Fibres have been used since ancient times to improve the material properties of building materials. At that time, for example, plant or animal fibres were added to the production of clay bricks and clay tiles to make the material behaviour more ductile. Nowadays, fibres play a particularly important role in concrete construction. The addition of fibres significantly improves the hardened concrete properties. This is due to the fact that fibres bridge any cracks in the concrete tensile zone and transfer the forces across the crack flanks. As a result, fibres in the concrete matrix also increase the tensile, bending and shear load-bearing capacity and are very effective in limiting the crack width. These advantages of fibre-reinforced concrete can be used to optimise component cross-sections and conventional steel reinforcement. The result is not only economic savings, but also sustainable advantages.