A Quantitative Study on the Synergistic Effect between Limestone Powder and Supplementary Cementitious Materials

Abstract

As an industrial solid waste of limestone quarry, limestone powder (LP) is often used in cement-based materials to reduce cost and carbon dioxide emission. It is well-known that the synergistic effect between LP and alumina-rich supplementary cementitious materials (SCMs) influences the properties of cement-based materials. To quantitative study the synergistic effect, the hydration heat, hydration products and porosity of cement pastes with different binders were investigated. Test results showed that the synergistic effect between limestone powder and fly ash (FA) or slag (S) improved the hydration degree and increased the total hydration heat of cement pastes. When fly ash and slag were incorporated, the 3d consumed CaCO3 content increased from 2.0 wt.% to 4 wt.%, and the 180d consumed CaCO3 content increased from 2.4 wt.% to 9.3 wt.% and 11.8 wt.%, respectively. The incorporation of fly ash or slag also increased the diffraction peak of carboaluminate, which indicated more carboaluminate were formed. The synergistic effect between limestone powder and supplementary cementitious materials refines the pore structure and reduces the porosity of cement pastes. The calculated synergistic effect between limestone powder and fly ash or slag increased the density of cement pastes by 1.04% or1.41%, respectively, and it correspondingly improved the compressive strength of cement pastes.