Heavyweight Concrete: Measuring, Mixing, Transporting, and Placing

Description

The procedures for measuring, mixing, transporting, andplacing heavyweight concrete are similar to those used in con-ventional concrete construction; however, special expertiseand thorough planning are necessary for the successful com-pletion of this type of concrete work. The use of heavyweightconcrete in construction is a specialized field, and it is advis-able that the work be undertaken by qualified personnel.

Heavyweight concrete is used in counterweights of bas-cule and lift bridges, but it is generally used in radiationshielding structures and differs from normal weight concrete by having a higher density and special compositions to im-prove its attenuation properties. When the heavyweight con-crete is used to absorb gamma rays, the density and materials costs are of prime importance.1

When heavyweight shieldingconcrete is used to attenuate neutrons, sufficient material oflight atomic weight, which produces hydrogen, should be in-cluded in the concrete mixture.2 Some aggregates are usedbecause of their ability to retain water of crystallization at el-evated temperatures, which ensures a source of hydrogen notnecessarily available in heavyweight aggregates.