A state-of-the-art review on the utilization of calcareous fillers in the alkali activated cement

Calcareous fillers (CF) are mineral materials with calcium carbonate as the main chemical composition, which are rich in resources and easy to handle. In recent decades, the applications of CF in alkali activated cement (AAC) to prepare low carbon emission and high performance cementitious materials have attracted extensive attention. However, the hydration behavior, performance evolution and relevant mechanism of AAC-CF system are still not fully clear. This paper provides a comprehensive review on the recent research progress of the AAC-CF system in order to fully understand the role of CF in AAC. The effects of CF on the workability, hydration, shrinkage, mechanical properties and durability of AAC are reviewed and discussed. Furthermore, crucial factors affecting the performance of the AAC-CF system are emphasized, such as content of CF, fineness of CF and concentration of activator. The action mechanism of CF in the AAC is proposed according to the review. Based on the literature review, future researches on the AAC-CF system are recommended.