High Performance and Ultra-High Performace Fibre Reinforced Concrete with Stabilized Homogeneity

This paper describes the segregation of fibres in high performance and high strength concretes. It focuses on both laboratory and practical conditions. It compares different mixtures produced and processed in the laboratory and in the precast concrete company. Two methods are chosen in the paper to avoid fibre segregation. The first method is a suitable mix design considering the water/cement ratio and the amount of superplasticizer. The second method is the addition of synthetic fibres to the mixture while maintaining sufficient workability. The paper examines the consistence of each mixture according to the concrete placement location, segregation of fibres in the fresh mixture and hardened composite. Both methods under laboratory and practical conditions have shown a positive impact on the reduction of segregation of steel fibres in the mixture. Simultaneously, the strength properties of all mixtures were compared, which depended mainly on the type of synthetic fibres used.