Fracture study of red mud-contained alkali-activated concrete under pure Modes I, II and III

As the alkaline content and mass production of red mud (RM)—the industrial waste of producing alumina from bauxite—involve many environmental problems, and the alkali-activated slag is an eco-friendly kind of cement with a high ability to consume such a waste. An effort has been made in this research to evaluate the effects of their combination on the fracture properties of alkali-activated slag–RM concrete. To this end, 0, 10, 20, 30 and 40% RM was substituted for slag, and the properties of concrete were evaluated by applying the fracture and pullout test. The concrete underwent different-mode fracture tests (tensile and in-/out-of-plane shear), and the results revealed that the failure probability predictions of Mode II based on the results of Mode I were successful. When assessing the adequacy of the two different versions of the Weibull probability distribution function, the three-parameter model was more promising. In determining the predictability of the probability curves at Modes II and III, it was concluded that if a shift factor was applied to the Mode I curve, that of Mode II was predictable while that of Mode III was not.