早龄期混凝土内部湿度场的测量与数值模拟

Measurement and Numerical Simulation of Internal Humidity Field in Early-age Concrete

通过对以往常用的混凝土内部相对湿度测试方法进行比较分析,研究开发能够准确、方便、数字化测试水泥基材料内部相对湿度的新型测试装置。基于新型测试装置对早龄期混凝土内部相对湿度进行了测量;并对混凝土内部湿度场进行了数值模拟。结果表明:新型测试装置结果要比预埋管法准确,装置的滞后性小;混凝土表面相对湿度降低较快,内部降低慢,水分含量沿试件高度分布不均,存在明显的湿度梯度;低水胶比混凝土的内部湿度场不仅受水分扩散的影响,还受到自干燥效应的影响;有限元数值模拟的计算结果与实测值有良好的一致性,有限元仿真计算能够较准确模拟混凝土的相对湿度,可用于分析不同构件混凝土的相对湿度变化规律。

By comparing and analyzing the commonly used test methods of internal relative humidity of concrete, a new type measuring device was developed,which could measure the internal relative humidity of cement-based materials accurately,easily and digitally. The internal relative humidity in early-age concrete was measured based on the new type measuring device,and the internal humidity field was simulated.Results show that the result mesured by the new type measuring device，which has small lag, is more accurate than that mesured by the preset pipe method. The superficial relative humidity decreases more rapidly than the internal relative humidity does,and the water content distributes unevenly along the specimen height, resulting in obvious humidity gradient; the internal humidity field of low water binder concrete is influenced both by moisture diffusion and by self-desiccation effect; the results of finite element numerical simulation and the measured values are in good agreement, finite element analysis can simulate the relative humidity in concrete accurately and be used to analyze variation of relative humidity in concrete of different components.