Difference Between Fine Aggregate and Coarse Aggregate

The words fine and coarse aggregate are used in conjunction with materials that are used to mix with concrete in construction activities. Aggregate is a composite material that helps in binding the concrete together as it adds strength and reinforcement to concrete. Aggregate is mixed with cement to form concrete that is used to lay the foundation of a road or even a roof in a building. Many materials are used to form aggregate such as sand, gravel, stone, crushed rock, and sometimes even waste slug from iron and steel industry. Aggregate is broadly classified as fine and coarse. The differences between these two types of aggregate will be discussed in this article.

Ingredients play a very important role in the performance of concrete. In low to moderate strength concrete, crushed stone that is coarse happens to be low cost as it helps in making up the volume needed to fill the foundation. But when high performance concrete is required where the strength of concrete is close to the strength of the aggregate, fine aggregate is needed so that there is no weakness in the structure.

It is important to mix both fine and coarse aggregate in concrete as coarse aggregate cannot cover the surface area in the manner that fine aggregate does. It is important to remember that the contribution of coarse aggregate in covering the surface area is much lower than fine aggregate. As far as shape is considered, spherical aggregate is considered the best to achieve maximum packing density followed by cubical and flaky shapes.

Oversize aggregate creates problems in setting the concrete in an easy manner on the site. Whether going for coarse or fine aggregate it has to be remembered that there should not be great variation in the size of the particles as it hampers a good performing concrete. To have a concrete that performs satisfactorily, particle size should be as uniform as possible whether coarse or fine aggregate is used. It is obvious that the concrete placer wants aggregate to be such that concrete can be placed and compacted with very little effort. To achieve this objective, the best way is to go for spherical aggregate particles.