Size effect on peak axial strain and stress-strain behavior of concrete subjected to axial compression

Twenty-four cylinders with different diameters (150 mm ≤ D ≤ 460 mm) and compressive strengths (C60, C45) were tested until failure to study the size effect behavior of concrete subjected to axial compression. The size effects on peak axial stress, peak axial strain, and elastic modulus were studied. Experimental results showed that peak axial stress and peak axial strain of the specimens tended to decrease with the increase in specimen diameter. The elastic modulus remained nearly constant when the specimen diameter increased, indicating that the size effect on the elastic modulus was insignificant. In addition, the size effects of peak axial stress and peak axial strain were analyzed based on existing theories and test data in the literature. A size-dependent stress-strain model of a concrete material subjected to axial compression was then proposed.