In this paper, the role of crushing operation on the cubical controlling features of coarse aggregates, and its influence on the shape distribution characteristics of aggregates (i.e. angularity, sphericity, and flatness & elongation ratio) were investigated through the second version of Aggregate Image Measuring System (AIMS II). Three types of aggregate from different origins were chosen and crushed by the vertical shaft impactor (VSI) with fixed rotational speed. The results indicate that the rotation speed of VSI is influenced by the input power of the machine to the particle sizes, and higher speed leads to more cracks on aggregates during the crushing process. By using X-ray diffraction (XRD), the aggregate samples from different origins and mineral compositions were analysed under the same working operation of crusher. Besides that, the correlation between particle shape characteristics influenced by the mineralogical composition, and their collision behaviours have been discussed according to the tested results. A recommendation for optimal operation of VSI on crushing granite aggregates is given based on this study. Whereas, the cubical condition of aggregates and energy saving factors were taken into account. Furthermore, petrographic analyses were imposed to correlate particle mineralogy to its collision behaviour during crushing.
Bibliographical noteFunding Information:
This work was supported by National Natural Science Foundation of China (NSFC) (No. 51878063, No. 51778062), and was based on a part of the research project carried out at the request of the German Research Foundation (DFG), under research project No. OE 514/1-2 (FOR2089/2). The first author also appreciated the support from Doctoral Program Foundation of Institutions of Higher Education of China (Grant No. 201706560034).
- Crushing operation
- shape property
- vertical shaft impactor