摘要 孔隙是离子在水泥基材料中传输的通道,随着水化的进行,孔隙结构的相关参数会发生较大变化,需要对其在不同水灰比和龄期下的参数取值进行定量计算。通过NEL(Nernst-Einstein lab)实验和核磁共振(Nuclear magnetic resonance,NMR)实验研究了不同种类的孔隙对氯离子扩散系数的影响规律,采用通用有效介质理论(General effective medium theory,GEM)拟合了水泥浆体尺度和水化产物尺度下氯离子扩散系数模型中的关键参数。结果表明,在不同条件下水泥净浆的孔隙结构会发生显著改变,在水泥浆体层面,氯离子倾向于在毛细孔中扩散,扩散系数与毛细孔隙率呈强相关性,水化产物相的扩散系数随着水灰比的增加而减少,随着龄期的延长而增大;在水化产物层面,凝胶孔对氯离子扩散的影响不可忽略,扩散系数和凝胶孔隙率呈强相关性,临界孔隙率为0.122~0.172,凝胶孔的渗流指数为1.880~2.241。该模型可以基于不同种类的孔隙率计算氯离子扩散系数,对参数取值进行了精确计算和表征,对工程结构的耐久性设计具有一定指导意义。
Abstract: Pores are the basic channels for ion transport in cementitious materials. As hydration proceeds, the relevant parameters of the pore structure will change, which needs to be quantitatively calculated in terms of the values of the parameters at different water-cement ratios and curing ages. The effects of different pores on the diffusion coefficient of chloride ions were studied by NEL (Nernst-Einstein lab) test and NMR(Nuclear magnetic resonance) experiment. The general effective medium (GEM) theory was used to fit the key parameter of chloride diffusion coefficient model at the scale of cement paste and hydration products. The results show that the pore structure of the cement paste changes significantly under different conditions. At the scale of the cement paste, ions are more inclined to diffuse into the capillary pores. The diffusion coefficient is strongly correlated with the capillary porosity, and the diffusion coefficient of the hydration product phase decreases with the increase of the water-cement ratio, and increases with the extension of the age. At the scale of the hydration product, the effect of the gel pores on the diffusion of ions is non-negligible, the diffusion coefficient and the gel porosity are strongly correlated with each other. The critical porosity is approximately 0.122 to 0.172, and the percolation index of gel pores is approximately 1.880 to 2.241. The model can calculate the chloride diffusion coefficients based on different types of porosities, and accurately assign the parameter values, which is of significance for the durability design of engineering structures.
田壮, 肖官衍, 夏晋, 金伟良. 基于通用有效介质理论的双尺度水泥浆体氯离子扩散系数模型[J]. 材料导报, 2025, 39(22): 24110133-7.
TIAN Zhuang, XIAO Guanyan, XIA Jin, JIN Weiliang. A Two-scale Chloride Diffusion Coefficient Model in Cement Pastes Based on General Effective Medium Theory. Materials Reports, 2025, 39(22): 24110133-7.
