Biochar derived from wood waste
The NUS team behind the innovation (L-R): Souradeep Gupta, Manikandan Jayaraj, Associate Professor Kua and Chakradhar Pedapati.

Biochar derived from wood waste could make concrete buildings 20 per cent stronger and 50 per cent more impermeable to water, according to new research out of the National University of Singapore.

The research found that adding a small amount of biochar made from sawdust improved both strength and permeability properties of concrete, thanks to biochar’s porous and fibrous structure and water absorption and retention properties, which enhance the curing and hardening process.

Associate professor Kua Harn Wei from NUS School of Design and Environment said the strategy dealt with both wood waste and building quality issues.

“This is a simple and affordable strategy to enhance our building structures, particularly in Singapore, where water leakage from rain and water pipes are common problems,” he said.

“At the same time, we are putting the large amount of wood waste generated in Singapore to good use.”

The country in 2016 produced 530,000 tonnes of wood waste, much of which went to landfill. 

The researchers also found that the increased strength could enable early removal of formwork, which translated into construction time and cost savings. 

Associate professor Kua said using biochar in concrete meant that the carbon emissions were locked in the material, which would otherwise be lost to the atmosphere through incineration or decay.

“Close to 50 kilograms of wood waste can be utilised for every tonne of concrete fabricated,” he said.

“We typically require 0.5 cubic metres of concrete for every square metre of floor area built in Singapore. This translates to around six tonnes of wood waste being recycled to build a typical four-room [Housing and Development Board] unit with a floor area of 100 square metres.”

The research team is currently in discussion with a local company to explore commercialisation paths, and is also working on other high-performance concrete composites. 

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  1. No, Steve, “the country produced 530,000 tonnes of wood waste, much of which went to landfill”. It’s a good question, where did the wood waste originate? And what was the impact of harvesting that wood on endangered species, either in Singapore, Australia or elsewhere?

  2. Janet, I believe the article is talking about wood waste from landfill. Regarding your assertion linking timber harvesting from native forests in Australia to species extinctions, please advise what species have been made extinct from native forest timber harvesting in Australia and the peer-reviewed evidence to support your claim?

  3. Dear responsible global business friends,
    What is the source of wood waste please ? In Australia the source of some so-called wood waste is Native Forest which is directly responsible for loss of rare wildlife habitat … in a world dominated by socio-economic concerns this is leading to the extinction of species at a rate that is not considering extinction-debt (ie by the time the problem is known it is too late to prevent extinction)
    Please advise if any of this wood is sourced from Australia?
    If locally sourced please check for the same problem.
    thank you for your concern for wildlife.