The Concrete Reinforcing Value of Recycled Steel Bars in Uganda

Abstract

The energy absorbing capacity of the reinforcement bars in concrete only occurs after the yield point. If the yield point of steel is too high, stresses in the concrete reach failure level before the yield point of the steel, allowing the formation of large shear and bond stresses at time of yield and ultimate brittle collapse. High yield is equally associated with reduced yield platform and energy absorption. Steel reinforcement bars in Uganda, mainly cold twisted, are often of high yield even though they amply meet the standard ductility requirements. This has largely been attributed to their recycled origin. This research investigates the relationship between the elevated yield values and the residual element content which in turn is a direct result of steel recycling.