Green ultra-high performance fiber-reinforced concrete (G-UHP-FRC)

This research first focused on developing a green ultra-high performance fiber-reinforced concrete (G-UHP-FRC) to reduce its cement content, and thus its carbon footprint and environmental impact. In this study, 50% of Portland cement by weight was replaced by 25% fly ash (FA) class F and 25% ground granulated blast-furnace slag (GGBFS). A comprehensive study was undertaken to achieve high workability while ensuring a minimum compressive strength of 125 MPa after 28 days of moist curing. The best performing G-UHP-FRC mixtures were selected for flexural as well as large-scale tensile testing. Ductility enhancement was achieved by optimizing a hybrid mechanism through combining three different types of micro and macro fibers. In order to investigate the synergy between G-UHP-FRC and steel reinforcement, two large-scale dogbone-shaped tension specimens of G-UHP-FRC reinforced with embedded steel rebars were tested in uniaxial tension up to fracture of the reinforcing bar. Results on its performance in regard to tension stiffening and cracking behavior as well as ultimate and post-peak deformation capacity are presented.