三元胶凝体系清水混凝土性能的试验研究

Experimental Research on Properties of Fair-faced Concrete in a Ternary Cementing System

采用混料试验设计方法研究了水泥、矿粉、粉煤灰三元胶凝体系新拌清水混凝土坍落度、倒筒排空时间以及7 d抗压强度的变化规律。研究结果表明,模型精度的方差分析处于十分显著水平(p≤0.01),能够对实际情况进行预测;随着粉煤灰掺量的增加,混凝土坍落度增加,倒筒排空时间减少,在粉煤灰掺量10%、矿粉掺量25%的条件下,混凝土工作性达到最佳水平;矿粉的加入会增加倒筒排空时间,提高混凝土屈服应力,不利于清水混凝土外观改善,但矿粉具有较高的活性,对清水混凝土7 d强度有一定提升。

Using mixture experiment design, the variation of concrete slump flow(SP), emptying time of inverted slump cone(ETISC) and 7 d compressive strength in a ternary cementing system are studied. The results indicate that mathematical model built is statistically significant(p≤0.01) through the analysis of variance(ANOVA), thus it is applicable for predicting the actual situation;with the increase of fly ash(FA) content, the SP increases and the ETISC decreases, the optimum mix amount of FA and slag is 10%, 20%, respectively. The addition of slag will increase the ETISC and yield stress of concrete, which is not conducive to improve the appearance of fair-faced concrete, but slag has a beneficial effect on the 7 d compressive strength of the concrete for its higher activity.