活性MgO固化淤泥水稳特性试验研究

将绿色、低碳、环保的活性MgO引入淤泥固化处理，通过对比活性MgO、MgO-粉煤灰及传统固化剂水泥固化淤泥试样，分析不同浸水时间下试样外观、质量、应力-应变关系和无侧限抗压强度等性质，综合评价活性MgO基材料固化淤泥的水稳特性.结果表明：活性MgO固化淤泥水稳性显著优于未固化淤泥，且水稳性随掺入MgO质量分数和标准养护龄期的增加而增强；粉煤灰的加入可以显著改善活性MgO固化淤泥的抗压强度和水稳性；浸水时间增加对固化淤泥无侧限抗压强度呈削弱效应，提高掺入活性MgO质量分数可以减小固化淤泥破坏应变；整体上，活性MgO-粉煤灰固化淤泥水稳性优于活性MgO，活性MgO优于传统固化剂水泥.微观分析表明：Mg（OH）₂和水化硅酸镁M-S-H等胶结物质是活性MgO和活性MgO-粉煤灰固化淤泥水稳性增强的最主要原因.

Experimental study on water stability property of dredged sludge solidified with reactive MgO

An experimental study was conducted to analyze the appearance, mass change, stress-strain relationship and unconfined compressive strength on the dredged sludge solidified with reactive MgO, MgO-fly ash and cement through full water immersion and unconfined compressive strength tests by introducing a low carbon, green and environmental-friendly binder. The obtained test results revealed the water stability performance of reactive MgO-solidified sludge. The water stability performance of reactive MgO-solidified sludge increases with MgO amount and curing time, and is evidently superior to non-solidified sludge. The addition of fly ash can greatly improve the compressive strength and water stability of reactive MgO-solidified sludge. The prolongation of water immersion duration weakens unconfined compressive strength of solidified sludge, while an increase in MgO mass fraction reduces its failure strain. The water stability of reactive MgO plus fly ash-solidified sludge is better than reactive MgO, which outperforms traditional at binder-cement on this point. The microstructural analysis indicates that Mg(OH)₂ and M-S-H are the most important materials why the water stability of reactive MgO-and MgO plus fly ash-solidified sludge is greatly enhanced.