Measurement of particle size distribution and specific surface area for crushed concrete aggregate fines

Published

December 30, 2016

Author(s)

Edward J. Garboczi, Chiara F. Ferraris, Rolands Cepuritis, Stefan Jacobsen, Bjorn Sorensen

Abstract

The study investigates which measurement methods are best applicable to crushed concrete aggregate fines smaller than about 250 µm to determine particle size distribution (PSD) and specific surface area: wet-method laser diffraction (LD), X-ray sedimentation (XS), X-ray microcomputed tomography (µCT) combined with spherical harmonic analysis, Dynamic Image Analysis (DIA) and nitrogen (N2) adsorption BET. Measurements were performed on 30 crushed concrete aggregate powder materials (fines) constituting three size fractions with d10 to d90 ranges of 4 µm to 25 µm, 20 µm to 60 µm and 40 µm to 250 µm from 10 different rock types. For fines passing 125 µm or 63 µm sieves, generally about 50 % of the surface area is concentrated among particles with equivalent sphere diameters below about 5 µm. Precise detection of the amount of these particles is therefore very important for accurate specific surface area determination. The XS method gives the most realistic PSD due to having suitable resolution and because of fewer uncertain input parameters. LD can introduce an error of up to 30 % in the measured specific surface area due to input uncertainties. The µCT results show that the error in calculated surface area via assuming spherical particle shape is of similar magnitude (20 % to 30 %) over the entire investigated particle size range, approximately 3 µm to 200 µm. This finding is important, since it simplifies surface area determination. This result is thought to be quite general, since the crushed aggregate fines investigated were produced from 10 rock types that had quite different mineralogy.

Citation

Powder Technology

Pub Type

Journals

Keywords

Crushed aggregate fines, particle size distribution, laser diffraction, sedimentation, dynamic image analysis, X-ray tomography

Citation

Garboczi, E. , Ferraris, C. , Cepuritis, R. , Jacobsen, S. and Sorensen, B. (2016), Measurement of particle size distribution and specific surface area for crushed concrete aggregate fines, Powder Technology (Accessed December 7, 2024)