Fibre-optic sensors and smart composites for concrete applications

Many extensive researches in the area of utilising fibre-reinforced plastic (FRP) materials for retrofitting and repairing existing damaged concrete structures have increasingly been made in recent years. The FRP can improve the overall flexural and compressive properties of the structures by using externally bonded FRP sheets. The conventional non-destructive inspection technologies such as strain gauge, and acoustic emission become inappropriate for structures after being repaired by externally bonded FRP materials. Optical fibre sensors have attracted considerable interest recently as non-destructive structural health monitoring devices for infrastructure elements. This paper gives a brief discussion of the principles of the fibre-optic technology for concrete structure assessment and its potential use in future engineering applications. Due to the increasing use of the FRP in most civil infrastructure elements, the conceptual idea of 'smart composites, which can be used as reinforcements as well as real-time structural health monitoring devices for concrete structures, is also discussed.