Pullout Behaviour of Different Types of Steel Fibres Embedded in Magnesium Phosphate Cementitious Matrix

A series of pullout tests were conducted to investigate the interface bond properties of seven types of steel fibres embedded in the magnesium phosphate cementitious matrix. The micromorphology of the interface transition zone between MPC and different types of fibres was examined by scanning electron microscope. Test results showed that smaller diameter steel fibres with brass coating surface achieved higher average bond strength, higher pullout energy per unit volume and a higher ratio of material use. The end hook deformation provided the mechanical bond locally whereas the deformation along the length of fibre provided the mechanical bond distributed along the fibre. The failure mode and group effect of steel fibres were also investigated and reported.