The effect of replacing sand by iron slag on physical, mechanical and radiological properties of cement mortar

In the present study, the effects of replacing sand by high percentages of basic-oxygen furnace slag on the compressive strength, bulk density and gamma ray radiation shielding properties of mortar have been investigated. Cement mortar of mix proportion 1:3 including various percentages of iron slag was designed. The percentages of replacement were 0%, 40%, 80% and 100% by weight of fine aggregate. Mortar mixes were prepared with water cement ratio of 0.44 and cured in potable water for 90 days. The attenuation measurements were performed using gamma spectrometer of NaI (Tl) detector. The utilized radiation sources comprised 137Cs and 60Co radioactive elements with photon energies of 0.662 MeV for 137Cs and two energy levels of 1.17 and 1.33 MeV for the 60Co. Likewise, half value layer (HVL), tenth value layer (TVL) and the mean free path (mfp) for the tested samples were measured. Results of this investigation indicated that the strength properties of mortars increased significantly upon replacing sand partially by iron slag. It was also observed that the inclusion of iron slag as partial replacement with fine aggregate enhances the bulk density of mortar. On the other hand, full sand replacement by iron slag has significant effects on shielding efficiency in thick shields, as it reduces the capture gamma rays better than normal mortar incorporating sand.