I have a job requiring heavyweight shielding concrete. How do I get this type of concrete?

Heavyweight concrete is used in walls as a protection from radiation of X-rays, gamma rays and neutrons. The effectiveness of shielding depends on the thickness of walls and weight of concrete. Heavyweight concrete permits reduction in wall thickness. Aggregates of high specific gravity are used in this type of concrete. The desired weight of the concrete is usually specified and the type of aggregate is also indicated.The proportions of the mix depend on shielding requirements, desired weight and job conditions. A few trial mixes are suggested with the materials to be used on the job. Physical properties, such as strength and volume change, are similar to normal-weight concrete. Mixing, placing and curing follow common concreting practices; it is important, however, to avoid overloading the mixer. Reduce batches to 1/2 of the rated mixer capacity. (One cubic yard of normal concrete weighs about 2 tons while the heavyweight concretes may weigh from 2 1/2 to 4 tons per cubic yard.)

Aggregate

Specific Gravity

Weight of Concrete (lb. per cu. ft.)

Limonite

3.4-3.8

180-210

Barite

4.0-4.4

220-230

Ilmenite

Hematite

Magnetite

4.2-4.8

210-260

Ferrophosphorus

5.8-6.3

280-330