New insights into long-term chloride transport in unsaturated cementitious materials

New insights into long-term chloride transport in unsaturated cementitious materials: Role of degree of water saturation

Zhang, Y. (TU Delft Materials and Environment; Fuzhou University)
Ye, G. (TU Delft Materials and Environment)
Yang, Zhengxian (Fuzhou University)

2020

Concrete is rarely saturated. Reliable durability design of marine concrete structures requires a solid understanding of the long-term chloride transport in unsaturated concretes. This paper presents a critical analysis of the time-dependent chloride diffusion coefficient in unsaturated cementitious materials exposed to marine environment. Evolutions of pore structure and chloride diffusion coefficient in saturated cementitious materials, along with the role of the degree of water saturation in long-term chloride diffusion, are analyzed. It is emphasized that the long-term sharp decrease of the chloride diffusion coefficient in marine cementitious materials is not primarily caused by densification of the microstructure due to hydration, but by the decreasing degree of water saturation with depth in the surface part of the materials. The effects of water/binder ratio and supplementary cementitious materials on chloride diffusion coefficient are different between saturated and unsaturated cementitious materials.

Cementitious material
Chloride
Degree of water saturation
Long-term transport
Pore structure

http://resolver.tudelft.nl/uuid:faacc554-0c12-4908-bfcc-5b52bcac6c36

https://doi.org/10.1016/j.conbuildmat.2019.117677

2021-12-06

0950-0618

Construction and Building Materials, 238

Accepted Author Manuscript

Institutional Repository

journal article

© 2020 Y. Zhang, G. Ye, Zhengxian Yang