Optimisation of fibre reinforcement with a combination strategy and through the use of self-compacting concrete

Abstract Both steel and polyolefin fibres have become an attractive alternative to steel bar reinforcement of concrete. Therefore, many research papers that deal with such a type of fibre reinforcement, as well as reports that examine structural applications, have been published. Fibre-reinforced self-compacting concrete uses the flowability of concrete in the fresh state to improve fibre orientation, in due course enhancing fracture behaviour. The residual strengths obtained from fracture tests are important values for structural design. Other possibilities to improve the residual behaviour are based on the development of new fibres with improved material properties and shapes that enhance the properties of the fibre–matrix system. That can be the case of the so-called 5D fibres or OL. Moreover, each fibre type performs depending on certain demands imposed for each element. This study proposes the optimisation based on the combined use of different fibre types. The results show the various advantages that can be obtained with the combination of the fibres; relevant information for future design of structural fibre reinforced self-compacting concrete is provided.