Abstract: To study the effects of basalt fiber on energy absorption and fractal characteristics of cement-soil, a series of impact compressive tests and dynamic tensile tests was conducted on cement-soil with different basalt fiber contents by using a Φ50 mm Split Hopkinson Pressure Bar (SHPB) apparatus. The relationship between the basalt fiber content and three factors (i.e., energy absorption, failure mode and fractal dimension ( ) of cement-soil) was analyzed. The test results show that energy absorption firstly increased and then decreased with the inclusion of basalt fiber, and due to the existence of weak-surface made by excess basalt fiber, the energy absorption capacity was unresponsive to an increase of basalt fiber content when the basalt fiber content was more than the optimum content. The fragment-size distribution of cement-soil had a fractal property with statistical sense of self-similarity. In the impact compressive test, mean diameter of fragments increased with the increase of basalt fiber content but its appropriate had a decreasing trend. In the dynamic tensile test, when the basalt fiber content was from 0 to 2.0%, the mean diameter of fragments increased and the value of decreased. However, the mean diameter of fragments decreased and increased when more than 2.0% of basalt fiber was added. Also, there was a close relationship between the energy absorption and . In the impact compressive test, energy absorption firstly increased and then decreased when was from 2.20 to 2.26. When was from 1.85 to 2.20, the energy absorption continuously decreased in the dynamic tensile test, which shows a negative correlation between and energy absorption. The optimum content of basalt fiber plays a positive role in the dynamic properties of cement-soil, therefore, this study presents a suggestion that the optimum content of basalt fiber is 1.5% to 2.0%.

Key words: basalt fiber, cement-soil, split Hopkinson pressure bar (SHPB), energy absorption, fractal dimension, broken fragments