Drying shrinkage of autoclaved aerated concrete

Autoclaved aerated concrete (AAC) is a commonly used building material which is favoredby many designers due to its good thermal properties, low bulk density, and easy and fast building. However, failures in the AAC constructionsin a form of cracking of interior or exterior surfaces were observed in the past which could possibly lead to serious consequences for practical applications of AAC. In this paper, moisture-induced length change of AAC is investigated as a very important parameter for designers. According to the producers' data sheets, the shrinkage of AAC is 0.5 mm/m betweenthe volumetric moisture contents of 40% and 5%. It agrees well with the results obtained in this paper. However, the highestlength changes are found between 5% andthe dry material. This property of AAC which is not considered by designers because of unavailability of necessary data may be responsible forsurface cracking in some cases.