Influence of Iron and Brass Filling Replacement on the Efficiency of Concrete as Radiation Shield

Abstract

This study investigates the effect of replacing different substances with 50% of sand on the radiation shielding performance of concrete used in medical structures. Seven groups of three samples have been prepared and tested based on an ordinary concrete batch. The first group (Re) was the reference group without any replacement casted with 7 cm thickness. In the second, third, and fourth groups (Fe groups), a 50% of sand was replaced with iron filings and the samples were casted with 5, 7, and 10 cm thicknesses, respectively. In the fifth, sixth, and seventh groups (Br groups), a 50% of sand was replaced with brass filings and the samples were casted with 5, 7, and 10 cm thicknesses, respectively. The average size of iron filings was (0.35 mm), while the average size of brass filings was (1.172 mm). All specimens have been exposed to radiation beam from Bi-207 which was coupled with NaI(Tl) detector. The results show that replacing sand with iron or brass, can improve the radiation protection efficiency of concrete. However, the results show a superiority in radiation attenuation of iron-filing specimens (0.0931 cm^–1) to that of its counterpart brass-filing specimens (0.0893 cm^–1). Hence, the bigger particle size of brass might be behind the deficiency of brass samples compared to their counterpart, iron-filings samples.