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Pro058

Physical & chemical modeling of the hydration kinetics of OPC paste using a semi-analytical approach



Title: Physical & chemical modeling of the hydration kinetics of OPC paste using a semi-analytical approach
Author(s): E. Guillon, J. Chen, G. Chanvillard
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: 165 - 172
Total Pages: 8
Nb references: 20
Language: English


Abstract: The hydration of a cementitious material is one of the most important stages in the life of a cement-based structure. The hydration "transforms" a mix of aggregates, cement powder, water and admixtures into a rigid material with mechanical properties to build structures. The cement paste is the key component. It is responsible for the mechanical properties of the hydrated material, but also on shrinkage, creep and durability. To evaluate these properties, it is capital to know precisely the physical and chemical state of the cement paste after a given time of hydration, from several hours to 28 days and more...
Numerous models have been developed to predict the evolution of the microstructure of cement paste during hydration. We propose here a semi-analytical approach to predict the evolution of the cement paste composition, porosity and hydration degree with time, pore solution composition as a function of the particle size distribution and the mineralogy of the cement. It appears that these output parameters are, in first-order approaches, sufficient to predict the durability, mechanical properties and shrinkage of material; spatial distribution of phases is not necessary.
Kinetics are governed by dissolution and diffusion laws, by self-desiccation and percolation of solid species, and the cement paste composition is evaluated using the PHREEQC speciation model. Global calculation time does not exceed 2 minutes on a laptop, and outputs of this model can be directly incorporated into higher-scale models to predict properties of the structured material, presented in joined papers.


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