Concretes Containing Hematite for Use as Shielding Barriers

Heavyweight concrete is widely used for radiation shielding of nuclear reactors and other structures that require radiation impermeability. Aggregates play here an important role - while hematite and other iron ores are commonly used for the purpose. However, little information on properties of hematite-containing concrete other than radiation shielding data has been reported. We have studied effects of different concentrations of hematite (10 to 50 volume % at 10 % intervals) on physical and mechanical properties of concrete. A unique water-to-cement ratio of 0.42 kg/m(3) and 400 kg/m(3) cement content was selected. Addition of hematite increases the unit weight (density) so that a smaller thickness of concrete is required to provide radiation shielding. After 30 freeze-thaw cycles the plain concrete looses 21.3 % of its compressive strength while the composite containing 10 % hematite looses only 7.8 % of the strength. Concrete and hematite composites have lower drying shrinkage than plain concrete, thus lowering stresses resulting from the shrinkage.