Permeability is a major indicator of concrete durability, and depends primarily on the microstructure characteristics of concrete, including its porosity and pore size distribution. In this study, a variety of concrete samples were prepared to investigate their microstructure characteristics via nuclear magnetic resonance (NMR), mercury intrusion porosimetry (MIP), and X-ray computed tomography (X-CT). Furthermore, the chloride diffusion coefficient of concrete was measured to explore its correlation with the microstructure of the concrete samples. Results show that the proportion of pores with diameters < 1000 nm obtained by NMR exceeds that obtained by MIP, although the difference in the total porosity determined by both methods is minimal. X-CT measurements obtained a relatively small porosity; however, this likely reflects the distribution of large pores more accurately. A strong correlation is observed between the chloride diffusion coefficient and the porosity or contributive porosity of pores with sizes < 1000 nm. Moreover, microstructure parameters measured via NMR reveal a lower correlation coefficient R² versus the chloride diffusion coefficient relative to the parameters determined via MIP, as NMR can measure non-connected as well as connected pores. In addition, when analyzing pores with sizes > 50 µm, X-CT obtains the maximal contributive porosity, followed by MIP and NMR.

渗透性是混凝土耐久性的主要指标，并且主要取决于混凝土的微观结构特征，包括其孔隙率和孔径分布。在这项研究中，准备了各种混凝土样品，以通过核磁共振（NMR），压汞法（MIP）和X射线计算机断层扫描（X-CT）研究其微观结构特征。此外，测量了混凝土的氯离子扩散系数，以探讨其与混凝土样品微观结构的关系。结果表明，尽管通过两种方法确定的总孔隙率差异很小，但通过NMR获得的直径<1000 nm的孔的比例超过了通过MIP获得的孔的比例。X-CT测量获得相对较小的孔隙率；然而，这可能会更准确地反映出大孔的分布。观察到氯化物扩散系数与尺寸小于1000 nm的孔隙的孔隙率或贡献孔隙率之间具有很强的相关性。此外，通过NMR测量的微结构参数显示出较低的相关系数相对于通过MIP确定的参数，R ²与氯化物扩散系数的关系，因为NMR可以测量非连通孔和连通孔。此外，当分析尺寸大于50 µm的孔时，X-CT会获得最大的贡献孔隙率，然后是MIP和NMR。