Abstract
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.