Fibre Reinforced Polymers and aramid ropes have been identified as suitable materials for reinforcing and prestressing concrete. Much research has been carried out over the last 20 years, but the take-up by industry has been very slow. The problem appears to be economic, but this topic is rarely addressed by researchers, who concentrate on the purely technical issues. This project, undertaken by Iannis Balafas, looks at the optimal design constraints, the rates of corrosion in structures reinforced with steel, and traffic delay costs. It has been shown that, if whole-life costing and realistic discount rates are used, it is worthwhile spending a little more on non-corroding materials when structures are first built. The image on the above shows part of a design chart for finding the optimal geometry.