Improving the workability and strength of silica fume concrete by using silane-treated silica fume

Mortar with high workability even without a water-reducing agent and with high tensile and compressive strengths (3.1 and 78 MPa, respectively) was obtained by using as an admixture silica fume that had been surface treated with a silane coupling agent. The treatment enhanced the wettability of silica fume by water, thereby increasing the workability of the mortar mix. It also enhanced the bond between silica fume and cement, thereby increasing the strength and modulus, both under tension and compression. In particular, the tensile strength was increased by 31% and the compressive strength was increased by 27%. Moreover, the flexural storage modulus, loss tangent, and density were increased.