Enhancing marine anti-washout concrete: Optimal silica fume usage for improved compressive strength and abrasion resistance

The anti-washout concrete (AWC) made with seawater and sea sand has a limited marine infrastructure application due to its unfavorable properties. Our study proposes an effective performance enhancement method for AWC using silica fume. A comprehensive examination was carried out to investigate the effects of silica fume on AWC's flowability, anti-washout ability, compressive strength, microstructure, permeability, and abrasion resistance, with the AWC prepared with seawater and sea sand, and molded in seawater. It was discovered that 10 % silica fume can most effectively improve the performance of AWC. This enhancement is due to the pore structure refinement realized with C-S-H gel generated from pozzolanic reaction. Exceeding 10 % silica fume content can have a detrimental effect on the slump-flow of mixtures, while only providing marginal improvements in impermeability and compressive strength. The study lays a fundamental groundwork for the wide use of sea-based resources and the application of AWC in marine engineering.