Study on properties of a composite cement with sulphoaluminate cement and Portland cement

The properties of a composite cement with Portland cement and sulfoaluminate cement,including of the water requirement of normal consistency,setting time,hydration thermal effect,mortar strength,expansibility,phase and micro morphology of hydration products were studied.The results showed that the water requirement of normal consistency of compound cement was influenced by proportion of two kinds of cements.The setting time was shortened remarkably relative to unitary cement.The early hydration rate of compound cement was improved,the hydration heat of 1d,7d was lower than unitary cement.The 28d compressive/flexural strength was less than pure Portland cement or sulphoaluminate cement.The proportion of cements varied the expansion ratio of compound cement.Hydration could be promoted as their composite,diffraction peak of Ca(OH)2 decreased with sulphoaluminate cement content increasing while AFt peak enhances.The hydration products of unitary Portland cement was dense,however,micro-cracks could be observed,owing to the composite with sulphoaluminate cement.