Characterization and Assessment of Fast Neutron Attenuation Properties of Developed Concrete Mixes at Different Temperatures

Abstract
Concrete is regarded as one of the most proper materials that can be used in many applications concerning with shielding against gamma radiation and neutrons since they are the most penetrating radiation. In this study three different concrete mixes were prepared with three different types of coarse aggregates: barite, goethite and dolomite. Fine aggregates are selected to be local sand and limonite. Additives used are silica fume (SF) and fly ash (FA) by replacement of the total cement weight. To examine the performance of these concrete mixes to be used as radiation shielding concretes, a set of physical, mechanical and radiation attenuation measurements were carried out. Such investigations include compressive strength, slump test, bulk density as well as gamma ray and fast neutron attenuation properties for the prepared mixes at room temperature and after heating up to 450⁰C. The experimental results revealed that all concrete mixes; barite concrete (labeled Ba.C), goethite concrete (labeled Go.C) and dolomite concrete (labeled Do.C) show adequate physical and mechanical properties that successfully classifying them as high performance concretes. In addition Ba.C has the higher γ-ray attenuation coefficients. For fast neutron attenuation measurements, it was found that Go.C mix has the highest integrated fast neutron removal macroscopic cross section (Σ) ,emitted from 252Cf, at room temperature and thus the corresponding minimum required HVL. The Ba.C mix came in the second place following the Go.C mix. Heating up to 450⁰C, fast neutron attenuation properties of Go.C mix were fully deteriorated because of certain reasons that are illustrated in this study.