The effect of equilibration time on Al uptake in C-S-H. (June 2021)

• Record Type: Journal Article
• Authors: Barzgar, Sonya; Tarik, Mohamed; Ludwig, Christian; Lothenbach, Barbara
• Is Part Of: Cement and concrete research. Volume 144(2021)
• Publication Date: 2021-06
• Subjects: C-A-S-H -- Equilibration time -- ICP-OES -- TGA -- FTIR; Cement -- Periodicals; Cement -- Research -- Periodicals; Concrete -- Periodicals; Concrete -- Research -- Periodicals; Ciment -- Périodiques; Béton -- Périodiques; Cement; Concrete; Periodicals; 620.135
• DOI: 10.1016/j.cemconres.2021.106438
• Languages: English
• ISSNs: 0008-8846

Abstract

Abstract: Calcium silicate hydrate (C-S-H) is the main hydration product of Portland cements. The partial replacement of Portland cements by supplementary cementitious materials can result in C-S-H with lower Ca/Si ratios and more aluminum and alkalis. The effect of equilibration time on Al uptake in C-S-H was investigated using equilibration times from 7 days up to 3 years. Lower Al concentrations were measured in the solution after longer equilibration times. In addition, a higher uptake of Al in C-S-H was observed based on the decrease in the content of secondary phases. Little further decrease in Al concentrations was observed after 2 years and longer at low Ca/Si. At high Ca/Si no significant change in solution concentrations was observed after more than 3 month, while the destabilization of secondary phases continued up to 1 year, indicating that a (meta)stable equilibrium was reached faster at higher Ca/Si ratios.