Experimental and numerical analysis of Brazilian discs with multiple parallel cracks

The pre-cracked Brazilian disc specimens of rock-like materials (Portland Pozzolana cement (PPC), fine sands, and water) are especially prepared in a rock mechanics laboratory to study the breaking process of brittle solids. The Brazilian discs may contain one, two, three, four, and five (parallel) center slant cracks (45A degrees to the horizontal) under compressive line loading. The breaking load of the pre-cracked disc specimens is measured showing that as the number of cracks increases, the final breakage load of the specimen decreases. The experiments are carried out under compression (just like the Brazilian tests used for measuring the indirect tensile strength of intact rocks). It has been experimentally observed that the wing cracks are produced at the first stage of loading and start their propagation toward the direction of compressive line loading in the pre-cracked Brazilian discs. The same specimens are numerically simulated by a higher order displacement discontinuity method (HDDM). The effect of bridge area and orientation of cracks on the cracks coalescence and breakage path of the pre-cracked Brazilian discs specimens are simultaneously studied.