Monitoring of the compatibility between the radon gas emanation and the self-compacting concrete properties using different mineral admixture

The relationships between radon gas emanation, permeability,and compressive strength in Self-Compacting Concretes containing different ratios of fly ash, silica fume, and ground granulated blast furnace slag (respectively of 5%, 12.5%, and 20%) were comprehensively investigated. Permeability tests were performed according to both traditional (sorptivity) and indirect (rapid chloride ion permeability) methods, and the relationship between Brunauer-Emmett-Teller analyses and radon concentration of self-compacting concretes was also analysed. Based on 120-day data, the optimum ratios for the combination of high compressive strength and low Average Radon Activity Concentration were determined to be 5% fly ash and 20% silica fume. As the sorptivity coefficients of self-compacting concretes containing silica fume and ground granulated blast furnace slag increased, the Average Radon Activity Concentration also increased. This later decreased with the increase in the sorptivity coefficient of the mixtures. The rapid chloride ion permeability of the control, fly ash-, ground granulated blast furnace slag-, and silica fume-added concrete was found to be 6077 Coulomb, 2989 Coulomb, 1668 Coulomb,and 1137 Coulomb, respectively. The relationship between rapid chloride ion permeability and Average Radon Activity Concentration of the mixtures varied depending on the type of mineral additive. The 90-day sample containing 12.5% fly ash had the highest Brunauer-Emmett-Teller surface area (33.01 m2/g) and cumulative pore volume (0.071 cm3/g) values. This study provides a novel perspective by simultaneously examining the relationships between radon activity concentration, permeability properties,and compressive strength of self-compacting concretes produced with different mineral additives. Unlike previous studies, this work establishes direct correlations between radon emanation and both sorptivity and chloride ion permeability, identifying silicafume and ground granulated blast furnace slag as effective additives for achieving low-permeability and low-radiation concrete.These findings offer a new approach for developing durable and radiologically safer self-compacting concrete mixtures.