Synergistic Roles of Slag and Silica Fume in Very High-Strength Concrete

Abstract

Abstract A very high-strength concrete (W/C = 0.20) containing 10% silica fume, 30% slag replacement for cement, and a high-range water-reducing admixture attained a compressive strength of 94 MPa at 28 days. The microstructural development of this concrete was studied from 1 to 28 days with SEM/EDXA and TEM. The slag used was reactive, with 70% melilite group phases and an index of hydraulicity of 1.2. Microstructural changes occurring in the first 28 days are presented. The factors responsible for promoting strength are also discussed.