ABSTRACT
The properties of the interfacial region between the fibres and matrix in a composite are critical to its behaviour, because the transfer of stresses between the matrix and the fibre takes place via the interface. The interfaces in frp and frc are very different. In frp, the matrix generally surrounds each individual filament regardless of the fibre architecture and material, whereas in frc the matrix often does not penetrate the interior of, for example, glass or polymer microfibre bundles but is expected to fully surround, for example, steel or polymer macrofibres. In monofilament/macrofibre frc (especially steel-frc), the fibre–matrix interface is generally considered to be very similar to that of the interface between clean rebars and concrete in normal reinforced concrete. Bond in frp can be assessed using direct tests or indirect tests. Frictional bonding dominates the important part of frc stress–strain behaviour – the post-cracking region – than other two bonding types.
