石粉对自密实混凝土收缩性能的影响

Effect of Limestone Powder on Shrinkage Performance of Self-Compacting Concrete

为了研究石粉对自密实混凝土收缩性能的影响,设计了不同水胶比和石粉质量分数的试验,得到了水胶比为0.30、0.34、0.37,石粉质量分数为0%、10%、20%时自密实混凝土28 d龄期内自收缩和干燥收缩的变化规律。结果表明:自收缩随着水胶比的减小而增大,随着石粉质量分数的增加而增大;水胶比在0.30~0.37时,其对干燥收缩的影响不大;适量的石粉对干燥收缩几乎无影响,当石粉质量分数达到20%时,干燥收缩明显增大。在试验的基础上提出了考虑水胶比和石粉质量分数影响的自密实混凝土自收缩与干燥收缩预测模型。

In order to study the effect of limestone powder on the shrinkage performance of self-compacting concrete, tests with different water to binder ratios and mass fractions of limestone powder were designed, and the change rules of autogenous shrinkage and drying shrinkage of self-compacting concrete at the age of 28 d with water to binder ratio of 0.30, 0.34, 0.37 and mass fraction of limestone powder of 0%, 10%, 20% were obtained. The results show that the autogenous shrinkage increases with the decrease of water to binder ratio, and increases with the increase of mass fraction of limestone powder. When water to binder ratio ranges from 0.30 to 0.37, its effect on drying shrinkage is not significant. The moderate amount of limestone powder almost has no effect on drying shrinkage, and when the mass fraction of limestone powder reaches 20%, the drying shrinkage increases significantly. The forecast models of autogenous shrinkage and drying shrinkage of self-compacting concrete considering the effect of water to binder ratio and limestone powder mass fraction were proposed on the basis of tests.