An experimental investigation on the effects of barite/hematite on the radiation shielding properties of serpentine concretes

摘要

To modify some properties of serpentine-based concretes, serpentine aggregate (S) was partially replaced with either hematite aggregate (H) or barite aggregate (B) at levels of 25 and 50, by volume. To evaluate the impact of these aggregates, selected physical properties of the prepared serpentine-barite (AB(25,) (50)) and serpentine-hematite (AH(25, 50)) concretes were measured and compared to those of the control serpentine concrete (A). In addition, the fast neutrons and gamma-rays shielding properties of these concretes in comparison with those of the control (A) were experimentally measured using a(239)Pu-Be source and stilbene detector. These shielding properties were determined by measuring the neutron and gamma-ray attenuation coefficients (Sigma(R) (E-n) and mu(E-gamma), respectively), as well as parameters of relaxation length (lambda) and half value length (HVL) at different energies. It was found that incorporation of B and H had a negative impact on the physical properties of the serpentine-based concretes except for density. On the other hand, this incorporation improved the attenuation properties of serpentine-based concretes. This improvement was more effective in the case of using B rather than H in the equivalent ratios. Finally, 50 B was the best ratio in enhancing the shielding of fast neutrons and gamma-rays.