Experimental study on dynamic compressive and splitting tensile properties of high strength expansive concrete

Concrete shrinkage usually results in the decrease in bearing capacity, durability and impact resistance of Concrete-Filled steel tube (CFST) structures during its service life. High strength expansive concrete (HSEC) is recently developed to deal with the shrinkage cracking in CFST structures. In this study, dynamic compressive tests and dynamic splitting tensile tests on the developed grade C60, C70 and C80 HSEC were performed using a split Hopkinson pressure bar device. Test results show that the expansive concrete is a typical rate-sensitive material, and its dynamic compressive strength and dynamic splitting tensile strength both increase with the strain rate. The compressive strength dynamic increase factor (DIFc) of HSEC is smaller than that of the ordinary concrete under the same strain rate, whereas the splitting tensile dynamic increase factor (DIFt) is larger than that of the ordinary concrete. All the test data were classified to establish calculation models of DIFc, peak toughness ( Rp), specific energy absorption (SEA), and DIFt, which provide a theoretical basis for the design and application of HSEC and CFST in engineering.