Investigation on Flexural Properties of Hybrid Fibre Reinforced Self-compacting Concrete

The paper considers compressive and flexural parameters of self-compacting concrete reinforced with combination of steel and polypropylene fibers. Three volume ratios of steel fibers (0.5%, 1.0%, 1.5%) were mixed with two amounts (0.3%, 0.9%) of two types of polypropylene fibers. The influence of hybrid fibers on the compressive strength of SCC was negligible and comprised in the range of -5 to 11% of the strength of the matrix. Based on the flexural tensile tests on hybrid fibre-reinforced mixes it was noticed that steel fibers play the most important role in enhancement of the mechanical parameters. Meanwhile, in the hybrid mix of polypropylene fibers only slightly improve the toughness, irrespectively of the length of the PP fibers. The highest applied amount of the longest polypropylene fibers indeed improved the flexural parameters of the SCC matrix reinforced with steel fibers but on the other hand such concrete did not satisfy the requirements for SCC in the fresh state.