High density concrete

High density or heavyweight concrete is concrete with a density greater than 2600kg/m³. Its primary use is in radiation shielding, either in nuclear power plants or in radiation therapy units. It can also be used as ballast in offshore locations such as pipelines.

High density concrete can be made from natural heavyweight aggregates such as barites or magnetite which typically give densities of 3500kg/m³ and 3900kg/m³ respectively. They can also be made using iron or lead as a replacement for a portion of the aggregate. These give even greater densities of 5900kg/m³ for iron or 8900kg/m³ for lead.

High density concretes should be specified to BS 8500-1 as a designed or a prescribed concrete in the same way as normal density concrete, with an additional clause specifying the target density. BS 8500-1 states that the density for heavyweight concrete should not be less than 130kg/m³ less than the specified target density. There is no upper limit on the density.

Heavyweight concretes can be designed in the same way as normal weight concretes, but the additional self weight should be taken into account. They can be transported and placed in the same way as normal weight concretes but the additional density means that smaller volumes can be transported and placed.