Failure Mode of Basalt Fibre Reinforced Concrete Beams

The experimental tests were carried out to assess the failure model of basalt fibre reinforced concrete beams. Experimental research was focused on observing the behavior of the tested elements depending on the amount of shear reinforcement and the content of fibres. Model two-span beams with a cross-section of 80x180 mm and a length of 2000 mm were tested. The beams had a varied stirrup spacing. The following amounts of basalt fibres in concrete were used: 2.5 kg/m³ and 5.0 kg/m³. At the same time, the concrete beams without fibres were examined. The beams were loaded in a five-point bending test until they were destroyed. Shear or bending capacity of the element was determined. Fibre reinforced concrete beams were not destroyed rapidly. Failure mode of beams varied in dependence on the amount of shear reinforcement and fibre content in concrete. Larger number of diagonal cracks with a smaller width were observed in fibre reinforced concrete beams. Failure of beams of concrete without fibres was rapid with a characteristic brittle cracking. Basalt fibres revealed the ability to transfer significant shear stress after cracking in comparison to plain concrete. (paper)