Rotation capacity of self-compacting steel fibre reinforced concrete beams
P. Schumacher1, J.C. Walraven1, J.A. den Uijl1, A. Bigaj-van Vliet2
1 Delft University of Technology, Faculty of Civil Engineering and Geosciences, The Netherlands
2 TNO Built Environment and Geosciences, Delft, The Netherlands
Steel fibres are known to enhance the toughness of concrete in compression and in tension. Steel fibres also improve the bond properties between concrete matrix and reinforcing steel bars. In order to investigate the effect of steel fibres on the rotation capacity of reinforced concrete members, four simply supported beams were loaded in three-point bending up to failure (steel bar rupture or concrete crushing). Test variables were fibre content and axial normal force. Remarkably, the specimens with conventional reinforcement had a larger rotation capacity than those with conventional reinforcement and fibres. This decrease in deformation capacity is explained by localization of the deformations in one large crack in case of the reinforced concrete (RC) specimens with steel fibres, compared to several large cracks in case of the RC specimens. A model to calculate the rotation capacity of self-compacting steel fibre reinforced concrete (SCSFRC) members is presented and validated against the beam test results.
Key words: Rotation capacity, self-compacting steel fibre reinforced concrete, strain localization