长江科学院院报2025，Vol.42Issue(10)：111-119,9.DOI:10.11988/ckyyb.20240833
多源固废协同固化红砂岩渣土配比及机理研究
Mix Ratio and Mechanism of Multi-source Solid-waste Co-curing for Red Sandstone Spoil
摘要
Abstract
[Objective]Extensive red sandstone spoil generated from highway tunnel projects in central-southern China poses significant disposal challenges due to its high water content,susceptibility to slaking and disintegra-tion,low strength,and high compressibility-characteristics that fail to meet subgrade material standards.To re-alise the goal of"treating waste with waste and turning waste into treasure",we use quicklime,calcined coal gangue powder,fly ash and cinder powder as multi-source solid-waste curing agents to explore the optimal ratio and mechanism for co-curing red sandstone spoil,providing a basis for resource utilisation.[Methods]Red sandstone spoil was served as the base material,quicklime,calcined coal gangue powder,grade-Ⅲ fly ash and cinder powder were selected as curing agents,with their chemical compositions determined by X-ray fluorescence spectroscopy.Single-mix tests were conducted to investigate the effect of each curing agent alone on the strength of the red sand-stone spoil and to determine appropriate dosage ranges.Then orthogonal experimental design was employed,using 7-day unconfined compressive strength(UCS)as the index to obtain the optimal ratio.Based on the optimal mix ra-tio,the red sandstone spoil was modified with curing agent dosages of 8％,10％,12％,and 14％,and cured for 3,7,14,and 28 days respectively.Unconfined compressive strength(UCS)was tested.Water stability coefficients were measured through water immersion tests.X-ray diffraction(XRD)and scanning electron microscopy(SEM)analy-ses were conducted to examine changes in microstructure and mineral phases before and after curing,revealing the stabilization mechanism.[Results]Optimal mix proportions and dosages:the optimal mass ratio was quicklime∶fly ash∶calcined coal gangue∶cinder powder=4∶8∶8∶7.The strength showed an initial increase followed by a de-cline with increasing total dosage,with 12％total dosage yielding the highest strength.Macro-scale performance im-provement:at 12％dosage,7-day UCS reached 1.659 MPa(16 times that of raw spoil)and 28-day UCS 2.255 MPa.Water stability was significantly improved,with the coefficient reaching 59.37％at 12％and 65.90％at 14％,with strength increasing over time,particularly rapidly between 3-14 days.Microscopic mechanism:XRD analysis showed that the contents of orthoclase and albite decreased in the improved red sandstone spoil,while the diffrac-tion peaks of quartz and calcite were enhanced,indicating that ion exchange and pozzolanic reactions occurred,generating cementitious products such as calcium silicate hydrate(C-S-H)and calcium aluminate hydrate(C-A-H).SEM observation revealed that the soil particles were loose and porous before improvement,while after im-provement,the cementitious products bonded the particles to form a dense skeletal structure,which became more complete with curing age.[Conclusion]The optimal co-curing ratio is quicklime∶fly ash∶calcined coal gangue∶cinder powder=4∶8∶8∶7 at 12％dosage,delivering the best mechanical properties and water stability.The mechanism is a lime-centred synergistic reaction:lime hydration provides an alkaline environment and Ca2+,trigge-ring ion exchange(soil particles changing from potassium/sodium type to calcium type)and pozzolanic reactions(forming cementitious products),while solid waste particles fill pores to reinforce the soil skeleton.This offers an economical and eco-friendly route for red sandstone spoil utilisation,with both engineering and ecological value.关键词
红砂岩渣土/多源固废/协同固化/正交设计/固化机理Key words
red sandstone spoil/multi-source solid waste/co-curing/orthogonal design/curing mechanism分类
建筑与水利引用本文复制引用
温树杰,黄英豪,赖光甜..多源固废协同固化红砂岩渣土配比及机理研究[J].长江科学院院报,2025,42(10):111-119,9.基金项目
江西省"双千计划"创新领军人才资助项目(JXSQ2021003) （JXSQ2021003）
