| 武汉东湖淤泥碳化-固化试验研究 |
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| 引用本文： | 王东星,肖杰,肖衡林,马强.武汉东湖淤泥碳化-固化试验研究[J].岩土力学,2019,40(5):1805-1812. |
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| 作者姓名： | 王东星 肖杰 肖衡林 马强 |
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| 作者单位： | 1. 武汉大学 土木建筑工程学院，湖北 武汉 430072；2. 天津城建大学 天津市软土特性与工程环境重点实验室，天津 300381；
3. 湖北工业大学 土木建筑与环境学院，湖北 武汉 430072 |
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| 基金项目： | 国家自然科学基金（No.51879202, No.51609180） |
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| 摘 要： | 引入活性MgO-粉煤灰固化材料，采用碳化-固化联合技术处理武汉东湖疏浚淤泥，通过无侧限抗压强度、扫描电镜和压汞试验，研究加压碳化模式、碳化时间、MgO-粉煤灰配比和固化剂掺量等因素下CO2碳化作用对固化淤泥力学性质和微观结构的影响。结果表明：活性MgO-粉煤灰固化淤泥碳化后抗压强度进一步增长，应力-应变关系曲线压密阶段应变缩小；不同固化剂配比的东湖淤泥试样具有不同的最佳加压模式，而加压模式决定了相同碳化时间下固化淤泥CO2吸入量，从而影响碳化-固化淤泥试样抗压强度；活性MgO掺量低时试样抗压强度整体较低，强度随碳化时间增加先增大后减小；MgO掺量较高时，碳化试样强度随碳化时间快速达到较高值，随后增长缓慢。微观分析表明：水碳镁石、球碳镁石和碳酸镁石等镁碳酸盐是碳化-固化联合技术增强淤泥强度的主要原因，其膨胀性和胶结作用促使土体中团粒内孔隙向颗粒间孔隙转化，土体更密实，抗压强度增加。
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| 关 键 词： | 疏浚淤泥 活性MgO-粉煤灰 碳化-固化 抗压强度 微观机制 |
| 收稿时间： | 2018-01-22 |
Experimental study of carbonated-solidified sludge in East Lake,Wuhan |
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| WANG Dong-xing,XIAO Jie,XIAO Heng-lin,MA Qiang.Experimental study of carbonated-solidified sludge in East Lake,Wuhan[J].Rock and Soil Mechanics,2019,40(5):1805-1812. |
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| Authors: | WANG Dong-xing XIAO Jie XIAO Heng-lin MA Qiang |
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| Institution: | 1. School of Civil Engineering, Wuhan University, Wuhan, Hubei 430072, China;
2. Key Laboratory of Soft Soil Engineering Character and Engineering Environment of Tianjin, Tianjin Chengjian University, Tianjin 300381, China;
3. School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, Hubei 430072, China |
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| Abstract: | The reactive MgO-fly ash cementing materials were innovatively introduced into the improvement of dredged sludge from East Lake, Wuhan by the combined technology of carbonation-solidification. Through unconfined compression strength, scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) tests, the effect of CO2 carbonation on the mechanical properties and microstructure was investigated under different carbonation modes, carbonation time, ratios of MgO to fly ash and dosages of binding agent. The results indicate that the strength of solidified sludge is evidently increased due to carbonation, accompanied by a narrowed compaction stage of stress-strain curve. The sludge specimens with different binding agents have different optimal pressurization modes, which determines the CO2 intake amount of solidified sludge for the same carbonation period, and affects the strength gain of carbonated samples. Low amount of reactive MgO leads to relatively low compressive strength, which firstly increases and then decreases as the carbonation time increases. The strength of carbonated sludge with relatively high amount of reactive MgO reaches rapidly certain higher value with carbonation time and then increases slowly. The microscopic experiments demonstrated that the formation of magnesium carbonate (e.g. hydromagnesite, dypingite and nesquehonite) is the main reason for enhancing the compressive strength of specimens by the combined carbonation-solidification technology. The expansibility and cementation of the magnesium carbonate promote the transformation of pore in aggregates into inter-granular pore, which makes the soil more compact and increases its compressive strength of carbonated-solidified sludge. |
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| Keywords: | dredged sludge reactive magnesia-fly ash carbonation-solidification compressive strength micro-mechanism |
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