Flexural behavior and bond coefficient of BFRP bar reinforced normal and high strength concrete beams: Fid-Bau Portal

Flexural behavior and bond coefficient of BFRP bar reinforced normal and high strength concrete beams

Mostafa, Omar M. / Rahman, Muhammad K. / Al-Zahrani, Mesfer M. / Adekunle, Saheed K. / Al-Osta, Mohammed A. / Najamuddin, Syed K.

Abstract

Highlights • Flexural behavior of 15 BFRP, GFRP, and steel reinforced normal (NSC) and high strength concrete (HSC) beams investigated. • Cracking and ultimate moments, deflection and crack widths compared with ACI 440 Guidelines. • BFRP bars exhibited 15% higher stress level at failure in HSC beams with elastic response and cracking moments similar to NSC beams. • Modified empirical equation based on earlier version of ACI 440 proposed to enhance the deflection predictions at service load. • The bond coefficient kb for predicting the crack width for BFRP reinforced normal and high-strength beams proposed.

Abstract Basalt fiber-reinforced polymer (BFRP) bars are emerging as potential non-metallic reinforcements for concrete structures due to the wide availability of their raw materials, their environmentally friendly manufacturing process, and their excellent mechanical and durability properties. This paper focuses on the flexural and deflection response of normal and high-strength concrete (HSC) beams reinforced with BFRP bars. A total of fifteen simply supported concrete beams were tested under four-point loading on a flexural span of 2.5 m. The study parameters were the reinforcement ratio, BFRP bar size, concrete strength and bar type (BFRP, GFRP and Steel). The experimental results were compared to ACI 440.1R-15 predictions. The prediction of ultimate moment capacity was in good agreement with the experimental result, while the cracking moment was overestimated. Furthermore, the mid-span deflection was significantly underestimated at service and ultimate loads. Modification in the empirical equations was proposed to enhance the predictions of mid-span deflection at service load. The bond coefficient $k_{b}$ used for predicting the crack width was estimated at 0.89 and 1.12 for BFRP-reinforced normal and high-strength beams.