Radiological Characteristics of Carbonated Portland Cement Mortars Made with GGBFS

Materials

Cristina Argiz¹  Marta Barragán²  José Antonio Suárez-Navarro²  Guillermo Hernáiz²  Miriam Cortecero³  Pedro Lorca³  Miguel Ángel Sanjuán⁴ 

[1] Department of Chemistry of Building Materials, Civil Engineering School, Technical University of Madrid (UPM), Ciudad Universitaria, C/Profesor Aranguren, s/n, 28040 Madrid, Spain;Department of Environment, Environmental Radioactivity and Radiological Surveillance (CIEMAT), Avenida Complutense 40, 28040 Madrid, Spain;IES Virgen de la Paloma, C/de Francos Rodríguez, 106, 28039 Madrid, Spain;Spanish Institute for Cement and Its Applications (IECA), C/José Abascal, 53, 28003 Madrid, Spain;

关键词: mortar;    ground granulated blast-furnace slag;    natural radioactivity;    microstructure;    gamma spectrometry;    radon emanation rate;   

DOI  :  10.3390/ma15093395

来源: DOAJ

【 摘 要 】

The objective of this study is to assess whether the carbonation process can modify the physicochemical characteristics of the natural radionuclides of the three natural radioactive series, together with ⁴⁰K. Three mortar specimens with different percentages of ground granulated blast-furnace slag (GGBFS), cured under water for 1, 3, 7, 14, or 28 days, were subjected to a natural carbonation process. Activity concentrations for the solid and ground mortars were determined by gamma spectrometry and by radiochemical separation of isotopic uranium. The novelty of this paper relies principally on the study we have carried out, for the first time, of the radiological characteristics of carbonated Portland cement mortars. It was found that the chemical properties of the 3 mortar specimens were not affected by the carbonation process, with particular attention placed on uranium (²³⁸U, ²³⁵U, and ²³⁴U), the activity concentrations of which were equivalent to the ²²⁶Ra results and ranged from 5.5 ± 1.6 Bq kg⁻¹ to 21.4 ± 1.2 Bq kg⁻¹ for the ²³⁸U. The average activity concentrations for the 3 types of mortars were lower than 20.1 Bq kg⁻¹, 14.5 Bq kg⁻¹, and 120.2 Bq kg⁻¹ for the ²²⁶Ra, ²³²Th (²¹²Pb), and ⁴⁰K, respectively. Annual effective dose rates were equivalent to the natural background of 0.024 mSv. In addition, it was observed that the variation rate for the ²²²Rn emanation was due primarily to the Portland cement hydration and not due to the pore size redistribution as a consequence of the carbonation process. This research will provide new insights into the potential radiological risk from carbonated cement-based materials. Moreover, the assessment that is presented in this study will convey valuable information for future research that will explore the activity concentration of building materials containing NORM materials.

【 授权许可】

Unknown