Modelling autogenous shrinkage of hydrating cement paste

Title: Modelling autogenous shrinkage of hydrating cement paste
Author(s): I. Jaouadi, A. Guidoum, K. Scrivener
Paper category : conference
Book title: International RILEM Symposium on Concrete Modelling - ConMod '08
Editor(s): E. Schlangen and G. De Schutter
Print-ISBN: 978-2-35158-060-8
e-ISBN: 978-2-35158-076-9
Publisher: RILEM Publications SARL
Publication year: 2008
Pages: 603 - 609
Total Pages: 7
Nb references: 6
Language: English

Abstract: Autogenous deformation is the self-created deformation of a cement paste, mortar or concrete during the hydration process. In ordinary concretes autogenous deformation is negligible if compared to drying shrinkage. On the contrary, in HPC the low water/cement ratio causes a significant drop of the internal relative humidity (RH) in the cement paste during sealed hydration under sealed conditions. Since autogenous shrinkage is closely related to autogenous RH change, it generally results in tensile stresses in the cement paste due to aggregate restraint. Autogenous shrinkage should be limited since it may induce microcracking and may damage the concrete quality.
The main objectives of this paper are to determine the evolution of mechanical properties and volume change of cement paste. To predict the mechanical properties of hydrating cement paste at early age, based on its microstructure and the characteristics of constituents, homogenisation process will be made on a computer-generated microstructure obtained by an existing continuum hydration model developed in our laboratory.
In the second step, the capillary pressure of the capillary water will be determined numerically at each step of hydration. By knowing the evolution of the porosity of the cement paste during hydration, the critical radius of gaseous pore can be determined. By knowing all this characteristics, the effective autogenous shrinkage as function of time and the water to cement ratio are calculated. All these numerical results are compared to the experimental ones.

Online publication: 2009-06-15
Publication type : full_text
Public price (Euros): 0.00

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