C(-A)-S-H gel solubility model development and its application to high content fly ash silica fume cement

Walker, C.*; Anraku, Sohtaro ; Sasamoto, Hiroshi   ; Mihara, Morihiro  

A thermodynamically credible calcium(-aluminate)-silicate-hydrate (C(-A)-S-H) gel solubility model has to consider a variety of features, including structure, composition, phase boundaries, measured/estimated thermodynamic properties, molar volumes, and, of course, solubility behavior in terms of pH values and Ca, Al and Si concentrations expressed as a function of C(-A)-S-H gel composition, temperature and ionic strength. This study provides an account of the rapidly growing body of data that are concerned with these features and of the more promising approaches that can be used to develop a C(-A)-S-H gel solubility model. JAEA research on the degradation of high content fly ash silica fume cement (HFSC) provides a good working example that highlights the need to develop a C(-A)-S-H gel solubility model.