不同水胶比混凝土内部温湿度长期变化规律研究

鉴于混凝土内部温湿度显著影响混凝土耐久性, 为研究混凝土内部温湿度长期的变化规律, 将不同水胶比混凝土放置于室内大气环境中, 并测量其距离表面3cm、5cm、7cm及9cm处140d内温湿度的演变规律. 研究结果表明: 正常室温条件下, 混凝土内部温度变化主要受环境温度影响, 且与环境温度变化趋势基本相同, 浇筑完成7d后内部温度与环境温度温差大约为2℃, 60d以后内外温差基本消失. 高水灰比混凝土内部含水量充足, 140d内部相对湿度一直保持在85%以上; 低水灰比混凝土内部含水量较少, 早期相对湿度变化受水化耗水影响明显, 混凝土内部相对湿度存在明显梯度差, 5cm、7cm处相对湿度最低分别为60.18%和29.83%; 随着水化作用进行, 长期来看混凝土内部湿度逐步与环境湿度趋于一致.

Study on the long-term variation law of temperature and humidity in concrete with different water binder ratio

The internal temperature and humidity of concrete significantly influence its durability. In order to investigate the long-term variation of temperature and humidity in concrete, concrete samples with different water cement ratio are placed in indoor environment, and temperature and relative humidity (RH) with distance of 3 cm, 5 cm, 7 cm and 9 cm from surface are investigated during a 140-day time-span. The results show that under normal room-temperature conditions, the variations of temperature inside the concrete are mainly related to the ambient temperature and the temperature variation trend basically keeps the same pace with the environment. At a 7-day observation, the temperature difference between internal and environment is about 2℃, and then zero difference is noted after a 60-day period. Besides, the internal moisture in the high water cement ratio concrete reaches the sufficiency level, and the RH remains at more than 85% in the 140-day test timeframe. Furthermore, a distinct RH gradient difference is noted inside the low water cement ratio concrete, and the deeper the depth is, the more relative humidity affected by hydration, and the minimum RH of 5cm and 7cm is 60.18% and 29.83%, respectively. The progress of hydration, the RH inside the concrete is, in the long run, consistent with the environmental humidity