硅灰对再生混凝土抗盐冻性能及微观结构的影响  

Effect of Silica Fume on Salt Frost Resistance and Microstructure of Recycled Concrete

作　　者：王晨霞 王金旭 王宇飞 梁卫国 苏天 曹芙波 WANG Chen-xia;WANG Jin-xu;WANG Yu-fei;LIANG Wei-guo;SU Tian;CAO Fu-bo(School of Civil Engineering,Inner Mongolia University of Science and Technology,Baotou 014010,China;Inner Mongolia Key Laboratory of Safety and Durability for Civil Engineering,Baotou 014010,China;Tianjin Inspection and Testing Center for Housing Quality&Safety Co.,Ltd.,Tianjin 300060,China;Baotou Urban Rural Development Group Co.,Ltd.,Baotou 014020,China;School of Civil and Architectural Engineering,Shandong University of Technology,Zibo 255000,China)

机构地区：[1]内蒙古科技大学土木工程学院 [2]内蒙古自治区土木工程安全与耐久重点实验室 [3]天津市房屋质量安全鉴定检测中心有限公司 [4]包头市城乡建设发展集团有限公司 [5]山东理工大学建筑工程学院

出　　处：《长江科学院院报》2024年第6期171-177,共7页Journal of Changjiang River Scientific Research Institute

基　　金：国家自然科学基金项目(51868061,52368024);内蒙古自然科学基金项目(2020MS05071,2022LHMS05011)。

摘　　要：为研究硅灰对内蒙河套盐碱地区的再生混凝土微观结构和抗盐冻性能的影响,以硅灰掺量为变量对再生混凝土(RAC)进行了冻融循环试验、抗氯离子渗透试验和电镜扫描试验(SEM)。结果表明:通过SEM能看出球状硅灰颗粒可以使结构变得致密,RAC的质量损失率、立方体抗压强度损失率和氯离子迁移系数均随硅灰掺量的增加呈现先减后增的趋势,但硅灰掺量为10%和15%的RAC相对动弹性模量却相差不大;综合来看硅灰掺量为10%时抗盐冻性能最好,90次冻融循环后RC10组的质量损失率、立方体抗压强度损失率和氯离子迁移系数分别仅为RC0组的54.3%、50.3%和49.81%;同时建立了以硅灰掺量和冻融循环次数为参数的冻融损伤模型,并对内蒙盐碱地区的RAC进行了寿命预测。研究成果有助于推动再生混凝土的合理利用。To investigate the impact of silica fume on the microstructure and salt frost resistance of recycled concrete in the Hetao saline-alkali area of Inner Mongolia,we prepared recycled concrete(RAC) with varying silica fume content for cyclic salt freeze-thaw tests,chloride ion permeation resistance tests,and scanning electron microscopy(SEM) analysis.Our findings reveal that the microstructure of RAC becomes denser due to the influence of spherical silica fume particles.This leads to an initial decrease followed by an increase in the mass loss rate,cubic compressive strength loss rate,and chloride ion mobility coefficient of RAC with rising silica fume content.However,the relative dynamic elastic modulus of RAC with 10% and 15% silica fume content shows minimal disparity after salt-frost cycles.Overall,the optimal salt-frost resistance is achieved when silica fume content is at 10%.In the RC10 group,the mass loss rate,cube compressive strength loss rate,and chloride ion mobility coefficient are only54.3%,50.3%,and 49.81% of those of RC0 group respectively after 90 salt-frost cycles.Additionally,we developed a freeze-thaw damage model accounting for silica fume content and freeze-thaw cycle number to predict the service lifespan of RAC in saline-alkali regions of Inner Mongolia.

关 键 词：再生混凝土 硅灰 盐冻循环 微观结构 寿命预测 

分 类 号：TU502[建筑科学—建筑技术科学]