碱激发地聚物固化海相淤泥质软土抗压强度及固化机制研究  

Compressive strength and curing mechanism of alkali-activated geopolymer curing marine silty soft soil

作　　者：刘景锦[1,2] 罗昊鹏 雷华阳[1,2] 郑刚[1,2] 程雪松[1,2] LIU Jingjin;LUO Haopeng;LEI Huayang;ZHENG Gang;CHENG Xuesong(School of Architecture and Engineering,Tianjin University,Tianjin 300354,China;Key Laboratory of Coast Civil Structure Safety of Ministry of Education,Tianjin University,Tianjin 300354,China)

机构地区：[1]天津大学建筑工程学院,天津300354 [2]天津大学滨海土木工程结构与安全教育部重点实验室,天津300354

出　　处：《铁道科学与工程学报》2024年第7期2745-2754,共10页Journal of Railway Science and Engineering

基　　金：国家自然科学基金青年基金资助项目(51908406);河南高校博士基金资助项目(2021BS034);河南省科技攻关计划项目(222102320382)。

摘　　要：海相淤泥质软土富含各类可溶性盐和有机质,使用水泥进行固化时易出现劣化效应。为了解决传统硅酸盐水泥固化常出现加固失效的工程问题,以NaOH为碱激发剂,使用地聚物-水泥联合固化海相淤泥质软土,研究水泥与地聚物掺量比、碱激发剂含量和养护龄期对固化土无侧限抗压强度的影响,并采用扫描电镜和X射线衍射试验分析碱激发地聚物固化海相淤泥质软土的微观形态和水化产物,进一步揭示其固化机制。研究结果表明:单独加入NaOH对水泥土强度的提升并不明显,水泥土强度并不会随着碱激发剂含量的增加而显著提高。同时不同钙系地聚物的固化效果差异显著:矿渣地聚物固化土早期强度增长迅速,后期强度增长缓慢,其无侧限抗压强度随NaOH含量的增加先增加后降低,随矿渣的掺量增加而提高。粉煤灰地聚物固化土强度增长较慢,NaOH含量越高其无侧限抗压强度越大,且强度随粉煤灰的掺量增加而降低。将1/2的水泥以矿渣替代,固化土28 d强度最高可达6.19 MPa,相较于水泥土提升了107.5%。而使用同样比例的粉煤灰替代,其28 d强度最高仅为3.012 MPa。微观试验分析表明碱激发剂和地聚物的加入,可促进可溶盐水化结晶和有机质碱性环境降解,有效增加有效水化产物,增强颗粒间的凝聚力使得土体结构更加紧密,宏观上表现为固化土强度的提升。研究结果可为解决水泥加固海相淤泥软土所引起的实际技术问题提供理论指导。Marine silty soft soil is rich in all kinds of soluble salts and organic matter,and is prone to deterioration effect when cement is used for curing to solve the engineering problem of reinforcement failure that often occurs in traditional silicate cement curing.In order to solve the engineering problems of traditional silicate cement curing,which often lead to reinforcement failure,NaOH was used as alkali activation.The geopolymer-cement combination was used for curing marine silty soft soil to study the effects of cement and geopolymer mixing ratio,alkali activation content and curing age on the unconfined concrete,and curing age on the unconfined compressive strength of the cured soil.It was to analyze the micromorphology and hydration products of alkali activate geopolymer curing of marine silty soft soil by scanning electron microscope and X-ray diffraction tests.It was to reveal the mechanism of its curing.The results of the study show that the addition of NaOH alone does not significantly increase the strength of the hydraulic soil,and the strength of the hydraulic soil does not significantly increase with increasing alkali activation content.At the same time,the curing effect of different calcium geopolymers varies significantly.The early strength of slag geopolymer cured soil increases rapidly and the late strength increases slowly,and its unconfined compressive strength increases and then decreases with increasing NaOH content and improves with increasing slag dosage.Fly ash geopolymer cured soil strength growth is slower,the higher the NaOH content of its unconfined compressive strength is greater,and the strength with the increase in the dosage of fly ash and reduce.Half of the cement is replaced by slag.The 28 d strength of the cured soil is up to 6.19 MPa compared to that of the hydraulic soil,which is 107.5%higher.The same proportion of fly ash replacement,the maximum 28 d strength of only 3.012 MPa.microscopic analysis shows that the addition of alkali activation and geopolymer can promote the solu

关 键 词：海相淤泥质软土 地聚物 碱激发 无侧限抗压强度 固化机制 

分 类 号：TU411[建筑科学—岩土工程]