掺预处理垃圾焚烧飞灰水泥土的抗剪强度和浸出毒性试验研究

Experimental Study on Shear Strength and Leaching Toxicity of Cement Soil Mixed with Pretreated Municipal Solid Waste Incineration Fly Ash

对垃圾焚烧飞灰进行水洗和硫酸亚铁预处理,将其掺入水泥固化软土中,通过三轴固结不排水试验和浸出毒性试验研究不同飞灰/水泥配比下所制得试样的抗剪强度和重金属浸出毒性,通过电镜扫描试验分析了掺垃圾焚烧飞灰的水泥土的微观特性,讨论了垃圾焚烧飞灰作为水泥土外掺剂的可行性。试验结果表明:相同水泥掺量下,随着飞灰含量增加,水泥土的抗剪强度增加,致密性和整体性增强。当水泥和飞灰掺量均为10%时,水泥土抗剪强度提高最显著。掺入垃圾焚烧飞灰的水泥土重金属浸出浓度符合《危险废物鉴别标准浸出毒性鉴别》(GB 5085.3-2007)。研究成果可为垃圾焚烧飞灰的工程应用提供理论依据和参数支持。

Municipal solid waste incineration(MSWI) fly ash was washed with water and pretreated with ferrous sulfate and incorporated into cement-cured soft soil. Triaxial consolidation undrained test and leaching toxicity test were used to study the shear strength and heavy metal leaching toxicity of samples prepared under different fly ash/cement ratios. Cement soil mixed with MSWI fly ash were analyzed by scanning electron microscopy. The feasibility of the application of waste incineration fly ash engineering was discussed. Results show that under the same cement content, the shear strength of cement soil increases as the fly ash content increases, and cement soil become more dense and integrated. When both cement and fly ash content are 10%, the cement soil strength increases most significantly. The concentration of heavy metal leaching in cement soil mixed with MSWI fly ash comply with the "Identification standard for hazardous wastes-Identification for extraction procedure toxicity"(GB 5085.3-2007). The research results can provide theoretical basis and parameter support for the engineering application of MSWI fly ash.