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拜耳法赤泥基泡沫轻质土的力学性能及应用研究
作者：成浩1，杨腾宇1，丁思尹1，2
（1.佛山市交通科技有限公司，广东 佛山 528000；2.广东盛瑞科技股份有限公司，广东 广州 511400）
摘要：为提高铝工业固废赤泥的资源利用率，利用拜耳法赤泥部分替代水泥制备赤泥基泡沫轻质土。通过设计正交试验，分析赤泥掺量、湿密度、水胶比等因素对赤泥基泡沫轻质土流动性、不同龄期无侧限抗压强度及微观结构的影响。试验结果表明：对赤泥基泡沫轻质土无侧限抗压强度影响最显著的因素是湿密度和赤泥掺量；对流动性影响最显著的因素是水胶比和赤泥掺量；采用功效系数法确定的最优因素水平组合为赤泥掺量20%、湿密度1000 kg/m3、水胶比0.4。SEM分析结果表明：赤泥基泡沫轻质土的水化产物主要为针棒状的钙钒石和水化硅酸钙，湿密度的变化对细观孔隙结构的分布及数量有显著影响；增加赤泥掺量可促进水化产物的生成，提高赤泥基泡沫轻质土的强度。试验段现场检测结果表明：赤泥基泡沫轻质土作为一种新型固废基轻质路基填料，其流动性和无侧限抗压强度均满足设计要求。
关键词：拜耳法赤泥；泡沫轻质土；正交试验；功效系数法
中图分类号：TU522.3+2 文献标识码：A 文章编号：1001-702X（2022）12-0051-06
Experimental study on mechanical performance and engineering application of foamed lightweight materials mixed with Bayer red mud
CHENG Hao1，YANG Tengyu1，DING Siyin1，2
（1.Foshan Transportation Science and Technology Co. Ltd.，Foshan 528000，China；
2.Guangdong Shengrui Science and Technology Co. Ltd.，Guangzhou 511400，China）
Abstract：In order to improve the utilization rate of solid waste red mud produced by aluminum industry，the Bayer red mud was reused to partially replace cement to prepare red mud-based foamed lightweight soil. The influence of red mud content，wet density and water-binder ratio on the fluidity，unconfined compressive strength at different ages and microstructure features of red mud-based foamed lightweight soil were analyzed through orthogonal experiments. Results show that the most significant factors affecting the unconfined compressive strength of red mud-based foam lightweight soil are wet density and red mud content; the most significant factors affecting the fluidity of red mud-based foam lightweight soil are the water-binder ratio and the content of red mud. The optimal factor level considering the fluidity and unconfined compressive strength is determined by the efficiency coefficient method，which is red mud content of 20%，wet density 1000 kg/m3，water-binder ratio 0.4. The results of SEM analysis show that the hydration products of red mud-based foamed lightweight soil are mainly needle-like ettringite and calcium silicate hydrate，and the change of wet density has a significant effect on the distribution and quantity of pore structure. The increasing content of red mud can promote the formation of hydration products and improve the strength of red mud-based foam lightweight soil. The on-site field test results show that as a new type of lightweight subgrade filler，properties of red mud-based foam lightweight soil can meet the design requirements in terms of fluidity and unconfined compressive strength.
Key words：Bayer red mud，foamed lightweight soil，orthogonal test，efficiency coefficient method