1 Jin W L, Zhao Y X. Durability of concrete structure, Science Press, China, 2014, pp.65(in Chinese). 金伟良, 赵羽习. 混凝土结构耐久性(第二版), 科学出版社, 2014, pp.65. 2 Collepardi M, Turriziani R, Marcialis A. Journal of the American Ceramic Society, 1972, 55(10), 534. 3 Yang L F, Zhu E. Material Reports, 2025, 39(21), 24100140(in Chinese). 杨绿峰, 朱恩. 材料导报, 2025, 39(21), 24100140. 4 Tong L Y, Liu Q F. Journal of Building Materials, 2023, 26(10), 1062(in Chinese). 童良玉, 刘清风. 建筑材料学报, 2023, 26(10), 1062. 5 Zhang J H, Wang W, Guan Z G. Material Reports, 2016, 30(S2), 401(in Chinese). 张菊辉, 王伟, 管仲国. 材料导报, 2016, 30(S2), 401. 6 Tiedje E W, Guo P. Journal of Materials Science, 2014, 49(16), 5586. 7 Chen J J, Hein K S, Lyu G, et al. Construction and Building Materials, 2025, 458, 139529. 8 Caré S. Cement and Concrete Research, 2003, 33(7), 1021. 9 Liu Q F. Journal of the Chinese Ceramic Society, 2018, 46(8), 1074(in Chinese). 刘清风. 硅酸盐学报, 2018, 46(8), 1074. 10 Yang C C, Su J K. Cement and Concrete Research, 2002, 32(10), 1559. 11 Basheer L, Basheer P, Long A E. Construction and Building Materials, 2005, 19(9), 682. 12 Zhou Y, Liu Q F. Material Reports, 2023, 37(24), 22070243(in Chinese). 周宇, 刘清风. 材料导报, 2023, 37(24), 22070243. 13 Tian Z, Xiao G Y, Jin W L, et al. Journal of Zhejiang University (Engineering Science). 2023, 57(7), 1393(in Chinese). 田壮, 肖官衍, 金伟良, 等. 浙江大学学报(工学版), 2023, 57(7), 1393. 14 Bejaoui S, Bary B. Cement and Concrete Research, 2007, 37(3), 469. 15 Zheng J, Zhou X. Journal of Materials in Civil Engineering, 2008, 20(5), 384. 16 Garboczi E J, Bentz D P. Journal of Materials Science, 1992, 27(8), 2083. 17 Bernard F, Kamali-Bernard F. Computational Materials Science. 2012, 61, 106. 18 Mclachlan D S, Blaszkiewicz M, Newnham R E. Journal of the American Ceramic Society, 1990, 73(8), 2187. 19 Oh B H, Jang S Y. Cement and Concrete Research, 2004, 34(3), 463. 20 State Administration for Market Regulation. Concrete admixtures:GB 8076-2008. Standards Press of China, China, 2008(in Chinese). 国家市场监督管理总局. 混凝土外加剂:GB 8076-2008, 中国标准出版社, 2008(in Chinese). 21 State Administration for Market Regulation. Standard for test methods of concrete physical and mechanical properties:GB/T 50081-2019, Standards Press of China, China, 2019(in Chinese). 国家市场监督管理总局. 混凝土物理力学性能试验方法标准:GB/T 50081-2019, 中国标准出版社, 2019(in Chinese). 22 Leng F G, Feng N Q, Lu X Y. Cement and Concrete Research, 2000, 30(6), 989. 23 China Civil Engineering Society. Guide to durability design and construction of concrete structures:CCES01-2004, China Architecture & Building Press, China, 2004(in Chinese). 中国土木工程学会. 混凝土结构耐久性设计与施工指南:CCES01-2004, 中国建筑工程出版社, 2004. 24 Zhuang R, Li Y, Huang J, et al. Journal of Environmental Chemical Engineering, 2024, 12(6), 114325. 25 Li C J, Sun Z P, Li Q, et al. Material Reports, 2016, 30(13), 133(in Chinese). 李春景, 孙振平, 李奇, 等. 材料导报, 2016, 30(13), 133. 26 Zhao H T, Qin X, Liu J P, et al. Construction and Building Materials, 2018, 189, 934. 27 Yang C C, Cho S W, Wang L C. Materials Chemistry and Physics, 2006, 100(2-3), 203. 28 Mehta P K, Monteiro P J M. Concrete:microstructure, properties, and materials. McGraw-Hill Education, America, 2014. 29 Li C, Song X, Gu X. Construction and Building Materials, 2022, 333, 127383. 30 Ma H, Hou D, Liu J, et al. Construction and Building Materials, 2014, 71, 392. 31 Lin J, Chen H. Powder Technology, 2018, 335, 388. 32 Garboczi E J, Bentz D P. Computational and Mathematical Models of Microstructural Evolution, 1998, 529, 89. 33 Liu Z, Zhang Y, Liu L, et al. Construction and Building Materials, 2013, 48, 647. 34 Christensen B J, Coverdale T, Olson R A, et al. Journal of the American Ceramic Society, 1994, 77(11), 2789. 35 Tennis P D, Jennings H M. Cement and Concrete Research, 2000, 30(6), 855. 36 Lyu K, She W, Chang H, et al. Construction and Building Materials, 2020, 248, 118559.