Researchers from the National University of Singapore (NUS) have found a way to use wood waste to strengthen building materials. The new method uses biochar, which is a material produced when heat is used to decompose sawdust.
The researchers from the School of Design and Environment said when biochar in powder form is combined with cement, it increases concrete’s strength and impermeability, which refers to the ability to prevent water from passing through. It can plug gaps that exist within the concrete mix, reducing water seepage through cracks that might form when it is set.
Dr Kua Harn Wei, one of the four involved in the research, said they found that adding biochar strengthened the concrete mix by 20 per cent and its impermeability by 50%.
The NUS team conducted experiments and found that a 50mm cube of pure concrete could take about 72.6 kilonewtons (kN) of force before cracking, withstanding the weight of about 119 people whose average weight is 62kg each. But when biochar was added, it took about 83kN of force, withstanding the weight of about 137 people.
The researchers said using biochar is also environmentally friendly, by helping to recycle wood waste.
Dr Kua believes that the new method will help to alleviate some of Singapore’s existing structural problems.
“This is a simple and affordable strategy to enhance our building structures,” said Dr Kua. “Particularly in Singapore, this will help to reduce the problems of water leakage from rain and water pipes that could potentially seep through our concrete ceilings.”
The team from NUS is currently in discussions with companies and government agencies to commercialise this technique, as well as researching further on cement composites to serve wider applications.
NUS’ new technique adds on to Nanyang Technological University’s own research on waste management and reuse, as both universities seek to develop greener building materials.
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Source: The Straits Times, 13 April 2018