改性再生混凝土高温性能  

Elevated temperatures performance of modified recycled aggregate concrete

作　　者：王永贵[1,2] 李帅鹏 HUGHES Peter 范玉辉[1] 高向宇[3] WANG Yong-gui;LI Shuai-peng;HUGHES Peter;FAN Yu-hui;GAO Xiang-yu(School of Civil Engineering,Henan Polytechnic University,Jiaozuo 454000,China;Henan Province Engineering Laboratory for Eco-architecture and Built Environment,Henan Polytechnic University,Jiaozuo 454000,China;College of Architecture and Civil Engineering,Beijing University of Technology,Beijing 100122,China)

机构地区：[1]河南理工大学土木工程学院,河南焦作454000 [2]河南理工大学生态建筑与环境构建河南省工程实验室,河南焦作454000 [3]北京工业大学建筑工程学院,北京100122

出　　处：《浙江大学学报（工学版）》2020年第10期2047-2057,共11页Journal of Zhejiang University：Engineering Science

基　　金：国家自然科学基金资助项目(51608179);河南省自然科学基金资助项目(182300410134);河南省科技攻关项目(182102310877);河南省高校基本科研业务费专项资金资助项目(NSFRF180418)。

摘　　要：为了改善再生混凝土的高温性能,通过玄武岩纤维及纳米氧化硅对再生混凝土进行改良.借助高温加热及抗压试验,测试25、200、400及600℃下改性再生混凝土的质量损失及抗压强度变化情况;结合电镜扫描及X射线衍射,分析高温后改性再生混凝土的微观结构.研究表明,随着温度的升高,质量烧失率增大,抗压强度及最佳纳米氧化硅质量分数降低,砂浆基体、界面过渡区性能及纤维与砂浆的黏结性能劣化情况加重,CH晶体及C-S-H胶凝质量浓度降低;随着取代率及氧化硅质量分数的增大,质量烧失率增大,抗压强度降低,砂浆基体较松散.结果表明,再生混凝土的抗压性能与微观结构受温度、取代率及纳米氧化硅质量分数的影响较严重,纤维质量掺量对抗压性能及微观结构不产生明显影响.Basalt fiber and nano-silica were used to improve the recycled concrete in order to improve the elevated temperature performance of recycled concrete.The changes of mass loss rate and cubic compressive strength of modified recycled aggregate concrete after 25,200,400 and 600℃were tested by means of the elevated temperature heating and compressive strength test.The microstructure of the modified recycled aggregate concrete after the elevated temperatures was analyzed by the scanning electron microscopy and X-ray diffraction.Results show that the mass loss rate increases with the increase of temperature.The compressive strength and the optimum mass fraction of nano-silica decrease.The mortar matrix,the performance of interface transition zone and the bonding performance between the fiber and the matrix deteriorate,and the mass concentration of CH crystal and CS-H gel decreases.The mass loss rate increases with the increase of the replacement ratio and the nano-silica mass fraction,the compressive strength decreases,and the mortar matrix is loose.Results show that the compressive strength and microstructures of recycled aggregate concrete are seriously affected by the temperature,replacement ratio and nano-silica mass fraction,while the basalt fiber dosage has no significant effect on the compressive strength and microstructures of recycled aggregate concrete.

关 键 词：再生混凝土 高温 玄武岩纤维 纳米氧化硅 质量烧失率 立方体抗压强度 微观结构 

分 类 号：TU528[建筑科学—建筑技术科学]