Study of erosion wear to concrete by different gravel particle sizes: Laboratory test and numerical simulation

Concrete bridge piers face relentless erosion from Wind Gravel Flow (WGF) in Lanzhou–Xinjiang High–Speed Railway, resulting in pronounced wear on their surfaces, which could potentially induce additional structural defects. This study aims at the erosion wear performance and its corresponding damage mechanisms in concrete under WGF, using the airborne sandblasting method as a tool for this analysis. The study suggests that the Concrete Erosion Rate (CER) intensifies parallel to increases in both erosion angle and wind speed. Low angle erosion predominantly causes surface damage through cutting, while high angle erosion results in erosion pits and cracks. Notably, CER initially rises but eventually stabilizes with varying erosion times. A widened gravel particle size interval leads to a consistent reduction in the CER, but it concurrently heightens the likelihood of erosion caused by individual gravel particles on the concrete surfaces. An expanded gravel particle size interval results in a considerable increase in both the size and depth of erosion pits on the concrete surface. On the other hand, a narrowed particle size interval contributes to a significant upsurge in the number of erosion pits, causing the CER to diminish as the particle size interval increases. A novel model adapted for concrete exposed to the windy conditions of the Gobi has been developed. The model's accuracy has been substantiated via numerical simulations, which illustrates that an uptick in erosion wind speed considerably boosts the airflow velocity around the concrete sample. In contrast, the pressure distribution on the surface steadily decreases from the center to the periphery. As erosion wind speed increases, airflow velocity and surface pressure around the concrete specimen rise significantly. Furthermore, the surface pressure of concrete increases with a broader gravel particle size interval. In conclusion, this study provides a strong scientific and theoretical underpinning for the protection of concrete bridge piers in the wind–prone Gobi regions.