What is the function of aggregate in concrete?

The function of aggregate in concrete is primarily to provide bulk and strength. Aggregates, which can be composed of natural or manufactured materials, account for a significant portion of the concrete mixture. They include coarse aggregates (gravel or crushed stone) and fine aggregates (sand).

The presence of aggregates enhances the compressive strength of concrete, as they create a framework that supports the hardened cement paste. This enables the concrete to bear loads effectively, ensuring durability and structural integrity in various applications, from buildings to bridges. By filling the voids in the cement matrix, aggregates also help to optimize the material's density and workability.

While other factors, such as the mix design and the proportions of water and cement, also contribute to the overall performance of concrete, it is the aggregates that primarily provide the necessary bulk and help impart strength to the finished product.