摘要
为解决淤泥、矿渣、粉煤灰等固体废弃物的堆积填埋和资源化利用问题,采用固体硅酸钠激发二元先驱剂(矿渣-粉煤灰基)合成地质聚合物,用以固化处理含水率为80%的淤泥,并将其作为骨料母体转化为可用于铁路、道路等岩土工程建设的再生细骨料。研究首先探讨了先驱剂比例、掺量、固体硅酸钠的模数以及硅酸钠溶解浓度等因素对固化后淤泥(即骨料母体)的无侧限抗压强度、劈裂抗拉强度和电阻率的影响。进一步通过侧限压缩试验,评估在上述各影响因素作用下形成的再生细骨料的压缩变形特性,并深入探讨了其与骨料母体物理力学性能之间的联系。研究结果表明:上述因素对母体的物理力学性能及细骨料的压缩变形特性有显著影响,并且存在最佳取值范围。当先驱剂比例为90%矿渣+10%粉煤灰,先驱剂掺量为30%,硅酸钠模数为0.8,浓度为1.8 mol/L时,母体的无侧限抗压强度、劈裂抗拉强度及电阻率达到最高值。在该条件下,细骨料在侧限压缩加载下的初始应变速率最低,最终应变最小,屈服强度最高。此外,母体的物理力学特性与细骨料的屈服强度呈非线性正相关,表明骨料不仅继承了母体的物理力学特性,还继承了其破碎前的孔结构特征。通过控制骨料母体性能来改善骨料的岩土力学特性,提升固废资源在岩土工程领域资源化利用的潜在能力,还为淤泥处理在减量化、稳定化、无害化和资源化目标的实现贡献新的思路。
To address the challenges of solid waste disposal and utilization,this study employed solid sodium silicate to activate a binary precursor system(comprising slag and fly ash)for synthesizing geopolymers.These geopolymers were then used to stabilize sludge with an 80%moisture content,transforming it into recycled fine aggregate for geotechnical engineering applications,such as railways and roads.The research initially examined the effects of precursor proportions,precursor content,sodium silicate molar ratio,and sodium silicate concentration on the unconfined compressive strength,splitting tensile strength,and electrical resistivity of the stabilized sludge(aggregate matrix).Subsequently,confined compression tests were conducted to evaluate the compressive properties of the recycled fine aggregate,considering the influence of these factors.Afterwards the relationship between the physical and mechanical properties of the aggregate matrix and the compressive characteristics of fine aggregates was established.The results demonstrate that precursor proportions,content,molar ratio,and concentration significantly affect both the physical and mechanical properties of the matrix and the compressive performance of the aggregate.There is an optimal range for these parameters:when the precursor consists of 90%slag and 10%fly ash,the precursor content is 30%,the sodium silicate molar ratio is 0.8,and the concentration is 1.8 mol/L,the matrix achieves its maximum unconfined compressive strength,splitting tensile strength,and electrical resistivity.Under these conditions,the fine aggregate exhibits the lowest initial strain rate under confined compression,the smallest final strain,and the highest yield strength.Furthermore,the physical and mechanical properties of the matrix are positively correlated in a nonlinear manner with the yield strength of the aggregate.This suggests that the aggregate not only inherits the physical and mechanical characteristics of the matrix but also retains the matrix’s pore structure.This study demonstrates how controlling the properties of the aggregate matrix can improve the geotechnical properties of the aggregates,thereby enhancing the resource utilization potential of solid waste in geotechnical engineering.It also offers new approaches for achieving sludge reduction,stabilization,harmlessness,and resource recycling.
作者
吴俊
闵一凡
征西遥
韩晨
牛富俊
朱宝林
WU Jun;MIN Yi-fan;ZHENG Xi-yao;HAN Chen;NIU Fu-jun;ZHU Bao-lin(School of Civil Engineering,Shanghai Normal University,Shanghai 201418,China;School of Urban Railway Transportation,Shanghai University of Engineering Science,Shanghai 201620,China;Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Urban Security and Disaster Engineering,Beijing University of Technology,Beijing 100124,China;School of Environmental and Geographical Science,Shanghai Normal University,Shanghai 200234,China;Shanghai Shentong Metro Construction Group Co.,Ltd.,Shanghai 200070,China)
出处
《岩土力学》
北大核心
2025年第S1期159-170,共12页
Rock and Soil Mechanics
基金
国家自然科学基金项目(No.42377201)
关键词
地质聚合物
淤泥
骨料母体
物理力学特性
再生细骨料
压缩变形特性
geopolymer
sludge
aggregate matrix
physical and mechanical properties
recycled fine aggregate
compression properties
