Influence of different fibre types on the rheology of strain hardening cementitious composites

Strain-hardening cementitious composites (SHCC) have a high tensile strength and display a remarkable strain-hardening behaviour. These unique characteristics make them an interesting choice for improving the strength and durability of new and existing structures. The tensile strain behaviour of SHCC is strongly influenced by its rheological properties as they determine the hardened state behaviour such as fibre-bridging strength and ultimately the degree of multiple cracking. The presence of fibres significantly affects the rheological performance of SHCC. This study aimed at investigating the relationship between rheological characteristics of SHCC mortar before and after the addition of different fibres. Polyvinyl alcohol (PVA), high modulus polyethylene (HDPE) and glass fibres were added at three different contents in order to assess their effect on the workability of SHCC. Flow tests along with rheological assessment were conducted to evaluate the fresh state behaviour of SHCC. The addition of fibres reduced the flowability of mix, especially at high dosages. A modified fibre influence factor was developed to characterize different types of fibres and was related to the viscosity and yield stress of the mix