The effect of test specimen size on the fracture toughness of concrete

Abstract The effect of test specimen size on the fracture toughness of plain concrete determined by means of the compact compression test geometry was investigated. The test specimens ranged from 100×100×100mm to 100×400×400× (width × depth × length). It was concluded that the fracture toughness increased with increasing test specimen size — the increase was negligible for the smaller specimens and was approximately 20% for the largest specimens tested. It was also concluded that the effect if self-weight was an important factor in the case of the larger test specimens and this effect must be taken into account in determining the fracture toughness. The results confirm some other recent test results in this area of study.