Oven Drying Method is used for determining the amount of water present in a specific soil.
1. Apparatus Required
i) Thermostatically controlled oven maintained at a temperature of 110 ± 5oC
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 lid
2. Quantity of Soil Required for Water Content Determination
|Size of particles more than 90% of passing||Minimum Quantity ( grams)|
|2 mm sieve||50|
|4.25 mm sieve||200|
|10 mm sieve||300|
|20 mm sieve||500|
|40 mm sieve||1000|
3. Procedures in Oven Drying Method of Soil
i) Clean the container, dry it and weigh it with the lid (Weight ‘W1‘).
ii) Take the required quantity of the wet soil specimen in the container and weigh it with the lid (Weight ‘W2‘).
iii) Place the container, with its lid removed, in the oven till its weight becomes constant (Normally for 24hrs.).
iv) When the soil has dried, remove the container from the oven, using tongs.
v) Find the weight ‘W3‘ of the container with the lid and the dry soil sample.
Let us consider,
Weight of container with wet soil = W 1
Weight of container with dry soil = W 2
Weight of Empty container = Wc
Weight of soil only = W1 – Wc
Weight of dry soil only = W2 – Wc
Weight of water = W1 -W2
WATER CONTENT = (Ww / Ws) 100% = [(W1 – W2) / (W2 – Wc)] * 100%
4. Observations and Calculations of Oven Dry Method
|Sl. No.||Observations and Calculations||Determination No.|
|2||Mass of empty container (M1)|
|3||Mass of container + soil (M2)|
|4||Mass of container + dry soil (M3)|
|5||Mass of water Mw= M2 – M3|
|6||Mass of solids, Ms= M3 – M1|
|7||Water content= (5)/(6)x100|
5. Result of Oven Dry Method
Water content of the given soil sample = ______%
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 to remove out from the oven.
c. For accurate calibration, the thermostat should be kept on checking on a regular basis.
|Read Also: Liquid Limit Test of Soil|