Evolution of Microstructure and Transport Properties of Cement Pastes due to Carbonation under a CO2 Pressure Gradient – A Modeling Approach

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Abstract

Most carbonation models only account for diffusion as the main transport mechanism rather than advection. Nevertheless, in the case of concrete used for underground waste disposal facilities, concrete may be subjected to a high hydrostatic pressure and the surrounding environment may contain a high dissolved CO2 concentration. Therefore, a combination of diffusion and advection should be taken into account. This is also the case in accelerated carbonation where a high CO2 pressure gradient is applied in which advection in the gas phase has a significant contribution to the carbonation process. This study aims at developing a model to predict the evolution of the microstructure and transport properties of cement pastes due to carbonation under accelerated conditions in which a pressure gradient of pure CO2 is applied. The proposed model is based on a macroscopic mass balance for carbon dioxide in gaseous and aqueous phases. Besides the prediction of the changes in transport properties (diffusivity, permeability), the model also enables to predict the changes in microstructure. Data from accelerated tests were used to validate the model. Preliminary verification with experimental results shows a good agreement.

Details

Original languageEnglish
Title of host publicationCONCREEP 10. Mechanics and Physics of Creep, Shrinkage, and Durability of Concrete and Concrete Structures
Place of PublicationUnited States
Pages1032-1041
Publication statusPublished - Sep 2015
EventMechanics and Physics of Creep, Shrinkage, and Durability of Concrete and Concrete Structures - CONCREEP-10 - TU Vienna (Vienna University of Technology), Vienna, Austria
Duration: 21 Sep 201523 Sep 2015
http://concreep10.conf.tuwien.ac.at/home/

Conference

ConferenceMechanics and Physics of Creep, Shrinkage, and Durability of Concrete and Concrete Structures - CONCREEP-10
Abbreviated titleCONCREEP
Country/TerritoryAustria
CityVienna
Period2015-09-212015-09-23
OtherWith a history going back to 1958, the CONCREEP conference series has
remained the key driving force when it came to gathering prominent
scientists and engineers from around the world to discuss the peculiar
time-dependent behavior of one of the oldest and most used, yet at the
same time least fundamentally understood construction materials: concrete.
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Keywords

  • carbonation model, concrete, cement paste, microstructure, transport properties, CO2

ID: 312503