Mesoscopic characteristics of carbonate erosion to shotcrete

Abstract

In the context of enhancing the durability of shotcrete used in construction, particularly in environments prone to carbonate erosion, this study investigates the mesoscopic characteristics of shotcrete subjected to such conditions. Despite extensive research on the durability of traditional concrete under various corrosive environments, the specific impacts of carbonate erosion on shotcrete remain underexplored. This study comprehensively examines the microscopic characteristics of shotcrete subjected to carbonate erosion, employing a combination of X-ray diffraction (XRD), scanning electron microscopy (SEM), and computed tomography (CT) scanning techniques. The unique contribution of this research lies in its comparative analysis of ordinary shotcrete and fly ash shotcrete under dry-wet cycles over periods of 0, 60, and 120 days. Utilizing CT scanning for three-dimensional reconstruction, XRD for phase composition analysis, and SEM for microstructural examination, the study provides a detailed analysis of internal pore structure changes and morphological transformations. The results indicate significant differences in erosion resistance between the two types of shotcrete, with fly ash shotcrete demonstrating superior resistance to carbonate erosion. This is evidenced by slower pore development and reduced structural degradation compared to ordinary shotcrete. These findings suggest that incorporating fly ash enhances the durability of shotcrete in carbonate-rich environments, making it a more viable material for infrastructure subjected to such conditions. The significance of this study lies in its profound revelation of the corrosion mechanisms of carbonate solutions on shotcrete from both microscopic and mesoscopic perspectives, offering valuable insights for further research on building materials.

Keywords

• Shotcrete
• CT scan
• Three-dimensional reconstruction
• Pore structure