New low-carbon 'concrete' made from desert sand

New low-carbon ‘concrete’ made from desert sand

A new construction material which is as strong as concrete but has half the carbon footprint has been developed by scientists at Imperial College London.

Called Finite, the material is a biodegradable product made from desert sand – a resource that has until now been useless for construction.

The breakthrough comes amid increasing concern about the world’s dwindling supplies of construction-grade sand, which are an essential ingredient in concrete.

While course, gritty construction-grade sand is stripped from beaches and river beds, desert sand has remained an untapped resource as its wind-swept grains are too fine and smooth to be used as filler in concrete.

Sand scarcity is a global issue

The world is facing a potentially disastrous sand shortage.Sand is the most consumed resource on earth after fresh water, yet sand is being excavated at a rate faster than it can renew itself.

This led the researchers the designers  to explore how different types of “wild” sand could be used to make glass.

‘Finite’ could change that. The binder ingredients are a guarded secret, but the scientists are confident that it outperforms concrete on key sustainability metrics. The main binder in concrete is responsible for five per cent of global CO2 emissions.

As well as being low-carbon and taking the strain off current sand sources, Finite is much more reusable than concrete, which often ends up in landfill. “If you make a block of it in the future it’s quite easy to recycle and not use any virgin material, whereas concrete needs to be essentially ground up and then used as filler for the next batch of concrete,” say the researchers.

Material suited to short-term infrastructure projects 

Finite is non-toxic and can be left to decompose naturally, or remoulded to be used in another project, the inventors claim. The material could be used to make pavilions, then after three months when the event ends it can be deconstructed safely, they suggest.

The team believe their material is ideal for use in the Middle East as the raw material for the concrete alternative can be scooped straight out of the desert, rather than being expensively imported.

New materials bring new opportunities

Early experiments with resin casting have demonstrated that the material can also be used to create objects such as vases and bowls. Left untouched, Finite takes on the colour and gradation of the filler, but natural dyes can be added in the mixing process.

Cost-wise, Finite should be a viable competitor to concrete in the construction industry once it is manufactured on a larger scale, because of the abundance of the raw materials.

Further information

 

February 15, 2019
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