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Moisture loss induced shrinkage of concrete



Title: Moisture loss induced shrinkage of concrete
Author(s): R. Mu, J.P. Forth
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: 767 - 773
Total Pages: 7
Nb references: 14
Language: English


Abstract: It is accepted that the shrinkage of concrete is closely related to moisture loss. However, the attempts to quantify this relationship have so far not been successful. One of the reasons is that the shrinkage of concrete is caused by the decrease in humidity within the concrete instead of a reduction in moisture content. The moisture in the pores in concrete is adsorbed by the pore surfaces, which impedes the vaporization and diffusion of moisture in voids and consequently influences the internal relative humidity in voids. The humidity change within a concrete sample following curing can be considered as follows: When a wet cured concrete initially exposed to drying, in the beginning the moisture loss (mainly in the form of vapour) hardly causes any decrease in humidity, as there is redundant moisture in pores which can vaporize easily to compensate for the loss in vapour due to diffusion and evaporation. When the redundant moisture is exhausted, the remaining moisture is effectively adsorbed by pore surfaces, which significantly impedes the vaporization of moisture in pores. So, the further loss in moisture (vapour) results in an obvious drop in the humidity in pores. Based on this, the relationship between decrease in relative humidity and moisture loss is derived.
Incorporating existing incorporating existing humidity-shrinkage models, the shrinkage of concrete can be predicted from moisture loss. The prediction is verified experimentally. Good agreement is achieved between the predicted and measured results.


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