Chemical composition of commonly used local and foreign steel reinforcements and the effects on the strength property of the material composites

Abstract

In recent times, structural failure of buildings and civil infrastructures are on the increase in developing countries. These failures can be attributed to the use of; poor material, influx of quacks, unethical professional practices, poor construction methodology and the use of unverified newly introduced reinforcements. This study investigated the chemical contents of commonly used new local steel reinforcements and imported steel reinforcements as to the level of compliance with ASTM A 706 and BS 4449 specifications. The effects of the percentage composition on the strength properties of the material and consequential effects on concrete composite were discussed. Chemical analyses of local bars revealed higher sulphur and phosphorus contents which increased brittleness though with enhanced strength. The higher contents of minor elements like silicon, Manganese, Chromium, Zinc in local steel specimens increased loss of mass in aqueous solutions and in water compared with the foreign specimens. In conclusion, while the imported bars satisfied the ASTM and BS standards in terms of the percentage composition of the elements, local bars did not meet these standards. Hence, it is recommended that the development of National Building Codes that reflect the actual material characteristics to avert premature failure for concrete structures reinforced with the local bars.