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Measurement of soil aggregate density by volume displacement in two non‐mixing liquids
Author(s) -
Sarli Guillermo O.,
Filgueira Roberto R.,
Giménez Daniel
Publication year - 2001
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2001.6551400x
Subject(s) - kerosene , aggregate (composite) , volume (thermodynamics) , porosity , surface tension , bulk density , physical property , mixing (physics) , mineralogy , materials science , soil water , geotechnical engineering , soil science , composite material , environmental science , chemistry , thermodynamics , geology , physics , organic chemistry , quantum mechanics
Soil aggregate density is an important property influencing soil biological, chemical, and physical processes. Current methods used to estimate soil aggregate density are based on more or less restrictive assumptions or require specialized equipment. This study was conducted to develop an alternative method for measuring aggregate density of soil and other porous objects that is both simple and theoretically sound. The proposed method solves the balance of forces resulting when a kerosene‐saturated aggregate is immersed in a mix of water and glycerin. We tested the accuracy of the method by measuring the volume of 40 aggregates with diameters ranging from 4 to 20 mm and with variable densities. Soil aggregates were saturated in kerosene, drained at a tension of −30 mm, and their volume estimated using a pycnometer. Upon resaturation, aggregates were suspended from a thread and successively weighed in air, in kerosene, and in a mix of water and glycerin. Aggregate volumes and densities varied between 1.20 × 10 −7 and 3.85 × 10 −6 m 3 and between 1.05 to 1.86 Mg m −3 , respectively. On average, aggregate volumes estimated with the pycnometric method were 2.6% smaller than the volumes obtained with the proposed technique, suggesting that the new method is less aggressive in evacuating pores open to the surface than a tension of −30 mm. The new method was easier to use, did not require previous preparation of the sample, and was less time‐consuming than older methods.