Statistics-assisted fracture modelling of small un-notched and large notched sandstone specimens with specimen-size/grain-size ratio from 30 to 900

Quasi-brittle fracture properties of a medium-grain sandstone with an average grain size G around 0.3–0.4 mm were investigated under three-point-bending (3-p-b) conditions. In total, 95 specimens were tested with the beam width W varying from 10 to 300 mm, or the specimen-size/grain-size ratio from 30 to 900. 45 medium-sized specimens (W = 30, 60, 100 mm) were tested first to determine the tensile strength ft, which was then used as a reference...