硅酸盐学报2017，Vol.45Issue(11)：1594-1604,11.DOI:10.14062/j.issn.0454-5648.2017.11.10
超低水胶比复合胶凝材料孔结构随养护制度和龄期的变化机理
Mechanism of Curing Effect on Pore Structure of Hardened Cementitious Composites with Ultra-low Water to Binder Ratio
摘要
Abstract
Based on the special rule of early shrinkage of cementitious composites with ultra-low w/b (water-binder) ratio, the chemical combined water and internal humidity were measured, and the pore structure of hardened slurry was investigated at different hydration time and curing conditions. The pore structure of hardened slurry at characteristic hydration time was determined by mercury intrusion porosimetry and BET specific surface area analysis. The microscopic mechanism of pore structure change was analyzed by scanning electron microscopy and transmission electrom microscopy. The results show that the early shrinkage of cementitious composites with ultra-low w/b ratio after sealed curing is greater than that of the dry condition. The pores between 20-30 nm in hardened slurry gradually increase, and the pores between 3-12 nm particles gradually reduce with the increase of hydration time. Some of the inter-crystallite pores (i.e., <3 nm) are also compressed. The driving force is confirmed as a self-drying effect of hydration in the middle and later stages. CSH gel is compressed to ball-shaped units, which shrink from 50 nm to 20-40 nm. The shrinkage increases the pores between the gel units, and decreases the pores between the gel particles. The change of pore structure does not affect the mechanical properties, permeability and durability of hardened cementitious composites, but it changes the early shrinkage of the hardened slurry.关键词
超低水胶比/孔结构/养护制度/水化龄期/水化硅酸钙凝胶Key words
ultra-low water/binder ratio/pore structure/curing/hydration time/hydrated calcium silicate gel分类
建筑与水利引用本文复制引用
韩松,刘丹,张戈,安明喆,余自若..超低水胶比复合胶凝材料孔结构随养护制度和龄期的变化机理[J].硅酸盐学报,2017,45(11):1594-1604,11.基金项目
中央高校基本科研业务费专项资金(2016JBM045) （2016JBM045）
国家自然科学基金(51408037,51578049) （51408037,51578049）
交通运输部应用基础研究项目(2014319494010) （2014319494010）
中交集团科技研发(2013-ZJKJ-11)资助项目. （2013-ZJKJ-11）
