ASTM D 2487 soil classification system, an ASTM version of the Unified Soil Classification System, classifies mineral and organo-mineral soils for engineering purposes based on its particle-size characteristics, liquid limit, and plasticity index. Please note that, this soil classification standard is limited to naturally occurring soils. Also, the group symbol portion of this classification system is applicable on the portion of the soil sample passing 75 mm (3 in.) sieve.
Using the Plot:
The generated plasticity chart is interactive and can be zoomed in or out and hovered over for
additional data
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Particles of rock that will not pass a 12 in. (300 mm) square opening.
Particles of rock that will pass a 12-in. (300-mm) square opening and retained on a 3-in. (75-mm) sieve.
Particles of rock passing a 3-in. (75-
mm) sieve and retained on a No. 4 (4.75-mm) U.S. standard
sieve. Further classified into Coarse and Fine Gravel.
Coarse Gravel —passing 3-in. (75-mm) sieve and retained on 3⁄4-in.
(19-mm) sieve.
Fine Gravel —passing 3⁄4-in. (19-mm) sieve and retained on No. 4
(4.75-mm) sieve.
Particles of rock passing a No. 4 (4.75-
mm) sieve and be retained on a No. 200 (75-μm) sieve with the following subdivisions:
Coarse Sand — passing No. 4 (4.75-mm) sieve and retained on No.
10 (2.00-mm) sieve
Medium Sand — passing No. 10 (2.00-mm) sieve and retained on
No. 40 (425-μm) sieve.
Fine Sand — passing No. 40 (425-μm) sieve and retained on No.
200 (75-μm) sieve.
Soils which are nonplastic or very slightly plastic and that exhibits little or no strength when air dry and passing a No. 200 (75-μm) sieve. For classification purposes, silt is considered as a fine-grained soil, or the fine-grained portion of a soil, with a plasticity index less than 4 or if the plot of plasticity index versus liquid limit falls below the “A” line (plasticity chart).
Soil passing a No. 200 (75-μm) sieve that can be made to exhibit plasticity within a range of water contents and that exhibits considerable strength when air dry. For classification, clay is a fine-grained soil, or the fine-grained portion of a soil, with a plasticity index equal to or greater than 4, and the plot of plasticity index versus liquid limit falls on or above the “A” line.
Silt with sufficient organic content to influence the soil properties. For classification, an organic silt is a soil that would be classified as a silt except that its liquid limit value after oven drying is less than 75 % of its liquid limit value before oven drying.
Clay with sufficient organic content to influence the soil properties. For classification, an organic clay is a soil that would be classified as a clay except that its liquid limit value after oven drying is less than 75 % of its liquid limit value before oven drying.
Soil composed of vegetable tissue in various stages of decomposition usually with an organic odor, a dark-brown to black color, a spongy consistency, and a texture ranging from fibrous to amorphous.
Coefficient of Curvature and Uniformity
Coefficient of Uniformity and Curvature
Coeff of Uniformity:
Coeff of Curvature:
ASTM Soil Classification
ASTM Soil Classification
Percent Gravel:
Percent Sand:
Soil Group Symbol:
Soil Group Name:
REPORT SECTION