混凝土自收缩与干燥收缩的统一内因

为考察混凝土内部相对湿度与自收缩和干燥收缩的关系,实验测量了在表面密封(试件Ⅰ)和表面先密封后暴露于环境中(试件Ⅱ)2种干燥条件下早龄期混凝土试件的自由变形和内部温湿度变化规律。实验结果表明:在3 d龄期前,同处于密封状态的两试件的自由变形和内部温湿度变化相同;从3 d龄期开始,试件Ⅱ在水分散失作用下内部湿度下降明显大于试件Ⅰ,相应地,由于叠加了干燥收缩,其变形也明显大于试件Ⅰ的自收缩变形。这说明混凝土试件在近似相同的温度历程下,内部相对湿度与其湿度变形,可作为混凝土自收缩与干燥收缩的统一内因进行统一描述。

Uniform driving force for autogenous and drying shrinkage of concrete

Experimental measurements of the shrinkage and interior humidity of very early-age concrete for both plastic sealed and various drying conditions was carried out to study the relationship between shrinkage strain and interior humidity.The experimental results show that before three days,the trend in the change of both the interior humidity and the shrinkage.After three days,the drying rapidly reduces the interior humidity and increases the shrinkage strain in nearly the same temperature history of concrete....