| 摘要: |
| 以赤泥、粉煤灰、脱硫石膏及一种碱性固体废弃物外加剂为胶凝材料，煤矸石为骨料，制备得到环境友好型全工业固废路面基层混合料（RFDC）.研究了4个龄期（7、28、56、90 d）下，不同粉煤灰掺量RFDC无侧限抗压强度（fUCS）和劈裂抗拉强度（fSTS）的发展规律，分析了抗压试件和劈裂抗拉试件的破坏形态，探讨了固废胶凝材料中3种氧化物摩尔比与RFDC 7 d fUCS的相关性，揭示了RFDC的强度形成机理.结果表明：当粉煤灰掺量为15%时，RFDC的力学性能最佳，抗压试件为典型的中心抗压破坏，劈裂抗拉试件为煤矸石粗集料破坏；固废胶凝材料的n（CaO）/［n（SiO2）+n（Al2O3）］值与RFDC 7 d fUCS的相关性最高；钙矾石（AFt）、水化硅（铝）酸钙（C-（A）-S-H）凝胶及沸石类物质等水化产物是RFDC强度的主要来源. |
| 关键词: 道路工程 赤泥 粉煤灰 煤矸石 力学性能 微观机理 |
| DOI：10.3969/j.issn.1007-9629.2023.07.009 |
| 分类号:U414 |
| 基金项目:国家自然科学基金资助项目（52178431）；山西省回国留学人员科研资助项目（HGKY2019031）；山西省优秀人才科技创新项目（201705D211030） |
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| Strength Characteristics and Mechanism of Red Mud-Fly Ash Stabilized Coal Gangue Base |
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MA Lulu1, ZHANG Xiao1, LIU Fang1, LIU Zefeng1, LI Feng2
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1.School of Civil Engineering，Taiyuan University of Technology，Taiyuan 030024，China;2.School of Transportation Science and Engineering， Beihang University， Beijing 100191，China
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| Abstract: |
| Using red mud， fly ash， desulfurized gypsum and an alkaline solid waste admixture as cementitious materials and coal gangue as aggregate， an environmentally friendly all industrial solid waste pavement base mixture （RFDC） was prepared. The development laws of unconfined compressive strength（fUCS） and splitting tensile strength（fSTS） of RFDC with different fly ash contents at 4 ages （7， 28， 56 and 90 d） were studied. Then the failure modes of the compressive and splitting tensile specimens were analyzed. The correlation between the molar ratio of three different oxides in solid waste cementitious materials and 7 d fUCS of the RFDC was discussed. The formation mechanism of RFDC strength was revealed. The results show that when the content of fly ash is 15%， the mechanical properties of the RFDC are the best. The compressive specimen presents a typical central compressive failure， and the split tensile specimen is damaged by coarse aggregate of coal gangue. The n（CaO）/［n（SiO2）+n（Al2O3）］ value of the solid waste cementitious material has the closest correlation with the 7 d fUCS of the RFDC. Ettringite（AFt），aluminum-modified calcium silicate hydrate（C-（A）-S-H） gel and zeolite-like substances are the main hydration products that provide strength to the RFDC. |
| Key words: road engineering red mud fly ash coal gangue mechanical property microscopic mechanism |
