Towards a durability framework for structural elements and structures made of or strengthened with high-performance fibre-reinforced composites

Abstract

High-performance fibre-reinforced cement-based composites (HPFRCCs) have great potential for application in structures exposed to severe mechanical or environmental loading. This paper presents an overview of the current knowledge on the durability of two prominent representatives of this new group of concrete materials: strain-hardening cement-based composites (SHCCs) and textile-reinforced concrete (TRC). Hereby not only the durability of these composites and their components are considered but special focus is centred on the protection of steel reinforcement when it is used in combination with SHCC, as in the case of R/SHCC structures or RC structures repaired with a layer of SHCC, or TRC, as in the case of the strengthening or repair of RC structures using TRC.Based on such considerations, transport properties in the cracked state, long term strain capacity, and resistance to aggressive environments have been identified as critical parameters. Current knowledge indicates that HPFRCCs show high long-term strain capacity and favourable transport properties in the cracked state. The composites also exhibit superior resistance to aggressive environments, as compared to ordinary concrete. However, there is little information available on the effects of aggressive environments on the mechanical properties of the materials.Since SHCC and TRC are new materials, there is no information available on their long-term performance in the field. To be able to utilise the superior qualities of these new materials fully, it will be necessary to develop a realistic and reliable performance-based durability design concept for structures made of or strengthened with high-performance fibre-reinforced cement-based composites.