Mix design of SFRC

As with any other type of concrete, the mix proportions for SFRC depend upon the requirements for any particular project, in terms ofworkability, strength, durability and so on. For relatively small fibre volumes (less than 0.5%), the conventional mix designs used for plain concrete, based on the normal strength and durability considerations, may be used without modification. However, for larger fibre volumes, mix design procedures which emphasize the workability of the SFRC should be used. A number of such procedures are available (e.g. 17-20). However, there are several considerations that are particular to SFRC. 

Edgington etal. [21] showed that for a particular fibre type, the workability of the mix decreased as the size and quantity of the aggregate particles larger than 5 mm increased the presence of aggregate particles less than 5 mm in size had little effect on the compacting properties of the mix. They proposed an equation with which to estimate the critical percentage of fibres which wouidjust make the SFRC unworkable  

It must be emphasized that the values given in Table 7.1 are only typical . Any given fibre must be evaluated on its own merits to find the optimum mix designs. 

5 mm maximum 19 mm maximum 38 mm maximum aggregate size aggregate size aggregate size  

0% steel fibres by volume have a weight of 783 kgfm.  

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