水环境下的混凝土湿度影响因素试验

Experimental study on concrete humidity under water environment

采用电热恒温鼓风干燥箱对不同强度等级、最大骨料粒径、试件尺寸的混凝土试件进行干燥,将干燥后试件置于水中自由吸水,分析其含水率和饱和度的变化规律,建立不同混凝土试件湿度随吸水时间变化的预测方程。结果表明:混凝土湿度随浸泡时间的延长而增大,强度等级越低,最大骨料粒径越小,比表面积越大,吸水速率越快,含水率越高。浸泡时间为72 h时,C15、C20、C30混凝土饱和度分别已达96.88%、96.59%、97.70%;随浸泡时间的继续延长,饱和度增加速度变缓。混凝土吸水过程近似可划分为近似线性吸水阶段、非线性吸水阶段、近似饱和阶段。

Concrete specimens of different strength grades,maximum aggregate particle sizes and specimen sizes were dried in an electro-thermal constant temperature blast oven.The specimens after drying were placed into water which was absorbed freely.The change rules of the moisture content and saturation were analyzed and the prediction formulas for concrete humidity with soak time were found.The results demonstrate that the concrete humidity exhibited a significant increasing trend with increasing soak time.Besides,the lower the strength grades,the smaller the maximum aggregate particle size,the larger the specific surface area,the water absorption rate is faster and the humidity is higher.When the soaking time is 72 h,the concrete saturation of C15,C20 and C30 specimens reaches 96.88%,96.59%and 97.70%,respectively.With the extension of soaking time,the concrete humidity increases slowly,and the water absorption process of concrete can be approximately divided into linear water absorption,nonlinear water absorption and approximate saturation stages.