HEAVY WEIGHT CONCRETE CONTAINING SILICA FUME USED AS RADIATION SHIELDING

This research was carried out in order to produce a heavy weight concrete containingsilica fume with different percentages, for studying the effect silica fume on bothmechanical and nuclear properties of concrete containing silica fume was investigated.The investigated concrete mixtures composed of local Barite ore (as coarse aggregate)and Serpentine ore (as fine aggregate) mixed with ordinary Portland cement and tapwater. Superplasticizer was added as chemical admixture to enhance the workability offresh concrete. Cement was replacing with Silica fume by weight as a percentage ofcement ranged (0%, 5%, 10% and 15%), Slump and unit weight of fresh concrete weremeasured. Compressive strength, indirect tensile strength, elastic modulus, andultrasound pulse velocity tests were carried out on hardened concrete at various agesafter casting. Furthermore, nuclear radiation attenuation properties (γ-ray) of suchconcretes were experimentally and theoretically evaluated. A collimated beam ofgamma rays emitted from Eu-152 source was used as a source of gamma rays. Theexperimental measurements of the attenuation of gamma rays at different energies insuch concrete samples have been carried out using 3” × 3” NaI (Tl) scintillation spectrometer. The theoretical calculations of both the total mass attenuation coefficientsfor gamma rays were carried out using the XCOM (version 3.1) computer program andcross-section data base for elements from Z= 1 to 100, and the elemental composition ofconcrete mixes. The results indicate that, in general, the rubberized heavy weightconcrete could be used more successfully than conventional concrete in the field ofradiation shielding.