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X-ray microtomography to evaluate the efficacy of paraffin wax coating for soil bulk density evaluation


Luis F. Pires

Professor of Soil Physics


Brian Atkinson


The paraffin-coated method is a well-used approach to measure the soil bulk density (BD). BD is a physical property of great importance for studies of soil quality and health. Therefore, representative measurements of this property are highly valued. Resin and paraffin wax are utilized to coat soil samples; however, if these materials ingress into the sample it could affect the representativeness of BD evaluation. The advance in three-dimensional (3D) image analysis techniques such as X-ray microtomography (?CT) offers a great opportunity to visualize and quantify the possible penetration of paraffin wax into clod samples. In this paper we investigated porous system morphological properties of soil samples coated with paraffin wax. The morphological properties of the pores filled with paraffin wax inside the samples were also studied. We observed qualitatively that samples with large pores close to their borders were more susceptible to the penetration of paraffin wax. Samples with pores >10?mm3 had the highest amount of paraffin wax into them. Triaxial shaped and complexly pores also offered less resistance to the ingress of paraffin wax. Positive relations between the amount of paraffin wax inside the samples and the volume of pores measured, pore tortuosity and degree of anisotropy were found. Conversely, the soil pore connectivity was not correlated with the penetration of paraffin wax into the samples, at least for the region of interest (?27.3?cm3) studied. Finally, an analysis of the impact of paraffin wax ingress inside the samples in measured BD showed increments of ?0.09 and ?0.11?g?cm?3 in this property when the paraffin wax penetrates into the large pores.


Pires, L. F., Mooney, S. J., Auler, A. C., Atkinson, B., & Sturrock, C. J. (2019). X-ray microtomography to evaluate the efficacy of paraffin wax coating for soil bulk density evaluation. Geoderma, 337, 935-944.

Journal Article Type Article
Acceptance Date Nov 8, 2018
Online Publication Date Nov 23, 2018
Publication Date Mar 1, 2019
Deposit Date Nov 9, 2018
Publicly Available Date Nov 24, 2019
Journal Geoderma
Print ISSN 0016-7061
Electronic ISSN 1872-6259
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 337
Pages 935-944
Keywords Soil Science
Public URL
Publisher URL
Additional Information This article is maintained by: Elsevier; Article Title: X-ray microtomography to evaluate the efficacy of paraffin wax coating for soil bulk density evaluation; Journal Title: Geoderma; CrossRef DOI link to publisher maintained version:; Content Type: article; Copyright: © 2018 Elsevier B.V. All rights reserved.


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