Concrete—4 billion tonnes of it poured worldwide in 2013—is the most used construction material on Earth, and its production generates 5–7% of man-made CO₂ emissions. Civil engineer Janet Lees aims to cut that environmental toll by designing reinforced concrete structures that use less cement without sacrificing strength or durability. Conventionally, engineers specify a single concrete mix for an entire bridge or building column, with minimum cement content set to resist chemical attack, chloride ingress, and mechanical loads. Lees proposes a radical alternative: treat each structure as a tailored continuum, placing high-cement material only where threats are greatest—boosting the concrete’s innate resistance to corrosion from road salt, for example, or its ability to adapt under heavy loads. Elsewhere, cement content can be reduced. If successful, the approach could slash the carbon footprint of new infrastructure while extending its lifespan and lowering lifetime maintenance costs. The UK construction sector, which contributes roughly £90 billion annually to the economy, would gain a world-leading capability in sustainable concrete design. This is applied engineering research with a direct path to industrial practice.
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The required global infrastructure investment from 2013-2030 is estimated to be £34 trillion. Thus there are significant social and economic ramifications associated with the utilisation and design of strategic infrastructure assets which are fit for purpose both now, and in the future. Nationally, the construction sector is vital and contributes around £90 billion annually to the UK economy. This EPSRC Established Career Fellowship will provide Dr Lees with the prestige and freedom to extend the impact of her research and develop a new field of research dedicated to the creation of tailored concrete infrastructure. The enhancement of the innate characteristics of reinforced concrete with a concurrent reduction in total cement content directly links to key Engineering global grand challenges for Sustainability and Resilience. Concrete is the most widely used construction material in the world, over 4 billion tonnes in 2013, and cement production is responsible for 5-7% of man-made CO2 emissions. 'Cradle to factory gate' emissions for CEM 1 are 913 kg CO2e for 1000 kg of cement. The sustainability credentials of the proposed research are to mitigate the scale of this environmental impact through the delivery of more durable construction, a reduction in the cement content in concrete products, and material efficiency. The 'innate' characteristics of our reinforced concrete infrastructure include an inherent resistance to a myriad of deterioration causes e.g. chemical attack, chloride ingress, and mechanical actions e.g. dead and live loads. To help achieve the desired resistance, minimum cement contents are specified for a required strength or durability. In conventional practice, the same concrete mix is used throughout a given structural element. A compelling new paradigm is to break from conventional thinking and reinterpret a reinforced concrete structure as a tailored continuum to meet a desired serviceability, strength and/or durability performance. Material with high cement content is used judiciously to boost the innate response of our reinforced concrete infrastructure by explicitly recognising, targeting and reacting to environmental and mechanical threats to structural performance. In this way, there is either no loss, or an enhancement, in structural and durability functions. The innate immunity against environmental actions is boosted for corrosion prevention whereas the adaptability in response to mechanical actions is enhanced through the novel design of the concrete continuum for a greater structural resilience. These deliverables present a unique opportunity for the PI, UK Academia and UK Industry, to establish a world leading capability in a nascent field while addressing Engineering Sustainability priorities for lifetime extension, reduced lifetime costs, energy minimisation and a reduction in over-engineering.
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