What is the primary purpose of conducting a Pycnometer test in soil mechanics?
- ATo determine the specific gravity of soil solidsCorrect
- BTo measure the water content of soil
- CTo assess the compaction of soil
- DTo calculate the permeability of soil
Solution
Concept
Purpose of pycnometer test in soil
Formula
NONE
Step-by-step solution
1. A pycnometer is a glass vessel used in soil laboratories to measure volumetric displacement of liquids. 2. Its primary function in geotechnical testing is determining the specific gravity of soil particles. 3. It can also be used to quickly estimate water content if the specific gravity is already known. Answer: A
Explanation
A pycnometer is a calibrated glass vessel used in soil mechanics laboratories primarily to determine the specific gravity of soil solids. By measuring the mass of displaced water, the specific gravity of soil particles can be precisely calculated. Therefore, option A correctly identifies the primary purpose of the pycnometer test.
Why the other options are wrong
B) Water content is primarily determined using the oven-drying method or rapid moisture meter. C) Soil compaction is assessed using the Proctor compaction test. D) Permeability of soil is determined using constant head or falling head permeameter tests.
Shortcut
Pycnometer test = Determines specific gravity (G) and water content of soil.
Common mistake
Selecting option B or C by confusing the primary purpose of specific gravity determination with moisture content testing.
Correct answer: A) To determine the specific gravity of soil solids