酸环境下石灰-偏高岭土改性遗址土的强度及色差分析
作者:
作者单位:

1.中原工学院 建筑工程学院,河南 郑州 450007;2.河南省环境岩土工程与地下工程灾害控制工程研究中心,河南 郑州 450007;3.河南省文物建筑保护研究院,河南 郑州 450002

作者简介:

李新明(1987—),男,河南修武人,中原工学院副教授,硕士生导师,博士. E-mail: xinmingli@163.com

通讯作者:

尹 松(1987—),男,吉林白山人,中原工学院副教授,硕士生导师,博士. E-mail: syin@zut.edu.cn

中图分类号:

TU599

基金项目:

河南省高等学校青年骨干教师资助计划项目(2019GGJS142,2020GGJS136);河南省科技攻关项目(202102310584,222102320060);河南省高等学校计划基础研究专项(20ZX009);河南省研究生教育改革与质量提升工程项目(YJS2022SZ16)


Strength and Color Difference Analysis of Lime-Metakaolin Modified Site Soil in Acidic Environment
Author:
Affiliation:

1.School of Civil Engineering and Architecture, Zhongyuan University of Technology, Zhengzhou 450007, China;2.Research Center of Environmental Geotechnical Engineering and Underground Engineering Disaster Control Engineering of Henan Province, Zhengzhou 450007, China;3.Henan Provincial Architectural Heritage Protection and Research Institute, Zhengzhou 450002, China

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    摘要:

    采用X射线衍射、热重分析、扫描电镜观测、色差分析和强度性能测试等方法,研究了酸环境下石灰-偏高岭土(L-MK)及天然水硬性石灰(NHL)改性遗址土强度与色差的变化规律,并探讨了其微观机制.结果表明:随着酸环境下干湿循环次数的增加,L-MK改性遗址土强度先增后减,而NHL改性遗址土则单调递减,且经历20次干湿循环后L-MK改性遗址土强度为NHL改性遗址土强度的1.6倍以上;与原样遗址土相比,8%偏高岭土掺量下L-MK改性遗址土色差最小,且小于8%及10%NHL改性遗址土,L-MK与NHL改性遗址土强度变化规律的差异性与水化产物水化硅酸钙(CSH)的稳定性及CaSO4·2H2O等膨胀性物质的生成量有关,采用L-MK替代NHL应用于土遗址修复领域是可行的.

    Abstract:

    Influenced by different dry-wet cycles combined with acidic environment, lime-metakaolin(L-MK) and natural hydraulic lime(NHL) modified site soils were tested for unconfined compressive strength and split tensile strength, and color difference analysis was carried out on the basis of color consistency. X-ray diffraction(XRD), thermo gravity(TG) and scanning electron microscopy(SEM) tests were used to explain the strength degradation mechanism. The results show that the strength of L-MK modified site soil increases first and then decreases with the increasing number of dry-wet cycles in acidic environment, while the strength of NHL modified site soil decreases monotonically. After 20 dry-wet cycles in acidic environment, the strength of L-MK modified site soil is more than 1.6 times that of NHL modified site soil. Comparing the color parameters of the earthen site soil, the color difference of the L-MK modified site soil (with MK content of 8%) is less than that of the NHL modified site soil. The variation of strength is depended on the stability of hydration product calcium silicate hydrate (CSH) and the amount of expansive material such as CaSO4·2H2O produced. It is feasible to use L-MK instead of NHL in the field of site soil restoration.

    表 2 偏高岭土、石灰和天然水硬性石灰的化学组成Table 2 Chemical compositions of metakaolin, lime and natural hydraulic lime
    图1 不同干湿循环次数下L-MK和NHL改性土的无侧限抗压强度Fig.1 Unconfined compressive strength of L-MK and NHL modified soils under different dry-wet cycles
    图2 干湿循环作用下试样6%L+4%MK的外观变化Fig.2 Appearance of sample 6%L+4%MK under dry-wet cycles
    图3 不同干湿循环次数下L-MK和NHL改性土的劈裂抗拉强度Fig.3 Splitting tensile strength of L-MK and NHL modified soils under different dry-wet cycles
    图4 无侧限抗压强度与劈裂抗拉强度破坏模式Fig.4 Failure modes for unconfined compressive strength and splitting tensile strength
    图5 试样8%L+8%MK和8%NHL经历0、10、20次干湿循环后的XRD图谱Fig.5 XRD patterns of sample 8%L+8%MK and 8%NHL after 0, 10, 20 dry-wet cycles
    图6 试样8%L+8%MK和8%NHL的SEM图片Fig.6 SEM images of sample 8%L+8%MK and 8%NHL
    图7 试样8%L+8%MK和8%NHL的TG曲线Fig.7 TG curves of sample 8%L+8%MK and 8%NHL
    表 1 遗址土的基本物理参数Table 1 Basic physical parameters of earthen site soil
    表 3 L-MK及NHL改性土试样的颜色空间值Table 3 Color space values of L-MK and NHL modified soils
    表 4 L-MK及NHL改性土经历20次干湿循环后与原样遗址土的色差值Table 4 Color difference between L-MK and NHL modified soils and site soil after 20 dry-wet cycles
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引用本文

李新明,武迪,张浩扬,尹松,任克彬.酸环境下石灰-偏高岭土改性遗址土的强度及色差分析[J].建筑材料学报,2023,26(7):783-791

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  • 收稿日期:2022-08-12
  • 最后修改日期:2023-01-07
  • 在线发布日期: 2023-09-15
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