Influence of fibre type and content on properties of steel bar reinforced high-strength steel fibre reinforced concrete

The effect of fibres in combination with steel bar reinforcement is still widely unexplored. For this reason a research program was started, focused on the influence of steel fibre types and amounts as well as different bar reinforcements on flexural tensile strength, fracture behaviour and workability of steel bar reinforced high-strength steel fibre reinforced concrete (HSSFRC). The parameters which were investigated are in detail the influence of fibre geometry (straight with end hooks, corrugated), tensile strength of fibres (1100 N/mm(2), 1900 N/mm(2)) and different steel bar reinforcements in combination with diverse fibre contents (20, 30, 40 and 60 kg/m(3)). The bases for evaluating the efficiency of the different steel fibres together with the reinforcing steel are force-displacement curves of steel fibre reinforced concrete (SFRC) beams, gained in four point bending tests. According to the regulations, published by the German Concrete Association (DBV), beams of 150 x 150 mm cross section with a length of 700 mm were used as specimens. By summarising the test results the paper gives a support of the choice of the suitable fibre types and dosages that interacted most efficient in the combination with steel bar reinforcement and shows the influence of the reinforcing steel on the distribution of fibres in the cross section.