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TOWARDS THE MEASUREMENT OF TIME AND LENGTH SCALES RELEVANT TO CONCRETE CARBONATION



Author(s): B. Huet, G. Pham, A. Bauland, M. Boumaaza, R. Barbarulo
Paper category: Proceedings
Book title: CO2STO2019 - International Workshop CO2 Storage in Concrete
Editor(s): Assia Djerbi, Othman Omikrine-Metalssi, Teddy Fen-Chong
ISBN:
e-ISBN: 978-2-35158-232-9
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 89
Total Pages: 1
Language : English


Abstract: From a durability perspective, the assessment of the dynamic of concrete carbonation via pH
front monitoring has proved as an excellent tool for service life estimation of concrete structure.
Nowadays, the physics and chemistry of concrete carbonation is ubiquitous to building
cementitious materials. Of course durability is still an issue but CO2 life cycle, property
optimization, cement hardening, concrete recycling also rely on specific aspects of carbonation
processes. This larger variety of applied processes calls for complimentary testing strategies
so as to minimize the number of tests. These strategies include testing for properties that
characterize an elementary step of the overall carbonation process.
CO2 uptake in cementitious materials relies on two key steps: CO2 diffusion into the concrete
matrix and CO2 reaction with cementitious phases to form calcium carbonate and other
products. Testing methods are first introduced and compared against usual ones in terms of
basic principles, laboratory practicality and source of uncertainties. Then results of reaction
time scale and diffusion coefficient on both C3S synthetic paste at various hydration degree
and CEM I paste fully hydrated are presented. Experimental data are then reconciled to derive
length scale over which processes compete for different relative humidity by using
dimensionless Damköhler number. Implications in terms of optimization of carbonation
processes are discussed: maximizing carbonation of recycled concrete aggregate or
minimizing carbonation depth of existing concrete structure.


Online publication : 2019
Publication type : full_text
Public price (Euros) : 0.00


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