CHARACTERIZATION OF INDIGENOUS STEEL BARS FOR USE IN HYDROELECTRIC PROJECTS IN BHUTAN

ABSTRACT Concrete intended to take high compressive stresses and not tensile stresses in the civil engineering structures. The steel bars are generally used in reinforced concrete structures to compliment concrete to provide the required tensile strength, rigidity, and durability. Because of the importance and role of steel bars in reinforced concrete structures, accurate information on the steel's physical and chemical properties are essential at the design stage. Theraw materials from different sources are used for manufacturing of steel bars. As a result, chemical composition, crystalline structure, and mechanical properties of these bars can vary from batch to batch are unavoidable. This variation also exaggerates when the steel produced from scrap. The use of indigenous materials in the construction industry lowers transportation costs, reduces custom taxes and reduces the risk of uninterrupted supplies of materials. It also supports local businesses improvement, local employment and also feeds money into the economy of the county. However, the quality of local material should be on par with the requirements of the quality standards. This study investigates the level of conformity of steel bars manufactured in Bhutan. Generally, the performance of steel bars characterized by checking the specific properties like chemical composition, strength, and elongation. For this purpose, an investigation carried out on the percentage of the chemical composition of elements, yield strength (YS), and tensile strength (TS) properties as per the procedure specified in national as well as international standards. A total of 124 and 169 numbers of random steel samples were collected periodically from the factory site. They were used for investigation of chemical composition and testing of physical properties of different sizes viz-16mm, 20mm, 25mm, 32mm, and 36mm, respectively. These samples were tested in the quality control laboratory of the manufacturer for assessing the physical and chemical parameters for its use in the Hydroelectric Power Project. The chemical composition and physical properties of these locally manufactured steel have met the specifications of national and even international standards. Hence, they are confirmed to fit for use in Hydroelectric Power Projects and other structures. Keywords: Chemical composition, Yield Stress or strength (YS), Tensile Strength (TS), Percentage Elongation.