铁尾矿砂混凝土的泌水特性

Bleeding Behavior of Concrete Prepared with Ferrous Mill Tailings as Manufactured Fine Aggregates

铁尾矿砂的集料性质决定了铁尾矿砂混凝土易于泌水的特点,用包括硅质石粉在内的矿物掺合料来控制水粉比,按最佳水粉比结合适当减少高效减水剂掺量对配合比进行优化,可有效控制混凝土泌水,并能获得良好的工作性。回归分析结果表明,混凝土拌和物各时刻的泌水率与静置时间的关系可用指数公式表征并分类为早快型、早慢型、晚快型和晚慢型。

The ferrous mill railings are byproducts of mining industry and can be considered as Manufactured Fine Aggregates （MFA）. However, the bleeding behavior is a difficulty to apply this kind of resource in concrete. Through optimization of mix proportion with mineral admixtures including fine mill railings to modulate water/powder ratio （w/p）, the bleeding can be controlled effectivdy by means of optimal w/p combined with appropriate reduction of superplasticizer dosage, and satisfactory workability was obtained. The result of regression analysis reveals that the relation between bleeding rate of the mixture and unperturbed time can be characterized by an exponential formula. With the parameters of the formula, the bleeding of the mixture can be classified into 4 types, i.e. early-rapid, early-slow, late-rapid and late-slow types.