A Probabilistic Approach to Determine Adequate Concrete Cover for Desired Service Life of RC Infrastructure in Corrosion Prone Environment

摘要

Requisite durability concerns of infrastructure often get undermined against strength considerations in prevalent construction practices of Bangladesh. A dominant factor behind durability and sustainability degradation of reinforced concrete (RC) structures has been chloride induced corrosion. The associated risk is largely dependent on concrete cover, which affects the ultimate serviceability of RC structures in corrosion prone environment. However, local guideline lacks specific directives on deducing adequate cover to ensure desired lifespan in different severe corrosion exposures. Hence, a probabilistic approach has been adopted to determine specific covers for ubiquitous concrete mixes with different water-cement ratios and cement type for a set of service lives and exposure conditions. Based on chloride diffusion coefficients from migration test, cover values have been determined while considering a fixed target time to initiate corrosion. The findings reveal significant impact of exposure condition on cover requirement, with magnitudes beyond recommended values in general guidelines of local codes, which urge special consideration to achieve desired service life. The obtained outcomes of this study manifest an immense scope as a preliminary quantitative guideline for necessary cover determination in order to safeguard the sustainability of RC infrastructure.