Impact of initial gradation on compaction characteristics and particle crushing behavior of gravel under dynamic loading

Gravel is a widely used construction material due to its versatility and cost-effectiveness. However, gravel particles are prone to crushing under dynamic loading, causing changes in gradation. The evolution of gradation and its effects on physical properties are not well understood. This study investigates the physical properties of gravel, such as dry density, void ratio, and relative crushing index, under different initial gradations (uniformity coefficient, C u ), using surface vibration compaction tests. A hyperbolic relationship was established between initial C u and dry density, showing that an increase in C u can result in a decrease in the void ratio and an increase in the coordination number until stabilization. Particle crushing increases with higher initial C u , correlating quantitatively with relative crushing indexes. Maximum dry density, minimum void ratio, and fractal dimension also correlate with these relative crushing indexes, suggesting intrinsic relationships among these properties and particle crushing. The size effect can be eliminated by establishing empirical relationships between crushing parameter and particle size.