Shear strengthening of metakaolin based reinforced concrete beams using carbon fiber reinforced polymer composites

Abstract

Due to the aging nature of the existing infrastructural elements, there is a high need for the strengthening to increase their overall performance in terms of strength and ductility. Different reasons that lead to the strengthening of RC members includes (a) loading different from actual design, (b) accidents such as fire, earthquake, etc., and (c) natural deterioration due to corrosion. There are various techniques for strengthening the concrete members. In specific, the reinforced concrete (RC) bridge elements can undergo brittle shear failure due to the exposure to extreme environmental conditions resulting in corrosion of transverse and longitudinal steel reinforcements. There is a growing need to enhance the durability of concrete structures using supplementary cementitious materials (SCM) such as fly ash, GGBS, silica fume, metakaolin, etc. However, the use of SCM can just postpone the degradation of concrete elements and cannot completely prevent the occurrence. Hence, this study focusses on the strengthening of metakaolin based RC beams under shear dominant loading. newlineThe major objective of this study is to understand the overall shear behavior of metakaolin based reinforced concrete beams strengthened using fiber reinforced polymer (FRP) composites. The overall objective was achieved in two phases. In the first phase of the experimental program, the material characterization of SCM based concrete was performed. Metakaolin, fly ash and lime were used as a partial substitute for cement up to 40 % withers as binary or combined replacements. Different trials were made to achieve a target cubic compressive strength of 30 MPa at 28 days of curing. In addition to the metakaolin, bio silica, bio char, egg shell powder was also used as a partial substitute for cement newline