Mechanical Properties of Reinforcement (Rebar) in Bangladesh

Abstract

The 500W locally produced Thermo mechanically treated (TMT) high-strength reinforcing steel bars have been collected from three different companies. Tensile tests were carried out using a Universal Testing Machine (UTM) to evaluate the tensile properties (tensile strength, yield strength, % of elongation) of the rebars in three different conditions, viz., with and without rib and without casing. Compressive tests were carried out using a Universal Testing Machine (UTM) to evaluate the bond between concrete and steel rebars crucial. The compressive strength of a reinforced concrete member is not solely determined by the concrete's strength but also by the performance of the embedded steel. Deformed rebars, with their surface ribs and lugs, are designed to enhance this bond, improving load transfer and overall structural integrity. The mathematical modelling was developed between the tensile properties (tensile and yield strength) and hardness in light of previous studies on it. Failure modes of the high-strength steel rebars in tensile loading were studied by observing fracture surfaces after tensile tests. the dissimilarity in tensile properties of the TMT steel rebars was found too. The evaluation of tensile property from the samples was consistent with the tensile properties obtained from the mechanical tensile tests. The yield strength calculated from the strength-hardness models also showed consistency with the test values. The effects of microstructures (consists primarily of two phases: ferrite -a relatively soft, ductile form of iron and pearlite-a lamellar or layered structure of ferrite and cementite, or iron carbide) and carbon equivalent on the hardness and tensile test results were evaluated. The calculated and test values of tensile properties showed good agreement with the microstructures. The fracture behaviors of the TMT steel rebars also showed good dependency on microstructures. Thus, overall structure-property relationship was established with existing samples. Keywords: Reinforcement properties, Construction materials Bangladesh, Tensile strength of rebar, Structural performance of rebar.