Effect of F-Ba and Pb-Zn tailing on the mechanical and radiation shielding properties of cement mortars

The use of mine waste and tailing in concrete and mortar has widely expanded in the past years. Several studies aim to contribute to the recovery of these rejects and preserve natural raw materials, on the other hand, to improve the physio-mechanical performance of concrete. In the present investigation, the impacts of Pb-Zn and F-Ba as fine aggregate replacement in mortar were analyzed. The outcomes indicated that substitution materials affect the mechanical strength and gamma radiation shielding properties of the mortar. In this regard, the compressive strength of samples made with substitutions of 5%, 10% and 20% of F-Ba tailings were slightly decreased with those of the reference test. However, the replacements with Pb-Zn tailings cause a significant strength decrease of mortar samples (from 68% to 94%). On the contrary, the flexural strength was improved adding one of these types of tailing. Concerning the absorption properties for gamma radiation, obtained results show that incorporation of these solid residues increases the attenuation of gamma rays. The mortars made with F-Ba tailings are more effective than others. The influence of tailings is significant mainly between 0.122 and 0.622 MeV and the highest attenuation is observed for Sample 5′ and 6′. This could be explained by the relative content of heavy minerals in each waste. Furthermore, the half thickness decreases with the increase of mine tailings percentage. The difference is more marked at high energies up to 0.15 MeV. Subsequently, the obtained materials could be utilized for shielding against gamma radiation.