Properties of freshly mixed carbon fibre reinforced self-consolidating concrete

This study examined the effects of discrete pitch-based carbon fibres on the fresh properties of self-consolidating concrete. Different carbon fibre reinforced self-consolidating concrete mixtures were produced incorporating 0%, 0.25%, 0.5%, 0.75% and 1% carbon fibres by concrete volume with two water-to-binder ratios (0.35 and 0.40). The flowing ability (filling ability and passing ability) of the concrete mixtures was determined with respect to slump flow, J-ring slump flow, and T50 slump flow time. The segregation resistance of the concrete mixtures was evaluated by using the sieve stability test. Visual stability index (VSI) was also used to assess the segregation resistance of concrete. Moreover, the freshly mixed concrete mixtures were tested for air content and unit weight. The hardened concretes were tested by a Scanning Electron Microscope to observe the distribution of fibres. Test results revealed that the increased amount of carbon fibres decreased the filling ability and passing ability of concrete. However, carbon fibres had no adverse effects on the segregation resistance of concrete. Also, no significant air entrapment occurred in the presence of carbon fibres. Carbon fibres were well-distributed and they slightly decreased the unit weight of concrete.