大流动度混凝土用细集料级配优化

Optimization of Fine Aggregate Gradation Used in High Fluidity Concrete

从流变学角度,讨论了不同粒径砂粒对大流动度砂浆流变性和触变性的影响,提出了适用于高强大流动度混凝土和普通大流动度混凝土的细集料级配。研究结果表明,中砂适合制备普通大流动度混凝土,而制备高强大流动度混凝土选用细度模数不超过3.30的粗砂为宜。在制备大流动度混凝土中,须注意各个粒径范围内的砂粒百分含量。0.315mm以下的砂粒含量在15%～30%之间为宜,0.60mm以下的砂粒含量在30%～45%之间为宜,1.18mm以下的砂粒含量在55%～75%之间为宜。

The effect of different particle size distribution of sand on the rheological behavior and thixotropy of high fluidity mortar has been discussed from the view of rheology in this paper.After that,gradation of the fine aggregate of high strength high fluidity concrete and ordinary high fluidity concrete was given.The results of the study show that,the medium sand was suitable for the preparation of ordinary high fluidity concrete,however it is best to choose the coarse sand with fineness modulus less than 3.30 to prepare the high strength high fluidity concrete.In the preparation of high fluidity concrete,much attention must be paid to the mass percentage of each particle size range.The best mass percentage is 15%~30% for the sand particle which smaller than 0.315 mm,30%~45% for which smaller than 0.60 mm and 55%~75% for which smaller than 1.18 mm.