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Effects of microstructure on restrained autogenous shrinkage behavior in high strength concretes at early ages



Title: Effects of microstructure on restrained autogenous shrinkage behavior in high strength concretes at early ages
Author(s): S. Igarashi, M. Kawamura
Paper category : conference
Book title: International RILEM Conference on Early Age Cracking in Cementitious Systems
Editor(s): K. Kovler and A. Bentur
Print-ISBN: 2-912143-29-2
e-ISBN: 2351580362
Publisher: RILEM Publications SARL
Publication year: 2003
Pages: 125 - 132
Total Pages: 8
Nb references: 8
Language: English


Abstract: Fluorescence microscopic examinations were conducted to identify damages induced by restraining autogenous shrinkage. Characteristics of fluorescent areas and their correspondence to autogenous shrinkage behavior of high strength concretes were discussed. Silica fume concrete exhibited a greater creep potential when loaded at very early ages. The microstructure in sealed concretes with an extremely low water/binder ratio was porous. The vicinity of aggregate grains was more porous and weaker than the bulk matrix in sealed concretes. In addition, sealed silica fume concretes contained many unhydrated cement particles which were profiled by thin gaps between the core cement particles and the surrounding cement paste matrix. These features of microstructure were not observed in water ponded concretes. The detected fluorescent areas may be defects caused by self-desiccation and autogenous shrinkage. The flaws had little effects on the development of strength. However, the presence of thin gaps around remnant cement particles may increase creep deformation to relieve internal stresses.


Online publication: 2010-06-02
Publication type : full_text
Public price (Euros): 0.00