碱激发粉煤灰固化淤泥微观机制研究

doi:10.13722/j.cnki.jrme.2018.0568

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Abstract To mitigate the thorny problems associated with traditional Portland cement production in terms of energy consumption，CO2 emissions and air pollution，a favorable alternative option-novel and low-carbon alkali-activated industrial by-products is proposed for sludge solidification. 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 mechanical strength，hydration product，section morphology，thermal stability and micropore structure of alkali-activated fly ash solidified sludge and to reveal finally their strength evolution and microstructural mechanisms. The test results demonstrate that the compressive strength of dredged sludge is significantly enhanced owning to the incorporation of alkali-activated fly ash. Compared to Na2CO3，NaOH and Na2SiO3?9H2O have gained much more attention because of their excellent performance to activate the potential activity of fly ash. Through the OH－ attack to the inner and outer glass sphere structure，fly ash is effectively activated by dissolution-polymerization to form aluminosilicate polymer gels N-A-S-H with different degrees of polymerization，binding fine particles together to increase the overall strength of solidified sludge. The increase in alkali activator content leads to an elevated production amount of N-A-S-H gels，an increase in thermogravimetric weight loss and a transformation of inter-aggregate pores to inter-particle pores. The above changes produce a denser micropore structure and better integrity，which promotes significantly the strength performance of solidified sludge. The obtained results deepen the understanding of macro- and micro- characteristics of alkali-activated fly ash solidified sludge，and establish the full microscopic reaction model of alkali-activated fly ash to clarify the intrinsic micro-mechanisms for strength improvement and to provide the theoretical basis for partial replacement of Portland cement by alkali-activated fly ash in sludge solidification.

Key words： soil mechanics alkali-activation fly ash sludge compressive strength micro-mechanisms

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	Articles by authors
	WANG Dongxing1
	2
	WANG Hongwei1
	2
	ZOU Weilie1
	2
	WANG Xiequn3
	LI Lihua4

Cite this article:

WANG Dongxing1,2,WANG Hongwei1, et al. Research on micro-mechanisms of dredged sludge solidified with alkali-activated fly ash[J]. , 2019, 38(S1): 3197-3205.

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https://rockmech.whrsm.ac.cn/EN/10.13722/j.cnki.jrme.2018.0568 OR https://rockmech.whrsm.ac.cn/EN/Y2019/V38/IS1/3197

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