Effect of Limestone Powder and Gypsum on the Compressive Strength Mixture Design of Blast Furnace Slag Blended Cement Mortar

This paper investigates the compressive strength development of blast furnace slag (BFS) blended mortar mixtures incorporating various mineral admixtures, namely BFS, limestone powder (LSP), and gypsum (CS). BFS replacement ratios of 15, 20, and 25 wt.%; LSP replacement ratios of 2, 3, 4, and 5 wt.%; and a CS replacement ratio of 2 wt.% are employed to improve the strength of BFS blended mortar mixtures. The hydration reaction and products resulting from the use of cement, BFS, and mineral admixtures are quantitatively examined with respect to the XRD/Rietveld method in order to investigate the relationship between the produced hydrates and the strength. Experimental investigation reveals that the mortar mixture with BFS 15 wt.%, LSP 4 wt.%, and CS 2 wt.% exhibits similar compressive strength to an ordinary Portland cement mortar mixture. In addition, the strength is found to be decreased as the BFS replacement ratio increases. At a BFS replacement ratio above 20 wt.%, LSP affects the strength improvement of BFS cement and CS affects the initial strength improvement of BFS cement.