Effects of Surface Layer on Moisture Transport in Cementitious Materials: Experimental Evidence and Simulation Results
Open access
Date
2023Type
- Conference Paper
ETH Bibliography
yes
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Abstract
Moisture in concrete is the essential factor of many degradation mechanisms to reinforced concrete structures, such as carbonation, chloride ingress, and frost attack. Therefore, it is important to arcuately determine and predict moisture state and moisture distribution inside the material. Most moisture transport models generally view concrete as a homogeneous material, which might be appropriate for the large scale. However, it is commonly found that the properties (chemical and microstructure) of the concrete surface layer are different from the bulk concrete. When considering the moisture exchange with the surrounding environment, this surface layer may unavoidably affect the process of moisture transport. In this study, water absorption tests were performed to investigate moisture transport in uncarbonated cement pastes and mortars. The results show that during the process of sample preparation, the microstructure of the surface layer was altered, leading to anomalous moisture transport, in which the conventional models can not predict the measured mass change. Based on the experimental results, the non-homogeneous simulation domain was created to represent the more realistic microstructure of concrete. The numerical simulation results show a similar trend of the mass change due to moisture transport to the experimental results. Therefore, the nonhomogeneous microstructure of concrete, in particular the different microstructure of the surface layer from the bulk concrete, can be one of the reasons that cause the anomalous moisture transport in cementitious materials. This also emphasizes the importance of sample preparation in the lab, which must avoid creating a surface layer with the different microstructure from the bulk concrete Show more
Permanent link
https://doi.org/10.3929/ethz-b-000638185Publication status
publishedExternal links
Book title
Proceedings of the 16th International Conference on Durability of Building Materials and Components (XVI DBMC)Publisher
ScipediaEvent
Subject
Moisture transport; Durability; Anomalous; Surface layerOrganisational unit
09593 - Angst, Ueli / Angst, Ueli
Funding
848794 - Towards mastering the long-standing challenge of ageing infrastructures in corrosive environments (EC)
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ETH Bibliography
yes
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