Post-fire flexural performance of hybrid-fibre-reinforced SCC symmetric inclination beams

Twelve post-fire self-consolidating concrete (SCC) symmetric inclination beams containing steel fibre, macroscopic polypropylene fibre, microscopic polypropylene fibre and their hybridisations were studied under the combined loading of flexure and axial compression to evaluate the effect of hybrid fibres on the flexural performance of tunnel segments. The effect of different fibres on the temperature field of the midspan cross-section was analysed. The load–deflection behaviour, crack patterns and crack width of post-fire flexural SCC symmetric inclination beams were investigated. A model for calculating the ultimate bearing capacity of flexural SCC symmetric inclination beams after fire exposure was proposed by considering the contribution of hybrid fibres to SCC in a tension zone. The results of the proposed model were found to agree well with the experimental data in this study. The proposed model can be employed to estimate the ultimate flexural bearing capacity of SCC symmetric inclination beams containing hybrid fibres after exposure to fire.