Effects of Different Expansive Agents on the Properties of Expansive Cementitious Materials

Abstract Cracking happens in the case of restricted volumetric shrinking in cementitious materials which has a negative influence on the mechanical characteristics and longevity of concrete materials and hence, reduces the life of concrete structures. Many techniques have been developed to reduce the shrinkage cracking of concrete among which, usage of expansive agents (EA) has been utilised for decades. Different types of EA creates divergence due to its chemical characteristics. In this paper, three main categories (CaO, MgO & Sulphoaluminate based) EA have been reviewed based on four criteria of concrete structures, such as strength, expansibility, durability and flowability. The review clearly indicates that CaO-based EA boosts the strength but unable to control the temperature rise, which results in thermal cracking in the long run. While MgO-based EA is vastly used in China and Sulphoaluminate based EA have been industrially used worldwide for decades, both of these agents can successfully compensate thermal shrinkage while maintaining adequate mechanical strength and durability. Beside all this differences, all types of EA have been reported to decelerate the flowability of the concrete.