In-Service Behavior of Reinforced Autoclaved Aerated Concrete Planks


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Title: In-Service Behavior of Reinforced Autoclaved Aerated Concrete Planks

Author(s): Anthony Goodier and Stuart Matthews

Publication: Special Publication

Volume: 170


Appears on pages(s): 1197-1214

Keywords: Autoclaved products; creep properties; deflection; performance; strength.

Date: 7/1/1997

Concerns have been expressed to the Building Research Establishment (BRE) by a number of United Kingdom (UK) structural engineering consultants and local government bodies about the in-service performance of reinforced autoclaved aerated concrete (RAAC) planks. Many RAAC roof planks are reported to have developed appreciable in-service deflections and soffit cracking, which has raised concerns about the implications for the future structural performance and safety of the planks. Exploratory structural testing has been undertaken with the general aim of establishing the current strength and deformation characteristics of a small number of RAAC planks removed from a roof. The testing found that the load capacity of the RAAC planks tested was adequate for the circumstances in which the planks were being used, even where the planks were exhibiting signs of appreciable in-service deflection and extensive cracking on their soffits. The ability of the RAAC planks to meet the standard deflection serviceability criteria used for beam and slab structures is more doubtful. There are a number of mechanisms which may be contributing deflection and cracking problems observed in RAAC roofs. to the