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Title: Hydration states of AFm cement phases

The AFm phase, one of the main products formed during the hydration of Portland and calcium aluminate cement based systems, belongs to the layered double hydrate (LDH) family having positively charged layers and water plus charge-balancing anions in the interlayer. It is known that these phases present different hydration states (i.e. varying water content) depending on the relative humidity (RH), temperature and anion type, which might be linked to volume changes (swelling and shrinkage). Unfortunately the stability conditions of these phases are insufficiently reported. This paper presents novel experimental results on the different hydration states of the most important AFm phases: monocarboaluminate, hemicarboaluminate, strätlingite, hydroxy-AFm and monosulfoaluminate, and the thermodynamic properties associated with changes in their water content during absorption/desorption. This data opens the possibility to model the response of cementitious systems during drying and wetting and to engineer systems more resistant to harsh external conditions.
Authors:
 [1] ;  [1] ;  [2] ; ;  [3]
  1. Innovation, Holcim Technology Ltd., CH-5113 Holderbank (Switzerland)
  2. Laboratory of Construction Materials, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland)
  3. Building Materials, Lund University, Box 124, 221 000 Lund (Sweden)
Publication Date:
OSTI Identifier:
22475511
Resource Type:
Journal Article
Resource Relation:
Journal Name: Cement and Concrete Research; Journal Volume: 73; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION; ALUMINATES; ANIONS; CALCIUM COMPOUNDS; CEMENTS; DESORPTION; DRYING; HUMIDITY; HYDRATES; HYDRATION; LAYERS; PHASE STABILITY; SHRINKAGE; SWELLING; THERMODYNAMIC PROPERTIES