HNO_(3)和H_(2)SO_(4)侵蚀作用下地质聚合物固化软土的抗酸性能研究  

Acid resistance performance of geopolymer-stabilized soft clay under HNO_(3)and H_(2)SO_(4)acid erosion

作　　者：蒋新彧 征西遥 吴俊[1,3] 杨爱武 李博 JIANG Xin-yu;ZHENG Xi-yao;WU Jun;YANG Ai-wu;LI Bo(School of Urban Railway Transportation,Shanghai University of Engineering Science,Shanghai 201620,China;School of Urban Construction,Beijing University of Technology,Beijing 100124,China;School of Civil Engineering,Shanghai Normal University,Shanghai 201418,China;College of Environmental Science and Engineering,Donghua University,Shanghai 201620,China;College of Architecture and Energy Engineering,Wenzhou University of Technology,Wenzhou,Zhejiang 325000,China)

机构地区：[1]上海工程技术大学城市轨道交通学院,上海201620 [2]北京工业大学城市建设学部,北京100124 [3]上海师范大学建筑工程学院,上海201418 [4]东华大学环境科学与工程学院,上海201620 [5]温州理工学院建筑与能源工程学院,浙江温州325000

出　　处：《岩土力学》2025年第3期851-866,共16页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.52078288,No.42377201)。

摘　　要：为解决水泥固化软土抗酸性能差及制备水泥时高污染、高能耗及高成本等问题,拟采用低成本的工业固体废弃物(不同矿渣(ground granulated blast furnace slag,简称GGBFS)与粉煤灰(fly ash,简称FA)比例)为前驱剂,固体氢氧化钠为激发剂,以“一步法”制备地质聚合物浆料用以固化软土。继而将地质聚合物固化软土试样分别浸润在不同pH值(2、4、6)的HNO_(3)和H_(2)SO_(4)溶液中,以质量损失、无侧限抗压强度(unconfined compression strength,简称UCS)、中性化深度(neutralization depth,简称ND)和pH值等4个指标对固化软土在不同侵蚀龄期(30、60、120、240 d)下的抗酸性能进行评估。并通过扫描电子显微镜-能谱仪(scanning electron microscope-energy dispersive spectrometer,简称SEM-EDS)研究试样在不同酸性环境侵蚀下的微观结构和水化产物组成的变化,揭示其劣化机制。试验结果表明:相较于H^(2)SO_(4)溶液,HNO_(3)溶液对固化软土的酸侵蚀较为缓和,其主要是由于固化软土中Ca^(2+)、K^(+)和Na^(+)离子在水中形成硝酸盐,可中和NO_(3)^(-)离子的侵蚀,从而缓解固化软土性能的劣化;当GGBFS与FA质量比为80:20时,地质聚合物固化软土的抗酸侵蚀性能达到最优,表明适量掺入FA可使试样形成致密的微观结构,有效阻碍H^(+)、NO_(3)^(-)和SO_(4)^(2-)离子侵入。研究结果可拓展低成本工业固体废弃物的应用范围,为一步法地质聚合物固化软土的耐久性评估奠定理论基础。To address the issues of poor acid resistance of cement-stabilized soft soil and the high pollution,energy consumption,and cost associated with cement production,this study proposes using low-cost industrial solid wastes(ground granulated blast furnace slag(GGBFS)and fly ash(FA)in varying ratios)as precursors,with solid sodium hydroxide as the activator,to prepare geopolymer grout through a‘one-step’process for stabilizing soft soil.Subsequently,the geopolymer-stabilized soft soil samples were immersed in HNO_(3)and H_(2)SO_(4)solutions with different pH values(2,4,and 6).The acid resistance of the stabilized soil was evaluated at different erosion ages(30,60,120,and 240 days)using four indices:mass loss,unconfined compressive strength(UCS),neutralization depth(ND),and pH value.Furthermore,the changes in microstructure and hydration product composition of the samples under different acidic environments were investigated using scanning electron microscope-energy dispersive spectrometer(SEM-EDS)to reveal the degradation mechanisms.The test results indicate that compared to H_(2)SO_(4)solution,HNO_(3)solution exerts a milder acid erosion effect on the stabilized soft soil.This is primarily because the Ca^(2+),K^(+),and Na^(+)ions in the stabilized soil form nitrates in water,which can neutralize the erosion of NO_(3)^(-)ions,thereby mitigating the degradation of the soil’s properties.When the mass ratio of GGBFS to FA is 80:20,the acid erosion resistance of the geopolymer-stabilized soft soil reaches an optimal level.This suggests that the appropriate incorporation of FA can form a dense microstructure in the samples,effectively impeding the intrusion of H^(+),NO_(3)^(-)and SO_(4)^(2-)ions.The research findings can expand the application scope of low-cost industrial solid wastes and lay a theoretical foundation for the durability assessment of one-step geopolymer-stabilized soft soil.

关 键 词：地质聚合物 抗酸性 固化软土 微观分析 

分 类 号：TU447[建筑科学—岩土工程]