Test for Moisture on soil or Determination of Water Content on soil

Test for Moisture content on soil or Determination of Water Content on soil

Following test conducted on soil for determination of water content or Moisture

1 Oven Drying Method 2 Sand Bath Method 3 Alcohol Method 4 Calcium Carbide Method 5 Pycnometer test 6 Radiation Method 7 Torsion Balance Method

Oven Drying Method

Oven drying method is the most accurate and simplest method for water content determination. In this method complete drying of soil sample occur and water content in sample is calculated accurately by a maintained temperature in the oven ( 105° C to 110° C) for 24 hours. Note: For highly organic soils a low temperature of about 60° C is preferable. If Gypsum is present, the temperature should not be more than 80° C but for a long time.

Table of Contents

•   1. Apparatus Required  
•   2. Quantity of Soil Required for Water Content Determination  
•   3. Procedures in Oven Drying Method of Soil  
•   4. Observations and Calculations of Oven Dry Method  
•   5. Result of Oven Dry Method  
•   6. Precautions in Oven Drying Method  

 

The Oven Drying Method is used to determine the water content in a specific soil.

This method is necessary to understand the bearing capacity as well as the probable settlement of the soil. It is carried out in the laboratory itself.

 

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  1. Apparatus Required  

i. Thermostatically controlled oven maintained at a temperature of 110 ± 5^oC

ii. Weighing balance, with an accuracy of 0.04% of the weight of the soil taken 

iii. Air-tight container made of non-corrodible material with a lid

iv. Tongs

 

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  2. Quantity of Soil Required for Water Content Determination  

Size of particles more than 90% of passing	Minimum Quantity ( grams)
425-micron sieve	25
2 mm sieve	50
4.25 mm sieve	200
10 mm sieve	300
20 mm sieve	500
40 mm sieve	1000

 

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  3. Procedures in Oven Drying Method of Soil  

The procedure for the oven drying method can be listed as follows:

i. The air-tight container along with its lid must be first weighed(W1).

ii. The specimen sample is then taken in the container, and the weight of a container along with the lid and sample is taken, say W2.

iii. Then, the container is left in the oven. The specimen is dried to a constant weight at temperatures ranging from 105 to 110 degrees Celsius for about 16 to 24 hours.

iv. The container, along with the lid and the dried sample, are finally weighed(W3).

v. The moisture content is then calculated using the following formula:

W= [ (W2-W3) / (W3-W1) ] * 100

Where,

W1= Weight of the container with a lid in grams

W2= Weight of the container with lid and wet sample in grams

W3= Weight of the container with lid and dry sample in grams

Note: To get an accurate value, a minimum of three soil samples should be taken to test, and average water content should be taken as a result. 

 

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  4. Observations and Calculations of Oven Dry Method  

Sl. No.	Observations and Calculations	Determination No.
		1	2	3
Observation
1	Container No.
2	Weight of empty container (W1)
3	Weight of container + soil (W2)
4	Weight of container + dry soil (W3)
Calculations
5	Weight of water Mw= M2 – M3
6	Weight of solids, Ms= M3 – M1
7	Water content= (5)/(6)x100

 

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  5. Result of Oven Dry Method  

Water content of the given soil sample = ______%

 

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  6. Precautions in Oven Drying Method  

a. Temperature of the oven should be maintained between (105°-110°)C.

b. Wait to cool for the dry soil in a container to remove from the oven ( or use tongs).

c. For accurate calibration, the thermostat should be kept on checking regularly.