“…In past few years, the semi-circular bend (SCB) specimen proposed by Chong et al (1987) has gained the attention of many researchers including Lim et al (1993Lim et al ( , 1994; Kuruppu (1997Kuruppu ( , 1998Kuruppu ( , 2000; Kuruppu and Chong (2012); Kuruppu et al (2014) and Ayatollahi (2015) for the measurement of fracture toughness, because of factors such as convenient sample preparation, simple geometry, minimal requirement of machining, loading configuration and the convenience of the experimental set-up that can be achieved by applying three-point compressive loading using a common laboratory load frame and low requirement of materials (Aliha et al, 2012;Ayatollahi and Aliha, 2007;Ayatollahi, 2015;Chong and Kuruppu, 1984;Kuruppu et al, 2014). Normally, geo-materials are weak under extensional force and, hence, the applied force for the measurement of fracture toughness should be such that it promotes tensile fracturing.…”