Gravel and bouldery fraction
At deposits of sand and gravel often there are boulders. If they were not processed on crushed stone and sand, then gravel and bouldery mix turns out. It contains not less than 10% of gravel and at least 5% of boulders.
Need for gravel and bouldery mix arises when carrying out widely a range construction and a roadwork. Because of the large size of the particles included in this mix it gained wide popularity when carrying out the most "rough" works. For example: as filling of railroad tracks.