无细观界面过渡区水泥基材料的设计及其性能

DESIGN AND PROPERTIES OF MESO-DEFECT INTERFACIAL TRANSITION ZONE-FREE CEMENT-BASED MATERIAL

为提高混凝土的耐久性,延长其服役寿命,通过对混凝土细观结构的性能优化,设计制备出无细观界面过渡区水泥基材料(meso-defect interface transition zone-free cement-basedmaterial,MIF),用于重大工程结构的功能梯度混凝土保护层,并对其抗渗性能、力学性能、体积稳定性以及微细观结构进行了试验及机理探讨。结果表明:相比于普通的混凝土保护层材料,MIF混凝土渗透性极低,氯离子扩散系数减小1个数量级,而材料的使用寿命增长10倍以上。材料的力学性能及体积稳定性优良,完全满足工程需要且整体结构的体积变形匹配性良好,表面未见开裂。MIF混凝土微细观结构均匀、致密。

To improve the durability and service life of cement-based materials, a meso-defect interface transition zone-free cement-based material （MIF） was designed by improving the meso-structure of concrete. Thus this material was applied in the functionally graded concrete cover of a significant project. Its macro-properties, including impermeability, mechanical properties and volume stability, were investigated. In addition, its micro-properties and meso-structure were also studied. The results indicated that the permeability of MIF concrete was very low compared with ordinary concrete, its chloride diffusion coefficient was one order of magnitude lower, while its service life was more than ten fold longer. Furthermore, the mechanical properties and the volume stability of MIF concrete were excellent, providing the required strength and showing better compatibility in the volume deformation of the whole structure, and no cracking was found on the concrete surface. The homogenous and compacted microstructures as well as meso-structure of MIF concrete guarantee the higher durability and longer life of MIF concrete.