ABSTRACT
Production of Portland cement (PC) causes significant CO2 emissions. A recently proposed family of alternatives are reactive magnesium oxide (MgO) cements. These are mixtures of normal hydraulic cements, such as PC, magnesium oxide and a pozzolan, such as pulverised fuel ash (pfa). In this paper, an overview will be given of ongoing research on these cements. The physical characteristics of the pastes and the hydration reactions that occur initially are described and supplemented with a description of the reactions that occur later on. The effect of carbonation on these materials is discussed. The chemical changes that occur in these materials are then correlated with measurements of strength or stiffness as a function of time. To illustrate possible applications the results of 2 case studies are summarised: (1) a light-weight masonry unit made almost entirely out of pfa, and (2) the use of these cements to produce standard aggregate-cement masonry units.
