Self-compacting FRC

Granju etal. [83] also made self-compacting FRC using a blend of amorphous metal fibres and polypropylene fibres (i.e. hybrid fibre reinforcement). They could achieve self-compaction using a maximum aggregate size of 10 mm, a superplasticizer, and a fine mineral filler. Their results suggest an improved fibre-matrix bond in the self-compacting mixes. 

From the studies cited above, the mechanical properties of self-compacting FRC show the strength and toughness that one would normally associate with various FRC mixes. In addition, Walter etal. [85] found a good bond between a thin self-compacting steel fibre concrete overlay cast on a steel plate, even though the only measure taken to prepare the steel surface was sandblasting. 

Clearly, the use of this technology, which is still in its infancy, will continue to grow, despite the initial high cost of the material, and the stringent quality control requirements. These can be more than offset by the quality of the resulting product, and by the ability to use FRC in very difficult placements. 

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Despite the reduced workability of FRC, recent studies have shown that it is possible to produce fibre-reinforced self-compacted concrete (FR-SCC), with good flow properties and suitable properties. Akcay and Tasdemir (2012) have studied steel fibre in FR-SCC and found that the main parameter affecting the flowability of FR-SCC is the geometry of fibres, rather that the fibre strength. El-Dieb and Taha (2012) show that suitable workability of FR-SCC depends on the fibre content. For polypropylene fibres, the maximum fibre content should be 1000, 1200 and 1300 g/m for SCC mixtures with cement content 350, 400 and 500 kg/m respectively. For steel fibres, one should limit the fibre aspect to 50, 90 and 100 kg/m for SCC mixtures with cement content of 350, 400 and 500 kg/m respectively. 

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