Journal of the European Ceramic Society vol:37 pages:841-848
With the aim to correlate the global properties of refractory mortars with the micro-mechanical processes, a series of uni-axial compression and shear tests was conducted. The test program was developed with the view that the shear grain slip and cracks are frequent failure mechanism under compressive loads. The micro-structural changes during compression were monitored by X-ray micro focus computed tomography. Discrete element modelling was used to highlight the effects of individual factors of influence. Mortars with a water glass binder of different maturity were tested. In compression the mortars demonstrated cracking and pore closure. Shear tests showed that the failure process consists of multiple local failure events. The combined effects of the porosity and immature binder promote increased tendency for crack branching and arrest. This results in low shear strength and high compressibility. Cohesion and interlocking between the grains prevents crack branching and increases the stiffness and the strength.