Degradation of cement pastes subjected to combined carbonation and leaching

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Abstract

Carbonation and leaching are likely to be the primary concrete degradation mechanisms for concrete utilized in geological repositories when the concrete is fully saturated and in contact with host rock pore water containing increased CO2 content. This work describes the changes in the microstructure and transport properties of cement pastes caused by coupled chemical degradation processes that occur at the cement paste-clay interface. In the laboratory, an experimental program was designed to accelerate the interface interaction under carbonation and leaching by bringing highly porous cement pastes (to mimic backfill materials used in geological disposal) and Boom Clay into contact in either accelerated percolation or batch-type experiments. Mercury intrusion porosimetry (MIP) was used to investigate the microstructural alteration. Inductively coupled plasma optical emission spectrometer (ICP-OES) and permeability, diffusion measurements were used to determine the evolution of chemical and transport properties, respectively. The results of the porosity change at the interface demonstrate an increase in porosity of the cement paste interface due to Ca leaching, which overwhelms the carbonation. As a result, the transport properties increase. This suggests that clogging of the cementitious material side is unlikely.
Original languageEnglish
Title of host publication16th International conference on durability of building materials and components
Subtitle of host publicationDBMC 2023, China
EditorsK.F. Li, D.P. Fang
PublisherTsinghua University
Number of pages8
StatePublished - 10 Oct 2023
Event2023 - XVI DBMC: 16th International Conference on Durability of Building Materials and Components - Liaoning International Hotel, Beijing
Duration: 10 Oct 202313 Oct 2023
http://dbmc2023.civil.tsinghua.edu.cn/

Conference

Conference2023 - XVI DBMC
Country/TerritoryChina
CityBeijing
Period2023-10-102023-10-13
Internet address

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