Moisture-density (Proctor) curve

AASHTO T 99 · T 180

Calculator

AASHTO T 99 · T 180

Fits a curve to your compaction points for maximum dry density and optimum moisture, with the zero-air-voids line.

Units US customary SI (metric)

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Enter each point as

Mass of mold and base plate, lb

Volume of mold, ft³

From standardizing the mold with water. A 4 in. mold is about 0.0333 ft³ (944 cm³); a 6 in. mold about 0.075 ft³ (2,124 cm³).

Specific gravity of the soil, G_s

For the zero-air-voids line. Measured by AASHTO T 100, or an assumed value such as 2.70.

Example values. Aim for three points dry of optimum and two wet of it.