The Young’s Modulus of polypropylene is much lower than that of steel. Does this mean the synthetic fibres stretch more?
A. No. Conventional steel fibres utilise end-anchorage to achieve the bond with the concrete. This is typically achieved with a flattened or hooked end. As a consequence of the end-anchorage, all the elongation in a steel fibre occurs over the full length of the fibre. In contrast, the Barchip synthetic fibres use continuous anchorage with full-length embossing, which means that the fibre elongation occurs only across the width of a crack and a small portion of the embedded fibre.