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 degrees 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. (C) 2012 Elsevier Ltd. All rights reserved.