混凝土氯离子扩散性能影响试验等效数值模拟  

Equivalent numerical simulation on experiment of influence from diffusion performance of chloride ion in concrete

作　　者：李杰 孔祥习 LI Jie;KONG Xiangxi(Anyang Career Technical College,Anyang 455000,Henan,China;Guizhou University of Engineering Science,Bijie 551700,Guizhou,China)

机构地区：[1]安阳职业技术学院,河南安阳455000 [2]贵州工程应用技术学院,贵州毕节551700

出　　处：《水利水电技术》2018年第9期184-190,共7页Water Resources and Hydropower Engineering

基　　金：国家自然科学基金项目(51168003)

摘　　要：针对混凝土中氯离子扩散的问题,拟通过混凝土骨料含量和界面体积分数对氯离子扩散的影响效果进行研究。将混凝土视为由骨料、界面区和砂浆所组成的三相复合材料,利用MATLAB软件建立混凝土粗骨料随机模型。把模型导入COMSOL软件,通过设定不同骨料含量和界面体积分数以探究其对氯离子扩散的影响。同时借助试验设计(DOE)的方法验证了模型的重复性和再现性,进而确定了其模拟精度;通过与试验数据的对比分析,验证了该方法的有效性。开展粗骨料含量和界面体积对混凝土氯离子渗透性能影响的模拟试验,结果表明:氯离子在混凝土中的扩散受骨料含量和界面体积分数的影响;骨料含量的增加抑制了氯离子的扩散性能,表现为骨料的曲折效应:当混凝土骨料体积分数由0上升到60%时,氯离子最终扩散深度分别下降18. 9%,32. 8%和55. 6%;界面区厚度的增加加速了氯离子的扩散性能,表现为界面效应:当骨料含量为60%时,其氯离子扩散深度增加了30. 3%;研究成果对海工混凝土耐久性具有参考价值。Aiming at the problem of diffusion of chloride ion in concrete,the influence effect of the chloride ion diffusion is studied herein through the aggregate content and the interface volume fraction of concrete.By taking concrete as a three-phase composite material composed of aggregate,interface area and mortar,a random model of concrete coarse aggregate is established with the software MATLAB.The model is introduced into the software--COMSOL to explore the influences from different aggregate contents and interface volume fractions on the chloride ion diffusion.Meanwhile,the repeatability and reproducibility of the model are verified by the method of experimental design(DOE),and then the simulation accuracy is determined.The effectiveness of the method is verified by comparing with the experimental data concerned.Subsequently,a simulative experiment on the influences from coarse aggregate content and interface volume on the chloride permeability of concrete is carried out.The result shows that chloride ion diffusion in concrete is affected by aggregate content and volume fraction of interface.The diffusion performance of chloride ion is inhibited by the increase of the aggregate content,which exhibits the tortuosity effect of the aggregate:when the aggregate concrete aggregate volume fraction is increased from 0 to 60%,the final diffusion depth of chloride ion is to be decreased by 18.9%,32.8%and 55.6%respectively,while the increase the thickness of the interfacial region accelerates the diffusion performance of chloride ion,which exhibits the interface effect:when the aggregate content is 60%,the diffusion depth of chloride is to be increased by 30.3%.The study result has a referential value for the study on the durability of marine concrete.

关 键 词：骨料含量 界面区 氯离子扩散 数值模拟 

分 类 号：TU528.01[建筑科学—建筑技术科学]