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Influence of pore solution chemistryon shrinkage of cement paste



Title: Influence of pore solution chemistryon shrinkage of cement paste
Author(s): P. Lura, B. Lothenbach
Paper category : conference
Book title: The 50-year Teaching and Research Anniversary of Prof. Sun Wei on Advances in Civil Engineering Materials
Editor(s): C. Miao, G. Ye and H. Chen
Print-ISBN: 978-2-35158-098-1
e-ISBN: 978-2-35158-099-8
Publisher: RILEM Publications SARL
Publication year: 2010
Pages: 191 - 200
Total Pages: 10
Nb references: 32
Language: English


Abstract: Reducing drying shrinkage is of practical importance for the concrete industry because it can reduce the risk of restrained shrinkage cracking. Cracking impairs strength, durability and aesthetics of concrete structures.
As concrete is exposed to an ambient with low relative humidity (RH), it loses moisture until its internal RH equilibrates with the external one. However, even when the concrete is saturated, its internal RH is lower than 100%, due to the presence of dissolved salts in the pore fluid. This initial RH depression can be estimated (e.g. with Raoult’s law) and can vary from cement to cement depending on the pore solution chemistry. Changes in the composition of the pore solution can consequently influence moisture loss and drying shrinkage of cement pastes and concrete, especially at high RH.
In this paper, the pore solution chemistry of different cements is compared and its impact on the initial RH drop is evaluated. Experimental data are compared to numerical simulations of the pore solution composition obtained by thermodynamic modelling. Finally, a methodology to assess the effect of the change in pore solution composition on the drying shrinkage of the cement pastes is proposed.


Online publication: 2010-04-22
Publication type : full_text
Public price (Euros): 0.00