工业废弃料在路基改良中的应用综述

Industrial Waste Materials Utilized in Subgrade Modification:A Review

当前,中国工业废弃料堆存量大且资源化利用率低,工业废弃料资源化利用对促进社会可持续发展意义重大。由于环保要求的加强和自然资源的短缺,采用工业废弃料改性不良路基土成为减轻道路材料短缺和加速绿色建筑材料开发的重要途径。详细综述了赤泥、矿渣、钢渣和粉煤灰等典型工业废弃料的工程特性和前处理工艺,及其改良路基土的关键技术方法。通常采用水洗法处理赤泥、矿渣和粉煤灰,采用蒸汽造粒法处理钢渣,接着利用单掺、工业废弃料-无机矿物复掺和工业废弃料碱激发等手段改良特殊土路基。针对膨胀土、黄土和重金属污染土的工程特性差异,通常采用工业废弃料单掺改良膨胀土和黄土,利用复掺处治重金属污染土。工业废弃料改良技术显著降低了特殊土的液限和塑性指数,提升了其强度和耐久性,并有效抑制了重金属离子的迁移过程。此外,还从力学特性、微观形貌、化学组成和反应机制等方面,详细归纳了工业废弃料改良土的宏微观物化特性,剖析了工业废弃料处治路基土的改良机理,提出不同特殊土路基的改良方案。目前,关于工业废弃料改良特殊土路基长期路用性能演化规律的研究成果甚少,建议针对该领域广泛开展研究。

Currently,China has a large stock of industrial waste materials(IWM)but a low recycling rate.The comprehensive utilization of IWM is of great significance for promoting the sustainable development of society.Owing to increasing environmental protection regulations and natural resource shortages,the application of IWM to treat poor subgrade soil has become an important approach to alleviate the road material shortages and accelerate green construction material development.This study used a typical IWM to provide a detailed overview of the entire subgrade soil modification process.The water washing method was used to process the red mud,slag,and fly ash,whereas the steam granulation method was employed to treat the steel slag.Subsequently,the preprocessed IWM was used to modify the engineering properties of the problematic soil subgrade via either the individual addition of IWM,joint addition of IWM and cement/lime,or alkaline activation of IWM.To address the different engineering properties of expansive soils,loess,and heavy-metal-contaminated soils,IWM is typically used to improve expansive soils and loess,and compound addition methods are used to treat heavy-metal-contaminated soil.Improved IWM technologies significantly reduce the liquid limit and plasticity index of problematic soils while improving their strength and durability and effectively suppress the migration of heavy metal ions.Thereafter,the macroscopic and microscopic physicochemical properties of the IWM-treated soil were summarized in terms of mechanical properties,microscopic morphology,chemical composition,and reaction mechanism.The mechanism by which IWM-treated subgrade soils improved was analyzed and improvement plans for different problematic soil subgrades was proposed.Currently,few studies consider the long-term performance evolution of IWM-modified problematic soil subgrades.Therefore,further extensive research in this field is recommended.