Correlation of residual strength and fibre orientation for highly anisotropic SFRC

The objective of this research was to evaluate the mechanical response of Steel Fibre Reinforced Concrete (SFRC) with high anisotropy (produced by spraying). The results of an experimental program conducted with the inductive method – to determine the fibre orientation – and the Barcelona Test – to evaluate the residual mechanical response – are presented and discussed. Results show that core failure planes in the Barcelona test, and therefore the residual strength, are highly determined by fibre orientation when SFRC has high anisotropy. The main crack in the Barcelona test takes place orthogonally to the direction with minimum fibre orientation. Therefore, the Barcelona test may underestimate the real strength capacity of structural elements in which the principal tensile stresses take place in directions away from the direction with minimum fibre orientation. Furthermore, it can potentially provide more realistic results in structures without a clearly defined cracking plane. Finally, based on the experimental results, a correction factor is proposed for design.