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Title: Plastic shrinkage of mortars with shrinkage reducing admixture and lightweight aggregates studied by neutron tomography

Water transport in fresh, highly permeable concrete and rapid water evaporation from the concrete surface during the first few hours after placement are the key parameters influencing plastic shrinkage cracking. In this work, neutron tomography was used to determine both the water loss from the concrete surface due to evaporation and the redistribution of fluid that occurs in fresh mortars exposed to external drying. In addition to the reference mortar with a water to cement ratio (w/c) of 0.30, a mortar with the addition of pre-wetted lightweight aggregates (LWA) and a mortar with a shrinkage reducing admixture (SRA) were tested. The addition of SRA reduced the evaporation rate from the mortar at the initial stages of drying and reduced the total water loss. The pre-wetted LWA released a large part of the absorbed water as a consequence of capillary pressure developing in the fresh mortar due to evaporation.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [5] ;  [3] ;  [1] ;  [6]
  1. Empa, Swiss Federal Laboratories for Materials Science and Technology, Concrete and Construction Chemistry Laboratory, Dübendorf (Switzerland)
  2. (Poland)
  3. Paul Scherrer Institute, Laboratory for Neutron Scattering and Imaging, Villigen (Switzerland)
  4. (Switzerland)
  5. Purdue University, School of Civil Engineering, West Lafayette (United States)
  6. (IfB), Zurich (Switzerland)
Publication Date:
OSTI Identifier:
22475513
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; CEMENTS; CONCRETES; DRYING; EVAPORATION; FLUIDS; MORTARS; NEUTRONS; PLASTICS; SHRINKAGE; SURFACES; TOMOGRAPHY; WATER