School of Civil and Transportation Engineering, Hebei University of Technology, 5340 Xiping Road, Beichen District, Tianjin, 300401, China.
Shanxi Provincial Highway Bureau, Yangquan Branch, No.20, Shifan Street, Wucheng Road, Xiaodian District, Yangquan, 045099, China.
Chemosphere. 2023 Dec;343:140281. doi: 10.1016/j.chemosphere.2023.140281. Epub 2023 Sep 25.
Using asphalt mixture to solidify heavy metals in municipal solid waste incineration fly ash can reduce pollution and realize resource utilization. In this study, the physical and chemical properties of washed fly ash were analyzed, and washed fly ash was added to asphalt mixture as filler instead of mineral powder. The study involved analyzing the mechanical attributes of asphalt mixtures containing washed fly ash, along with examining the characteristics of asphalt binder that incorporates the washed fly ash. Subsequently, assess the potential leaching hazards associated with asphalt mixture incorporating washed fly ash. The test results showed that washed fly ash was a Si-Al-Ca system material, which had small particle size, large specific surface area and many pores. It increased the contact area with asphalt, which improved encapsulation of asphalt and aggregates. The optimal dosage of washed fly ash is 2.5%. At this dosage, the mixture attains optimal high-temperature performance, while both low-temperature performance and the characteristics of washed fly ash asphalt binder align with requirements. Asphalt mixture has solidification on heavy metals, with strongest solidification for Zn, followed by Cu, Cr. A prediction model of leaching amount versus time was constructed for Pb, Ba and Ni, which have weak solidified ability. The cumulative leaching amount of the road within 15 years of service life was calculated through the model, and it was obtained that the addition of washed fly ash will not cause pollution to environment. Overall, this study showed that asphalt mixtures can be used for stabilization/solidification of washed fly ash while saving natural mineral, providing a theoretical basis for the resource application of washed fly ash in asphalt road construction.
利用沥青混合料固化城市生活垃圾焚烧飞灰中的重金属，可以减少污染，实现资源利用。本研究分析了水洗飞灰的物理化学性质，并用水洗飞灰代替矿粉作为沥青混合料的填料。研究内容包括分析含有水洗飞灰的沥青混合料的力学性能，以及研究含有水洗飞灰的沥青胶结料的特性。然后，评估含有水洗飞灰的沥青混合料的潜在浸出危害。试验结果表明，水洗飞灰为 Si-Al-Ca 体系物质，颗粒粒径小、比表面积大、孔隙多，增加了与沥青的接触面积，有利于沥青对集料的包裹。水洗飞灰的最佳掺量为 2.5%。在此掺量下，混合料具有最佳的高温性能，同时低温性能和水洗飞灰沥青胶结料的特性均符合要求。沥青混合料对重金属有固化作用，对 Zn 的固化作用最强，其次是 Cu、Cr。建立了 Pb、Ba、Ni 浸出量随时间的预测模型，它们的固化能力较弱。通过该模型计算了在 15 年使用寿命内道路的累积浸出量，结果表明添加水洗飞灰不会对环境造成污染。综上所述，本研究表明，沥青混合料可用于水洗飞灰的稳定/固化，同时节省天然矿物资源，为水洗飞灰在沥青路面建设中的资源化应用提供了理论依据。
