A Comparative Study on the Influence of Supplementary Cementitious Materials on Marine Concrete

Abstract In this study, the influences of fly ash, ground granulated blast furnace slag (GGBS), silica fume (SF), and metakaolin (MK) on seawater resistance of cement-based materials are investigated and compared. The obtained results revealed that calcium hydroxide and ettringite (AFt) in matrix are dissolved completely during seawater immersion, whereas Friedel’s salt and brucite are deposited in pores. Seawater corrosion enlarges the capillary pores, increasing the critical pore size and capillary pore volume, resulting in decreased permeability of the matrix. SF and MK effectively contribute to pore refinement and exhibit less water-induced degradation at the early stage. GGBS and MK possess active aluminum, which transforms into AFt during interactions with seawater. Employment of MK maintains the stability of ettringite to some degree.