The size effect of axial compressive strength of concrete was experimentally investigated.
Based on the concept of the fracture mechanics and size effect law, theoretical studies for axial compressive failure of concrete were reviewed, and two failure modes of concrete specimen under compression were discussed. In this study, experiment of axial compressive failure, which is one of the two failure modes, was carried out. By using double cantilever fracture specimen. By varying the slenderness of cantilevers and the eccentricity of applied loads with respect to the axis of each cantilever, the size effect of axial compressive strength of concrete was checked, and predicted by Bazant's size effect law.
The test results show that size effect appears conspicuously for all series of specimens. By varying the eccentricity of loads, the influence of tensile and compressive stress at the notch tip is significant and so that the size effect is varied. In other words, if the influence of tensile stress at the notch tip grows up, the size effect of concrete increases. And the fact that the fracture process zone must be sufficiently secured for more accurate experiment was affirmed.
