Evaluation of gamma and neutron radiation shielding properties of the GGBFS based geopolymer concrete

Superior characteristics of the ground granulated blast furnace slag (GGBFS) based geopolymer concrete (GGC) compared with the ordinary Portland cement (OPC)-based concrete (OPCC), have made it a more preferable choice for being used in the radiation shielding. The aim of this study is to investigate the radiation shielding properties of the GGC containing different contents of magnetite aggregates in separate and cover-layer forms. In this study: 1)gamma and neutron attenuation capacities of one-layer samples, including the OPCC containing 100 % normal-density aggregates, the GGC containing 0 % to 100 % magnetite aggregates and the steel fiber reinforced GGC containing 100 % magnetite aggregates have been evaluated, 2)the OPCC containing 100 % normal-density aggregates specimens have been covered with 5 cm layer of the concretes studied at the first stage to investigate their effects on radiation attenuation and 3)a comparison between a two-layer specimen and an equivalent mixed sample has been conducted. The main results obtained are: a)when the ordinary aggregates are replaced by the magnetite ones from 0 to 100 volume percentages, the parameters such as the linear attenuation coefficient (mu) and the removal cross section (sigma R) are respectively increased from 0.14225 to 0.18055 cm-1 and from 0.116086 to 0.143864 cm-1 in the GGC, b)adding 1.5 vol% of steel fibers to the GGC containing 100 % magnetite aggregates leads to increase in mu and sigma R respectively equal to 2.697 % and 6.5819 %, c)for gamma radiation, ratios of the transmitted rays to the incident ones in sample covered with the GGC containing 100 % magnetite aggregates and the specimen covered with the GGC containing 100 % ordinary aggregates have been obtained respectively equal to 0.197563 and 0.250297. For neutron radiation, these ratios have been obtained equal to 0.261019 and 0.346008, respectively and d)radiation attenuation capacity of the two-layer specimen has been obtained higher than that of its equivalent mixed sample.