Quantify effects of stage crushing on dimensional distribution of basaltic aggregates using image technique.

The present study evaluates the effects of two different aggregate production (crushing) mechanism, i.e. Jaw-Horizontal Shaft Crusher (HSI) named as JH and Jaw-Jaw-HSI-Vertical Shaft Impact Crusher (VSI) known as JJHV on aggregate dimension distribution. Both crushing mechanisms represents wide range of crushers and stage of crushing (i.e. JH and JJHV as two-stage: 2S and four-stage: 4S, respectively). The study considered three different size of coarse aggregates, namely P19-R12.5, P12.5-R9.5 and P9.5-R4.75. The aggregate dimensions are measured using aggregate image measurement system (AIMS). Further, the dimension based parameters, i.e. Flatness (F), Elongation (E) and Flatness and Elongation (F&E) were determined. In addition, the dimension distribution of aggregate is further analyzed using Zingg distribution, where the aggregate is classified in Rod (R), Blade (B), Disk (D) and Cube (C). The study also discuss algorithm behind measurement of aggregate dimensions using image analysis in AIMS. The result shows that aggregate produced from two stage crushing had higher F and higher E compared to four stage. Similarly, JH produces higher percentage of aggregates with given F&E ratio (i.e. 1:3 and 1:5) compared to JJHV. Additionally, it was found that stage crushing had more significant effect on F compared to E. Further, the Zingg classification revealed that compared to JH, JJHV produces more cube shape aggregates. Whereas, inverse trend was observed for percentage of particle in B and R ranges. Additionally, it has been observed that in image analysis aggregate orientation and pixel spread is function of individual particle co-variance matrix. [ABSTRACT FROM AUTHOR]