Search results for "calcium silicate hydrate"
showing 3 items of 33 documents
Experimental and theoretical evidence of overcharging of calcium silicate hydrate
2007
International audience; Electrokinetic measurements such as electrophoresis may show an inversion of the effective surface charge of colloidal particle called overcharging. This phenomenon has been studied by various theoretical approaches but up to now very few attempts of confrontation between theory and experiment have been conducted. In this work we report electrophoretic measurements as well as Monte Carlo simulations of the electrokinetic potential for the surface of calcium silicate hydrate (Csingle bondSsingle bondH), which is the major constituent of hydrated cement. In the simulations, the surface charge of Csingle bondSsingle bondH nanoparticles in equilibrium with the ionic solu…
Uptake of actinides by calcium silicate hydrate (C-S-H) phases
2018
Abstract The sorption of actinides (Th, U – Am) was studied in dependence of the solid-to-liquid (S/L) ratio (0.5–20.0 g/L) and the calcium-to-silicon (C:S) ratio. The C:S ratio was varied between 1.80 and 0.70 to simulate the changing composition of the C-S-H phases during cement degradation from high to low C:S ratios. The decrease of the calcium content in the C-S-H phases by time is accompanied by a decrease in pH in the corresponding suspensions from 12.6 to 10.2. X-ray photoelectron spectroscopy (XPS) of the C-S-H phases showed an increasing depletion of Ca on the surface with increasing C:S ratio in comparison to the composition of the solid phase as a whole. The sorption experiments…
Calcium silicate hydrates: Solid and liquid phase composition
2015
© 2015 Elsevier Ltd. This paper presents a review on the relationship between the composition the structure and the solution in which calcium silicate hydrate (C S H) is equilibrated. The silica chain length in C S H increases with the silicon concentration and the calcium content in the interlayer space with the calcium concentrations. Sodium and potassium are taken up in the interlayer space preferentially at low calcium concentrations and thus by low Ca/Si C S H. Aluminium uptake in C S H increases strongly at higher aluminium concentrations in the solution. At low Ca/Si aluminium substitutes silica in the bridging position at Ca/Si. > 1 aluminium is bound in TAH. Recently developed ther…