Study of the flexural behavior of basalt fiber-reinforced concrete beams with basalt fiber-reinforced polymer bars and steel bars

Basalt fiber-reinforced polymer (BFRP) bars offer a reliable alternative to steel reinforcement in concrete beams, addressing corrosion issues. The bending performance of the beams highly depends on the properties of the concrete and the amount of reinforcement. Fiber reinforced concrete (FRC) is widely used in structural engineering due to high ductility and sufficient durability. To examine the impacts of fiber content, reinforcement ratio and type on the bending performance of basalt fiber reinforced concrete (BFRC) beams, this study explores the flexural behavior of BFRC beams with steel or BFRP bars through experiments, theoretical analysis, and finite element (FE) modeling. The results show that higher reinforcement ratios significantly enhance post-cracking bending stiffness and flexural capacity, while increased fiber content leads to modest improvements. The crack width at serviceability showed a significant decrease with increasing the reinforcement ratio, while a slight decrease with an increase of fiber content. The test results also show that the deformation capacity and crack width were affected significantly by the reinforcement type. For steel-reinforced BFRC beams and their BFRP-reinforced counterparts with similar tensile capacity of longitudinal reinforcement, the BFRP-reinforced beams demonstrate a larger deformation capacity and crack width at the same applied load. Comparison with ACI 440 code provisions revealed that the bending capacity of BFRP- reinforced BFRC beams was overestimated, although the predicted mid-span deflection under service conditions remained reasonably accurate. Additionally, theoretical and FE models were developed to predict the bending performance of BFRC beams and were confirmed by experimental results.