ASTM D422-63 (R2007)e2 PDF Download

The ASTM D422-63 (R2007)e2 standard outlines a procedure for quantitatively determining the distribution of particle sizes in soils. The test method involves two main steps: sieving and sedimentation.

In the sieving process, particles larger than 75 µm (retained on the No. 200 sieve) are separated and their distribution is determined. The size of the sieve can be adjusted depending on the specific requirements, with options including the No. 4 (4.75-mm), No. 40 (425-µm), or No. 200 (75-µm) sieves. The results from the sieving process are reported, including the size of the sieve used.

For particles smaller than 75 µm, a sedimentation process is employed. A hydrometer is used to gather the necessary data, allowing for the determination of the particle size distribution in this range. Two methods of dispersion are provided: a high-speed mechanical stirrer and air dispersion. The use of air dispersion is recommended due to its advantages, including better dispersion of plastic soils below 20 µm and less degradation for sandy soils. However, it should be noted that the results obtained from these two dispersion methods may differ, particularly for particles finer than 20 µm.