Why is it that structures built in Roman times have resisted the elements for thousands of years when more modern structures have suffered?

This was a question posed in a recent BBC news story ‘Scientists explain ancient Rome’s long-lasting concrete’ that caught my eye since we have pondered the question here at Malvern before as you can see in this application note “Component Characterization of Cements” where the Morphologi G3-ID was used to study and compare the composition of different cements.

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How is the concrete made?

Ancient structures are built using concrete made from lime and volcanic ash. This cement sets more slowly than modern Portland cements and slowly increases in strength over time especially when in contact with sea water. The news report shows the latest findings and indicates how techniques such as X-ray micro-diffraction and Raman spectroscopy have been used to gain a deeper understanding of the chemistry at play. It’s believed that the long-term exposure to sea water helped crystals of certain elements to keep on growing over time, reinforcing the concrete and preventing cracks from developing.

Whilst global demand for cement continues to grow so does its environmental impact with the manufacture of modern day cement accounting for over 5% of global CO2 emissions. Therefore, there is clear desire to reduce the environmental impact of cement manufacture through process optimization and use of clinker substitutes.

Our recorded webinar “Cement – composition, structure and fineness” reviews the importance of elemental and mineralogical analysis and discusses the importance of particle size analysis in relation to production control and efforts to optimize grinding and reduce energy consumption.

It certainly seems there is still a thing or two we can learn from the Romans.