The behaviour of concrete structures in fire

The nature of concrete-based structures means that they generally perform very well in fire. However, concrete is a complex material and its properties can change dramatically when exposed to high temperatures. This paper provides a ‘state of the art’ review of research into the effects of high temperature on concrete and concrete structures, extending to a range of forms of construction, including novel developments. The principal effects of fire on concrete are loss of compressive strength and spalling, the forcible ejection of material from the member. Though a lot of information has been gathered on both phenomena, there remains a need for a wider understanding of the response of concrete members to different heating regimes and the performance of whole-frame structures subjected to realistic fire exposures. Model based approaches can also be used, but the non-homogeneous nature of the material makes this challenging and there is a lack of data available from real structures for validation. Very few full-scale tests have been undertaken, and though some useful insights can also be gained from the observations and assessment of concrete performance in real fires, further work is still required to broaden the domain of knowledge