- Faculty & Staff
Concrete is a widely used 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. But this may not be so. In a new article published in the journal “Forensic Science International” Dr. Tanya Kerr (Dept. of Physics, The UWI Mona) and her collaborators M. Vetter and J Gonzalez-Rodrigues (University of Lincoln, UK) explore this. In the article, “Evaluating residual compressive strength of post-fire concrete using Raman Spectroscopy”, 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 researchers show 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. 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 e.g. 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.
Published on 01 Oct, 2021