PERFoRM · Passive layER FailuRe Mechanisms for Steel Embedded in Alkali-Activated Slag Materials

PERFoRM will unveil how in-service environmental conditions influence the stability of the passive layer on steel rebar embedded in concretes based on low-carbon cementitious materials (i.e. near-neutral salt activated slag materials (NnSAS)), when exposed to environmental threats. NnSAS offer high carbon emission savings, compared to other construction materials, however their long-term performance is largely unknown. PERFoRM will implement non-destructive techniques (NDTs) for the in-situ diagnosis of steel reinforced concretes, and in-situ tracing of aggressive ions; along with cutting-edge electrochemical techniques to determining corrosion rates closely resembling in-service concrete structures. Advanced characterisation of the passive layer using environmental XPS, and the steel-concrete interface using u-CT will also be carried out. The main scientific focus areas of PERFoRM will be:• Developing novel durability wireless embedded (D-WirE) sensors for in-situ tracing of aggressive ions (e.g., chlorides) and monitoring of internal factors (e.g. relative humidity, pH) in concrete• Ground-breaking work monitoring chemical and physical changes induced by carbonation/chloride penetration in NnSAS mainly using NDTs• Advanced characterisation of the passive layer growth, breakdown, and failure rates of steel rebars embedded in NnSAS • Creation of service-life models by incorporation of in-situ carbonation and chloride penetration regression models PERFoRM will bring unique insight about all potential aspects influencing corrosion mechanism and stability of the passive layer forming in steel embedded in NnSAS. This will enable performance-based materials design, and selection of remediation strategies to ensure the safety of in-service novel self-sensing and low-carbon NnSAS. PERFoRM will be integrated with collaborative programmes coordinated by RILEM and EFC, providing a direct route to international awareness and utilisation of the fellowship outcomes.