再生骨料混凝土抗氯离子侵蚀的多相数值研究  

Multi-phase Numerical Analysis of Chloride Resistance of Recycled Aggregate Concrete

作　　者：胡志[1] 毛丽璇 刘清风[1] HU Zhi;MAO Li-xuan;LIU Qing-feng(Shanghai Key Laboratory of Digital Operation and Maintenance of Public Buildings and Infrastructure,School of Naval Architecture,Ocean&Civil Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学船舶海洋与建筑工程学院,上海市公共建筑和基础设施数字化运维重点实验室,上海200240

出　　处：《硅酸盐通报》2020年第8期2425-2432,共8页Bulletin of the Chinese Ceramic Society

基　　金：国家自然科学基金(51978396);中国科协青年人才托举计划(2018QNRC001);上海市“青年科技启明星计划”(19QA1404700)。

摘　　要：为定量分析再生骨料混凝土各组成相对其抗氯离子侵蚀性能的影响,研究建立可实现任意体积分数再生粗骨料随机分布的再生混凝土五相细微观数值模型,包括新砂浆、新界面过渡区、旧砂浆、旧界面过渡区和核心区原始天然骨料。根据各相氯离子扩散性能和几何性质的不同,探究再生粗骨料体积分数、旧砂浆附着率及新、旧界面过渡区厚度等关键几何参数对再生混凝土抗氯离子侵蚀性能及离子时空分布的影响。结果表明:作为再生骨料混凝土的重要组成部分,附着旧砂浆和核心区天然骨料的性质与含量对其抗氯离子侵蚀性能起着相互博弈的效应,导致再生骨料混凝土有效氯离子扩散系数随着骨料体积分数的增大而产生明显波动,尤其是当旧砂浆附着率较小时,此现象尤为明显;当骨料体积分数一定时,再生骨料混凝土氯离子扩散性能随着旧砂浆附着率的增大而增强,且增幅随着骨料体积分数的增大而增大;再生骨料混凝土抗氯离子侵蚀性能与新、旧界面过渡区的厚度呈负相关关系。To quantitively analyze the effect of each component of recycled aggregate concrete(RAC)on its chloride resistance,this paper presents a meso-and microscopic numerical model of five-phase RAC that can achieve random distribution of recycled coarse aggregates(RCA)at any volume fraction,including new mortar,new interfacial transition zone(ITZ),adhesive old mortar,old ITZ and core natural coarse aggregate.According to the differences in chloride diffusivity and geometric properties of each phase in RAC,the effects of a series of key geometric parameters on the chloride resistance of RAC and chloride distribution in RAC were studied,such as the volume fraction of RCA,the adhesive ratio of old mortar,the thickness of the new and old ITZ.The obtained results indicate that,as the key components of RAC,the adhesive old mortar and core natural coarse aggregate play mutually gambling effects on the chloride resistance of RAC.When the adhesive ratio of old mortar is too low,the chloride diffusivity of RAC against different volume fraction of RCA shows a trend of obvious fluctuation.The chloride diffusivity of RAC of given volume fraction of RCA increases with the thickening of old mortar,and its increment increases with the increasing volume fraction of RCA.The investigation finds a negative correlation between chloride resistance of RAC and the thickness of old and new ITZ.

关 键 词：再生骨料混凝土 旧砂浆附着率 氯离子 耐久性 数值模型 

分 类 号：TU528[建筑科学—建筑技术科学]