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Evaluation of municipal solid waste incineration filter cake as supplementary cementitious material
Construction and Building Materials ( IF 7.4 ) Pub Date : 2020-03-28 , DOI: 10.1016/j.conbuildmat.2020.118833
V. Caprai , K. Schollbach , M.V.A. Florea , H.J.H. Brouwers

Worldwide, the incineration of household waste generates high amounts of Municipal Solid Waste Incineration (MWSI) bottom ashes (BA). In some European countries, the Filter Cake (FC) is also collected (below 0.25 mm) by the wet sieving treatment of coarse BA (4–32 mm). By using centrifugation, the presence of readily soluble contaminants in FC is decreased. In addition, for reducing the leaching of heavy metals the use of FC in combination with cement represents a valuable option, due to cement immobilization capacity and the FC appropriate particle size and chemical composition. However, to the best of the authors’ knowledge, FC has not often investigated as binder replacement. Therefore, this paper addresses the suitability of FC as substitution for CEM I 52.5 R, between 1 and 20% replacement, by mass. Due to its porous structure, the FC lowers the bulk and particle density of the mixtures and increases the water demand, and widens the particle size distribution. The XRD analysis evidences the formation of layered double hydroxides (LDH) in the early stage of the reaction (1, 2, 7 days) incorporating contaminants as Cl. Kinetically, the hydration of C3S is delayed according to the FC replacement without affecting the long-term flexural strength. Despite this, the presence of FC minimally contributes to the increase of cement reaction degree. Tested accordingly to the EN 124-57, the 28 days mortars fulfill the Dutch legislation for contaminants leaching as unshaped material, independently on the substitution rate.



中文翻译:

市政垃圾焚烧滤饼作为辅助胶凝材料的评价

在世界范围内,生活垃圾的焚化产生大量的城市固体废物焚化(MWSI)底灰(BA)。在某些欧洲国家,也通过湿筛分粗BA(4–32 mm)来收集滤饼(FC)(0.25 mm以下)。通过离心,减少了FC中易溶污染物的存在。此外,由于水泥的固定能力和FC合适的粒径和化学组成,为了减少重金属的浸出,FC与水泥的组合使用是一种有价值的选择。但是,据作者所知,FC并未经常作为粘合剂的替代品进行研究。因此,本文论述了FC替代CEM I 52.5 R的适用性,其替代质量为1%至20%。由于其多孔结构,FC降低了混合物的体积和颗粒密度,增加了需水量,并扩大了粒径分布。XRD分析表明,在反应的早期阶段(1、2、7天)会形成层状双氢氧化物(LDH),其中掺入了杂质Cl。从动力学上讲,C的水合根据FC的更换,3 S会延迟,而不会影响长期抗弯强度。尽管如此,FC的存在对水泥反应度的增加影响很小。经过28天的迫击炮砂浆按照EN 124-57的规定进行了测试,符合荷兰关于不定型物质浸出的污染物法规的要求,而与替代率无关。

更新日期:2020-03-28
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