of MgO obtained from calcination of magnesium carbonate at different temperatures
has been investigated by means of hydration in a constant relative humidity
environment at 40°C for periods up to 24 days. Natural magnesite and AR
grade basic MgCO3 calcined in the range of 500–1000°C
was characterised in terms of surface area, crystallite size, morphology,
and hydration rate.
It was found that the hydration rate is dependent
on the surface area and crystallite size where temperature was the main variable
affecting them. The most reactive MgO was produced at the lowest calcination
temperature with the highest surface area and the smallest crystallite size.
The basic MgO specimens showed higher degree of hydration compared to the
natural MgO specimens due to the smaller surface area and larger crystallite
size. The low MgO content of the starting natural magnesite is also attributable
to the lower reactivity. This preliminary study serves as a mean to investigate
potential utilisation of reactive MgO as a supplementary cementitious material
in eco-friendly cements.