Hydration properties of the alite-ye'elimite cement clinker synthesized by reformation

An expansive high early strength alite-ye'elimite clinker containing 4.8% ye'elimite was synthesised by annealing without addition of mineralizer into the raw meal. The reformation of ye'elimite was achieved by C₃A reacting with C$ in clinker. The microstructure of the paste was characterised by SEM, MIP and N₂ adsorption/desorption. DSC-TG and XRD were used to investigate the hydration products of the paste. Mortar tests on the clinker yielded values of 30.0 MPa, 42.3 MPa and 55.8 MPa at 1, 3 and 28 days, respectively. Due to the presence of AFt in the hydrated paste, the expansive behaviour resulted in a reduction in the total pore volume by 29-62% (0.01-10 μm), but there were more mesopores (2-50 nm) due to the crystalisation of AFt. The linear expansion converged after ∼150 days with maximum expansion of 0.136%.