Review: alkali-activated blast furnace slag for eco-friendly binders

From infrastructure to national defense construction, concrete has been a key enabler in human history. While as the main binding material, ordinary Portland cement production indirectly threatens the human health due to the CO2 emissions contributing to the greenhouse effect. Alkali-activated materials show great promise to be one type of feasible alternative binder. Blast furnace slag (BFS) is one of the commonly used precursors that used to preparation alkali-activated slag (AAS) due to the higher content of glassy components. Accelerating the wide application of AAS requires the reaction behavior of BFS to be clearly understood. Such reaction behavior is strongly related to the BFS structure. Thus, it is crucial to identify and decipher how the basic structure of BFS control their engineering properties. Here, we review some of the recent efforts in this direction. In the present review, we report how the BFS structure controls the reaction kinetics and reaction products as well as the mechanical properties of AAS. We also envisage a perspective in which the BFS reaction behavior can be investigated and interpreted by combining topology constraint theory, machine learning and atomic simulation.