Tailoring the orientation of fibres in high performance fibre reinforced cementitious composites: part 2 - correlation to mechanical properties and design implications

Incorporating fibres into a matrix with adapted rheology can lead, thanks to the elimination of vibration and to the rheological stability of the same matrix, to a randomly uniform dispersion of fibres within structural elements. It has also been recently recognised that, through a suitably balanced performance of the fluid mixture, fibres can be effectively aligned along the casting-flow direction. This highlights the need, in promoting high end engineering applications of advanced fibre reinforced cementitious composites, of designing the material for the performance required by the intended structural application. Furthermore, the casting process can be tailored to obtain, e.g., the required, or most suitable, alignment of fibres, e.g., as close as possible with the direction of principal tensile stresses within the element when in service. In part 1 of this paper, the experimental evidence was revision of a flow induced orientation of fibres in highly flowable FRCCs, the mechanisms of orientation of fibres in a yield stress fluid flow and the most recent developments in the field of predictive modelling and non-destructive monitoring of fibre dispersion. This second part of the companion paper will highlight the outcomes of the aforementioned phenomena in terms of structural design of engineering applications.