Limits of spalling of fire-exposed concrete

Abstract Spalling may be a violent effect to fire-exposed concrete destroying the entire cross-sections or reducing the load-bearing capacity of a construction substantially. Spalling must therefore be considered when designing a concrete construction for fire. The paper discusses the present knowledge on the nature of spalling, add the latest findings from the research of the author, and derives limits within which spalling should not take place. Some guidelines are formulated based on experience from research and practice for reducing the spalling risk for constructions beyond the safe design limits. The limits provided are those, which can be stated at present, but further research is in progress, identifying more precisely the range of materials susceptible to spalling and contributing to the full understanding of the phenomenon.