孔隙结构及饱水度对水泥基材料透气性的影响

Influence of Pore Structure and Degree of Saturation on Gas Permeability of Cement Based Materials

以不同砂浆及混凝土试件为研究对象,用比重法、压汞法测试材料孔隙结构,用CEMBUREAU气体渗透法测试不同饱水度下砂浆及混凝土的气体渗透性,研究了渗透系数与孔隙结构之间的关系。结果表明:砂浆材料气体渗透系数与孔隙率φ以及平均孔径D的平方的乘积φD2成线性关系,而混凝土的这一关系不明显;随着饱水度降低,砂浆及混凝土的气体渗透系数增大,增大程度与其孔隙结构有关;利用Van Genuchten-Mualem模型可以很好地表征水泥基材料相对气体渗透系数随饱水度的变化规律。

Based on the gas permeability of different mortars and concretes at different degree of saturation measured by CEM- BUREAU method and the pore structure investigated by mercury intrusion porosimetery, the influence of pore structure and degree of water saturation on gas permeability was investigated. The results show that, mortars and concretes have very differ- ent gas permeability. And the gas permeability coefficient of mortar shows liner relationship with φD2 （where, 9 is porosity and D is average pore diameter）. Lower degree of water saturation leads to higher gas permeability. The relationship between rela- tive gas permeability and degree of saturation can be described by Van Genuchten-Mualem model.