Continuous optical in-situ pH monitoring during early hydration of cementitious materials. (December 2021)

• Record Type: Journal Article
• Authors: Galan, Isabel; Müller, Bernhard; Briendl, Lukas G.; Mittermayr, Florian; Mayr, Torsten; Dietzel, Martin; Grengg, Cyrill
• Is Part Of: Cement and concrete research. Volume 150(2021)
• Publication Date: 2021-12
• Subjects: pH -- Luminescent sensors -- Cement -- Hydration -- Calcium aluminate -- Sulfoaluminate; Cement -- Periodicals; Cement -- Research -- Periodicals; Concrete -- Periodicals; Concrete -- Research -- Periodicals; Ciment -- Périodiques; Béton -- Périodiques; Cement; Concrete; Periodicals; 620.135
• DOI: 10.1016/j.cemconres.2021.106584
• Languages: English
• ISSNs: 0008-8846

Abstract

Abstract: A luminescent sensor technique for pH analyses has been tested in cementitious media. The optical sensors monitor in-situ pH every 5 s during early hydration reactions over a period of 100 h from initial fluid up to consolidated stage. The pH development was analysed in calcium aluminate, calcium sulfoaluminate and OPC/slag cements up to a pH level of 13.3 and directly correlated with the heat of hydration. Thus tracing the dissolution and formation processes of solid phases via pH sensor monitoring is possible. This measurement technique enables the recording of continuous and highly reproducible pH data sets from slurries, pastes, and hardening materials leading to new vistas for individual (trans)formation pathways of solids, hydration and consolidation reactions in high alkaline cementitious systems. Graphical abstract: Unlabelled Image