Three dimensional shape analysis of concrete aggregate fines produced by vertical shaft impact crushing

Published

December 8, 2016

Author(s)

Edward Garboczi, Rolands Cepuritis, Stefan Jacobsen

Abstract

We studied the 3-D shape of concrete aggregate fines (3 µm to 250 µm) produced by high-speed VSI crushing of rock types from 10 different quarries representing a wide range of local Norwegian geological variety with respect to mineralogy and mechanical properties. This included igneous (intrusive and extrusive), metamorphic and sedimentary rocks that are both mono- and multi-mineralic. Vertical shaft impact (VSI) crushing seems to be able to affect the shape of crushed concrete aggregate fines for the whole analyzed size range, independent of the mineralogical composition of the rocks included in the study. The improvement of shape was somewhat lower for the size range of particles smaller than about 15 µm of equivalent size where influence of the crystallographic structure of the individual mineral seems to prevail more. Particles of the rock type containing the highest mica content (5.5 %, by mass) indicated the least equi-dimensional shape. The most equi-dimensional shape in the studied particle size range was found for both analyzed limestone rock types. A new shape parameter, micro-Flakiness Index (µFI), has been proposed to describe the shape of the fine crushed concrete aggregate particles.

Citation

Powder Technology

Volume

308

Pub Type

Journals

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DOI Link

Keywords

crushed aggregate fines, vertical shaft impact crushing, VSI, X-ray computed tomography, microFlakiness index.

Citation

Garboczi, E. , Cepuritis, R. and Jacobsen, S. (2016), Three dimensional shape analysis of concrete aggregate fines produced by vertical shaft impact crushing, Powder Technology, [online], https://doi.org/10.1016/j.powtec.2016.12.020 (Accessed December 10, 2024)