[论文解读] Valorization of incinerator bottom ash for the production of resource-efficient eco-friendly concrete: Performance and toxicological characterization

B. M. Ramesh, Rahul Murali Vongole+6 more|arXiv (Cornell University)|Apr 26, 2021

Recycling and utilization of industrial and municipal waste in materials production参考文献 39被引用 16

一句话总结

本研究提出一种新型预处理方法，将城市固体废物（MSW）焚烧炉底灰及拆除废料资源化利用，作为生态友好型M20混凝土中细骨料和粗骨料的部分替代品。最优配合比——5%焚烧炉底灰与40%再生拆除废料——在实现优异强度与耐久性的同时，有毒元素浸出极低，扫描电镜（SEM）分析显示其具有致密、低孔隙率的微观结构。

ABSTRACT

The disposal of incinerator bottom ash usually produced by the incineration of inorganic constituents of the municipal solid wastes (MSW) in an eco-friendly way is one of the issues of concern, globally. By the way, the present study is related to the utilization of MSW incinerator bottom ash and recycled demolition waste aggregate as partial replacement materials for fine and coarse aggregate, respectively to produce eco-friendly concrete. This study adopted an innovative pretreatment technique for stabilizing the MSW incinerator bottom ash. Five distinct M20 grade concrete mixes were produced with different proportions of fine aggregate, MSW incinerator bottom ash, coarse aggregate, and recycled demolition waste aggregate along with cement and water. The incinerator bottom ash was replaced at 5% and 10% quantities with fine aggregate and the recycled demolition waste aggregate was replaced at 40% and 60% of the weight of the coarse aggregate. The strength and durability properties of the M20 grade concrete were analyzed. It was noticed that the strength and durability properties of the eco-friendly concrete specimens produced by incorporating 5% - incinerator bottom ash and 40% - recycled demolition waste aggregate were superior to that of the control mix concrete. Laboratory tank leaching tests showed that the eco-friendly concrete do not pose any significant environmental hazard. Furthermore, the microstructural analysis through scanning electron microscope (SEM) images, revealed dense aggregate paste matrix interfaces with less micro-pores and insignificant micro-cracks due to the incorporation of incinerator bottom ash as a partial replacement to the fine aggregate.

研究动机与目标

• 应对日益增长的城市固体废物（MSW）焚烧炉底灰及建筑与拆除（C&D）废物管理的全球性挑战。
• 通过用MSW焚烧炉底灰和再生拆除废料替代天然骨料，开发一种可持续的废物资源化解决方案。
• 通过预处理与全面表征，确保生态友好型混凝土的环境安全与结构性能。
• 研究在不同替代水平下，掺入这些固废材料的混凝土混合物的力学性能、耐久性及毒性行为。

提出的方法

• 采用一种新型预处理技术，稳定MSW焚烧炉底灰，降低其活性并提升与水泥的相容性。
• 制备五种M20等级的混凝土混合物，其配比分别为：5%和10%焚烧炉底灰替代细骨料，40%和60%再生拆除废料替代粗骨料。
• 在7、14、21和28天进行抗压强度测试，以评估其力学性能。
• 开展耐久性评估，包括吸水率、可渗透孔隙体积及抗冻融性能。
• 进行为期64天的实验室槽式浸出试验，评估环境毒性，测定浸出液中重金属的浓度。
• 利用扫描电子显微镜（SEM）分析微观结构，重点关注界面过渡区（ITZ）与孔隙结构。

实验结果

研究问题

• RQ1 在生态友好型混凝土中，MSW焚烧炉底灰与再生拆除废料骨料的最佳替代水平为何，可使强度与耐久性达到最优？
• RQ2 焚烧炉底灰的预处理如何影响所得混凝土的力学性能与微观结构特性？
• RQ3 浸出试验在多大程度上表明该生态友好型混凝土在重金属释放方面的环境安全性？
• RQ4 混凝土的微观结构——特别是界面过渡区（ITZ）——如何影响其耐久性与强度？

主要发现

• 5%焚烧炉底灰与40%再生拆除废料骨料的配合比在28天时达到最高抗压强度，优于对照组。
• 生态混凝土的可渗透孔隙体积显著低于对照组，表明其耐久性更优且渗透性更低。
• 64天的浸出试验表明，大多数有毒元素（如铅、铬、镉）的浓度低于法规限值，但硼在M3、M4和M5配合比中超过限值。
• SEM分析显示，混凝土具有致密、紧凑的微观结构，微孔隙极少，界面处无明显微裂纹，这得益于焚烧炉底灰的有效掺入。
• 焚烧炉底灰的预处理成功稳定了活性化合物，防止其对水化反应及强度发展产生不利影响。
• 钙硅酸盐水合物（C-S-H）及钙铝硫酸盐水合物的形成，有助于构建耐久、低渗透性的基质，并通过化学吸附与类质同象置换有效固定重金属。