Fracture of AAC as Influenced by Specimen Dimension and Moisture

Abstract

An experimental investigation into fracture of autoclaved aerated concrete (AAC), a lightweight building material, is presented. The experiments indicate that AAC is a softening material, and the fracture process can be considered as a steady degradation of the composite structure consisting of a microporous matrix and artificially induced air pores. In terms of fracture mechanisms, there exists a similarity between AAC and structural concrete, and the fracture process can be described by the fictitious crack model that is used for concrete. Fracture properties such as the specific fracture energy, GF, depend on the specimen geometry, i.e., GF increases with increased fracture ligament length and specimen thickness. The softening diagram of AAC is numerically evaluated through data fit of numerical and experimental force versus deformation curves of the specimen. The characteristic length, lch, is proposed to be a material parameter to assess the quality of AAC regarding fracture. The fracture properties of AAC at room temperature are not affected by moisture content.