DETERMINATION OF MOISTURE CONTENT



OBJECTIVE

Determine the natural content of the given soil sample.

NEED AND SCOPE OF THE EXPERIMENT

In almost all soil tests natural moisture content of the soil is to be determined. The knowledge of the natural moisture content is essential in all studies of soil mechanics. To sight a few, natural moisture content is used in determining the bearing capacity and settlement. The natural moisture content will give an 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 percentage.

APPARATUS REQUIRED

    1. Non-corrodible air-tight container.  
    2. Electric oven, maintain the temperature between 1050 C to 1100 C. 
    3. Desiccator. 
    4. Balance of sufficient sensitivity. 

PROCEDURE

1. Clean the container with lid dry it and weigh it (W1). 
2. Take a specimen of the sample in the container and weigh with lid (W2). 
3. Keep the container in the oven with lid removed. Dry the specimen to constant weight maintaining the temperature between 1050 C to 1100 C for a period varying with the type of soil but usually 16 to 24 hours. 
4. Record the final constant weight (W3) of the container with dried soil sample. Peat and other organic soils are to be dried at lower temperature (say 600 ) possibly for a longer period. 

  Certain soils contain gypsum which on heating loses its water if crystallization. If itb is suspected that gypsum is present in the soil sample used for moisture content determination it shall be dried at not more than 800 C and possibly for a longer time.

OBSERVATIONS AND RECORDING

Data and observation sheet for water content determination  

S.No.

Sample No.

1

2

3

1

Weight of container with lid W1 gm

 

 

 

2

Weight of container with lid +wet soil W2 gm

 

 

 

3

Weight of container with lid +dry soil W3 gm

 

 

 

4

Water/Moisture content

W = [(W2-W3)/(W3-W1)]´100

 

 

 

   

INTERPRETATION AND REPORTING

  RESULT

The natural moisture content of the soil sample is ________

  GENERAL REMARKS

1. A container with out lid can be used, when moist sample is weighed immediately after placing the container and oven dried sample is weighed immediately after cooling in desiccator.

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

 

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