ABSTRACT
Fracture in fibre-reinforced cement composites can be usefully described by the crack-toughness (T) curve methodology based on linear elastic fracture mechanics analysis using the K-superposition principle. With the simplified assumptions of a power law strain-softening characteristics of the damage zone (i.e. fibre bridging zone and/or matrix fracture process zone) and a linearized crack profile the stable crack growth in fibre-cement composites can be readily modelled with T-curves and the associated load-deflection diagrams obtained. The relationship between the T-curve and the damage zone over which bridging stresses are transferred in accordance with the strain-softening law is emphasized. It is also shown that whilst specimen geometry and size have some significant effects on the T-curve, the matrix fracture process zone effect is quite small considering the usually large scatter of the experimental data. Using the crack-toughness curve concept the Weibull strength distribution of short fibre cement composites is also studied and it is shown that the Weibull modulus is considerably increased due to the T-curve effect.
