Exposed aggregate is a pea-gravel finish. It is acheived by washing or "exposing" the surface of the concrete after the concrete is hard enough to walk on. The cement is blasted off of the surface and the pea gravel becomes exposed. Usually brown in color, exposed agg can create a highly custom look to your concrete project with little contrast to trhe landscape. A heavy brown tone sealer is usually applied to the finished project to protect the exposed pebbles and bring out the color. Exposed concrete can be colored integrally or acid stained to change the colors. It can also be washed at different depths to make for a more smooth or rough texture.