多孔建筑材料毛细吸水过程研究进展综述

毛细吸水作为水分在非饱和建筑材料中的主要传输方式,是影响结构长期性能(如耐久性)的关键因素。从试验研究和理论分析两个方面,论述了多孔建筑材料毛细吸水过程研究的进展和最新成果。在试验研究中,将吸水率(sorptivity)定义为累计吸水量曲线的斜率。采用该参数的优点是便于实验室测量,通过吸水率的测量预测分析水分在材料中的传输过程。理论分析的主要困难是准确确定水分扩散系数的解析表达式,这是对非线性水分扩散方程进行求解的前提。本文综合论述了几种求解非线性扩散方程的近似解析方法,最后给出了需要进一步研究的内容和方向。

Review on Study for Capillary Absorption of Porous Building Materials

The capillary absorption plays a dominant role in the ingress of water in unsaturated porous building materials,and therefore is a key influencing factor in the long-term performance such as the durability of structures.The progress and achievement in the research of capillary absorption of porous building materials are reviewed here in terms of the experimental investigation and theoretical analysis.In test,the parameter of absorptivity is defined as the slope of cumulative water content curve.The advantage of using absorptivity is that it could be easily measured in a common laboratory using the gravimetric technique.When it is determined experimentally,the transport process of water in porous materials would be predicted subsequently.Regarding the theoretical method,the difficulty is how to obtain the exact analytical expression of hydraulic diffusivity.Several approximate analytical solutions of nonlinear diffusion equation are introduced in this paper.Finally,the directions for further study are presented.