石粉掺量对人工砂混凝土内部湿度及自收缩的影响

Effect of stone powder content on the internal humidity and autogenous shrinkage of manufactured sand concrete

为了探究石粉掺量对人工砂混凝土内部湿度及自收缩的影响,根据最少浆体理论,设计不同石粉掺量(0%、6%、12%、18%、24%和30%,即石粉占总粉料的质量比)的人工砂混凝土,测试其内部湿度和自收缩。研究结果表明,随着石粉掺量的增大,人工砂混凝土内部湿度先增大后降低;掺量为24%时,湿度达到最大值。当龄期为28 d时,随着石粉掺量增加,水泥用量减少,这减少了水泥水化产生的收缩;同时石粉具有微集料填充作用,也会一定程度降低自收缩,因此各组人工砂混凝土的自收缩呈现略微降低趋势。建立了基于石粉掺量和龄期的人工砂混凝土自收缩模型,为石粉在人工砂混凝土中的应用和研究提供参考。

In order to investigate the effect of stone powder content on the internal humidity and autogenous shrinkage of manufactured sand concrete,based on the least paste theory,the internal humidity and autogenous shrinkage of manufactured sand concrete with different stone powder contents(0%,6%,12%,18%and 24%,i.e.the mass ratio of stone powder to total powder)were designed and tested.The studied results show that the internal humidity of the manufactured sand concrete increases and then decreases as the increasing of stone powder content,reaching a maximum value at 24%of stone powder content.When the curing age is 28 d,the amount of cement decreases with the increasing of stone powder content,which reduces the shrinkage caused by cement hydration.At the same time,the stone powder has the effect of micro-aggregate filling,which also reduces the autogenous shrinkage to a certain extent.Therefore,the autogenous shrinkage of manufactured sand concrete in each group shows a slightly decreasing trend with the increasing of stone powder content.A model for the autogenous shrinkage of manufactured sand concrete based on the stone powder content and curing age was established to provide a reference for the application and research of stone powder in manufactured concrete.