基于砂浆流变性能的自密实混凝土制备方法研究

Research on preparation method of self-compacting concrete based on rheological properties of mortar

通过测定机制砂掺量、胶砂比和粉煤灰掺量因素下砂浆剪切应力随着剪切速率的变化规律,根据宾汉姆流体模型线性拟合,结果得到的屈服应力和塑性黏度指导砂浆组分优化,并基于砂浆-粗骨料两相悬浮原理制备自密实混凝土(SCC)。试验结果表明:混合使用超细砂与机制砂、增大胶砂比及掺入粉煤灰都可以有效地改善砂浆流变性,制备强度等级为C50的SCC时,机制砂用量为40%、胶砂比为1.0、粉煤灰掺量为30%的砂浆具有较小的屈服应力和适宜的塑性黏度,其对粗骨料的动力传输能力及包裹性也最佳,制备的SCC表现出优良的工作性能。

Based on the linear fitting of Bingham fluid model,the yield stress and plastic viscosity obtained by measuring the change law of mortar shear stress with shear rate under the factors of machine-made sand content,cement-sand ratio and fly ash content were used to guide the optimization of mortar components,and self-compacting concrete(SCC)was prepared based on the two-phase suspension principle of mortar and coarse aggregate.The experimental results show that the mixture of superfine sand and mechanism sand,the increase of cement-sand ratio and the incorporation of fly ash can effectively improve the mortar rheology,and the mortar with 40%of mechanism sand,1.0 of cement-sand ratio and 30%of fly ash has smaller yield stress and suitable plastic viscosity when preparing SCC with strength grade C50,and its power transmission ability and inclusions of coarse aggregate are also optimal.The SCC showed excellent working performance.