Water ingress and steel corrosion in carbonated low-clinker concrete

Please check whether enrolling in this project is possible by directly contacting the responsible supervisor(s) indicated below as soon as possible. Note that although we announce many topics, we won't be able to offer all of them simultaneously due to limited lab capacity.

The carbonation of concrete is a well-known phenomenon that reduces the pH of the pore solution, potentially causing corrosion of the steel reinforcement. This is particularly concerning for low-clinker cements, which are more susceptible to carbonation and thus are often considered less corrosion resistant. Although the risk of corrosion in carbonated concrete is widely acknowledged, a critical aspect defining the actual corrosion rate of steel is the presence of water at the steel-concrete interface. In this context, understanding water ingress in low-clinker concrete is crucial to accurately assess and predict the corrosion behavior of steel reinforcement.

This project aims to investigate how water ingress impacts the corrosion kinetics of steel in carbonated low-clinker mortars, with a particular focus on the effects of the concrete cover depth. The study will be conducted using pre-prepared and carbonated low-clinker mortar samples. These samples, initially in a dry state, will be exposed to wet-dry cycles designed to simulate natural rain events. The evolution of the mortar resistivity, as well as the corrosion potential and corrosion rate of the steel will be monitored as the water ingresses the sample. In addition, the water ingress in the mortar will be quantified by capillary absorption experiments.

By combining electrochemical data, resistivity measurements, and capillary absorption results, the study will develop a comprehensive understanding of how different low-clinker cement mixes influence water ingress and, consequently, steel corrosion. Such findings can have implications for improving the durability of low-clinker cement-based structures, and changing the paradigm of avoiding carbonation to an approach that limits water ingress in reinforced concrete.

Students enrolling for this project will gain valuable theoretical and practical knowledge in electrochemistry and water transport in cementitious materials. If you are interested, please feel free to contact the project supervisors for an informal discussion. We highlight that this project could also be shared by two students, with one student focusing on the corrosion measurements and the other on the water ingress.