Eccentric loading behavior of fibrous self-consolidated concrete columns reinforced with basalt FRP (BFRP) bars and spirals

Abstract

Limited experimental research has been conducted to investigate the eccentric behavior of fibrous self-consolidating concrete (FSCC) columns reinforced with basalt fiber-reinforced polymer (BFRP) bars. In this study, ten full-scale FSCC columns reinforced with BFRP bars were designed and tested under eccentric loading to examine the effects of longitudinal reinforcement ratio (2.2 % and 3.3 %), varying eccentricities (25, 50, 100, and 200 mm), and the inclusion of synthetic macro fibers in concrete. The findings reveal a transition from compression-controlled failure at low eccentricity to flexural–tensile failure at higher eccentricities. The use of FSCC delayed concrete cover spalling and resulted in a more gradual and less brittle failure. On the other hand, the specimens' mechanical behavior and capacity increased somewhat when the longitudinal reinforcement ratio was increased from 2.2 % to 3.3 %. Consequently, the effect of this ratio was more noticeable in the post-peak behavior. The BFRP reinforcement significantly improved the overall eccentric load behavior across different eccentricities, maintaining integrity up to the limits set by CSA S806. Additionally, a novel model based on ACI-544.4 R-18 for predicting the P–M interaction diagram of FSCC columns was developed, showing better alignment with the observed behavior compared to existing approaches in ACI 440.1 R and CAN/CSA S806, which do not account for FSCC properties.