氧化镁活性对碳化固化效果影响研究

刘松玉; 李晨

doi:10.11779/CJGE201501018

氧化镁活性对碳化固化效果影响研究 English Version

刘松玉^{1, 2},
李晨^{1, 2}

1. 江苏省城市地下工程与环境安全重点实验室,江苏南京 210096; 2. 东南大学岩土工程研究所,江苏南京 210096

基金项目: 国家自然科学基金项目（51279097,51379117,51479108）

详细信息

作者简介:
刘松玉(1963- ),男,教授,博士生导师,主要从事土力学理论、桩基工程、特殊地基和路基稳定、地下空间技术、原位测试技术等方面的研究。E-mail: liusy@seu.edu.cn。

中图分类号: TU472
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出版历程
- 收稿日期: 2014-06-19
- 发布日期: 2015-01-19

Influence of MgO activity on stabilization efficiency of carbonated mixing method

LIU Song-yu^{1, 2},
LI Chen^{1, 2}

1. Jiangsu Key Laboratory of Urban Underground Engineering & Environmental Safety, Nanjing 210096, China; 2. Institute of Geotechnical Engineering, Southeast University, Nanjing 210096, China

摘要

摘要: 碳化固化技术是近年来提出的一种低碳搅拌处理软弱土创新技术。该技术先采用MgO水泥与土进行搅拌,再利用CO₂对之进行碳化,以达到快速提高强度的目的。针对MgO活性对碳化固化的影响规律进行了室内试验研究,并分析了其微观机理。结果表明：试样能在3~6 h内完成大部分碳化,碳化24 h后达到稳定,氧化镁活性对碳化固化效果有显著影响,具体表现为氧化镁活性越高,试样碳化后碳化度越高、碳化产物越多、孔隙体积越小、微观结构越密实;试样碳化后体积明显增长,但氧化镁活性对体积变化影响不大,3种氧化镁试样体积膨胀均为16%左右;氧化镁活性越高试样强度越大,高活性氧化镁试样碳化6 h的强度可达标准养护28 d水泥土强度,稳定强度达到2.5 MPa,而低活性氧化镁试样强度仅为0.5 MPa;试样碳化稳定后高活性试样pH值为9.6,低活性试样pH值为9.0,均低于水泥土pH值。
- 地基处理 /
- 固化 /
- 碳化 /
- 无侧限抗压强度 /
- 机理
Abstract: The carbonated deep mixing method is an innovative CO₂ consuming method for ground improvement, in which the MgO binder is firstly mixed with the soft soils and then CO₂ is injected for carbonating in few hours. Using the carbonated mixing method, higher soil-MgO stabilized strength can be obtained in very short time. The influence of MgO activity on the stabilization efficiency and its mechanism were studied in this paper. A typical clay from Wuhan was used as the target soil and three different activities of MgO were selected as binders for laboratory tests. The results show that the carbonated degree with different active MgO binders can be predominantly completed in 3~6 hours and reaches stability after 24 hours. There are almost the same volume expansion of about 16% during carbonating process at all MgO binders. While the MgO activity has significant influences on the efficiency of the carbonated mixing method. With the higher activity MgO binder, the higher carbonated degree and more carbonated products forming denser texture are observed. Its unconfined compressive strength after carbonating 6 hours with higher activity MgO gets to the similar strength of 28 day-cured cement-stabilized soils. The final strength with higher activity MgO carbonated mixing soils can reach 2.5 MPa, while that with much lower activity MgO is only 0.5 MPa. The carbonated MgO-stabilized soils have considerable lower pH value (9.0~9.6) than the pH value (12) of the cement-stabilized soils.
- ground improvement /
- stabilization /
- carbonation /
- unconfined compressive strength /
- mechanism

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参考文献(15)

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文章访问数: 465
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氧化镁活性对碳化固化效果影响研究 English Version

作者简介: 刘松玉(1963- ),男,教授,博士生导师,主要从事土力学理论、桩基工程、特殊地基和路基稳定、地下空间技术、原位测试技术等方面的研究。E-mail: liusy@seu.edu.cn。

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Influence of MgO activity on stabilization efficiency of carbonated mixing method

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作者简介:
刘松玉(1963- ),男,教授,博士生导师,主要从事土力学理论、桩基工程、特殊地基和路基稳定、地下空间技术、原位测试技术等方面的研究。E-mail: liusy@seu.edu.cn。