CHARACTERISTICS OF SHRINKAGE COMPENSATING EXPANSIVE CEMENT CONTAININGA PRE-HYDRATED HIGH-ALUMINA CEMENT-BASED EXPANSIVE ADDITIVE

Research directed at developing a new composite expansive additive for use in producing shrinkage-compensating cement by addition to Portlan d cement is reported. Setting time, flow loss, free expansion, restrai ned expansion and compressive strength results were obtained for cemen t pastes and mortars containing different amounts of expansive additiv e. The effect of superplasticizer on the properties of fresh and harde ned expansive cement mortar was also investigated. Results indicated t hat expansive cement with an appropriate amount of pre-hydrated high a lumina cement based expansive additive passes all the requirements of relevant ASTM standards and is potentially of practical use.