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对干湿交替下混凝土表层内水分传输过程进行了理论和试验研究。针对混凝土多孔材料内部水分传输的主要机理,分析了材料在干燥和湿润过程中宏观传输速率差异的基本原因。在此基础上,提出用扩散方程的形式描述干湿交替下混凝土内水分传输的总效果,并对干燥、湿润过程采用不同的扩散系数,建立了相应的数学计算模型。对混凝土干燥和湿润过程进行了试验研究,得到了混凝土材料等温吸附曲线、干燥过程和吸水过程曲线等水分传输的基本参数,测量了干湿交替下混凝土内部相对湿度的变化。用建立的干湿交替模型和测量的材料水分传输基本参数计算了试验中混凝土内部湿度变化,并与实测值进行了比较,实测值和计算值基本吻合,证明了该模型用于分析干湿交替下混凝土表层内水分传输过程的合理性。
Theoretical and experimental studies on the moisture transport in the concrete surface under alternating wet and dry conditions were carried out. Aiming at the main mechanism of water transport inside porous concrete, the basic reasons for the difference of macro-velocity in drying and wetting are analyzed. On this basis, the general effect of moisture transfer in concrete with alternating wetting and drying is described in the form of diffusion equation, and different diffusion coefficients are used for drying and wetting processes. Corresponding mathematical models are established. The drying and wetting process of concrete were studied. The basic parameters of moisture transmission such as isothermal adsorption curve, drying process and water absorption curve of concrete were obtained. The relative humidity inside concrete was measured with alternate wetting and drying. The change of humidity inside the concrete was calculated by using the established alternate model of wetting and drying and the measured basic parameters of moisture transfer in concrete. The measured values were basically in agreement with the measured values. It is proved that the model is suitable for the analysis of alternating wet and dry The Rationality of Water Transfer in the Concrete Surface.