Effect of superfine blast furnace slags on the binary cement containing high-volume fly ash

High-volume replacement of ordinary Portland cement (OPC) by FA usually results in comparatively lower compressive strength and delayed setting. We investigated the effect of superfine blast furnace slags (S-BFS) on the properties of high-volume FA cement. The flowability, initial setting time, mechanical properties and the hydration phase assembles as well as the pore structure were investigated. The results showed that the addition of S-BFS could significantly enhance the unconfined compressive strength (UCS) while decrease the flowability. This problem was alleviated by the incorporation of polycarboxylate superplasticizers (PCEs). X-ray powder diffraction (XRD), thermogravimetric (TG) analysis and mass balance calculations indicated the formation of more hydrotalcite like phases (Ht) with the addition of S-BFS, contributes to the development of UCS due to the reduction in cumulative pore volume. With the incorporation of S-BFS and PCEs, the binders offer low cost with improved environmental performance. (C) 2020 Elsevier B.V. All rights reserved.