OBJECTIVE

To determine the Water Content of Soil by Oven Drying Method which is expressed as a percentage of the mass of dry soil. This is termed the moisture content of the soil.

Water Content of Soil by Oven Drying Method

NEED AND SCOPE OF THE EXPERIMENT

It is very important in almost all soil tests, the natural moisture content of the soil is to be determined very carefully. The knowledge of the natural moisture content is very crucial in studies of soil mechanics nowadays. The natural moisture content of the soil is used in determining the bearing capacity and settlement of soil. The natural moisture content will give an estimated idea of the state of soil in the field.

DEFINITION

The natural water content also called the natural moisture content is the ratio of the weight of water to the weight of the solids in a given mass of soil. This ratio is usually expressed as a percentage.

Also Read

• Specific Gravity of Cement by Specific Gravity Bottle
• Sp. Gravity & Water Absorption Of Coarse Aggregate
• Sp. Gravity & Water Absorption of Fine Aggregates

APPARATUS REQUIRED

Drying oven,

Non-corrodible metal cans with lids

Balance (0.001 g accuracy for fine-grained soils)

Spatula

Gloves

Tongs

PROCEDURE

1. Record the number of can and lid.

2. Clean, dry, and record the weight of the container with lid (W1).

2. Using a spatula, place about 15-30 g of moist soil in the cantainer. Secure the lid carefully, weigh and record the container with lid carefully (W2). 

3. Keep the container in the oven with the lid removed. Maintain the temperature of the oven at 110 ± 5°C.

3. Dry the specimen for a period varying with the type of soil but usually 16 to 24 hours.

4. After drying, remove the can carefully from the oven using gloves or tongs. Allow it to cool to room temperature. 

5. Weigh the dry soil in the can along with lid carefully (W3).

6. For each soil, perform at least 3 sets of the test.

NOTE: Peat and other organic soils are to be dried at a lower temperatures (say 600) possibly for a longer period. Certain soils contain gypsum which on heating loses its water. If it is suspected that the gypsum is present in the soil sample used for moisture content determination, it shall be dried at not more than 800 degrees C and possibly for a longer time.

OBSERVATIONS AND RECORDING

Data and observation sheet for water content determination :

RESULT

Average moisture content = ………………………………. %

GENERAL REMARKS

1. A container without a lid can be used, when a moist sample is weighed immediately after placing the container and oven-dried sample is weighed immediately after cooling in a desiccator.

2. As dry soil absorbs moisture from wet soil, dried samples should be removed before placing wet samples in the oven.