Heavy Concrete:
Heavy concrete is also called as heavy-weight concrete or high density concrete. Heavy concrete can be produced by using especially heavy weight aggregates and compacting well by mechanical means. Both natural and artificial heavy aggregates are available. The huge density aggregates are heavy iron ores such as magnesite or haematite and etc. Well natural sand is used as fine aggregate. The density of such concrete is around 3400 kg/m3. The heavy aggregate is crushed to produce a fine material and this is used as a fine aggregate instead of sand to produce extra heavy concrete. Steel shots and iron punching are the artificial aggregates. Artificial aggregate used should be free from oil, which prevents bond. The artificial aggregates are very costly compared to natural aggregates. Heavy concrete produced from artificial aggregates may have a density of about 5500 kg/m3.The density of heavy weight concrete varies from 3360 to 5280 kg/m3.
Heavy weight concretes can be suitably used for gravity dams, retaining walls or special atomic power plants, vessels, etc. It is also suitable for preparing counter- balance weights for lift bridges or ballast blocks for ships, whereas the high density of heavy concrete reduces the volume of concrete required to produce the same dead weight, leading to economy.