青岛滨海环境温湿度作用与混凝土内部温湿度响应

Temperature and Relative Humidity Response of Concrete in Marine Environment of Qingdao

摘要: 国内外研究人员往往在实验室通过干湿循环试验，研究氯离子在混凝土内部的传输规律。然而，不同研究人员采用的干湿比和干燥温度差异性非常大，导致不同加速制度下的试验结果无法对比，室内加速试验与暴露试验的相关性也没有达成共识。本文通过实测青岛滨海环境温湿度作用和混凝土内部温度和湿度响应，为合理设置室内加速试验制度提供依据。研究发现：浪溅区混凝土内部的温度受潮高、大气温度和太阳辐射的影响变化趋势与大气温度有明显差异，呈现三类典型的变化规律。潮汐区混凝土内部的温度响应具有明显的季节性特征。冬季，高潮位混凝土内部温度低于低潮位混凝土内部温度。其他季节，高潮位混凝土内部温度高于低潮位混凝土内部温度。水下区混凝土内部温度与海水温度基本一致。浪溅区混凝土表层0~10 mm范围以内相对湿度基本维持在95%以上，混凝土表面下25 mm及更深处混凝土基本处于饱和状态。水下区、潮汐区混凝土内部也基本上处于饱和状态。建议室内干湿循环试验干湿比为1:5~5:1。在进行室内加速试验的过程中，不建议将混凝土试块烘干，否则将改变混凝土内部的氯离子传输机理，与实际不符。亟需建立统一的室内加速试验制度，并给出加速系数。

Abstract: Researchers always studied migration mechanism of chloride into concrete through drying-wet cycle test in laboratory. However, dry-wet ratio and drying temperature used by different re-searchers are totally different, which leads to the incomparability of test results under different acceleration regimes, and there is no consensus on the correlation relationship between acce-leration test and exposure test. In this paper, the temperature and relative humidity response of concrete under marine environment of Qingdao are measured, which provides a basis for set-ting up accelerated test regimes. Results showed that the temperature response of concrete in the splash zone is obviously different from that of air, which shows three typical changing rules. The temperature response of concrete in tidal zone has obvious seasonal characteristics. In winter, the temperature of concrete in high tide area is lower than that of low tide concrete. In other seasons, the internal temperature of high tide concrete is higher than that of concrete in low tide area. The temperature of concrete in underwater area is basically the same as that of seawater. The relative humidity of the concrete in the splash zone is above 95% within 0 - 10 mm, and the concrete at 25 mm and deeper is almost saturated. The concrete in underwater area and tidal area is almost saturated. It is suggested that the dry-wet ratio of accelerated test is 1:5 - 5:1. In the process of accelerated test, it is not recommended to dry the concrete into un-saturated condition, otherwise the migration mechanism of chloride into concrete will be changed, which is inconsistent with reality. It is urgent to establish unified accelerated test re-gimes which can reflect the real situation of chloride penetration into concrete and the coeffi-cient of acceleration is also needed.