Experimental study on dynamic compression behaviors of steel-PE hybrid fiber reinforced cementitious composites at sub-high temperatures

Dynamic compression tests on steel-polyethylene (PE) hybrid fiber-reinforced engineered cementitious composite (S/PE-HFRECC) specimens with different fiber volume content were conducted using a split Hopkinson pressure bar (SHPB) at sub-high temperatures (200 ℃, 250 ℃, 300 ℃, and 350 ℃). This study investigates the effects of sub-high temperatures, impact loading, and fiber parameters on the failure state, peak stress, dynamic pre-peak stress toughness, peak strain, and dynamic increase factor (DIF) of the specimens. The test results indicate the following: The static compressive strength of ECC specimens after cooling from sub-high temperatures can be categorized into three stages. PE fibers inhibit the formation and propagation of microcracks, while steel fibers are effective against macrocracks. The dynamic compressive strength, toughness, and DIF of ECC are strain-rate sensitive, showing a marked increase at higher loading rates. Based on an analysis of the dynamic compressive properties (including strength, peak strain, and toughness) at high strain rates (92–228 s⁻¹) revealed that the composite with a total fiber volume of 2 % exhibited superior impact resistance when reinforced with a hybrid ratio of 0.5 % polyethylene (PE) to 1.5 % steel fibers.