Concrete Aggregates Clause Samples
The 'Concrete Aggregates' clause defines the requirements and standards for the materials used as aggregates in concrete mixtures. It typically specifies acceptable types, sizes, and quality of aggregates, as well as testing and approval procedures before use in construction. By setting these criteria, the clause ensures that only suitable aggregates are incorporated, which helps maintain the structural integrity and durability of the finished concrete, thereby reducing the risk of defects or failures in the project.
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.
Concrete Aggregates. Concrete aggregate shall conform to the requirements of subsection 311.2.2 and 311.2.3 under Item 311 of Volume II, (Blue Book) and ASTM C 33 for lightweight aggregates, except that aggregates failing to meet these specifications but which have been shown by special that or actual service to produce concrete of adequate strength and durability may be used under method (2) of determining the proportion of concrete, where authorized by the Engineer. Except as permitted elsewhere in this section, the maximum size of the aggregate shall be not larger than one-fifth (1/5) of the narrowest dimensions between sides of forms of the member for which the concrete is to be used nor larger than three-fourths of the minimum clear spacing between individual reinforcing bars or bundles of bars or pretensioning strands.