PERFORMANCE OF CONCRETE IN STRUCTURAL ELEMENTS

Abstract

In the design of any structural element, the various factors affecting the actual behavior of the structure are material behavior, uncertainties in loading and construction practices adopted. In such a scenario, the actual behavior of the structural member varies appreciably from the behavior foreseen and anticipated during design. The main objective of this study is to examine performance of concrete in the structural members, RC beams in this case. The main variables affecting the strength of a concrete are w/c ratio and cement content. In this study, an attempt has been made to study the performance of a concrete in tension, compression and flexure using different combinations of w/c ratio, cement content and tension reinforcements. A cement content of 350 kg/m3, 375 kg/m3 and 400 kg/m3 of concrete was used in each of the two w/c ratios of 0.45 and 0.42. Further the tension reinforcement was altered in each of these cases. A total of 50 beams were cast using the various combinations of w/c ratio, cement content and percentage of tension reinforcement. In addition, cubes, cylinders and prisms were also molded and tested to get a general idea of the behavior of concrete. The present study highlights the various factors influencing the uncertain behaviors of concrete in a structural member. Also it is found that underestimation of material strength is the root cause of the discrepancy of theoretical and actual results. The overall safety margin provided by conventional design (Limit state) is found in the range of 40 to 60 percent.