颗粒整形后粗骨料特征及其对混凝土性能的影响

Research on the Characteristic of Coarse Aggregate After Particle Shaping and the Influence on the Concrete Performance

摘要:

以小型球磨机为模拟整形动力来源，研究了颗粒整形后粗骨料基本特征参数的变化规律，并与其应用性能进行关联分析.结果表明：整形过程根据粗骨料颗粒变化情况分为三个阶段：针片状颗粒转换阶段，棱角消除阶段以及颗粒破碎阶段；适当的颗粒整形使粗骨料配制混凝土的流动度有较大提升同时不降低强度，但是过度整形会对流动度和强度产生不利影响；在整形前期，针片状转换造成的堆积密度增加是影响混凝土流动性的关键参数，整形后期，粗骨料颗粒形貌的圆形化是影响混凝土流动性的主要因素；堆积休止角作为综合评价粗骨料颗粒间内摩擦力的参数对于整形后粗骨料与流动性的关联性最为紧密.

Abstract:

By using small ball mill as the shaping source, the change of basic characteristics of coarse aggregate after particle shaping was studied and correlation analysis was conducted between the aggregate characteristics and its application performance. The results show that according to the change of the coarse aggregate particles, the shaping process is divided into three stages: transformation stage of elongated and flaky particles, roundness improve stage and particle crushing stage. Appropriate particle shaping process can make the aggregate use in the concrete to increase significantly the flowability of concrete and not to reduce the strength, but excessive shaping will be harmful to the flowability and strength. In the early stage of the particle shaping, packing density increasing caused by needle flake transformation is the key parameters affecting the concrete flowability. In the latter particle shaping process, roundness of coarse aggregate is the main factors influencing the concrete flowability. As a comprehensive parameter to evaluate the friction between the coarse aggregate particles, angle of repose of aggregate particles has high correlation with the flowability of concrete.