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Lab Services: Soil testing

Lab Services: Soil testing

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Test Method Title

Standard Test Methods for Particle-Size Distribution (Gradation) of Soils Using Sieve Analysis

Reference Number

ASTM D6913



Test Property

Grain size

Description of Test

This test method is used to determine the particle-size distribution (gradation) of a soil sample. A representative specimen must be obtained from the sample by one of three procedures (moist, air-dried or oven-dried). For specimens containing relatively small particles, the specimen is sieved in its entirety, using single sieve-set sieving. However, the specimen may contain a wide range of particle sizes and may require separating the soil into two, or three size ranges for more efficient sieving, using one or two designated separating sieve(s). This process is termed composite sieving. For a single separation (two portions), the coarser portion is sieved in its entirety, while the finer portion is split into a smaller subspecimen for sieving. These results are mathematically combined. For specimens containing very large particles, the specimen may require two separations; i.e., three portions (1st and 2nd coarser portions and 2nd finer portion), see Fig. 1(a) and Fig. 1(b). Prior to sieving, as applicable, the material will be washed to remove fine particles and oven dried. The material to be sieved will be placed on the coarsest sieve size of each sieve set and mechanically shaken. The mass of particles retained on each sieve will be determined. The results will produce a tabulation of sieve sizes versus percent passing that can be graphically presented as a gradation curve (a plot of the percent passing versus the log of the particle size in mm.).

Preferred Test Sample Size

Number of Test Specimens


Test Specimen Size

Material passing #10 sieve of 115 grams for sandy soil and 65 grams for silt and clay soil


Grain size, particle-size, sieve analysis

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