梯度结构混凝土的离子传输性能与微观结构  

ION TRANSPORT PROPERTY AND MICROSTRUCTURE OF GRADIENT STRUCTURAL CONCRETE

作　　者：王信刚[1] 马保国[2] 陈礼和 

机构地区：[1]南昌大学建筑工程学院,南昌330031 [2]武汉理工大学硅酸盐材料工程教育部重点实验室,武汉430070 [3]江西省第一建筑有限责任公司,南昌330001

出　　处：《硅酸盐学报》2008年第7期920-926,共7页Journal of The Chinese Ceramic Society

基　　金：国家“863”计划(2005AA332010)资助项目

摘　　要：引入梯度结构设计原理进行梯度结构混凝土的设计,采用加速扩散法、自然扩散法测试其离子传输性能,采用压汞法、扫描电子显微镜测试梯度结构混凝土的微观结构。结果表明:与单层结构的高性能混凝土(high performance concrete,HPC)相比,梯度结构混凝土的Cl–扩散系数DNEL下降了2个数量级,6h导电量Q下降了30%～40%,表观Cl-扩散系数Da下降了25%～45%。可见,梯度结构混凝土的抗离子渗透性能显著提高。无细观界面过渡区水泥基复合材料(meso-interfacial transition zone-free cement-based materials,MIF)孔结构的改善程度比低渗透混凝土(low permeability concrete,LPC)的更大,MIF的孔隙率、最可几孔径、孔径≥50nm的孔含量均小于LPC的。MIF的集料–水泥石界面过渡区的改善程度比LPC和HPC的更大,MIF的界面过渡区也更为致密。同时,MIF–HPC的界面结合区的结构比LPC-HPC的更为致密。最后提出了梯度结构混凝土抗离子渗透性能的简化物理模型。A gradient design theory is introduced to the structural design of concrete used in underground engineering, and gradient structural concrete （GSC） is proposed. The ion transport property of GSC was investigated by accelerated diffusion method and natu- ral diffusion method, and its microstructure was investigated by mercury intrusion porosimetry and scanning electron microscopy. In comparison with monolayer structure high performance concrete （HPC）, the chloride diffusion coefficient DSEL of the GSC was decreased by two orders of magnitude, the conductive charge Q for 6 h was decreased by 30% to 40%, and the apparent chloride diffu- sion coefficient Da was decreased by 25% to 45%. Thus, the chloride ion penetration resistance of GSC was obviously increased. The pore structure of the meso-interfacial transition zone-flee cement-based materials （MIF） is superior to that of low permeability concrete （LPC）. The porosity, the most probable pore radius and the number of pores with radii bigger than 50rim are all smaller in MIF than in LPC. Furthermore, the interracial transition zone between the aggregate and cement paste in MIF has a greater degree of modification than that of LPC and HPC, and the interracial transition zone of MIF is denser than that of LPC and HPC. In addition, the interfacial bond zone of MIF-HPC is denser than that of LPC-HPC. A simplified physical model of the ability to resist chloride ion penetration of GSC was also proposed.

关 键 词：梯度结构混凝土 离子传输 孔结构 界面过渡区 

分 类 号：TU528[建筑科学—建筑技术科学]