骨料对混凝土干缩性能的影响

Influence of Aggregate on Dry Shrinkage of Concrete

采用收缩试验针对骨料对混凝土干缩的影响进行研究。主要分析不同骨料体积含量下骨料的约束作用、过渡区湿扩散作用对干缩影响的权重，以及骨料最大粒径和砂率对于缩影响。结果表明：骨料体积含量小于66％时，约束起主导作用；骨料体积含量介于66％-68％之间时，约束与过渡区湿扩散共同起主导作用；骨料体积含量大于68％时，约束再次起主导作用。骨料最大粒径和砂率的变化对干缩几乎没有影响，只有在单位用水量变化时对于缩产生影响。

Influence of aggregate on dry shrinkage of concrete by shrinkage test is investigated in this paper. The weight of the constraints effect and the moisture diffusion of intcffaeial transition zone（ITZ） under different aggregate volume content influencing the drying shrinkage is analyzed, as well as the effects of maximum aggregate size and sand ratio on drying shrinkage. The results show that, when the content of aggregate volume is less than 66%, the constraints play a leading role ; when the content of aggregate volume is between 66% to 68%, both the constraints and the moisture diffusion of ITZ are dominant; and when the aggregate volume content runs over 68%, the constraints play a leading role again. Changes in the maximum aggregate size and the percentage of sand have rarely effect on the drying shrinkage unless the unit water consumption changes.