Permeability is an important indicator of the durability of cement-based materials. Surface treatments are effective in reducing permeability, and thus improving durability. In this study, CO₂ surface treatment, as a new method, was investigated explore the efficiency on cement-fly ash-slag ternary concrete. The results show that the CO₂ surface treatment densified surface microstructure and reduced both air and water permeability of concrete. With increase in fly ash and slag contents, the efficiency of CO₂ surface treatment in reducing concrete permeability was enhanced. The results of thermogravimetric analysis (TGA), X-ray diffraction (XRD), environmental scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) indicated that CO₂ surface treatment consumed calcium hydroxide (CH) and formed calcium carbonate (CaCO₃). Moreover, the calcium-to-silicon ratio (Ca/Si) of calcium silicate hydrate (C–S–H) decreased after surface treatment and CaCO₃ was covered by C–S–H during further hydration.

渗透性是水泥基材料耐久性的重要指标。表面处理可有效降低渗透性，从而提高耐用性。在这项研究中，CO ₂表面处理作为一种新方法，研究了水泥-粉煤灰-矿渣三元混凝土的效率。结果表明，CO ₂表面处理使混凝土表面微结构致密化，降低了混凝土的透气性和透水性。随着粉煤灰和矿渣含量的增加，CO ₂表面处理降低混凝土渗透率的效率提高。热重分析 (TGA)、X 射线衍射 (XRD)、环境扫描电子显微镜 (SEM) 和能量色散 X 射线光谱 (EDX) 结果表明 CO₂表面处理消耗氢氧化钙（CH）并形成碳酸钙（CaCO ₃）。此外，硅酸钙水合物（C-S-H）的钙硅比（Ca/Si）在表面处理后降低，CaCO ₃在进一步水化过程中被C-S-H覆盖。