Effect of Prestatic Loading on Dynamic Tensile Strength of Concrete under High Strain Rates

Abstract

The static bending tests and the split Hopkinson pressure bar (SHPB) dynamic bending tests of concrete are investigated in this paper, and the effects of different initial static loading history on the dynamic tensile strength of concrete are explored. The initial static loadings are divided into five grades, 0, 25, 50, 75, and 90% of static tensile strength, respectively. A large number of mesostructure images of specimens have been obtained by the means of a scanning electron microscope (SEM) and used to analyze the influence of the microstructure and microcrack propagation on the dynamic performance of concrete. In addition, the Weibull distribution model is introduced to analyze the test results, which show that the dynamic tensile strength of concrete increases significantly with an increase in strain rate. When the initial static loading level does not exceed 50%, dynamic tensile strength is basically stable; but when the initial static loading level is more than 75%, dynamic strength begins to decrease.