Experimental Study of the Dynamic Mechanical Properties of High-Performance Equal-Sized–Aggregate Concrete

Abstract

The preparation of high-performance equal-sized–aggregate (HPESA) concrete has reversed current thinking about targets pertaining to high density and strength when designing traditional concrete materials. Maintaining the integrity of aggregates to prevent explosive failure at low strain, allowing use as an antiexplosion buffer filling layer in underground engineering works, is important. It is possible to repair the structures in situ after a disaster. Dynamic mechanical properties at different strain rates and obtaining optimal mix design parameters under impact loads were studied. According to the application requirement of antiexplosion buffer filling material in underground engineering, 16 groups of specimens were prepared with different mix designs. These were subjected to split Hopkinson bar (SHPB) testing at different impact-loading strain rates. The dynamic mechanical properties of HPESA concrete materials were correlated with impact-loading strain rates. At different strain rates, three types of stress–strain curves were exhibited: single-peak, double-peak, and transition types. The sensitivity of materials to strain rates was positively correlated with aggregate sizes. The energy dissipation of HPESA concrete materials under impact loading can be divided into damage fracture energy and inertial potential energy. The effects of four influencing factors (aggregate size, polymer–cement ratio, water–cement ratio, and cement–aggregate ratio) on energy dissipation in the specimens were explained theoretically. From the range analysis results of orthogonal tests, the primary and secondary order of the influencing factors on energy consumption indices was obtained, and the optimal energy-consumption ratio parameters of the material for antiexplosive buffer filling materials were determined, which lays a foundation for the subsequent application of this material.