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从宏观和微观尺度上研究了纳米SiO2改性对早龄期混凝土中界面过渡区(ITZ)力学行为的影响。测试了混凝土的强度及弹性模量,采用纳米压痕技术并结合统计手段对ITZ进行了表征。同时,从2个尺度层面分别建立了模型进行分析。结果表明:纳米SiO2的掺入有效提高了早龄期混凝土的综合力学性能,并主要提高了ITZ的力学性能,使ITZ与浆体本体的模量比从50%提升到80%。纳米SiO2改性机制以加速水化反应为主,在早期生成大量水化产物,尤其是低密度水化硅酸钙凝胶,进而填充微孔,改善ITZ的微观组织结构。
Abstract：The effect of nano-silica modification on the mechanical behavior of the interfacial transition zone(ITZ) in early age concrete was investigated in macro-and micro-scales. The strength and elastic modulus of concrete were examined. The ITZ samples were characterized by a nano-indentation technique with statistical method. The results show that the addition of nano-silica improves the overall mechanical properties of concrete in early ages. The mechanical performance of ITZ is enhanced. The ratio of the modulus of ITZ to that of bulk paste increases from approximately 50% to 80%. The hydration acceleration effect of nano-silica dominates in the modification. A large amount of hydration products, especially for low density C-S-H gel, appear in early ages, which can fill the micro-pores. As a result, the microstructure of ITZ can be refined.
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基本信息:
DOI：10.14062/j.issn.0454-5648.2018.08.02
中图分类号:TU528
引用信息:
[1]徐晶,王先志.纳米二氧化硅对混凝土界面过渡区的改性机制及其多尺度模型[J].硅酸盐学报,2018,46(08):1053-1058.DOI:10.14062/j.issn.0454-5648.2018.08.02.
基金信息:
国家自然科学基金(51378011);; 国家重点研发计划(2016YFC 0700802)
2018-05-24
2018-05-24
2018-05-24