Mechanical and Microstructural Properties of Steel Reinforcing Bars Produced from Different Manufacturing Industries as Available in Nigeria Market

The performance of reinforced concrete (RC) infrastructure in service is largely a function of the constituent materials and construction technology. However, lack of reliable information of the physical, mechanical and microstructural properties of construction materials has culminated in structurally deficient and functionally obsolete constructed facilities. This paper reports the study conducted on the quality assurance of steel reinforcing bars produced from different major steel manufacturing industries distributed in the Nigeria and compared with the imported steel bars. The purpose of the study was to investigate the quality assurance of the local and imported steel bars in terms of the geometric, mechanical and microstructural properties. The findings of the study showed that the imported steel bars were more consistent in size and relative rib area (0.55% ≤ COV ≤ 0.94%) than the local bars (0.80% ≤ COV ≤ 1.91%). PRISM steel rebar had Vickers Hardness value of 18.5% above the recommended standard value. The tensile test results showed that Eurotherm steel bars were more elastic than other steel types by 10%, but of lesser strength. XRF and SEM showed that STAR and TOP steel bars had less inclusions unlike PRISM and DUST steel rebars with more inclusions which trigger brittle facture in steel bars. The study concluded that PSL steel bars performed better in RC than Prism and TMT steel bars.