Ballast: These are the coarsest form of aggregates. Generally used for concrete mixes, in concreting foundations, in filling gaps and even used as a stability-aid for vehicles, boats, and ships.
Armour Rocks: 500mm to 1000mm in size. These are used to prevent/mitigate erosions. Typically used as protection to canal banks and to armor shorelines, streambeds, and other shoreline structures for stabilization and is used in applications where its mass can provide scour protection from fast flowing waves or water currents.