# Introduction of Bulk Density and % of Voids of Fine Aggregates

In construction, the term ‘aggregate’ refers to a range of particulate materials including sand, gravel, crushed stone, slag, and recycled concrete. Bulk density is a measure of an aggregate’salternative to principal weight per unit volume. It is calculated by dividing the weight of an aggregate by its volume. The bulk density of an aggregate is affected by the porosity of the particles and the voids between them. The percentage of voids is a measure of the empty space within an aggregate, and is calculated by dividing the volume of voids by the total volume of the aggregate. The bulk density and percentage of voids of an aggregate are important properties that influence the strength and workability of concrete.

## What Is Bulk Density and % of Voids of Fine Aggregates

• The bulk density of fine aggregates is the mass of the aggregate particle divided by the volume that it occupies
• The % of voids is the percentage of the overall volume that is empty space.

## Types of Bulk Density of Fine Aggregate

• There are three types of bulk density of fine aggregate:

1

• Total bulk density: This is the density of the aggregate when all voids are filled.

2

• Loose bulk density: This is the density of the aggregate when all voids are not filled.

3

• Tamped bulk density: This is the density of the aggregate when all voids are filled and compacted.

## Types of Fine Aggregate According to Packing

• There are three types of fine aggregate according to packing:

1

• Coarse sand: This type of fine aggregate has a large diameter and is typically used in concrete mixes.

2

• Medium sand: This type of fine aggregate has a medium diameter and is often used in mortar mixes.

3

• Fine sand: This type of fine aggregate has a small diameter and is often used in plaster mixes.

## How to Calculate % of Voids in Fine Aggregates

• There are a number of ways to calculate the percentage of voids in fine aggregates, but the most common method is to use the coarse aggregate method
• This method simply uses the proportion of coarse aggregate to fine aggregate to calculate the percentage of voids
• To calculate the percentage of voids using this method, first determine the total volume of the fine aggregate
• This can be done by weighing the fine aggregate and using the following equation:

Total Volume of Fine Aggregate (VFA) = Weight of Fine Aggregate/Bulk Density of Fine Aggregate

Once the total volume of the fine aggregate is known, the percentage of voids can be calculated using the following equation:

% Voids = (1 – Coarse Aggregate/Total Volume of Fine Aggregate) x 100

## Conclusion

The bulk density of an aggregate is the mass of the aggregate that is required to fill a given volume. The % of voids is the volume of the voids in the aggregate that is required to fill a given volume. The voids in the aggregate are the spaces between the particles of the aggregate.

The bulk density and % of voids are important properties of aggregates that are used in concrete. The bulk density of the aggregate affects the amount of concrete that is required to fill a given volume. The % of voids in the aggregate affects the amount of water that is required to fill a given volume.