Functionally graded concrete: Design objectives, production techniques and analysis methods for layered and continuously graded elements

The pressing need to reduce global carbon emissions together with recent advances in automated manufacturing have driven a growing interest in functionally graded concrete. In functionally graded concrete, the material composition is spatially varied to meet performance demands that differ within regions of a structural element. This offers significant potential to reduce cement consumption. Step-wise layered and continuously graded concrete systems are introduced and investigations of concrete mix combinations to achieve durability, fracture resistance, strength, ductility, cost saving, weight reduction or lower embodied energy improvements are discussed. Production techniques for horizontally layered and vertically layered structural elements in the context of fresh-on-hardened and fresh-on-fresh casting as well as emerging continuously graded processes are presented. Challenges associated with fresh-state deformations, layer interfaces and the need for appropriate fresh and hardened-state modelling tools are critically assessed.