Thursday, 26 February 2015

Soil water Content Determination (By Oven Drying)

Introduction: 

Soil contains some amount of water in its pores. The water content of soil (w) may be defined as ratio of mass of water to the mass of solids in soil.

W= M2-M1/M3-M1
M1=mass of container with lid
M2 = mass of container with wet soil and lid.
M3= mass of container with dry soil and lid.

Equipment:

 Thermostatically controlled oven, Weighing balance with accuracy of 0.04% accuracy of weight, desiccators, airtight containers, Tongs.
Soil specimen: 90% of soil sample should pass through 425 micron sieve; the minimum quantity should be taken equal to 25 g.


Procedure:

Clean and dry the container, then weight it (M1).
Take the require quantity of wet specimen in container and weight it (M2)
Place the container in oven for 24 hours at temperature of 110±5o c.
When soil has dried remove the sample from oven with help of tongs.
Replace the lid on container cool it; weight the container (M3).

Observations:

M1=mass of container with lid
M2 = mass of container with wet soil and lid.
M3= mass of container with dry soil and lid.
W=M2-M1/M3-M1
W= water content of soil.
Units= expressed in form of % age

Conclusion:

Moisture content in soil determines most of properties of soil, like shear strength, bearing capacity of soil etc. like in case of clay, clay do not have a good intimacy with water. But if it mixed with optimum moisture content (OMC) it provides maximum dry density, it behaves like strong cement stones. In case of construction of water bound macadam roads, making subgrades of roads or making cores of dams clay has to be compacted at optimum moisture content. So a soil engineer must have knowledge about calculation of soil moisture content.








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