Utilization of titanium slag in cement grout for gamma radiation shielding: hydration, microstructure, mechanical properties and gamma-ray attenuation performance

The utilization of industrial waste materials for civil engineering structures has received massive attention in recent decades. In this work, the feasibility of using titanium slag to enhance the radiation attenuation properties of cementitious grout at the ages of 3 days and 2 years was studied. Titanium slag (TS) was incorporated as cement grout replacement at 0%, 10% 20% and 30%. Hardened blocks in dimension of 146 x 146 x 30mm were fabricated. The porosity of titanium slag was characterized while the phases in the raw materials as well as the fabricated grout were identified. The influence of the titanium slag addition on the grout hydration kinetics, density, compressive strength and porosity of hardened grouts was evaluated. The results show a decrease in density with the increase of titanium slag content as well as a decrease in compressive strength at curing ages of 3, 7 and 28 days. The slag also refined the microstructure, leading to a reduction in average pore diameter. Furthermore, the hardened blocks were subject to gamma-ray sources such as 137Cs (0.662 MeV) and 60Co (1.173 and 1.332 MeV) and the Linear Attenuation Coefficient (LAC) and Half Value Layer (HVL) were evaluated. The results show that increasing curing age improves the shielding performance of the composite. At 30% replacement, the LAC improvement of the samples exposed to Co sources (1.173 and 1.332 MeV) at 3 days was 11.7% and 12.8% respectively while at 2 years, 9.9% and 9.8% improvement was obtained. Reduced HVL is obtained for an increase in replacement percentage and increased curing age. Therefore, this gives an indication of the possibility of developing low-density radiation shielding cement-based materials.