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。
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 vapor sorption isotherms （WVSI） of ordinary concretes and mortars were measured. The intrinsic permeability of specimens with different levels of cracking extent was regression analyzed via the measurements of mean relative mass during drying test. The drying process was simulated using the WVSI and water transport model. The geometry parameters on 2D cracked surface, i.e., crack density p, orientation and crack opening aperture, were evaluated. The relationship between the geometry characteristics of crack networks and the relative permeability was investigated. The results show that the crack density has a possitive impact on the increase of the relative permeability when p is 〉0.3, which is related to the percolation characteristics of crack networks. The relative permeability of mortar and concrete scales to crack opening through a power law with exponent as 1. 945.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2015年第8期1047-1054,共8页
Journal of The Chinese Ceramic Society
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
cement-based materials
crack network
intrinsic permeability
crack opening aperture
crack density
