AGGREGATES

AGGREGATES

Fine and coarse aggregate make up the mixture of concrete, Sand, crushed stone, natural gravel are used for this purpose. Recycled aggregates from construction are used as patrol replacement of natural aggregates increasingly, while a number of manufactured aggregates (such as cooled, slag, bottom ash are also permitted).

Fine aggregate (sand)

Sand is one of the important constituent of concrete, is according to Sengupta (2008), a natural product from riverbeds, the mining of which is expensive Sharp river quartzite sand that is free of clay, loam, dirt and any organic or chemical matter is used. It is sieved with the 3.35mm zone of British standard (BS) test sieves. The sand has a specific gravity of 2.66 and an average moisture content of 0.90%. Increase compressive strength, but since the cement content of sand Crete is small, so is the amount of water that is added to the sand/cement mix to cure it. Adding more solid materials makes the mix much less fluid, making it difficult to cast into blocks. Fine aggregate should have the following qualities:

• Good sand should have coarse and angular grains of pure silica
• The grains of sand should be hard, strong and durable
• It should be free from silt, clay or any such salts that may attack the reinforcement
• It should be free from any organic matter
• It should be well graded (i.e. should contain in suitable proportions particles of various     sizes).
• It should be free from hygroscopic matter