ABSTRACT
Size effect studies are reported for torsion test specimens prepared from cylinders and/or cores and compact compression test specimens. Since both geometries are compact test specimens they allow varying sizes to be readily investigated. In the torsion tests, the approximate Size-Effect Law proposed by Bazant is shown to be only reasonably applicable to the experimental results. The variation between actual experimental results and those determined from the application of the Size-Effect Law is significant. In the compact compression tests, the results show that this specimen is an excellent test geometry to study size effects and that in the case of specimens with shallow notch depths, the type of failure approaches that which corresponds to LEFM. Finally a new brittleness number, based on strain energy density calculations is proposed which can be used to compare the relative brittleness of different test specimens as well as the effect of notch depth.
