Moisture stability of crystalline alkali-silica reaction products formed in concrete exposed to natural environment. (October 2020)

• Record Type: Journal Article
• Authors: Leemann, Andreas; Shi, Zhenguo; Wyrzykowski, Mateusz; Winnefeld, Frank
• Is Part Of: Materials & design. Volume 195(2020)
• Publication Date: 2020-10
• Subjects: Alkali-silica reaction -- Concrete -- Reaction products -- Crystallinity -- Water vapor sorption; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2020.109066
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: Crystalline ASR products were extracted from concrete exposed to natural environment and analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, Raman microscopy, X-ray diffraction and dynamic water vapor sorption. All extracted samples display similar compositions and Raman spectra. They sorb a limited amount of water vapor between 70 and 97% relative humidity (RH), amounting to 13–25 mass-%. Three different phases are identified, with d-spacings at low diffraction angles of 13.4, 12.3 and 10.8 Å. However, none of the phases show a change in d-spacing going from dry (~50% RH) to moist (~100% RH) conditions, indicating that no extra water is sorbed in the interlayer. This clearly indicates that swelling of crystalline ASR products is not responsible for stress generation and concrete cracking. Graphical abstract: Unlabelled Image Highlights: Dynamic water vapor sorption of crystalline ASR products formed in field exposed concrete shows a relatively low mount of sorbed water No change of d-spacing of the three identified crystalline ASR products going from 50 to 100 % relative humidity Water sorption of the identified crystalline ASR products can be excluded as mechanisms for ASR-induced cracking of concrete