Abstract
Based on the compiled literature and the availability of materials that
could be used, concrete was selected as the best shielding material. Further work
was carried out to develop a specific mixture that would shield the radioactive
energies. The important special concrete ingredients that were considered in the
mix design were high density aggregates and boron-containing aggregates.
Various high density concrete mixtures of w/c (water/cementitious ratio) = 0.42,
0.45, 0.5 and 0.6, were prepared and adjusted appropriately in order to obtain the
desired mix characteristics.
The final (high density shielding concrete) mix produced was workable and
cohesive with average 28- day compressive cube strength of 30 MPa, w/c = 0.51
and density of 4231 kg/m3. The concrete had high slump with a height and spread
of 230 mm and 510 mm respectively. It was composed of CEM 52.5 N, silica
fume, water, hematite sand, hematite stones, steel shots, colemanite and chemical
admixtures.