Mechanical properties of SFRC composites

The mechanical properties of SFRC are influenced by a number of factors  

It must be remembered that, when examining or describing the effects of fibre additions, changes in SFRC properties are always expressed in terms of average fibre content. It is implicitly assumed that the fibres are uniformly distributed throughout the matrix, and, moreover, that they are randomly oriented. Unfortunately, neither assumption is likely to be correct after the SFRC has been placed and compacted by vibration [23], and this leads not only to a considerable amount of scatter in the test data, but also to a considerable variability in measured values due to the direction of loading (in relation to the direction of casting). 

Finally, on any cross section of a beam, the fibres are unlikely to be truly uniformly distributed, and this, too, will depend on the orientation of the cross 

As has been shown byVodicka eta/. [30], anon-homogeneous fibre distribution becomes increasingly likely for very low fibre contents (less than about 25 kg/m  

Despite the above qualifications, it as quite possible to produce SFRC with an acceptably low variability in fibre distribution, as long as proper mixing, handling, placing and finishing procedures are followed, as shown, for example, by Taerwe etai [33]. Indeed, Benson and Karihaloo [34] were able to achieve uniform fibre distributions of short steel fibres at volume fractions of up to 8%. 

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