Explain with sketch specific gravity determination by pcynometer.
Determination of specific gravity by pycnometer test:
Precedure :-
1. Dry the pycnometer and weigh it with its cap (W1)
2. Take about 200 g to 300 g of oven dried soil passing through
4.75mm sieve into the pycnometer and weigh again(W2)
3. Add water to cover the soil and screw on the cap.
4. Shake the pycnometer well and connect it to the vaccum pump to remove entrapped air for about 10 to 20 minutes.
5. After the air has been removed, fill the pycnometer with water and weigh it (W3).
6. Clean the pycnometer by washing thoroughly.
7. Fill the cleaned pycnometer completely with water up to its top with cap screw on.
8. Weigh the pycnometer after drying it on the outside thoroughly (W4).