Radiation shielding concrete is used to shield X-rays, and Y-rays in the concrete, as building materials for devices containing radioactive sources like atomic reactors, particle accelerator and so on. By increasing unit weight of radiation shielding concrete and using crystal water in cement stone or aggregate to slow down fast neutron, the shielding effect to X-rays and Y-rays can be improved.
To increase the unit weight of radiation shielding concrete, heavyweight aggregate (containing iron ore, barite, iron sand, steel and so on) is always adopted. The density of concrete is about 3500kg/m3; that of concrete with steel is 5500kg/m3. High density cement like barium cement and strontium silicate cement is adopted when necessary. The proportions of separate component materials in radiation shielding concrete are quite different. In order to prevent segregation and to improve the effect of consolidation, special measures like grouting are available during casting of the concrete.
Hydrogen nucleus could defend the fast neutrons, and water has more hydrogen elements, so material with more crystal water can be used for radiation shielding concrete. To increase the content of crystal water, bauxite cement and gypsum alumina expansive cement should be used for cementing material. Radiation shielding concrete with admixture or aggregate containing boron and lithium can absorb more neutrons.