, it was confirmed that the maximum amplitude of the obtained waveform adequately reflects the changes in shear resistance of cement paste. On the other hand, change in ultrasonic wave velocity is well correlated with the formation of ettringite crystals as observed by SEM and powder X-ray diffraction analysis.
