To determine the specific gravity of soil solids

 AIM 

To determine the specific gravity of soil solids.

THEORY  

 

Specific gravity of soil solids is the ratio of weight, in air of a given volume; of dry soil

solids to the weight of equal volume of water at 4ºC.Specific gravity of soil grains gives

the property of the formation of soil mass and is independent of particle size. Specific

gravity of soil grains is used in calculating void ratio, porosity and degree of saturation,

by knowing moisture content and density. The value of specific gravity helps in

identifying and classifying the soil type. 

APPARATUS REQUIRED

1. Pycnometer

2. 450 mm sieve

3. Weighing balance

4. Oven

5. Glass rod

6. Distilled water 

PROCEDURE

1. Dry the pycnometer and weigh it with its cap. (W1)

2. Take about 200gmof oven dried soil passing through 4.75mm sieve into the 

pycnometer and weigh again (W2).

3. Add sufficient de-aired water to cover the soil and screw on the cap.

4. Shake the pycnometer well and remove entrapped air if any.

5. After the air has been removed, fill the pycnometer with water completely.

6. Thoroughly dry the pycnometer from out side and weigh it (W3).

7. Clean the pycnometer by washing thoroughly.

8. Fill the cleaned pycnometer completely with water up to its top with cap screw on.

9. Weigh the pycnometer after drying it on the outside thoroughly (W4). 

10.Repeat the procedure for three samples and obtain the average value of specific gravity.

 

RESULT

 

Average specific gravity of soil solids G =