Partners

Abstract:
This study investigates the effects of low-dose gamma irradiation (50 and 100 kGy) on the mechanical, thermal, and mineralogical properties of cement and geopolymer mortars, with and without barite as a radiation-shielding additive. Mortars were evaluated through flexural and compressive strength testing, thermogravimetric analysis (TG/DSC), X-ray diffraction (XRD), mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM). Gamma irradiation enhanced flexural strength in cement mortars and had a stabilizing effect on geopolymer systems, with minimal impact on compressive strength across all formulations. XRD and TG/DSC analyses revealed radiation-induced carbonation in cement mortars, marked by increased formation of calcite, vaterite, and aragonite, and a corresponding decline in portlandite. In contrast, geopolymer mortars showed high phase stability, with only minor traces of nahcolite detected. These findings indicate that while cement-based mortars undergo measurable mineralogical changes under gamma exposure, geopolymer mortars, especially those based on fly ash, exhibit superior resistance and are better suited for use in radiation-exposed environments

Keywords:
Geopolymer matrix, Cement matrix, Gamma irradiation, Barite modification, Microstructure, Mechanical properties