What does maximum dry density mean?

The dry density obtained by the compaction of soil at its optimum moisture content. Ref: Hammond.

What is the importance of knowing the optimum moisture content and the maximum dry density for a particular soil?

Optimum moisture content/maximum dry density (OMC/MDD) – when placing soils as fill materials, it is important to achieve suitable compaction, primarily in order to reduce the susceptibility of a soil to settlement.

Why is maximum dry density of soil determined?

The determination of maximum dry density and optimum moisture content of the soil is a measure of compaction level of soils. Both the tests help to determine the optimum moisture content that is required for soil to attain maximum compaction i.e maximum dry density for performing construction.

Why does dry density decrease with moisture content?

When we added water to it, the water forms a thin film around the each soil particle and this film helps the particles to contact with each other. If water is added beyond the optimum moisture content, the water will occupy the extra space since there is no air volume and dry density will reduce.

Why is optimum moisture content of soil important?

The optimum moisture content provides the maximum dry unit weight that can be obtained. The increase in the dry unit weight means improving the soil properties; increased strength, decrease in permeability and compressiblity. So it is better to use the optimum moisture content.

What does dry density mean?

The weight of a unit volume of a dry sample of soil, after the latter has been heated at a temperature of 103 degrees C.

Why is dry density used as a measure of compaction?

As water is added to a soil ( at low moisture content) it becomes easier for the particles to move past one another during the application of the compacting forces. As the soil compacts the voids are reduced and this causes the dry unit weight ( or dry density) to increase.

What is dry density of soil?

Dry density of soil is defined as the ratio of Mass of solids to the total volume of the soil. It is represented by. To obtain relationship between the moisture content and dry density, multiply the numerator and denominator of expression of dry density with “M” which is mass of soil sample.