Crushed stone 101- Everything you need to know and more
Aggregate or crushed stone is used in a multitude of different types of building applications. For example, under the majority of concrete flat work, crushed stone or aggregate will be installed as preparatory bedding. That underlying or substrate bedding allows for better drainage away from the underside of the concrete slab and a better distribution of weight or load of the concrete slab above.
The picture below shows an example of a number 57 stone, which is a common type of crushed rock or aggregate that ranges in size from number 5 through 7 and therefore includes stone sizes number 5, number 6, and number 7.