Simultaneous study of mechanical property development and early hydration chemistry in Portland cement slurries using X-ray diffraction and ultrasound reflection

A sample cell for the simultaneous measurement of synchrotron X-ray powder diffraction and ultrasound shear-wave reflection data from cement slurries is described. White cement slurries at 25 and 50 °C with 0–3% bwoc CaCl2 were studied to illustrate the potential of the apparatus. The decrease in reflected S-wave amplitude, in dB, showed a linear correlation with C3S hydration. CaCl2 retarded the development of G′ and G″ relative to the extent of C3S hydration. At short times, there was a correlation between the time evolution of both G′ and G″, and the amount of precipitated CH seen by diffraction, which was almost independent of CaCl2 concentration and temperature. CaCl2 addition resulted in a decrease in the amount of CH visible to X-rays, relative the degree of C3S hydration. This may indicate a change in C–S–H gel C:S ratio or the presence of nanoscale CH that could not be seen by diffraction.