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Title: Sand Particle Size Analysis by SedImaging in a Field Lab
SedImaging is an innovative alternative particle size analysis method developed to obtain high-resolution particle size distributions (PSDs) of sands. It was developed at the University of Michigan (UM) and is based on wet processing and digital image analyses of fine to medium sands. This work summarizes a variant of the SedImaging method, named FieldSed, which was first applied in a field lab setting for a sediments site by the authors and colleagues in October 2017. The goal of this work was to detect subtle variations in the fine sand and fines compositions as a pilot test at a field laboratory, without use of a sieve set or oven drying. The testing program included replicates, independent testing by UM, and other quality control measures. Sediment processing included wet-removal of fines and particles larger than coarse sand; preparation of the sample in a pre-sorter tube followed by sedimentation in a tall, water-filled column to sort the sands; and the collection and analysis of high-resolution digital imagery of the settled sand. The FieldSed method included variations to estimate mass percentages of oversized (> 2 millimeters [mm]) and undersized (< 0.075 mm) sediments, and throughput improvement. Wet sieving and air drying were used to separate and prepare oversized sediments for weighing. Multiple decants of sediment-water mixtures were used to wash out more dispersive fines. Decanted fines contents were estimated by differences in wet weights and by specific gravity approximations. Digital images were analyzed and used to generate highresolution PSDs, which typically included more than 80 size bins from 2 mm to less than 0.050 mm. The FieldSed method was successful in clearly distinguishing coarse and fine material, as well as defining the gradient between medium sands, fine sands, and coarse silts. Color, angularity, and other grain characteristics from the digital imagery were noted. With further testing to improve processing rates and efficiencies, the method could be applied to provide same-day field decisions. More efficient and faster processing could be achieved for characterization of cleaner sands, and applications could be expanded further, such as to assess suitability of post-dredge sand cover materials in the field.  more » « less
Award ID(s):
1825189
PAR ID:
10562401
Author(s) / Creator(s):
; ; ; ;
Editor(s):
Hayes, Donald F
Publisher / Repository:
Western Dredging Association (WEDA)
Date Published:
Page Range / eLocation ID:
56-67
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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