Common use of Concrete Aggregates Clause in Contracts

Concrete Aggregates. All concrete aggregates (sand & gravel) shall be furnished by the Contractor from any source approved by the Engineer. They shall be free from organic material, lumps of soft material, clay, chalk, lime, peat, loam, soft clayey shale or decomposed stone, vegetable and other impurities that may be harmful to concrete. Sand for concrete shall be free of stones larger than 2 mm and not include significant amounts of silt and clay. If sand, when dried after wetting, adheres together then it shall be considered unsuitable. Gravel for concrete shall be uniformly graded and consist of hard and dense rock. The gravel shall be free of materials finer than 5 mm and the surface shall be clean. Gravel for use in reinforced concrete shall be crushed rock. Generally, crushed rock particles shall be spherical or cubical in shape. The maximum nominal size of the gravel shall be (30) mm in mass concrete, forty (20) mm in structural concrete and twenty (20) mm in other thin concrete structures like slabs.