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含裂纹网络水泥基材料的渗透性
作者:李乐 庞晓贇 李克非 
单位:教育部土木工程安全与耐久重点实验室 清华大学土木工程系 北京 100084 
关键词:水泥基材料 裂纹网络 本征渗透系数 裂纹宽度 裂纹密度 
分类号:TU528
出版年,卷(期):页码:2015,43(8):1047-1054
DOI:10.14062/j.issn.0454-5648.2015.08.05
摘要:

 为了研究裂纹网络对水泥基材料渗透性的影响,采用人工制造裂纹再拼接的方法得到不同开裂程度的薄片试件,对开裂试件表面的二维裂纹形貌特征进行了定量分析,包括裂纹的密度、取向、裂纹宽度等。测试了普通混凝土和砂浆材料的等温吸附与脱附曲线,得到两种材料的水分特征曲线。并用水分迁移的多相流模型模拟试件的干燥过程,同时对比干燥实验中不同开裂程度试件的质量变化以回归其对应的本征渗透系数。结果表明:裂纹密度大于临界阈值0.3 时,相对渗透系数增加迅速;渗透系数与裂纹的宽度成指数关系,指数为1.945,接近立方定律中渗透系数与宽度的二次方关系。

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 In order to investigate the influence of crack network geometry on the permeability of cracked cement-based materials,cracks were artificially made in mortar and concrete slice specimens to obtain a two dimension(2D) crack network. The water vaporsorption isotherms (WVSI) of ordinary concretes and mortars were measured. The intrinsic permeability of specimens with differentlevels of cracking extent was regression analyzed via the measurements of mean relative mass during drying test. The drying processwas simulated using the WVSI and water transport model. The geometry parameters on 2D cracked surface, i.e., crack density ρ,orientation and crack opening aperture, were evaluated . The relationship between the geometry characteristics of crack networks andthe relative permeability was investigated. The results show that the crack density has a possitive impact on the increase of the relativepermeability when ρ is >0.3, which is related to the percolation characteristics of crack networks. The relative permeability of mortarand concrete scales to crack opening through a power law with exponent as 1. 945.

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作者简介:
第一作者:李 乐(1987—),女,博士研究生。 通信作者:李克非(1972—),男,博士,教授。
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