UWI Research Collaboration Questions Strength of Post-Fire Concrete

UWI Research Collaboration Questions Strength of Post-Fire Concrete

construction material in Jamaica and around the world. The assumption by most is that after a fire a concrete building will retain its structural integrity, even if its contents are destroyed. However, Dr Tanya Kerr, the “Fire Doctor” of the Department of Physics at The University of the West Indies, Mona, in a recent research collaboration has found that this may not be so. 

In the new article published in the journal “Forensic Science International” Dr. Kerr and her collaborators M. Vetter and J Gonzalez-Rodrigues (University of Lincoln, UK) explored this in the article entitled, “Evaluating residual compressive strength of post-fire concrete using Raman Spectroscopy”.

The significance of the research lies in its potential to help determine the safety of a structure following a fire, especially since it can be modified to inspect structures from long distances, for example, by being connected to a drone. This would remove the need for investigators to enter the building before a more detailed inspection can be done, thereby reducing risk.

The researchers explain that concrete is composed of sand, gravel, cement and water in various proportions depending on the intended purpose. When these elements are combined, the water reacts with the cement to form a critical gel/glue called calcium silicate hydrate (CSH). It is CSH that holds all the sand and gravel together to give concrete its strength. In many instances though the concrete does not show obvious post-fire damage (except in extreme cases), inspectors and fire investigators may be entering into a dangerous environment because the CSH glue may be compromised.

The study presents a non-destructive approach to assessing the chemical changes (decomposition) to CSH at different temperatures. The technique uses Raman spectroscopy which allows for the investigative-instrument to be aimed at the concrete material and a fingerprint identifying the material to be generated. The research shows that the fingerprint of CSH/concrete changes when exposed to different temperatures and that those changes correspond to changes/reductions in concrete strength. The detected changes can therefore be used to assess dangers in the structure after a fire.

To read the article: Tanya Kerr, Marleen Vetter, Jose Gonzalez-Rodriguez. Evaluating residual compressive strength of post-fire concrete using Raman Spectroscopy. Forensic Science International, Volume 325, 2021, 110874, ISSN 0379-0738. https://doi.org/10.1016/j.forsciint.2021.110874

To learn more about MFIRE (Mona Fire Research Group) and Dr. Kerr’s research click here.