Pore structure characteristics of MgO–SiO <sub>2</sub> binder
Vineet Shah, Yuvaraj Dhandapani, Allan Scott
Abstract
Abstract This paper reports on an investigation into the pore structure characteristics of MgO–SiO 2 binders. Paste specimens were prepared using two MgO/SiO 2 ratios (1 and 1.5), two silica sources (Silica fume‐SF and Metakaolin‐MK), two water to binder ratios (0.5 and 0.6) and compared to a portland cement (PC) control mix. Mercury intrusion porosimetry was used to understand the evolution of pore structural features of the binder with hydration period. A continued reduction in porosity and refinement of pores was observed with the progress in hydration irrespective of the type of the silica source or the initial MgO/SiO 2 ratio. The MgO–MK mixes exhibited a finer and denser microstructure as compared to the equivalent MgO–SF mixes. The formation of hydrotalcite in addition to M‐S‐H in MgO–MK mixes was postulated to be the primary reason for the difference in microstructural characteristics, compared to MgO–SF mixes. The space‐filling capacity of hydration products of MgO–MK binder was found to be better than PC.