This is the least expensive finish available in external residential applications. It is used mainly for areas that will eventually be tiled and bases for timber decks or pavers. It is also used in large driveways or areas where visual appeal are less of a consideration. Over time when exposed to the elements and constant traffic the surface can wear to expose a small amount of the rock in the mix but this is rarely a problem when used in the above applications.
We still use plain grey broom finished concrete around many new homes where clients intend to use a paint or other surface application in the future to cover it. This can be a disappointing or expensive mistake in some instances. Please get in touch if you need more info.