Load carrying behavior of concrete reinforced with bundled BFRP bars by using DIC

Abstract

Recently, basalt fiber-reinforced polymer (BFRP) has gained attention in the construction industry because of its worldwide availability and eco-friendly nature. Different from conventional steel bars, BFRP bar do not corrode being an ideal reinforcing material in structures surrounding magnetic fields and marine environments, given its chemical stability. This study investigated the load carrying behavior of concrete beams reinforced with conventional deformed steel bars and seven-bundled BFRP bars through four-point flexural test. For each case, two beams were prepared; one beam was designed with a low reinforcement ratio and another with a high reinforcement ratio in order to obtain a load carrying capacity of around 330–368 kN and 483–519 kN, respectively. Deflection, crack width evolution, and strain behavior of each beam were comparatively analyzed using a digital image correlation (DIC) based technique. The DIC analysis results showed that the neutral axis of bundled BFRP reinforced cases move to the upper end in an early loading stage, with larger cracks width, and the deflection is larger in BFRP cases than in those of steel-reinforced beams with the respective reinforcement ratio. However, the four-point flexural test results revealed that bundled BFRP bars can be used as an alternative to conventional steel bars. The load carrying capacities were obtained similarly to designed values, around 364 and 551 kN for low and high reinforcement ratio cases, respectively.