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SINGAPORE: A new technique of mixing concrete could make buildings more durable and put wood waste to good use, shared researchers from the National University of Singapore (NUS) on Thursday (Apr 12).

The researchers found that combining cement with recycled saw dust made from wood waste or what is known as Biochar, can enhance the curing and hardening process for concrete or mortar mixtures, making the concrete stronger.



This is because Biochar is porous and made of a carbon-rich material, and retains water well.

"Biochar acts like a reservoir or a regulator, it helps to hold onto the water, so that it can be retained in the mixture during the hydration process and this will help to harden it," said lead researcher Associate Professor Kua Harn Wei.

In the experiments, researchers found that the new concrete mixing method could create structures that can withstand up to 20 per cent more weight than those created by conventional methods.

Concrete structures made with biochar mix can withstand up to 20 per cent more weight than those created by conventional methods. (Photo: Vanessa Lim)



It could also potentially help cut the construction’s industry carbon footprint as well.



By strengthening the concrete mixture, items could be made thinner and lighter while still retaining its strength. This could mean less concrete is used.

Concrete manufacturing accounts for about 5 per cent of global emissions of carbon dioxide, which is a main cause of climate change.

Beyond this, the new method could also provide a solution for Singapore’s growing mountain of waste.



Last year, out of the 424,100 tonnes of wood waste generated in Singapore, only 77 per cent was recycled. In 2016, 530,000 tonnes of wood waste was generated.



Researchers are also in talks with government agencies to use the method for local construction projects. (Photo: Vanessa Lim)

By using biochar, nearly 50kg of wood waste will be recycled for each tonne of concrete fabricated.

This translates to about six tonnes of wood waste being recycled to build a typical four-room HDB unit.

The researchers are currently in discussion with a local company to commercialise it.

They are also in talks with government agencies to use the method for local construction projects.



