Fracture toughness of clay stabilized with different additives: An experimental and theoretical study

This study introduces the Straight Through Notch Bend Disc (STNBD) specimen for fracture toughness testing of clay, offering easier preparation compared to conventional test specimens. Mode I fracture toughness (KIc) of clay using STNBD was approximately 38 kPa.m0.5, closely aligning with results from the Semi-Circular Bend (SCB) specimen, with only a 10 % discrepancy. Theoretical analysis confirmed the effects of specimen geometry on fracture behavior. Adding cement or polypropylene fibers enhanced KIcand fracture energy (GIc). For both the clay and clay-cement mixtures, a clear increasing trend and a reasonable correlation were observed between unconfined compressive strength (UCS) and the fracture parameters.