活性MgO碳化固化疏浚底泥的影响因素及作用机理

Influencing Factors and Mechanism of Dredged Sediment Carbonated and Solidified with Reactive MgO

关键词:  疏浚底泥  活性MgO  碳化  影响因素  微观机理

Key words:  dredged sediment  reactive MgO  carbonization  influencing factor  micro-mechanism

摘要:

采用MgO碳化技术对疏浚底泥进行固化处理，通过强度试验和微观特性试验，系统分析了活性MgO碳化固化底泥的主要影响因素及微观机理.结果表明：增加活性MgO掺量能生成较多的水化产物和碳化产物，使得底泥强度明显增大；土体含水率与压实度能够影响CO₂在土体内部的运移，二者增大导致CO₂吸附量减少，从而影响底泥的碳化固化效果；长时间的碳化作用导致部分碳化产物发生变质反应，底泥强度随碳化时间的延长呈先增后减趋势；水化产物和碳化产物对土颗粒的包裹、胶结和孔隙填充是活性MgO碳化固化底泥的主要作用机理.

Abstract:

MgO carbonization technology was used to solidify the dredged sediment. The main influencing factors and micro-mechanism of reactive MgO carbonization solidification of sediment were systematically analyzed through strength tests and microscopic characteristic tests. The results indicate that more hydration products and carbonization products can be generated with the increase of reactive MgO content， and the strength of sediment increases significantly. The water content and compaction degree are two main factors that affect the transport of CO₂ in soil， and the increase of both will lead to the decrease of CO₂ absorption， thus affecting the carbonization and solidification effect of sediment. The long-term carbonization can cause some carbonization products to undergo metamorphic reaction， so the strength of sediment increases first and then decreases with the increase of carbonization time. The encapsulation， cementation and pore filling of soil particles by hydration products and carbonization products are the main mechanism of reactive MgO carbonization solidification of sediment.