纳米级偏高岭土对再生骨料混凝土抗折和劈拉强度影响的试验研究

兰州理工大学学报 ›› 2023, Vol. 49 ›› Issue (6): 107-113.

纳米级偏高岭土对再生骨料混凝土抗折和劈拉强度影响的试验研究

阎杰¹, 罗岩², 柏永清¹, 邢国斌¹, 谢军^*1

1.河北建筑工程学院土木工程学院, 河北张家口 075000;
2.福州外语外贸学院智能建造学院, 福建福州 350202

收稿日期:2021-11-09 出版日期:2023-12-28 发布日期:2024-01-05
通讯作者: 谢军(1979-),男,辽宁营口人,博士,副教授.Email:xiejun79@hebiace.edu.cn
基金资助:
河北省教育厅自然科学重点项目(ZD2021041),2024年度河北省高等学校科学研究项目(ZC2024136),张家口市科技计划项目(2322145D)

Experimental study on the influence of nano-scale metakaolin on flexural and splitting tensile strength of recycled aggregate concrete

YAN Jie¹, LUO Yan², BAI Yong-qing¹, XING Guo-bin¹, XIE Jun¹

1. School of Civil Engineering, Hebei University of Architecture, Zhangjiakou 075000, China;
2. School of Intelligent Construction, Fuzhou University of International Studiesand Trade, Fuzhou 350202, China

Received:2021-11-09 Online:2023-12-28 Published:2024-01-05

摘要/Abstract

摘要： 为探究纳米偏高岭土对再生混凝土力学性能的影响,试验采用纳米偏高岭土(NMK)掺量(3%、5%、7%)及再生骨料取代率(30%、50%、100%)为变量制备纳米再生混凝土并进行劈拉、抗折强度试验.结合光学显微镜、扫描电子显微镜(SEM)、比表面积及孔径分析仪研究破坏面和界面过渡区(ITZ)微观形貌以及孔径分布特征,揭示NMK对再生混凝土劈拉、抗折强度的影响关系.试验结果表明,NMK的掺入对不同取代率的再生混凝土劈拉、抗折强度均有改善作用.比表面积及孔径分析研究表明,NMK填充再生混凝土内部部分大孔、中孔孔隙,降低总孔体积和比表面积,细化再生混凝土的孔隙结构、提高结构密实度.在显微镜下的微观结构分析显示,随着NMK掺量的增加,水化反应产生的C—S—H凝胶在逐渐增加,内部结构中孔隙和裂缝减少,再生混凝土内部微观结构整体更加密实.

关键词: 纳米级偏高岭土, 再生混凝土, 抗折强度, 劈拉强度

Abstract: To investigate the influence of nano-metakaolin on the mechanical properties of recycled concrete, the experiment used the dosage of nano-metakaolin (NMK) (3%, 5%, 7%) and the replacement rate of recycled aggregate (30%, 50%, 100%) as variables to prepare nano-recycled concrete and splitting tensile and flexural strength tests were conducted. By combining optical microscopy, scanning electron microscopy (SEM), specific surface area and pore size analyzer, the microstructure and pore size distribution characteristics of the failure surface and interface transition zone (ITZ) were studied, revealing the influence of NMK on the splitting tensile and flexural strength of recycled concrete. The experimental results show that the addition of NMK has an improvement effect on the splitting tensile and flexural strength of recycled concrete with different substitution rates. The analysis of specific surface area and pore size shows that NMK filled recycled concrete has some large and mesoporous pores inside, which can reduce the total pore volume and specific surface area, refine the pore structure of recycled concrete, and improve the structural density. The microstructure analysis under the microscope shows that with the increase of NMK content, the C—S—H gel produced by hydration reaction is gradually increasing, the pores and cracks in the internal structure are reduced, and the internal microstructure of recycled concrete is more dense.

Key words: nano-metakaolin, recycled concrete, flexural strength, splitting tensile strength

中图分类号:

TU528

阎杰, 罗岩, 柏永清, 邢国斌, 谢军. 纳米级偏高岭土对再生骨料混凝土抗折和劈拉强度影响的试验研究[J]. 兰州理工大学学报, 2023, 49(6): 107-113.

YAN Jie, LUO Yan, BAI Yong-qing, XING Guo-bin, XIE Jun. Experimental study on the influence of nano-scale metakaolin on flexural and splitting tensile strength of recycled aggregate concrete[J]. Journal of Lanzhou University of Technology, 2023, 49(6): 107-113.

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