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Title: Sorption kinetics of superabsorbent polymers (SAPs) in fresh Portland cement-based pastes visualized and quantified by neutron radiography and correlated to the progress of cement hydration

Water sorption of two superabsorbent polymers in cement-based pastes has been characterized by neutron radiography. Cement pastes with W/C of 0.25 and 0.50 and one additionally containing silica fume (W/C = 0.42) were investigated. The SAPs differed in their inherent sorption kinetics in extracted cement pore solution (SAP 1: self-releasing; SAP 2: retentive). Desorption from SAP 1 started very early after paste preparation. Hence, its individual non-retentiveness governs its behavior only. SAP 2 released water into all matrices, but its kinetics were different. In the paste with the highest W/C, some moderate water release was recorded from the beginning. In the other two pastes, SAP 2 retained its stored liquid during the dormant period, i.e., up to the percolation threshold. Intense desorption then set in and continued throughout the acceleration period. These findings explain the pronouncedly higher efficiency of SAP 2 as internal curing admixture as compared to SAP 1.
Authors:
 [1] ;  [1] ; ; ;  [2]
  1. Technische Universität Dresden, Fakultät Bauingenieurwesen, Institut für Baustoffe, DE-01062 Dresden (Germany)
  2. Paul Scherrer Institut, Laboratory for Neutron Scattering and Imaging, CH-5232 Villigen/AG (Switzerland)
Publication Date:
OSTI Identifier:
22475519
Resource Type:
Journal Article
Resource Relation:
Journal Name: Cement and Concrete Research; Journal Volume: 75; 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; COMPARATIVE EVALUATIONS; CURING; DESORPTION; EFFICIENCY; HYDRATION; LIQUIDS; MATRIX MATERIALS; NEUTRON RADIOGRAPHY; POLYMERS; PORTLAND CEMENT; SILICA; WATER