Lesson 4/Learning Event 5
LEAD-THROUGH PRACTICAL EXERCISE
FIELD DENSITY (SAND METHOD)
SITUATION: The density of a compacted base course for an airfield being constructed in the Theater
of Operations was checked by means of the sand method.
The following data was obtained in calibrating the sand to be used in the field density test.
Weight of Sand Required to Fill
Proctor Compaction Mold Plus
Weight of Mold
Weight of Proctor Mold
Volume of Proctor Mold
0.033 cu. ft.
From the calibration data, what is the unit weight of the sand to be used in the field density test
1. Average Weight of Sand Plus Mold = 12.63 lbs
2. Average weight of Sand in Mold
3. Unit Weight = Weight/Volume
____________ lbs/cubic ft
In the field, 7.62 pounds of wet soil was removed from the compacted subbase. Results from the
alcohol method of rapid water content determination showed the soil has a water content of 13.6
percent. In addition, it took 4.83 pounds of the calibrated sand to fill the hole from which the
compacted subbase sample was taken.
1. What was the volume of the compacted subbase sample when:
What is the wet unit weight of the compacted subbase when:
What is the dry unit weight of the compacted subbase when: