Grain-Size - The University of Missouri Columbia Civil and Environmental Engineering GRAIN-SIZE ANALYSIS PURPOSE The purpose of this laboratory is

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The University of Missouri - Columbia Civil and Environmental Engineering GRAIN-SIZE ANALYSIS PURPOSE The purpose of this laboratory is to teach you how to measure grain-size distribution curves using sieve analysis and hydrometer analysis. Sieve analyses are performed in large numbers on coarse-grained soils and are used in classifying sands and gravels and in estimating the engineering characteristics of these types of soil. Hydrometer analyses are used for fine-grained soils, but because there is little or no link between the size of soil particles in a fine-grained soil and the engineering properties of that soil, hydrometer analyses are less common than sieve analyses. The reason that hydrometer analyses are still performed on silts and clays is not entirely clear, but in many instances it seems likely that the engineer is just curious about how much of the soil might be composed of silt-sized particles and how much might be clay-sized. For whatever reasons, grain-size analyses remain an important facet of soil testing for engineering purposes and therefore warrant our careful attention. SIEVE ANALYSIS The procedure for performing a sieve analysis is outlined in ASTM standard D422, "Standard Method for Particle Size Analysis of Soils." To perform a sieve analysis, a series of wire screens (called "sieves") with different mesh sizes are stacked on top of one another, with the coarsest mesh on top and the finest mesh on the bottom. The screens are mounted in rings such that a space of about 2 inches separates each screen. Usually a "pan" is placed beneath the lowest sieve in the stack to catch any soil that passes through all the sieves. A lid may be placed on top of the upper sieve in the stack to prevent loss of soil in the form of dust during shaking of the sieves. The sizes of the most commonly used sieves are listed in Table 1. The ASTM standard D422 recommends that sieve analyses be performed using sieve numbers 10, 20, 40, 60, 140, and 200. We ’ll use numbers 4, 10, 20, 40, 60, 100, 200. The following procedure should be used for sieve analysis: 1. Weigh a sample of the coarse-grained soil that is to be used. The sample should weigh about 500 g. Assume that the air-dry weight is the same as the oven-dry weight and record the weight on the attached data form. 2. Place the soil to be sieved on top of the upper sieve in the nest of sieves. Place the lid on the upper sieve, put the stack of sieves in the mechanical sieve shaker, and shake the sieves for about 5 minutes.
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The University of Missouri – Columbia Civil and Environmental Engineering Grain-Size Analysis p.2 Table 1 -- Standard Sieve Numbers and Sizes Sieve Number Opening (mm) 4 4.76 10 2.00 16 1.18 20 0.85 30 0.60 40 0.43 50 0.30 60 0.25 100 0.150 140 0.106 200 0.075 3. Remove the stack of sieves from the shaker. Pour the contents of the coarsest sieve into a bowl whose weight has already been determined and recorded on the data form. Use a brush to dust off the wire mesh and thereby remove soil particles that are
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This note was uploaded on 09/23/2011 for the course CIVIL ENGI CE 3400 taught by Professor Rosenblad during the Spring '11 term at Missouri (Mizzou).

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Grain-Size - The University of Missouri Columbia Civil and Environmental Engineering GRAIN-SIZE ANALYSIS PURPOSE The purpose of this laboratory is

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