摘要
在老砼表面涂覆硅溶胶分散硅粉浆液吸收新老砼界面区内富集的Ca(OH)2,形成CSH凝胶,改善甚至消除界面过渡区,提高界面粘结强度,通过扫描电镜研究了新老砼粘结界面的强化机理,结果表明,采用低水灰比水泥净浆界面处理时,新老砼粘结界面仍存在CH富集的界面过渡区,新老混凝土粘结试样3d、7d和28d界面粘结强度增大幅度仅为未处理试样同龄期界面粘结强度的11%、8%和12%,而采用硅溶胶分散硅粉浆液进行界面处理时,新老砼粘结界面区几乎不存在界面过渡区,而形成丰富的CSH凝胶水化产物层,与未经界面处理相比,新老砼粘结试样3d、7d和28d界面粘结强度增大幅度分别高达71%、68%和52%。
Surface treatment of the old concrete by coating of silica fume slurry dispersed in silica sol was developed to improve the interracial adhesive strength of the fresh-old concrete through absorbing the accumulated and oriented calcium hydroxide in the interracial transition zone （ITZ） between the fresh and old concrete by pozzolanic reactions with the coating materials, and the strengthening mechanism was studied through SEM and EDAX. The results show that there still was obvious ITZ and the interracial adhesive strength was only enhanced by 11%, 8% and 12% at 3 d, 7 d and 28 d, respectively, compared to that without any surface treatment at the same curing age when the old concrete was surface-treated with low-water-cement-ratio paste. However, the accumulated CH in the interface was nearly consumed over and the interracial adhesive strength of the fresh-old concrete specimen was improved up to 71%, 68% and 52% at 3 d, 7 d and 28 d, respectively, compared to that without any surface treatment at the same curing age when the old concrete was treated by a kind of silica fume slurry dispersed in silica sol.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2008年第A02期695-699,共5页
Rare Metal Materials and Engineering
基金
国家自然科学基金项目(50578147)
杭州市科技局计划项目(200433134)
关键词
硅溶胶
硅粉
界面过渡区
强化
新老混凝土
silica sol
silica fume
interracial transition zone
strengthening
fresh-old concrete
