Experimental analysis on the relationship between pore structure and capillary water absorption characteristics of cement‐based materials
Experimental analysis on the relationship between pore structure and capillary water absorption characteristics of cement‐based materials
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DOI：
10.1002/suco.201900184
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发表时间：
2019-08
影响因子：
3.2
通讯作者：
Haitao Zhao;Jian Ding;Yuyu Huang;Yimin Tang;Wen Xu;Donghui Huang
中科院分区：
文献类型：
--
作者：
Haitao Zhao;Jian Ding;Yuyu Huang;Yimin Tang;Wen Xu;Donghui Huang
毛细吸水能力对混凝土的耐久性有重要影响，并与孔结构密切相关。在这项研究中，样品的孔结构和毛细管吸水率分别通过低场核磁共振光谱和重量法测定。试验结果表明，水泥基材料的最可几孔径和等效孔径随水灰比（w/c）和粉煤灰掺量（FA）的增加而增大，随养护龄期和灰砂比（c/s）的增加而减小。水泥基材料的孔隙率随w/c和c/s的增加而增加，随养护龄期的增加而减小，随FA含量的增加先减小后增大。不同影响因素下水泥基材料试件单位面积毛细吸水量随时间平方根的变化曲线相似，呈现出明显的线性稳定阶段。毛细吸收系数与水灰比、碳灰比呈近似线性关系，与养护龄期、FA含量呈非线性关系，与孔隙率、等效孔隙半径的平方根呈良好的相关性。提出了考虑孔隙结构的毛细吸收系数修正模型，理论计算结果与试验结果吻合较好。
Capillary absorption capacity has an important influence on the durability of concrete and is closely related to pore structure. In this study, the pore structure and capillary water absorption of samples were determined by low‐field nuclear magnetic resonance spectroscopy and the gravimetric method, respectively. The test results show that the most probable pore diameter and equivalent pore diameter of cement‐based materials increase with increasing water to cement ratio (w/c) and fly ash (FA) content and decrease with increasing curing age and cement to sand ratio (c/s). The porosity of cement‐based materials increases with increasing w/c and c/s, decreases with increasing curing age, and first decreases and then increases with increasing FA content. The curves for the amount of capillary water absorption per unit area in specimens with the square root of time for cement‐based material under different influence factors are similar and show obvious linear and stable stages. The capillary absorption coefficient is nearly linearly related to w/c or c/s, and nonlinearly related to curing age or FA content, observation that are well correlated with the porosity and square root of the equivalent pore radius. A modified model is proposed for the capillary absorption coefficient with consideration of the pore structure, and the theoretical results of the model are in good agreement with the test results.