External wall the structures are made of three material layers: substrate concrete, adhesive mortar, and ceramic tiles. Between these material layers, bi-material interfaces are inevitably formed, and these interfaces are a potentially weak location. With different mechanical and thermal properties of the material layers and under environmental loadings, shear stresses can be cyclically applied, and they may lead to fatigue at the interfaces, leading to delamination and to the fall-off of tiles and adhesive mortar. For understanding mechanisms and developing durable interfaces and the structures, this paper presents the investigation of the reaction of bi-material interface. First, field observations are conducted in order to obtain the the surface temperature variations in a real environment, and the maximum temperature is obtained for four seasons in Tokyo. Next, with the maximum temperature as a boundary condition, a heating experiment is conducted with a small size specimen. The specimen is heated up, and the thermographic measurements are carried out to obtain the temperature distribution through material layers. Finally, with the temperature of each material layer as an input, stresses are estimated with analytical models for normal and shear direction. The estimated stresses are discussed together with the resistance of the interface.
