活性MgO–粉煤灰固化淤泥微观机制研究

doi:10.13722/j.cnki.jrme.2018.1400

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Abstract The macro-efficiency and intrinsic mechanisms of low-carbon and environmental-friendly reactive MgO-fly ash blend，which is innovatively introduced into solidification of dredged sludge from Wuhan Eastlake，China，are deeply discussed. Based on unconfined compressive strength，X-ray diffraction，scanning electron microscopy，thermogravimetric and mercury intrusion porosimetry tests，a systematical study has been performed to analyze the strength，hydration products，structural morphology，thermal stability and microscopic pores of reactive MgO-fly ash solidified sludge. The test results indicate that the unconfined compressive strength of reactive MgO-fly ash solidified sludge increases with curing time，MgO-fly ash content and MgO/fly ash mass ratio. The formation of Mg(OH)2 and M-S-H(magnesium silicate hydrate) gel is the main reason why the strength property of solidified sludge is obviously improved. The increase in reactive MgO-fly ash content and MgO/fly ash mass ratio leads to an intensified diffraction peaks of Mg(OH)2 and M-S-H，an increase in thermogravimetric weight loss，a transformation of inter-aggregate pores to inter-particle pores. This induces a denser microstructure and better integrity，which promotes greatly the strength gain of solidified sludge. The obtained result further deepens the understanding of macro- and micro-characteristics of reactive MgO-fly ash solidified sludge，and establishes a full microscopic reaction model of reactive MgO-fly ash to clarify the intrinsic micro-mechanisms for the property improvement of solidified soils. The research results provide a theoretical basis for the application of green and low-carbon reactive MgO-fly ash blends in the practical engineering such as sludge solidification.

Key words： soil mechanics sludge reactive MgO-fly ash solidification compressive strength micro-mechanism

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	WANG Dongxing1
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	WANG Hongwei2
	WANG Ruihong3

Cite this article:

WANG Dongxing1,2,WANG Hongwei2, et al. Micro-mechanisms of dredged sludge solidified with reactive MgO-fly ash[J]. , 2019, 38(S2): 3717-3725.

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http://rockmech.whrsm.ac.cn/EN/10.13722/j.cnki.jrme.2018.1400 OR http://rockmech.whrsm.ac.cn/EN/Y2019/V38/IS2/3717

[4]	HIGGINS D. Briefing：GGBS and sustainability[J]. Construction Materials，2007，160(3)：99–101.
[5]	SHAND M A. The chemistry and technology of magnesia[M]. New York：John Wiley and Sons，2006：231–238.
[1]	曹玉鹏，卞夏，邓永锋. 高含水率疏浚淤泥新型复合固化材料试验研究[J]. 岩土力学，2011，32(增1)：321–326.(CAO Yupeng，BIAN Xia，DENG Yongfeng. Solidification of dredged sludge with high water content by new composite additive[J]. Rock and Soil Mechanics，2011，32(Supp.1)：321–326.(in Chinese))
[6]	HARRISON A J W. Reactive magnesium oxide cements[P]. EP，US，2008：7347896 B2.
[9]	YI Y L，LISKA M，UNLUER C，et al. Carbonating magnesia for soil stabilization[J]. Canadian Geotechnical Journal，2013，50(8)：899–905.
[11]	薄煜琳，于博伟，杜延军，等. 淋滤条件下GGBS-MgO固化铅污染黏土强度与溶出特性研究[J]. 岩土力学，2015，36(10)：2 877–2 891.(BO Yulin，YU Bowei，DU Yanjun，et al. Strength and leachability of lead contaminated clay stabilized by GGBS-MgO[J]. Rock and Soil Mechanics，2015，36(10)：2 877–2 891.(in Chinese))
[16]	JIN F，AL-TABBAA A. Strength and hydration products of reactive MgO-silica pastes[J]. Cement and Concrete Composites，2014，52(21)：27–33.
[17]	SHEAR D L，OLSEN H W，NELSON K R. Effects of desiccation on the hydraulic conductivity versus void ratio relationship for a natural clay[R]. Washington D C：National Academy Press，1993：1 365–1 370.
[3]	范昭平，朱伟，张春雷. 有机质含量对淤泥固化效果影响的试验研究[J]. 岩土力学，2005，26(8)：1 327–1 330.(FAN Zhaoping，ZHU Wei，ZHANG Chunlei. Experimental study on influence of organic matter content on solidified dredging[J]. Rock and Soil Mechanics，2005，26(8)：1 327–1 330.(in Chinese))
[7]	VANDEPERRE L J，LISKA M，AL-TABBAA A. Hydration and mechanical properties of magnesia，pulverized fuel ash，and portland cement blends[J]. Journal of Materials in Civil Engineering，2008，20(5)：375–383.
[8]	AL-TABBAA A，LISKA M. Ultra-green construction：reactive magnesia masonry product[J]. Waste and Resource Management，2009，162(4)：185–196.
[13]	WANG D X，DU Y Y，XIAO J. Shear properties of stabilized loess using novel reactive magnesia-bearing binders[J]. Journal of Materials in Civil Engineering，2019，31(5)：04019039.
[15]	吴传明. 水介质长期作用下的粉煤灰性能研究[博士学位论文][D]. 重庆：重庆大学，2009.(WU Chuanming. Research on fly ash properties of long-term wetting[Ph. D. Thesis][D]. Chongqing：Chongqing University，2009.(in Chinese))
[2]	王宏伟，王东星，贺扬. MgO改性淤泥固化土压缩特性试验[J]. 中南大学学报：自然科学版，2017，48(8)：2 133–2 141.(WANG Hongwei，WANG Dongxing，HE Yang. Experimental study on compressibility behavior of solidified dredged sludge with reactive MgO[J]. Journal of Central South University：Science and Technology，2017，48(8)：2 133–2 141.(in Chinese))
[10]	刘松玉，郑旭，蔡光华，等. 活性MgO碳化固化土的抗硫酸盐侵蚀性研究[J]. 岩土力学，2016，37(11)：3 057–3 064.(LIU Songyu，ZHENG Xu，CAI Guanghua，et al. Study of resistance to sulfate attack of carbonated reactive MgO-stabilized soils[J]. Rock and Soil Mechanics，2016，37(11)：3 057–3 064.(in Chinese))
[12]	WANG D X，WANG H W，WANG X Q. Compressibility and strength behavior of marine soils solidified with MgO-A green and low carbon binder[J]. Marine Georesources and Geotechnology，2017，35(6)：878–886.
[14]	中华人民共和国行业标准编写组. JTG E40—2007 公路土工试验规程[S]. 北京：中华人民共和国交通部，2007.(The Professional Standards Compilation Group of People?s Republic of China. JTG E40—2007 Test method of soils for highway engineering[S]. Beijing：Ministry of Transport，2007.(in Chinese))