再生骨料混凝土在荷载-冻融条件下的多场耦合数值模拟  

Multi field coupling numerical simulation of recycled aggregate concrete under freeze-thaw conditions

作　　者：雷斌[1] 黄威武 王时彦 徐震寰 LEI Bin;HUANG Weiwu;WANG Shiyan;XU Zhenhuan(School of Infrastructure Engineering,Nanchang University,Nanchang 330031,China)

机构地区：[1]南昌大学工程建设学院,江西南昌330031

出　　处：《南昌大学学报（工科版）》2023年第2期144-153,共10页Journal of Nanchang University(Engineering & Technology)

基　　金：国家自然科学基金项目(51968046、52268043);江西省主要学科学术和技术带头人培养计划领军人才项目(20204BCJ22003)。

摘　　要：由于混凝土服役时通常处于多因素耦合环境,单一的冻融循环场不能反映服役混凝土的工作状态。考虑了不同新、老界面渗透率、不同降温速率和是否存在外加荷载等因素,分析了再生混凝土第一主应力分布、孔隙水压力、各细观成分应变参数的变化。通过Python编写再生混凝土的二维随机骨料模型,利用Python对Comsol进行二次开发,从细观层面上分析了荷载-冻融循环作用下再生混凝土的性能。结果表明:新、老界面渗透率过高会导致试件第一主应力下降,导致砂浆发生受拉破坏;降温速率过快导致孔隙水结冰速率提高并使结冰量增大,水相变引起的体积膨胀导致孔隙壁受到更大压力;外加荷载的存在加快了冻融过程中老砂浆与新水泥基质的剥离。Since concrete in service is usually in a multi-factor coupled environment,a single freeze-thaw cycle temperature field cannot completely reflect the working condition of concrete in service.In this paper,considering the factors such as different permeability of new and old interface transition zones,different cooling rate and whether there is external load,the meso component changes of the first principal stress distribution,pore water pressure and strain parameters of recycled concrete were analyzed.The two-dimensional random aggregate model of recycled concrete was compiled by Python,the performance of recycled concrete under load freeze-thaw cycle was analyzed from the meso level by the Comsol,which is continually developed by Python.Results showed that the first principal stress of the specimen decreases and the mortar is in tensile when new and old ITZs permeability are high.The freezing rate of pore water and the amount of freezing were increased when the cooling rate was rapidly,and the volume expansion caused by the water phase change leads to higher pressure on the pore wall.The presence of the external load accelerated the stripping of the new cement matrix from the old mortar during the freeze-thaw process.

关 键 词：再生混凝土 数值模拟 冻融模拟 随机骨料 多场耦合 

分 类 号：TU361[建筑科学—结构工程]