HOW TO DETERMINE WATER CONTENT OF SOIL ON SITE USING ALCOHOL METHOD? (IS-2720-PART-2)

Water Content Test of Soil by Alcohol Method

Purpose

It is a rapid method of determining the moisture content. Though less accurate, it is more suitable as a field test. The method shall not be used if the soil contains a large proportion of clay, gypsum, calcareous matter or organic matter.

Apparatus

  • Evaporating Dish– 10 to 15 cm in diameter.
  • Palette Knife or Steel Spatula-having a blade 10 cm long and 2 cm wide.
  • Balance – of sufficient sensitivity to weigh the soil samples to an accuracy of 0.4 percent of the mass of the soil taken for the test.
  • Methylated Spirit
methylated spirit (alcohol) used for on site determination of water content of soil
methylated spirit (alcohol) used for on site determination of water content of soil

Procedure

  1. Clean the evaporating dish, dry and weigh (W1).
  2. Take appropriate quantity of soil specimen in the evaporating dish and weigh (W2).
  3. Pour methylated spirit over the soil at the rate of about one millilitre for every gram of soil taken so that the soil is well covered.
  4. Work the methylated spirit well into the soil with the palate knife and break up any large lumps of soil.
  5. Place the evaporating dish on a surface which will not be affected by heat and ignite the methylated spirit. Stir the soil constantly with the spatula or knife taking care to see that none of the soil is lost.
  6. After the methylated spirit has burnt away completely, allow the dish to cool and weigh it with the contents (W3).

Calculations

The percentage of water content shall be calculated as follows:

W = [(W2 – W3) / (W3 – W1)] * 100

Where,

W = water content present

W1 = mass of dish in g

W2 = mass of dish with wet soil in g

W3 = mass of dish with dry soil in g

Reference

IS – 2720 – Part – 2

7 thoughts on “HOW TO DETERMINE WATER CONTENT OF SOIL ON SITE USING ALCOHOL METHOD? (IS-2720-PART-2)”

  1. One can understand that it is not suitaible for organic soils and soils containing gypsum.But why this method is not suitaible for clay?

    Reply
    • Because organic matter would burn, lose mass and overstate the moisture calculation. Similarly limestone type material can decompose and offgas with the same outcome.

      Reply
    • The calcicum content or simply gypsum has loosely bound water of hydration also known as structural water. At the normal temperature of 110+-5 degree celcius will bring out that structural water. Hence this will give us false readings. So we want temprature not more than 60-80 degree celcius for such soils. In this method there is no controle over the temprature. Hence this method is not used for soil containing calcareous content.
      Same for organic soil, at higher temperature than 60 degree celcius, organic matter will decompose and organisms will be killed. Hence this will not show the true water content for the organic soil. Hence this soils cannot be be anyalised by this method.

      Reply

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