Multiscale freezing-thaw in concrete: A numerical study

• Published in: Composite structures 2023-04, Vol.309, p.116758, Article 116758
• Main Authors: Dong, Xuan, Yu, Tiantang, Zhang, Qing, Bui, Tinh Quoc
• Format: Article
• Language: English
• Subjects: Air-entrained concrete; Freezing-thaw; Multiscale analysis; THM
• ISSN: 0263-8223; 1879-1085
• DOI: 10.1016/j.compstruct.2023.116758

This paper presents a fully coupled multiscale thermo-hydro-mechanical model that describes partially saturated air-entrained concrete under freezing-thaw conditions. According to the topological configurations of concrete, a mesoscale model of mortar is developed by considering cement paste, fine aggregates and interracial transition zone for evaluating the thermal, seepage, and mechanical properties of concrete. In macroscale, we present a fully coupled thermal-hydraulic-mechanical model for unsaturated air-entrained concrete by using a non-equilibrium approach under freezing-thaw conditions, including heat transfer, water migration, and mechanical behavior. In addition, coarse aggregates, cement mortar and interracial transition zone are also considered in macroscale model. The accuracy of the model is verified through freezing-thaw experimental observations. Several parameters that affected the model are further discussed. Numerical simulations illustrate the roles of air-entrained pores, aggregate volume fraction, permeability, porosity of mortar, and aggregate gradation during the freezing-thaw process, where it is observed that they significantly influence the response of concrete under freezing-thaw conditions. •3D mesoscale structure of mortar in concrete is modeled.•Computational homogenizing method is adopted for the mesoscale model to determine physical properties in concrete.•A coupled THM model to describe freezing-thaw process in unsaturated air-entrained concrete is presented.•The parameter sensitivity analysis is conducted in the macroscale model of concrete.