摘要
基于Fick第二定律,建立了硫酸盐在混凝土桩中的扩散反应方程.采用分离变量法和Danckwerts法,结合初始和边界条件,推导出扩散反应方程解析解.进一步考虑硫酸盐侵蚀过程中孔隙填充与膨胀裂缝对硫酸盐扩散系数的影响,提出了混凝土侵蚀劣化全过程有效扩散系数模型.基于硫酸盐扩散反应方程解析解和有效扩散系数模型,获得硫酸盐在混凝土桩中的浓度分布规律,并与试验结果对比,验证了解析解的有效性.算例分析表明:孔隙的填充对硫酸盐扩散的阻碍效果显著,而裂缝的发展促进了硫酸盐的扩散反应;水灰比越小,硫酸盐侵入深度越浅,浓度也越低.
Based on the Fick's second law,a diffusion reaction equation of sulfate in concrete piles was established.With the method of separation of variables and Danckwerts,according to initial conditions and boundary conditions,the diffusion reaction equation was deduced.Furthermore,considering the effect of pore filling and crack on diffusion coefficient,an effective diffusion coefficient model was proposed to show the variation of the diffusion coefficient during the degradation process of concrete piles.Sulfate concentration profiles were obtained by the solution and the effective diffusion coefficient model,which agrees well with the experiment data to verify the validity of the proposed analytical solution.Case study shows that the inhibition effect of pore filling on sulfate diffusion is remarkable. The development of the crack promotes the diffusion reaction of sulfate. With water-cement ratio decreasing,the invasion depth of sulfate decreases,as well as the concentration of sulfate in concrete piles.
作者
李镜培
姚明博
LI Jingpei;YAO Mingbo(College of Civil Engineering, Tongji University, Shanghai 200092, China;Key Laboratory of Geotechnical and Underground Engineering of the Ministry of Education, Tongji University, Shanghai 200092, China)
出处
《同济大学学报(自然科学版)》
EI
CAS
CSCD
北大核心
2018年第5期588-592,共5页
Journal of Tongji University:Natural Science
基金
国家自然科学基金(41772290)
关键词
混凝土桩
硫酸盐
扩散反应
裂缝
孔隙填充
concrete pile
sulfate
diffusion reaction
crack
pore filling