EXPERIMENTAL INVESTIGATION OF CRACKING BEHAVIOUR OF CONCRETE BEAMS REINFORCED WITH STEEL FIBRES PRODUCED IN LITHUANIA

Concrete is the most widely used material for bridge structures in Lithuania. A case study performed by the authors revealed that application of fibres might improve serviceability of such structures. However, adequacy of prediction of the post-cracking behaviour of steel fibre reinforced concrete might be insufficient. The latter issue is closely related to the assessment of the residual strength of steel fibre reinforced concrete. The residual strength, in most cases, is considered as a material property of the cracked concrete. However, in the prediction of the structural behaviour of the concrete members with bar reinforcement, a straightforward application of the residual strength values assessed by using standard techniques might lead to incorrect results. The present study deals with the post-cracking behaviour of structural elements made of concrete with aggregates and fibres provided by Lithuanian companies. Test results of three full-scale and sixteen standard steel fibre reinforced concrete beams with two different content of fibres (23.6 kg/m(3) and 47.1 kg/m(3)) are presented. The full-scale beams were reinforced with high-grade steel bars. Effectiveness of the application of the minimum content of the fibres in combination with bar reinforcement was revealed experimentally.