http://www.gharexpert.com/category/1398/Coarse-Aggregate-0.aspx?CatID=1398Coarse Aggregate information at GharExpert.com. Coarse Aggregate shall consist of natural occurring stones ( crushed, uncrushed or broken) . It shall be hard, strong, dense, durable, and clean.http://www.gharexpert.com/articles/Coarse-Aggregate-1502/Purchasing-Guidelines-Coarse-Aggregate_0.aspx?PL=2&ArticleID=1502&CatID=1398Sub standard material reduces the strength of RCC, Reinforced Cement Concrete, by 10 to 30 %. Use these steps to ensure the procurement of right quality material at right pricehttp://www.gharexpert.com/articles/Coarse-Aggregate-1028/Specification-Coarse-Aggregate_0.aspx?PL=2&ArticleID=1028&CatID=1398Coarse Aggregate consists of crushed, uncrushed or broken stones. Check the grading of sand for proper sizes.