Atterberg Limits - Soil Moisture Test

Ever wonder what happens in a soil test lab after a site survey for building and/or road construction? The following are some of the steps involved in a soil moisture content test, which is also called the Atterberg limits in your civil engineering class.

1. Clay from the soil sample is mixed with water in proportions up to 425 microns.

2. This clay sample is then soaked for about 16 hours.

3. Two different samples are used for testing. One with moisture content and one without moisture content.

4. A piece of equipment called the Cassagrand Apparatus is used to record several blows. This measurement will eventually be used to measure soil moisture content using some basic math.

5. Record blows and test tube number in the Atterberg Limits Table

6. Take an Empty test vessel. Measure the weight of this empty vessel on the scale and record it.

7. Scrape out a soil sample and pour it into the test vessel. Weigh this sample of soil on a scale.

8. Bake this sample in the oven at 110 degrees. Wait for 4 hours for this sample to turn dry before removing it from the oven.

9. Now, weigh and record the weight of dry soil on a scale.

10. The moisture content is the difference between the weight of clay mixed with water and dry soil/clay. You may use a calculator for this test to get accurate results.