Size effect in dynamic splitting tensile strength of concrete: Experimental investigation

Abstract

The static size effect of concrete is well-known, but there is limited knowledge of the dynamic size effect. It is essential to understand the dynamic size effect so that the laboratory investigation of dynamic test results can be applied to real full-scale structures subjected to dynamic or impact loading. In this study, four sizes of C30 concrete discs in the diameter of 70 mm, 100 mm, 150 mm and 200 mm were prepared with the water-to-cement ratio of 0.61 and tested in tension under a wide range of strain rates, from 2 × 10−5 s−1 to 12 s−1. The experimental results show that the dynamic size effect is obviously observed. At the strain rate below 2 × 10−3 s−1, the dynamic size effect is similar to the static size effect, that is, the specimens of smaller sizes have greater tensile strength. However, the higher strain rate above 2 s−1 is found to enhance the more dynamic strength of greater size specimens. The greater size specimens exhibit higher dynamic tensile strength. The dynamic increase factor of strength (DIF) is strain rate- and size-dependent. A modified DIF formula, considering both the strain rate effect and size effect, is proposed to predict the DIF of concrete.