Compressive behavior of steel slag fine aggregate concrete under impact loading

Abstract

To investigate the compressive behavior of steel slag fine aggregate concrete (SSC) under impact loading, the normal concrete and steel slag fine aggregate concrete with varying steel slag fine aggregate (SSA) contents were prepared and a Split Hopkinson Pressure Bar (SHPB) with a diameter of 100 mm was used for the dynamic compression testing under various strain rates. The microstructure characteristics of concrete specimens were observed by scanning electron microscopy to investigate the impact behavior changes mechanism of SSC under dynamic loading. The research results indicate that the compressive strength, DIF, and impact toughness of the specimens exhibit significant strain rate effects, all of which increase with the increase of strain rate. At similar strain rates, both impact toughness and dynamic compressive strength show an upward trend with the increase of steel slag content, while DIF decreases with the increase of steel slag content. The microstructure of SSC is denser, and the hydration product of SSA fills the internal defects of concrete and significantly enhances the interface transition zone (ITZ) between fine aggregates and cement matrix, which has an enhancement effect on impact toughness and the dynamic compressive strength of concrete. The empirical formulas were proposed based on the testing results to predict the DIF of SSC with various SSA contents. The compression constitutive models considering strain rate and steel slag content of SSC were established, and the fitting consequences with the test results accord rather well.