Difference in carbonation behavior at 0.04%, 1% and 10% CO2 for High-Volume Fly Ash (HVFA) mortar: effect on internal humidity and resistivity

Author(s): Philip Van den Heede, Nele De Belie
Paper category: Proceedings
Book title: Proceedings of the International Conference on Sustainable Materials Systems and Structures (SMSS2019) Durability, Monitoring and Repair of Structures
Editor(s): Ana Baričević, Marija Jelčić Rukavina, Domagoj Damjanović, Maurizio Guadagnini
ISBN: 978-2-35158-217-6
e-ISBN: 978-2-35158-218-3
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 317-324
Total Pages: 813
Language: English

Abstract: Today, there is more and more agreement on the fact that accelerated carbonation experiments involving CO2 levels that exceed the atmospheric CO2 concentration of ±0.04% too much, seriously alter the carbonation process. It is expected to result in important chemical, microstructural and mineralogical changes as well as excess water production in the pore system, all having an effect on the transport properties of cementitious binders. This behaviour is not well understood yet, especially for binder systems with high cement replacement levels such as High-Volume Fly Ash (HVFA) mortar. In this research, HVFA mortar was carbonated at 0.04%, 1% and 10% CO2, while maintaining the ambient temperature and relative humidity (RH) at 20°C and 60%, respectively. During these carbonation experiments, changes in internal humidity due to carbonation related water production were monitored with embedded humidity sensors and multi-ring electrodes for resistivity assessment as a function of depth. All test results seem to point out a key role for excess water production during carbonation in the significant underestimation of the field carbonation coefficient when estimated from accelerated carbonation tests at 10% CO2.

Online publication :2019
Publication type : full_text
Public price (Euros) : 00

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