高掺量粉煤灰对水泥稳定煤矸石基层性能影响  

Effect of replacing aggregate with fly ash on performance of cement⁃stabilized coal gangue base

作　　者：张博杰 俞莉 张东生 张文博[1] 杨秋宁[1] ZHANG Bojie;YU Li;ZHANG Dongsheng;ZHANG Wenbo;YANG Qiuning(School of Civil and Hydraulic Engineering,Ningxia University,Yinchuan 750021,China;Department of Civil Engineering,KU Leuven,Bruges 8200,Belgium)

机构地区：[1]宁夏大学土木与水利工程学院,宁夏银川750021 [2]鲁汶大学土木工程系,比利时布鲁日8200

出　　处：《中国粉体技术》2024年第4期43-50,共8页China Powder Science and Technology

基　　金：国家自然科学基金项目,编号:51768058;宁夏回族自治区重点研发计划项目,编号:2021BEE03004。

摘　　要：【目的】为提高粉煤灰和煤矸石的利用率、减少天然碎石的开采,研究高掺量粉煤灰对水泥稳定煤矸石基层性能的增强机制,为高掺量粉煤灰在水泥稳定煤矸石基层中的应用提供理论依据。【方法】用煤矸石全部替代天然碎石作为骨料、并掺入适量粉煤灰替代骨料,制备水泥稳定煤矸石基层混合料;通过无侧限抗压试验、劈裂试验、抗压回弹模量试验、水稳定性试验、冻融试验研究混合料的力学性能和耐久性能;研究不同粉煤灰掺量(质量分数)下混合料的强度形成机制。【结果】粉煤灰质量分数为4%、8%时,水泥与粉煤灰发生火山灰效应,生成新的水化产物填充胶凝材料内部孔隙,提高了混合料的力学性能;粉煤灰质量分数为12%时,混合料的抗压回弹模量最大,荷载作用下混合料的变形量最小;粉煤灰掺量为16%时,粉煤灰在混合料中的微集料效应充分发挥,28 d龄期无侧限抗压强度和劈裂强度有明显提升,但抗压回弹模量减小。【结论】在不同粉煤灰掺量下,随着粉煤灰掺量的增加,混合料的无侧限抗压强度、劈裂强度逐渐增大,抗压回弹模量先增大后减小;粉煤灰掺入后,混合料的水稳定性能和抗冻性能略有降低。Objective With the global emphasis on environmental protection and resource conservation,improving the utilization rate of industrial waste and reducing the exploitation of natural resources have become research hotspots.Fly ash and coal gangue are the major wastes from thermal power generation and coal mining processes.Their large-scale accumulation not only occupies valuable land resources,but also pollutes the environment.Therefore,this study aims to explore the enhancement mechanism of high-content fly ash on the performance of cement-stabilized coal gangue base.It provides a new way for the effective utilization of industrial waste while reducing the exploitation of natural gravel,thereby achieving the dual goals of environmental protection and resource conservation.Method In this study,high-quality coal gangue was selected as the aggregate to replace traditional natural gravel.Appropriate amounts of cement were selected as the bonding material,and different proportions of fly ash(4%,8%,12%,16%)were mixed.Through accurate calculations and optimized design,the composition of the mixture with different proportions was determined.To evaluate the mechanical properties of the mixture,unconfined compressive strength tests,splitting tests,and compressive rebound modulus tests were carried out.These tests comprehensively reflected the key mechanical indicators of the mixture such as compressive strength,splitting strength,and elastic modulus.To evaluate the durability of the mixture,water stability tests and freeze-thaw tests were carried out.The water stability tests simulated the performance changes of the mixture under water immersion,while the freeze-thaw test simulated the performance changes after freeze-thaw cycles in cold areas.The study also discussed the strength formation mechanisms of mixture with different fly ash content.Result When fly ash was added to the cement at a content of 4%and 8%,a pozzolanic reaction occurred between the cement and fly ash,producing new hydration products.These newly generate

关 键 词：煤矸石 粉煤灰 力学性能 耐久性 

分 类 号：U414[交通运输工程—道路与铁道工程] TB4[一般工业技术]