INFLUENCES OF LIMESTONE POWDER ON THE EARLY HYDRATION PRODUCTS AND STRENGTH OF HIGH VOLUME BLAST FURNACE SLAG CEMENT

Abstract

The effect of limestone fine powder （LSP） on the early hydration products and strength of high volume blast furnace slag cement （HVBFSC） was investigated, considering the increase of small amount of mineral components in ordinary Portland cement as a measure to reduce CO₂ emissions. The compressive strength of HVBFSC and the activity index of BFS can be evaluated by the F value of BFS modified basicity （F value） considering TiO₂ and MnO, even when LSP is added.Blast furnace slag （BFS） with larger F value is highly reactive. By using of BFS having higher F value and higher reactivity, the formation amounts of ettringite （AFt） is reduced and the formation amounts of monosulfate （AFm） is increased in hydrated HVBFSC. But the amounts of AFt is increased by addition of LSP. Without LSP, the Ca/Si ratio of C-S-H in hardened HSVBFSC is 1.34 to 1.39, and when LSP is added, the Ca/Si ratio of C-S-H increases to about 1.38 to 1.50. When LSP is added, the compressive strength of HVBFSC is slightly lower than that without LSP, but the strength of HVBFSC with LSP is not a problem in practical use.