Chapter 5: Material selection to improve durability

This chapter describes construction materials that can be used to improve the durability of reinforced concrete structures. These include chemical admixtures, mineral admixtures (pulverised fly ash, ground granulated blast-furnace slag, condensed silica fume (microsilica) and metakaolin) and alternative reinforcing materials to conventional steel reinforcement (black bars) (epoxy-coated steel reinforcement, galvanised steel reinforcement, stainless steel reinforcement and glass-fibre-reinforced polymers). The first section deals with chemical admixtures, including their composition, the beneficial properties they impart on fresh and hardened concrete, and their mode of action in concrete. The second section deals with supplementary cementitious materials, otherwise known as mineral admixtures or pozzolans, which can be used to improve the durability of reinforced concrete structures. The section discusses their method of manufacture, chemical composition and their mode of action in concrete (fresh and early-age properties and hardened properties, especially with respect to improving the resistance of concrete to degradation mechanisms). The last section describes four alternative reinforcing materials that can be used in concrete structures in place of conventional steel reinforcement (black bars).