Effects of aggregate preheating and polymer fibers on the mechanical, thermal and radiation shielding properties of barite concrete

The presence of microcracks in the structure of barite aggregates and the occurrence of heat generation during the radiation shielding process contribute to a certain degree of deterioration of barite concrete. To address these challenges, an aggregate preheating method was proposed in this study, and the effects of aggregate preheating, addition of different polymer fibers on the mechanical, thermal, and radiation shielding properties of barite concrete were investigated. The influence mechanisms of aggregate preheating, as well as type and content of polymer fibers were further investigated by SEM, XRD, TG, and other experimental techniques. The results shown that the aggregate preheating and the incorporation of an appropriate amounts of fibers significantly improve the mechanical properties and thermal stability of the barite concrete. Fibers with smaller lengthdiameter ratios are more suitable for preparation of concrete with high mechanical properties, nevertheless, excessive fiber decreases the mechanical properties of the barite concrete. The aggregate preheating facilitates the premature fracture of barite aggregate and improves the microcrack structure of the barite, reducing the defects of the aggregates themselves, and increasing the failure path of the aggregates during the concrete failure process. Furthermore, aggregate preheating has a slight decreased effect on neutron shielding properties of barite concrete, whereas this adverse effect is compensated by the incorporation of polymer fibers.