Project title
Sustainability of reinforced concrete structures made with low-carbon concrete in conditions of climate change
Project abstract
Portland cement (PC) accounts for nearly 8% of global anthropogenic CO₂ emissions, making the transition to low-carbon concretes essential for sustainable infrastructure. Supplementary cementitious materials (SCMs) such as ground granulated blast-furnace slag (GGBS), fly ash (FA), limestone powder (LP), and limestone calcined clay cement (LC3) offer pathways to reduce clinker content and embodied carbon. However, uncertainties remain regarding their long-term durability under carbonation- and chloride-induced corrosion, particularly under climate change. This thesis addresses these gaps by combining experimental testing, probabilistic durability modelling, and integrated life-cycle assessment (LCA) and life-cycle cost analysis (LCCA).
An experimental programme evaluated PC and SCM concretes at water-to-binder ratios of 0.40 and 0.55, assessing compressive strength, accelerated carbonation, electrical resistivity, and chloride migration. Results confirmed that SCM concretes exhibit superior resistivity and chloride resistance compared to PC, whereas PC retains higher carbonation resistance. LC3 demonstrated high resistivity and competitive chloride performance, though with greater carbonation depths, underscoring the need for mechanism-specific mix design.
A probabilistic modelling framework was then applied to RC bridge elements, incorporating uncertainties, two limit states (initiation and propagation), exposure classes, and climate projections (SSP2-4.5 and SSP3-7.0). Simulations revealed that water-to-binder ratio is the dominant durability factor, while binder selection must align with the governing deterioration mechanism. PC often outperformed SCMs under carbonation, while FA and GGBS were more resilient to chlorides; LC3 displayed mixed performance, with elevated cover demands in carbonation-prone environments.