Concentrically loaded recycled aggregate geopolymer concrete columns reinforced with GFRP bars and spirals

The increased quantity of construction and demolition waste and the high carbon footprint of cement production is creating significant environmental problems. This study explored the use of recycled coarse aggregates (RCA) in geopolymer concrete (GPC) and reinforced with glass fiber reinforced polymer (GFRP) bars and spirals to fabricate novel and structural GRAGC columns. A total of 9 GRAGC columns with 1150 mm in height and 250 mm in diameter were tested to failure under axial compression. The influence of a different number of longitudinal GFRP bars and spiral spacing on the cracking behaviour, ductility, and axial load-carrying capacity (LCC) were investigated. A nonlinear finite element model (FEM) was implemented to predict the axial compressive response of GRAGC columns. The experimental results depicted that an improvement in the ductility and lateral confinement was observed by decreasing the spacing of GFRP spirals. GRAGC columns with eight longitudinal GFRP bars portrayed the highest LCC. All tested GRAGC columns portrayed similar failure modes with the damage at the central region of the specimens. The theoretical model suggested over a database of 225 GFRP reinforced columns showed a high accuracy compared with the previous models. The present study suggests an efficient and environmental-friendly compression member.

Automated summary

The study investigated the use of recycled coarse aggregates and glass fiber reinforced polymer reinforcement to fabricate novel GRAGC columns, demonstrating improved ductility and lateral confinement. The experimental results and theoretical model showed high accuracy and efficiency in predicting the behavior of the columns under axial compression.