Abstract

Thermodynamic and kinetic modelling is currently an important tool in cement chemistry which enables to predict the evolution of the solid and liquid phases of a given cementitious system. To date, it has been able to predict several characteristics of Portland cement-Fly Ash (FA) and PC-slag blended cements: the composition of phase hydrate assemblages, the kinetic reactivity of slag/FA particles, and more recently the state of alkali ions in the pore solution. However, some of these models cannot yet predict the experimental observations made on the overall pore solution characteristics of PC-slag/FA blended cements. Our research uses the geochemical speciation code (GEMS-PSI) to investigate the unmodelled observations in terms of the properties of the pore solution of PC blended with FA and slag. We use recent kinetic modelling data describing experimentally observed behaviour of the dissolution of the major and minor phases present initially in PC-slag/FA cementitious systems as input data in GEMS -PSI to predict the pore solution chemistry development of PC-slag/FA blended cements. The results obtained with this model are compared with the latest relevant experimental data found in the literature on PC-FA blended cements.