According to Statista, earthquakes were the cause of over 800 000 deaths between 2000 and 2015. In 2009, World Bank research found that natural disasters caused roughly 60 000 deaths per year, mostly from building collapse. Over and above casualties, earthquakes can lead to homelessness among those impacted, decimating cities and cultural icons.
Engineers and architects alike aim to pre-empt natural disasters like earthquakes, of which 1566 or so took place in 2017. The development of crumb rubber concrete (CRC) is among these recent innovations; while still under research, CRC is a promising substitute for concrete that might otherwise crumble in an earthquake and also helps to recycle used vehicle tires.
A standard cement mix will use cement parts and aggregates – typically sand and gravel; however, to make CRC, a portion of the aggregate solution is removed and replaced with the rubber of used vehicle tires.
Experimental research in CRC found that cement columns fitted with the rubber aggregate were more ductile, and sustained less damage under pressure, than regular concrete columns. Further research showed that by introducing crumb sizes of 1.18-2.36mm, virtually no impact was made in terms of the relevant attributes while a crumb size of 6mm was significant. Research has yet to find what crumb size yields the mix best suited to avoiding building collapse.
Another reason to feel hopeful about CRC is recycling: in the US, which discards almost 300 million tires each year, tire recycling is a robust industry with over 80% of used tires recycled or reused (Used tires can be shredded, repurposed or burned for industrial processes.)
The green benefits of CRC are thus patent. In a world plagued by climate change and which discards a billion used tires each year, we would be wise to consider our impact on the environment and how natural processes – even earthquakes – are affected.