A Brief Characterization of the Steel Rods for Reinforcing Concrete from Two Steel Mills in Nigeria

There is a need for adequate and reliable information on the actual characteristics of reinforcing steel bars for structural concrete in the construction sector. This is crucial since a lot of building collapses other than a natural disaster such as an earthquake involves faulty design and construction, foundation failures and also use of substandard materials particularly, reinforcing steel bars. Building collapses is a serious problem across the world including Nigeria. The current work concentrated on the 10, 12 and 16mm bars of reinforcing steel produced from recycled steel scrap by two distinctive steel industries in Nigeria, namely; Ajaokuta and Dawanau rolling mills in order to ascertain the conformity of their chemical and mechanical properties with the international standards as well as to determine their suitability for structural applications. The analyses of chemical compositions revealed that all tested samples had values above the standard individual elemental compositions in steel as established by standard bodies. The 12 mm and 16 mm bars showed higher amounts of carbon contents which corresponded to higher tensile strengths. It was noted that the tensile strengths for all the tested samples increased when subjected to rolling above 500°C. In general, it was noted that steel bars from Dawanu mill were superior in hardness and impact tests while steel bars from Ajakuta were better in tensile strength.