基于流变特性的粗骨料级配优化设计

Optimization of Coarse Aggregate Gradation Based on Rheological Behavior

采用ICAR流变仪测试了三级配粗骨料不同比例组成时新拌混凝土的性能,在宾汉姆模型的基础上,得到了流变参数。探究了粗骨料级配对扩展度、屈服应力和塑性粘度的影响,进而综合评述屈服应力和塑性粘度的最优范围,对混凝土三级配粗骨料组成进行了优化。结果表明,改变粗骨料的级配组成能够明显影响混凝土的流动性和流变参数,另一方面,通过控制新拌混凝土流变参数,可以确定不同级配粗骨料的最优组配。因此,通过限定适宜的流变参数范围,可以指导混凝土的组成设计。

Based on Bingham model,the rheological properties of fresh concrete with varied coarse aggregate gradation of three sizes were tested using an ICAR rheometer. The effects of coarse aggregate gradation on slump flow,yield stress and plastic viscosity of concrete were investigated and then the coarse aggregate gradation were optimized. Results indicate that the gradation of coarse aggregate has significant effects on flowability and rheological parameters of fresh concrete. On the other hand,the optimum composition of three sizes aggregate could be determined by controlling the rheological parameters of concrete. Therefore,it is a better way to optimize the concrete mixture design by limiting the range of rheological parameters.