Volcanic ash can be used as sustainable concrete to build cities: Study
Fine volcanic ash can be used as a sustainable additive in concrete, and significantly reduce the energy spent in building infrastructure, a study has found.
Researchers at Massachusetts Institute of Technology (MIT) in the US found that, by replacing a certain percentage of traditional cement with volcanic ash, they can reduce a concrete structure’s “embodied energy” – the total energy that goes into making concrete.
According to their calculations, it takes 16 per cent less energy to construct a pilot neighbourhood with 26 concrete buildings made with 50 per cent volcanic ash, compared with the energy it takes to make the same structures entirely of traditional Portland cement.
When they ground volcanic ash down to increasingly small particle sizes, the researchers found that a mixture of the finer powder and cement produced stronger concrete structures, compared with those made from cement alone.
However, the process of grinding volcanic ash down to such fine particles requires energy, which in turn increases the resulting structure’s embodied energy, researchers said.
There is, then, a tradeoff between a concrete structure’s strength and its embodied energy, when volcanic ash is used.
Based on experiments with various concrete and volcanic ash mixtures, and calculations of the resulting structure’s embodied energy, the researchers …read more