Effect of Pore Physical and Chemical Microstructure Properties on Durability and Rebar Corrosion of Self-Compacting Concretes Containing Silica Fume and Metakaolin

AbstractThis study aims to investigate the effect of pore physical and chemical microstructure factors on the durability properties of self-compacting concrete containing metakaolin and silica fume. This study identified the pore physical microstructure characteristics including pore size distribution, total porosity, pore connectivity factor, and the volume of large and small capillary pores. The pore chemical microstructure factors, including the concentration of potassium and sodium ions, were analyzed. The durability of self-compacting concretes including electrical resistance, chloride ion migration, and resistance to rebar corrosion (using rebar corrosion rate) was evaluated. The self-compacting concrete mixtures were considered based on the water-to-cementitious materials (W/Cm) ratios of 0.35, 0.45, and 0.55 and using silica fume substituting 0% and 8% of cement by weight, Also, for W/Cm of 0.45, metakaolin and silica fume and cement were considered as the binder. Results indicate that in self-consolidating concretes (SCCs) without pozzolans, the volume of the large capillary pores affects the rate of rebar corrosion. No significant relationship was observed between the pore physical microstructure characteristics and rebar corrosion rate of pozzolanic SCCs.