摘要
基于Fick第二定律,建立一维扩散模型,推导半无限介质对有限区域的扩散方程,设计混凝土单面冻融试验;通过对试验初始条件的控制,使扩散方程适用于冻融试验,提出冻融扩散方程,通过试验,得到扩散系数随冻融时间、混凝土饱水度的变化规律。研究结果表明：在冻融过程中,根据饱水度的时间梯度趋势曲线,将水分扩散分为一般扩散、缓慢扩散、急剧扩散3个阶段;水分扩散系数的数量级变化范围为10^-9-10^-8 m^2/s,且呈先减小后增大的趋势,在28次冻融时,扩散系数达到极小值。
Based on Fick＇s second law, the one-dimensional diffusion model was established, and subsequently the diffusion equation of semi-infinite media was inferred in the finite region. A relevant single-side freeze-thaw test was suggested, maintaining the concrete soaking height at the same level, so that the diffusion equation of semi-infinite media was available. Specifically, and the relationship between the diffusion coefficient and the level of saturation as well as the freeze-thaw cycles was obtained by solving the diffusion equation. The results show that the moisture diffusion can be divided into three stages, i.e., common diffusion, slow diffusion and rapid diffusion according to the trend of gradient curves. The magnitude range of the diffusion coefficient is 10^-9-10^-8 m^2/s, which is decreased to the minimum at the time of 28 freeze-thaw cycles, and then the diffusion coefficient increases until the end of the test.
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2015年第8期3118-3123,共6页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(51278059)~~
关键词
水泥混凝土道面
单面冻融
饱水度
扩散系数
扩散方程
cement concrete pavement
single-side freeze-thaw
degree of saturation
diffusion coefficient
diffusion equation
