Abstract:
With the continuous improvement of performance requirements for concrete materials in modern engineering construction, especially in the field of impact engineering, studying the dynamic mechanical behavior of high-performance concrete is of great significance. Mechanized sand, as a sustainable alternative material for fine aggregates, has received widespread attention due to its abundant resources and superior economic viability.To investigate the impact resistance of high-strength machine-made sand concrete, this study conducted impact tests on steel- Polyvinyl Alcohol (PVA) fiber-reinforced machine-made sand concrete. Split Hopkinson Pressure Bar (SHPB) tests were performed on four mix proportions to analyze dynamic compressive strength, dynamic increase factor (DIF), impact toughness, and fragment size distribution. The results revealed that when the strain rate was about 130 s
−1, the impact compressive strength, DIF, and impact toughness of the specimens mixed with machine-made sand and PVA fibers were the highest, with an increase of 37.05%, 9.47%, and 149.17% compared to the control group, respectively. Compared to the control group, the residual fineness modulus increased by 32.9% under low strain rate and 22.4% under high strain rate, indicating enhanced structural integrity after impact failure. The synergistic effect between machine-made sand and fibers notably improved strain rate sensitivity and impact resistance by suppressing crack propagation and enhancing energy dissipation. This study provides a multi material collaborative optimization direction for the design and application of concrete in impact engineering.