Rethinking concrete durability for low-carbon concretes through climate-informed corrosion modelling.

Decarbonizing concrete is essential for meeting global climate targets. Many effective strategies to reduce greenhouse gas emissions result in lower concrete alkalinity, which has traditionally been viewed as a durability concern, namely promoting steel corrosion in concrete. This prevailing durability paradigm - firmly embedded in engineering mindsets and industry standards - hinders the practical implementation and thus the realization of the full potential of low-carbon concretes. To resolve this situation, we propose a conceptual framework that offers a perspective on ensuring the durability of reinforced concrete, while tolerating reduced concrete alkalinity. Our approach is inspired by empirical observations and recent scientific insights that consistently pinpointed the decisive role of moisture in concrete durability. We leverage advancements in moisture transport modeling in porous media and corrosion science to predict the time-evolution of the microclimate and corrosion kinetics at the steel-concrete interface. By drawing on time-resolved meteorological data from four examples in Europe, Asia and South America, we showcase the approach, underlining the critical role of local climate for predicting the durability performance of concrete. This work establishes the basis for developing test methods, standards, and predictive tools to promote eco-friendly concrete and evaluate how climate change impacts their durability for generations to come.