Determination of Moisture Content of Soil

 

Lab Journal: Determination of Moisture Content of Soil Using Oven Drying Method (As per IS 2720)

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Experiment No.:

Date:

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Objective:

To determine the moisture content of a given soil sample using the Oven Drying Method as per IS 2720 (Part 2): 1973.

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Apparatus:

1. Oven – Capable of maintaining a temperature of 110°C ± 5°C.
2. Weighing Balance – Sensitive up to 0.01g.
3. Moisture Tins or Containers – Non-corrosive, air-tight, and of known weight.
4. Desiccator – To cool down the dried sample without absorbing moisture.
5. Tongs – For handling hot containers.

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Theory:

Moisture content is a critical property of soil that affects its strength, compaction, and other engineering properties. The Oven Drying Method is based on the principle that soil loses moisture when dried at a temperature of 110°C ± 5°C until a constant weight is achieved. The difference in the weight of the soil before and after drying gives the moisture content.

The Moisture Content (w) is expressed as the percentage of the dry weight of the soil.

$$w = \frac{(W2 - W3)}{(W3 - W1)} \times 100$$

Where:

• W1 = Weight of empty container.
• W2 = Weight of the container with wet soil.
• W3 = Weight of the container with dry soil.

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Procedure:

1. Weighing the Container (W1):

   • Take a clean and dry container and weigh it using a balance. Record the weight as W1.

2. Weighing Wet Soil (W2):

   • Place the wet soil sample into the container and weigh the container with the wet soil. Record the weight as W2.

3. Drying the Soil:

   • Place the container with the wet soil sample in a pre-heated oven set at 110°C ± 5°C.
   • Leave the sample in the oven for 16 to 24 hours, or until a constant weight is achieved.

4. Cooling the Sample:

   • After drying, remove the container from the oven using tongs and cool it in a desiccator to room temperature.

5. Weighing Dry Soil (W3):

   • Weigh the container with the dried soil and record the weight as W3.

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Observations:

                                                                            sample-1       sample-2   sample-3  

serial No of container 

Weight of container   W1

weight of container+ wet soil  W2

weight of container + Dry Soil   W3

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Calculation:

Using the formula:

$$w = \frac{(W2 - W3)}{(W3 - W1)} \times 100$$

Perform calculations for each sample and determine the moisture content.

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Result:

The moisture content of the given soil sample is determined as:

$$\text{Average Moisture Content} = \ldots\%$$

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Discussion:

• The moisture content influences the soil's behavior during construction, such as compaction, shear strength, and foundation stability.
• The oven temperature must be strictly maintained at 110°C ± 5°C for accurate results.
• For organic or gypsum-rich soils, a lower temperature (around 60°C to 80°C) may be required to prevent decomposition.