Into how many groups are aggregates classified?

Aggregates are classified into two main groups: fine aggregates and coarse aggregates. Fine aggregates consist of smaller particles, typically less than 4.75 mm in size, and are primarily used to fill voids between larger particles in a concrete mix. Coarse aggregates, on the other hand, include larger particles, generally greater than 4.75 mm, and serve as the primary structural framework in concrete.

The distinction between these two groups is essential in construction and materials engineering as it influences the mechanical properties of concrete, such as strength, workability, and durability. Each type of aggregate plays a specific role in determining the overall performance of concrete in various applications, thus reinforcing the importance of understanding their classification in roadway and structural projects.