Compressive failure of brittle heterogeneous materials such as rock and concrete is strongly influenced by weak planes or layers contained in these materials. Those weak layers can be due to either the damage accumulation through localised micro-cracking or the inherent…
Compressive failure of brittle heterogeneous materials such as rock and concrete is strongly influenced by weak planes or layers contained in these materials. Those weak layers can be due to either the damage accumulation through localised micro-cracking or the inherent defects the heterogeneous structures. To study the influence of the weak layers on compressive failure concrete-like materials, mortar specimens with controlled weak layers have been tested. The weak layer in a specimen has pre-determined thickness and angle, and its strength is controlled by the water/cement and sand/cement ratios. Specimens with weak layers of 5, 10 and 15 mm thick and -:lngles from 0° to 55° have been tested. The shear strain- softening of the weak layer material has been deducted from stable displacement curves. Creep and stress relaxation can also be studied and monitored because of the pre-determined damage zone - the weak layer.