Application of light-burnt dolomite as a mineral addition in concrete

Growth in the production of cement has led to increasing demands for mineral additions. This study was conducted to develop an alternative addition by calcining dolomite at 800°C to obtain a mixture of periclase (MgO) and calcite (CaCO₃). The light-burnt dolomite (LBD) was used to prepare blended cements. The hydration, setting time and microstructure of the cement were assessed and the compressive strength and deformation of concrete made using the LBD cements were measured. The results showed that the blended cement had no unfavourable effects on setting time or hydration. It was also found that the autogenous shrinkage of concrete can be mitigated with a replacement of LBD up to 20% and the free expansion levelled off early and was kept at a low level. The compressive strength of concrete made with the blended cement, especially with 10% LBD, was higher than that of plain concrete, which is partly related to the decrease of porosity, the fineness of pore diameters and interface enhancement due to the interaction of the LBD and the clinker.