Ultra-high gamma irradiation of calcium silicate hydrates: Impact on mechanical properties, nanostructure, and atomic environments. (August 2022)

• Record Type: Journal Article
• Authors: Baral, Aniruddha; Rodriguez, Elena Tajuelo; Hunnicutt, William A.; Cakmak, Ercan; Sun, Hongbin; Ilavsky, Jan; Le Pape, Yann; Rosseel, Thomas M.; Garg, Nishant
• Is Part Of: Cement and concrete research. Volume 158(2022)
• Publication Date: 2022-08
• Subjects: Calcium silicate hydrate -- Gamma irradiation -- Nanoindentation -- 1H NMR -- Basal spacing -- 29Si NMR; Cement -- Periodicals; Cement -- Research -- Periodicals; Concrete -- Periodicals; Concrete -- Research -- Periodicals; Ciment -- Périodiques; Béton -- Périodiques; Cement; Concrete; Periodicals; 620.135
• DOI: 10.1016/j.cemconres.2022.106855
• Languages: English
• ISSNs: 0008-8846

Abstract

Abstract: The concrete biological shield in a nuclear power plant receives ~100–200 MGy gamma dosage during an 80-year design life. However, precise changes in the mechanical properties and atomic environments of C-S-H at ultrahigh irradiation dosages have not been systematically documented. Here, we report that irradiation decreases C-S-H basal spacing (~ 0.6 ± 0.1 Å for 189 MGy) and increases its Young's modulus, which is attributed to the lower basal spacing as the nano porosity potentially increased and microporosity remained unchanged. Irradiation also decreased the molecular water content and increased hydroxyl groups in C-S-H, showing that interlayer water removal reduces the basal spacing. Finally, 1 H and 29 Si NMR results indicate some disorder in the local proton CaO-H species and slight depolymerization of the silicate structure. Together, these results indicate that the C-S-H gel stiffens upon ultrahigh gamma irradiation dosage, a finding which concerns long-term nuclear power plants operations worldwide.