Shielding of gamma radiation by heavy concrete includes lead slag

Heavy concrete is an excellent shielding material most widely used for radiation shielding of gamma rays. It is possible to use lead slag as a partial replacement of aggregates to increase the density of concrete shields. From an environmental point of view, substitution of natural aggregate with lead slag can saves our natural resources and land. Also, using lead slag resulted in an increase of the attenuation of gamma radiation.The main goal of the present work is to study the possibility of using lead slag extracted from recycling of the spent batteries as concrete aggregates. The mechanical properties and linear attenuation coefficients of concrete samples fabricated by using lead slag as 40 to 60 percent replacement of fine aggregates were experimentally examined. Also the effects of lead powder on setting time of cement pastes were investigated.Experimental results indicated that the partial replacement of sand by fine lead slag increases the mechanical strength of concrete. Radiation absorption tests showed also a superior absorption of gamma rays with the use of lead slag as concrete aggregate. But, Addition of lead powder significantly delays the setting time of the cement pastes.Consequently, Lead slag concrete could be preferred for construction of shields with lower cost and better capacity of radiation absorption.