摘要
采用试验的方法探究了纳米SiO_(2)界面剂对新旧混凝土界面劈裂黏结强度和抗渗性能的影响,其使用形式包括喷洒稀释溶液及作为增强相的砂浆界面剂两种方式,并与整体现浇试件及传统界面凿毛组的抗渗性能进行对比分析.同时,借助扫描电子显微镜(SEM)对不同纳米界面剂的黏结面微观结构进行了探究.最后,从界面强度、抗渗性能和微观机理3方面分析了纳米SiO_(2)界面剂对新旧混凝土界面黏结性能的影响.结果表明:两种纳米SiO_(2)界面剂均能不同程度地提高界面黏结强度及其抗渗性能,其中纳米SiO_(2)砂浆界面剂效果明显优于纳米SiO_(2)溶液组,且两者均存在最优掺量,分别为3.75%和2.5%;随着界面粗糙度的增加,黏结试件渗水高度和相对渗透系数逐渐降低;界面相对渗透系数与劈裂强度呈负相关,且相比于劈裂强度,相对渗透系数对界面缺陷更敏感.微观分析结果表明:纳米SiO_(2)的掺入改变了界面过渡区(ITZ)水化产物数量和C-S-H凝胶形貌,有效抑制了界面孔隙网络贯通,使ITZ微观结构更为致密.
The effects of nano-SiO_(2)on the splitting bond strength and impermeability between new and old concrete were experimentally investigated.The application forms of nano-SiO_(2)include spraying diluted solution and mortar as interfacial bonding agents and reinforcing phase.Monolithically cast substrate and four interface roughness groups were concluded for comparison.Furthermore,microstructure characteristics of the specimens with different bonding agents were inspected by means of scanning electronic microscopic(SEM).Finally,the influences and reinforcing mechanisms of nano-SiO_(2)were verified from the bond strength,permeability coefficient,and microstructures,respectively.The experimental results showed that both forms of the nano-SiO_(2)agents can improve the interfacial performances to a certain extent.And there is optimal concentration for each form,3.75%for mortar and 2.5%for spray treatment.Wherein,incorporating into mortar-base is more effective than the spray treatment.The increase in surface roughness benefits reducing the seepage height and permeability coefficient of bonded specimens.The permeability coefficient is more sensitive to the interfacial defects between overlays than the bond strength tests.Microstructure observations verified that the presence of nano-SiO_(2)benefits the amount of hydrate products and leading to a more compact C-S-H phase,which inhibits the formation of connected porous networks.
作者
周韬剑
杨才千
李科锋
曾领雄
许福
ZHOU Taojian;YANG Caiqian;LI Kefeng;ZENG Lingxiong;XU Fu(School of Civil Engineering,Xiangtan University,Xiangtan 411105,China;Jiangsu ZYZ Intelligent Operation&Maintenance Institute,Nanjing 211505,China;School of Civil Engineering,Southeast University,Nanjing 214135,China)
出处
《湘潭大学学报（自然科学版）》
CAS
2024年第1期14-23,69,共11页
Journal of Xiangtan University(Natural Science Edition)
基金
国家自然科学基金(52078122)
南京国际合作基金(2022SX00001057)
准格尔旗科技支撑计划(2019003)。
关键词
界面剂
界面处理
纳米SIO2
黏结性能
渗透试验
interfacial bonding agents
interface treatment
nano-SiO_(2)
bond performance
permeability tests
