Study on Impact Resistance of All-Lightweight Concrete Columns Based on Steel Fiber Reinforced and Various Axial Compression Ratio

Concrete columns in service are exposed to threats such as accidental impacts and explosions, which pose potential risks to the safety of buildings. Although fully lightweight concrete elements prepared from non-sintered fly ash ceramic pellets and pottery sand are widely used in engineering practice, the dynamic response of such elements under impact loading is not supported by adequate research data. Therefore, in this study, the dynamic response of all-lightweight concrete columns under impact loading with different axial compression ratios (0.1, 0.2, and 0.3) was investigated by means of drop hammer impact tests, and the potential of shear wave steel fibers in mitigating structural damage and preventing structural failure was investigated. The results of the study reveal that the specimens primarily exhibit shear and bending damage under impact loading. With an axial compression ratio of 0.1, the specimen is dominated by bending damage. As the axial compression ratio increases from 0.1 to 0.3, the specimen’s damage mode transitions to shear damage dominance. This change results in a larger impact force and displacement response while experiencing lower displacement acceleration. Additionally, the introduction of steel fibers improves the strength and stiffness of the specimens, shifting their behavior from shear to bending damage. Consequently, this reduces impact damage, mid-span displacement, and displacement acceleration while enhancing the specimen’s response to the impact force and its capacity for deformation energy dissipation.