Long-term performance of concretes exposed to severe environments

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In the UK, 50% of the annual infrastructure budget is allocated to its maintenance, repair and replacement. With the projected new infrastructure (£480Bn by 2025), it is imperative to improve and predict the resilience of construction materials. A critical threat to concrete is carbon dioxide, which is present in the atmosphere at record levels. When CO2 enters concrete it reacts, a phenomenon known as carbonation. This leads to corrosion of steel reinforcement as well as changes in the integrity of the cement, accelerating damage particularly when coupled with extreme wintery weather.This project aims to evaluate performance of structural concretes when subjected to loading in combination with carbonation and/or freeze-thaw, as a new approach to simulate realistic in-service conditions. Specific objectives are to (i) define equivalent performance between different concrete chemistries, (ii) develop integrated assessment methods linking the microstructure of concretes to their performance; and (ii) create new conformity durability criteria of concretes when assessed under realistic simulated conditions.The research work will be conducted in collaboration between Highways England, the UK's authority responsible for the road network's long-term operation and integrity, the UKCRIC Centre for Infrastructure Materials and Bragg Centre of Materials Research at the University of Leeds. The PhD researcher will have access to brand new laboratories for the development, characterisation and performance assessment of cementitious materials, including access to our own spectroscopy and microscopy facilities including a unique X-ray microtomography instrument for in-situ monitoring of pore structure changes and microcraking under controlled environments (e.g. temperature, gas atmosphere, humidity).