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Grain-Size Distribution
Published in Alan J. Lutenegger, Laboratory Manual for Geotechnical Characterization of Fine-Grained Soils, 2023
The sieve analysis is used for the coarse fraction and separates particles into different sizes by passing the soil through a series of screens or sieves. The sieves are stacked with the largest size sieve opening at the top and the smallest size sieve opening at the bottom. A pan is placed below the smallest sieve on the bottom to catch any soil that falls through the last sieve. The stack of sieves is usually called a “nest” of sieves. Dry soil is poured into the top sieve, the lid is placed on top and the sieves are placed on a mechanical shaker so that particles fall by gravity until they are held on a screen with an opening smaller than the equivalent diameter of the soil particle. After shaking, the sieves are taken apart and weighed so that the mass of soil held or retained on that sieve is determined. The sieve analysis works best for coarse-grained soils, such as gravels and sand, which have particles that are large enough to be seen by the naked eye and are easily separated.
Soil properties and classification
Published in Buddhima Indraratna, Ana Heitor, Jayan S. Vinod, Geotechnical Problems and Solutions, 2020
Buddhima Indraratna, Ana Heitor, Jayan S. Vinod
Oversize and coarse-grained soils are classified on the basis of the size and distribution. Particle-size distribution (gradation) is a descriptive term referring to the proportions by dry mass of a soil distributed over specified particle-size ranges that is typically determined via sieve analysis and/or sedimentation method. The sieve analysis is used for determining gradation of particles having a nominal size larger than the 74 µm sieve, whereas sedimentation or hydrometer method is used for the fraction finer than the 74 µm sieve and larger than about 0.2 µm. The results are presented as the mass percent finer versus the logarithm of the particle diameter. Alternatively, the gradation of the fraction finer than 74 µm can also be determined using laser diffraction particle analysis. However, due care must be exercised as this method computes the percentage of particles by volume rather than by mass.
Aggregates
Published in M. Rashad Islam, Civil Engineering Materials, 2020
A gradation test (Figure 2.14) is performed on a sample of aggregate in a laboratory. A typical sieve analysis involves a nested column of sieves with a wire mesh cloth (screen). A representative weighed sample is poured into the top sieve, which has the largest screen openings. The column is typically placed in a mechanical shaker. The shaker shakes the column for a fixed amount of time. After the shaking is complete, the material on each sieve is weighed. The weight of the sample on each sieve is then divided by the total weight of the batch to calculate the percentage retained on each sieve. Then, the ‘Cumulative % Retained’ is calculated by summing up the ‘% Retained’ in the corresponding sieve plus that on the larger sieves. The ‘Percent Finer’ for a certain sieve is calculated as 100 minus the ‘Cumulative % Retained’ for that sieve. The results of sieve analysis are provided in a graphical form to identify the type of gradation of the aggregate. A common practice is to present a ‘Percent Finer versus Particle Diameter’ curve.
Hydraulic conductivity estimation of sandy soils: a novel approach
Published in ISH Journal of Hydraulic Engineering, 2023
Mohammad Aasif Khaja, Shagoofta Rasool Shah, Ramakar Jha
The traditional sieving procedure was used to analyze the particle size distribution of the samples following the relevant codes of the American Society of Testing and Materials (ASTM) and Bureau of Indian Standards (BIS) as described by Khaja et al. (2022). Test sieves with a mesh opening of 4.75 mm, 2.36 mm, 1.18 mm, 600 μm, 425 μm, 300 μm, 150 μm, and 75 μm were employed for sieve analysis with a lid on top and a pan at the bottom. Each sample weighing up to 500 g was placed in the top sieve (4.75 mm) before the whole arrangement of stacked sieves (mesh size decreasing downward) was shaken mechanically for about 10 minutes. To ensure there was no calculation error or sediment loss, the amount of each sample fraction retained on the individual sieve and pan was weighed up to 0.01 g accuracy, recorded, and added after the sieving operation. Based on the total mass of the soil sample taken, the percentage of soil passing through each sieve was finally computed. Grain size distribution curves of all the soil samples were plotted with percent finer (%) as the ordinate and particle size (mm) as the abscissa (expressed on a logarithmic scale) to obtain the complete gradation indexes.
Application of the agglomeration process on spinach juice powders obtained using spray drying method
Published in Drying Technology, 2020
The sieve analysis procedure is performed on the agglomerates to determine the mean particle diameter. The weight of the remaining agglomerates on each sieve (Jeotest, Türkiye) is measured and the amounts remaining in a single sieve were expressed as a mass fraction (Xi). Then, the mean particle diameter of the agglomerates was calculated by Equation (2) using the mean particle diameter (Dpi) determined by taking the arithmetic mean of the largest and smallest diameters. For this purpose, the sieves with 200 µm, 300 µm, 500 µm, 710 µm, 1 mm, and 2 mm diameter were used in the sieve analysis. where, Ds = volume-surface mean particle diameter (mm); Xi = mass fraction; Dpi = mean particle diameter (the mean of the largest and smallest diameters) (mm)
An investigation into the use of CFD to model the co-firing of Jatropha curcas seed cake with coal
Published in International Journal of Green Energy, 2018
Buddhike Neminda Madanayake, Suyin Gan, Carol Eastwick, Hoon Kiat Ng
The most fundamental uncertainties were with respect to the particle size and the devolatilisation kinetics. Although the samples used in the DTF had been sieved to less than 1 mm, an accurate distribution within this size fraction could not be determined. A tendency of the particles to agglomerate resulted in ineffective sieving at fine mesh sizes, and hence a sieve analysis could not be performed. This issue also meant that an optical particle analysis using a Retsch Camsizer (Retsch Technology 2016) also did not yield reliable data as clumping of particles occurred. Figure 3 is the particle size distribution for the untorrefied type A, obtained from the Camsizer. The normal-like distribution which would be expected is observed in the 0–300 µm range, with a centre of approximately 200 µm. A small peak is observed at approximately 400 µm, followed by a much larger peak centred at ~ 600–700 µm. It can be postulated that these latter peaks are the result of the agglomeration of two or more 0–300 µm particles. The fact that the latter peaks occur approximately at multiples of 200 µm further supports this. Hence, although the Camsizer results are far from conclusive, they support the possibility that the majority of the individual particles are in the 200 ± 50 µm range.