Hydration and microstructure of glass powder cement pastes – A multi-technique investigation

Abstract

The industrial adoption of new supplementary cementitious materials requires the understanding of their effects on the hydration and on the long-term properties of concrete, in order to adapt design and construction methods. Although the evolution of properties differs from that of Portland cement systems, the constructability of glass powder (GP) blended-cement systems was found to be maintained (i.e., similar 2-day strength) and gains were observed in the long-term performances (i.e., similar strength but higher resistivity, suggesting higher durability). This paper aims to understand and describe the mechanisms responsible for these behaviours using a multi-technique investigation approach (calorimetry, XRD-Rietveld-PONKCS, thermodynamic modelling, quantitative chemical analyses, and more). The results disclose the chemo-physical effects of GP on early age hydration kinetics, the impact of cement dilution on phase assemblage, and the long-term pozzolanic reaction of GP leading to C-S-H with a lower calcium content, a higher alkali uptake and a refined porosity.