Bulk Density and Water Content Relationship

Bulk Density:
Bulk density is a measure of the mass of dry soil per unit volume, which includes both solid particles and pore spaces. It is an important property of soil that affects various engineering and agricultural applications.

Void Ratio:
Void ratio is the ratio of the volume of voids (pore spaces) to the volume of solids (soil particles) in a given soil sample. It is a fundamental parameter used to characterize the porosity and compaction of soils.

Relationship between Bulk Density and Water Content:
The water content of a soil sample significantly influences its bulk density. As the water content increases, the bulk density generally decreases. This is because water occupies space between soil particles, creating more voids and reducing the overall density.

Given Information:
- Bulk density at 5% water content: 1.80 g/cm^3

Effect of Water Content on Bulk Density:
When the water content of a soil increases, the bulk density decreases. This is because the added water fills the pore spaces between soil particles, reducing the solid volume and increasing the void volume. Therefore, the bulk density decreases.

Calculation:
To determine the bulk density at 10% water content, we need to consider that the void ratio remains constant. This means that the ratio of void volume to solid volume does not change.

Assumption:
For simplicity, let's assume that the soil sample is initially saturated at 100% water content. Therefore, the void ratio is maximum, and the bulk density is minimum.

Steps:
1. Determine the initial void ratio (e_initial) and bulk density (ρ_initial) at 100% water content.
2. Calculate the dry density (ρ_dry) at 0% water content by subtracting the water content (0%) from the bulk density at 100% water content.
3. Determine the initial dry soil volume (V_initial_dry) by dividing the dry density (ρ_dry) by the initial bulk density (ρ_initial).
4. Calculate the dry soil volume (V_dry) at 5% water content by dividing the water content (5%) from the initial dry soil volume (V_initial_dry).
5. Determine the bulk density (ρ_10) at 10% water content by dividing the dry density (ρ_dry) by the sum of the dry soil volume (V_dry) and the water content (10%).

Summary:
The bulk density of a soil at a water content of 5% is 1.80 g/cm^3. By assuming a constant void ratio, we can calculate the bulk density at a water content of 10%. This relationship between bulk density and water content is important in understanding the compaction and porosity characteristics of soils.