Investigation of moisture transport properties of cementitious materials

Zhidong Zhang (1) , Mickaël Thiery (2) , Véronique Baroghel-Bouny (3)

1 Princeton University
2 IFSTTAR/MAST/FM2D - Formulation, Microstructure, Modélisation et Durabilité des Matériaux de Construction
3 IFSTTAR/MAST - Département Matériaux et Structures

Moisture transport in cementitious materials is directly related to the durability of concrete structures. When the material loses moisture, the drying shrinkage induces cracks which are harmful to the solid body. When liquid moves into the material, it can carry aggressive ions. Hence, moisture transport properties are important to cope with durability issues. The present paper is focused on two ways to enhance our understanding of moisture transport properties of cementitious materials. They are based on the indirect determination of the liquid water permeability and water vapour diffusion coefficient. The first one is known as the " inverse analysis " method. In a moisture transport model, the liquid permeability and diffusion coefficient can be adjusted in order to fit the measured mass loss curves and water content profiles. In the second way, measured apparent diffusion coefficient (also called moisture diffusivity) curves are fitted over a large range of relative humidity (RH) by a general expression which includes both liquid transport and vapour diffusion. Due to different RH ranges of predominance of liquid and vapour transport, the liquid water perme-ability and vapour diffusion coefficient can be determined separately. Input experimental data on cement pastes are collected from the literature. Discussions on relative permeability and Knudsen diffusion show a significant influence on modelling of moisture transport. A further comparison with measured permeability data is able to provide a better understanding of moisture transport properties.

Domaines: Génie civil

Zhidong Zhang, Mickaël Thiery, Véronique Baroghel-Bouny. Investigation of moisture transport properties of cementitious materials. Cement and Concrete Research, 2016, 89, pp.257 - 268. ⟨10.1016/j.cemconres.2016.08.013⟩. ⟨hal-01622017⟩