A group of rocks is known as an aggregate. While it sounds very simple and unimportant, people and vehicles depend upon aggregates for their transportation needs. These small rocks come in a variety of sizes and materials that have been mined. The majority of them are used to form a foundation or bed for roads being built. Without them, roads would sag and crumble due to weather as well as wear and tear.
Roads are built from the ground up. The road bed must be prepared and layers of support are added. These support layers consist of aggregates such as gravel, small stones, ground stone or sand. Each layer provides a base for the layer above. In this manner, the road surface is supported as vehicles go over it. These layers are also a foundation that helps contain and control rain water to keep the road surface as safe as possible.