Experimental Study on Dynamic Tensile Properties of Macro-Polypropylene Fiber Reinforced Cementitious Composites

Using a high-speed photography system and a split Hopkinson pressure bar, macro-polypropylene fiber reinforced cementitious composites are tested to reveal the effects of the macro-polypropylene fiber volume fraction and loading rate on the dynamic tensile strength and failure mode. We also analyze the functional relationship between the dynamic tensile strength, loading rate, and fiber volume fraction, and study the splitting failure process using digital image correlation technology. The evolution law of the strain and displacement fields of the specimens is obtained, and the effect of the fiber volume fraction on the crack initiation strain value is quantitatively studied. The results show that the appropriate fiber content (1.5–2%) can significantly improve the dynamic tensile strength, while a higher fiber content (2.5%) leads to deterioration of the specimen. Adding macro-polypropylene fiber prevents the specimen from undergoing central tensile fracturing under dynamic loading, and distributes the impact load more evenly, thus improving the ability of the specimen to resist cracking.