Water content and void ratio in soil:
Question Three
A sample of saturated clay was placed in a container and weighed. The weight was 6N. The clay in its container was placed in an oven for 24 hours at 105o The weight reduced to a constant value of 5N. The weight of the container is 1N. If Gs = 2.7, determine the; –
- water content
- void ratio
- bulk unit weight
- dry unit weight
- Effective unit weight.
Solutions
Water content
NOTE
The water content (w), also known as natural water content or natural moisture content, is the ratio of the weight of water to the weight of the solids in a given mass of soil. This ratio is usually expressed as percentage. When voids are completely filled with air, water content is equal to zero (dry soil)
Moisture content is one of the most important index properties used for the correlation of soil behavior and its index properties. The moisture content of the soil is used to express the phase relationships of water, air, and solids in a given volume or weight of the material.
Water content determination purpose: This test is performed to determine the water (moisture) content of soils. The water content is the ratio, expressed as a percentage, of the mass of “pore” or “free” water in a given mass of soil to the mass of the dry soil solids.
The most crucial factor in civil engineering designs is the proper assessment of the water content of on-site soil because its mechanical reaction to weight loading ultimately depends on its moisture content at the time of building.
