What is stone used to surface roads?

The stone used to surface roads is typically called aggregate. Aggregate is a mix of stones and sometimes sand and gravel that is used in the construction of roads. The most common types of stones used in road surfaces are granite, basalt, limestone, and gravel. The size of the stones used can vary depending on the road's intended use and geographic location, but usually ranges from 0.25 to 1 inch in diameter.

The process of surfacing roads with aggregate involves laying down a base layer of larger stones, followed by a layer of smaller stones, and finishing with a layer of gravel. This helps to create a stable surface that can hold up to heavy traffic and withstand various weather conditions. Different types of aggregate can also be used to create specific surface properties, such as high skid resistance or low noise levels.

Aggregate is also used in the construction of sidewalks, bike paths, and parking lots, as well as in the production of concrete. However, it is important to note that the mining and transportation of aggregate can have environmental impacts, such as air and water pollution and habitat destruction. To mitigate these impacts, sustainable sourcing and transportation practices can be implemented.