混凝土温湿耦合效应研究综述

Literature review of heat and moisture diffusion in concrete

阐述了混凝土温湿耦合研究的目的及意义,总结了温湿耦合研究的理论和方法。限于目前的观测手段,直接观测温度传导和湿度运移较为困难,较精确的方法则是运用数值计算。湿度场的求解较温度场困难,其扩散方程具有高度的非线性特征,扩散系数受到温度、湿度以及混凝土类型的影响。宏观尺度上的温湿变化都是由细观结构内的变化所引起的,因此,从细观角度着手研究混凝土的温湿耦合效应更有助于深入探讨其内在机理。此外,温湿耦合应力致使的混凝土裂缝对温度的传导不利,但能加强湿度的扩散。混凝土是典型的非均匀材料,但目前的数值计算方法中还很少涉及到混凝土的非均匀性对温湿耦合作用的影响,因此,开展损伤演化过程中非均匀材料的温湿耦合效应的研究更能有效地反应混凝土内部温度和湿度的变化规律。

This paper presented the purpose of study on the coupling of heat and moisture diffusion in concrete,and then offered a literature review of this topic.Due to the limitation of experiments in measuring the heat and moisture transfer,numerical simulation is usually employed to obtain the temperature and moisture data.Moisture diffusion is more difficult to compute than heat transfer because the control equation of moisture diffusion is highly nonlinear,and the moisture diffusion coefficient greatly depends on the temperature,moisture content and the types of concrete.Because the change of temperature and moisture at the macroscopic level can be reflected by their variation at the mesoscopic level,it is helpful to study the coupling mechanism at the mesoscopic level.The stresses produced by temperature and shrinkage may result in cracks in concrete,which halters the heat transfer but enhances the moisture diffusion.Concrete is a typical heterogeneous material,however,few literatures focuse on the influence of heterogeneity on the coupling of heat and moisture diffusion in concrete at present.Thus,studies on the coupling of heat and moisture diffusion with damage evolution of the heterogeneous material are greatly helpful to understand the coupling mechanism.