HOMOGENIZATION OF SOLIDIFYING RANDOM POROUS MEDIA: APPLICATION TO AGEING CREEP OF CEMENTITIOUS MATERIALS

Author(s): J. Sanahuja
Book Title: RILEM International Symposium on Concrete Modelling - CONMOD 2014
Editor: Kefei Li, Peiyu Yan and Rongwei Yang
ISBN: 978-2-35158-139-1
e-ISBN: 978-2-35158-140-7
Publisher: RILEM Publications SARL
Publication year: 2015
Pages: 176-182
Total Pages: 7
Language: English

Abstract: Some porous media such as cementitious materials exhibit a strong time evolution of their physical properties. This maturation process is not an issue for behaviours which do not involve time, such as elasticity. The case of creep is much more complex, as another time scale appears. To build predictive models, ”uncoupling” contributions of the maturation process and of the elementary constituents delayed behaviour is highly desirable.

The solidification theory proposed by Baˇzant allows this, considering gradual precipitation of solids into pore space. Thus, even if the behaviour of the precipitated material is non ageing, the effective behaviour exhibits ageing due to the microstructure evolution. The solidification theory only considered a simplified parallel arrangement of precipitating layers. However, cementitious materials are much more complex.

This contribution takes advantage of ageing viscoelastic homogenization of random media to propose a micromechanical extension of the solidification theory, allowing more realistic precipitation scenarii. Both the solidification mechanism and kinetics are found to highly influence the effective ageing creep behaviour. A simplified model of solidifying cementitious material is then proposed, considering progressive precipitation of a C-S-H gel, whose elementary behaviour comes from homogenization at the lower scale.

Online publication: 2015
Publication Type: full_text
Public price (Euros): 0.00