Explosive spalling of concrete under fire load - A review of spalling theory development

In this work, we will present the most important findings and events concerning the explosive spalling of concrete since its first written account in 1854. As explosive spalling is a very complex process, essential knowledge about the basics of this phenomenon will be discussed. When concrete is heated, it undergoes numerous physical and chemical modifications. Over the years various theories and models have been developed to describe explosive spalling but leave gaps in understanding the leading causes of this phenomenon. Spalling is considered to be a result of a combination of thermo-mechanical and thermo-hydro changes which trigger the formation of cracks. The theories still considered plausible today will be described in more detail and underline the topic complexity. Today, spalling of concrete due to fire is still topical due to the development of alternative binder systems and additives that may change the microstructure of concrete which therefore may show a different behavior under high temperatures.