Resistance of concretes containing low grade calcined clays and LC۳ blended cements against chloride ions induced corrosion

Corrosion of rebars is a notable degradation mechanism in reinforced concrete structures, especiallyin environments with elevated concentrations of chloride ions, such as seawater. To enhance the durabilityof concrete against chloride-induced corrosion, the use of supplementary cementing materials has emergedas a well-established solution. These materials have been employed over the past decades to extend theservice life of structures. Recently, the development of ternary blended cement, which incorporateslimestone powder and calcined clays (referred to as LC۳ cement), has shown promise as an environmentallyfriendly option. LC۳ cement offers low carbon dioxide emissions along with promising mechanical andpermeability properties. This study investigates the impact of incorporating four different types of calcinedclays, with kaolinite contents ranging from ۱۹.۴% to ۶۶.۰%, on the durability of reinforced concrete againstchloride-induced corrosion. In this context, various properties including compressive strength, capillarywater absorption, chloride ion diffusion coefficient, and half-cell potential of reinforced concrete specimenswere evaluated to assess mechanical properties, permeability, and durability of concrete mixtures.The results indicate that although the compressive strengths of concrete mixtures containing lowgradecalcined clays are lower compared to those of the control mixture, the corrosion resistance of theseblends is significantly improved. Moreover, an increase in kaolinite content correlates with enhanceddurability of concrete specimens against chloride ion attack.

Keywords:

Chloride ions ingress , Compressive strength , Limestone calcined clay cement , Permeability , Reinforcement’s corrosion.