Corrosion vulnerability of reinforced concrete structures with different blended cement due to chloride ingress

Abstract

Indifference towards adequate durability concerns hampers the sustainability of Reinforced Concrete (RC) structures in adverse weather conditions, like the marine regions, where premature structural damages due to chloride ion induced corrosion leads to reduced service life. In strength focused mix design of concrete, selection of materials and mix parameters are usually oriented towards target strength with little or no consideration of associated corrosion risks. Therefore, absence of adequate durability-focused design guidelines can further exacerbate this alarming issue. As a potential remedy, it is substantial to focus on material development, aligning with a performance-based design approach, to safeguard durability of RC structures in extreme conditions. Although previous studies by the authors have observed significant improvement in concrete microstructure and permeation characteristics due to various binder types, however, there are no significant studies to quantify the corrosion risks associated with different Supplementary Cementitious Materials (SCM) contents. In this regard, this study has incorporated a full probabilistic approach to evaluate the corrosion risks, in terms of corrosion probability, associated with different SCM types (fly-ash and slag) and replacement proportions (up to 40%). The corrosion probabilities of mixes with a moderate strength have been estimated for a wide range of cover values and series of desired service life in marine environment. An overall quantitative overview of the corrosion probabilities, portrayed in the study can be utilized to conduct further studies for developing tentative guidelines to optimize binder type and proportion to ensure maximum safety against the corrosion risks.