Unveiling the Influence of Varied Alumina Sources on Fresh Properties of Ordinary Portland Cement Mortar and Concrete: A Comprehensive Review

The fresh properties of ordinary Portland cement (OPC) have garnered significant consideration due to their significant influence on the physical and mechanical behavior of OPC under normal and aggressive media. While numerous research articles and reviews have explored the influence of several organic and inorganic additives on the fresh properties of OPC, there is a limited focus on comprehensively understanding the impact of the chemical reaction mechanism of these additives on the early performance of OPC. Therefore, this study aims to examine the impact of alumina from different sources, such as supplementary cementitious materials (SCMs), calcium aluminate and calcium sulfoaluminate cement (CAC and CSAC, respectively), and chemical admixtures, on the hydration heat, setting times, and workability of PC. After analyzing the data published in the literature, it has been discovered that the impact of alumina on the fresh performance of OPC primarily relies on the reactivity of SCMs, superplasticizer (SP) content, and water demand. However, other alumina-rich materials demonstrate an increase in the initial flow and hydration rate, which is accompanied by workability loss and setting time shortening. The authors have also thoroughly discussed the reaction mechanism of each alumina source. Finally, the missing topics and proposed future directions for this research were identified. From the literature survey, it is recommended that the synergy between alumina and sulfate, as well as alumina and carbonate, is important in controlling the hydration reaction of Portland cement.