A multi-scales approach for the physico-chemical deformations of solidifying cement-based materials

Title: A multi-scales approach for the physico-chemical deformations of solidifying cement-based materials
Author(s): F. Grondin, M. Bouasker, P. Mounanga, A. Khelidj
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: 317 - 324
Total Pages: 8
Nb references: 20
Language: English

Abstract: At early stages of hydration, solidifying cementitious systems exhibit dimensional variations caused by their thermal, hydrous, chemical and microstructural evolutions. If restrained, these deformations can induce the development of internal stresses high enough to generate cracking of the hardening material. This study focuses on early-age autogenous strain of cement-based materials, which develops following two main processes: Le Chatelier contraction (also called chemical shrinkage) and self-desiccation shrinkage. Chemical shrinkage results from the difference of absolute density between reactants (anhydrous cement and water) and hydration products. Early-age self-desiccation shrinkage is generally attributed to the development of a negative capillary pressure in the porous network related to the water consumption by the hydration reactions. The purpose of this research work is to propose a multiscale approach to model the rate of autogenous shrinkage of cement-based materials at very early-age, between 0 and 48h. Le Chatelier contraction is computed from the chemical equations of hydration and the specific volume of each phase, whereas a homogenization method based on the self-consistent scheme is applied to calculate the self-desiccation shrinkage. Computed results are discussed and analyzed. Good agreements between experiments and simulations are achieved and a sensitivity study is performed to assess the influence of the cement fineness and the fraction of granular inclusion on early-age autogenous strain.

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