Fibre Reinforced Polymers Bars in Low-Carbon Concrete: Bond and Durability

The construction sector generates a lot of carbon emissions. In particular, cement and steel production contribute approximately 17-20% of greenhouse gas emissions. Advances in material science have led to the development of low-carbon concretes which incorporate Supplementary Cementitious Materials (SCMs). These SCMs act as partial replacements to Ordinary Portland Cement (OPC) since OPC has significantly higher embodied carbon than the SCMs. Similarly, Fibre-Reinforced Polymer (FRP) bars may be an eco-friendly and durable alternative to steel rebar. However, research shows that utilising some low-carbon concretes with steel rebar accelerates corrosion of the rebar which undermines the integrity of structures. Consequently, this study postulates that the optimum combination for the reduction of carbon emissions while ensuring durability is to pair low-carbon concretes with FRP bars instead of steel. An experimental campaign to compare the bond and durability of steel and FRP rebars in different low-carbon concretes is proposed. The pull-out test will be used to establish the bond strength of the embedded bars over time in concrete manufactured with various SCMs. The empirical results will provide a performance metric for the interaction between concrete and the embedded bars and a novel perspective of employing the pull-out test as a durability index. These findings will be highly relevant in the characterisation of different SCMs and the validation of structural simulations sensitive to the concrete-rebar interface. In addition, the insight of the bond interface will guide on the design procedures for low-carbon materials, ensure structural resilience and environmental sustainability in construction.