A Better Way to Build
Singapore company NeWall Tech has found a way to recycle construction debris into eco-friendly wall panels that are also economical and requires less labour to put up.
BY SASHA GONZALES
PHOTOS THE STRAITS TIMES, LIANHE ZAOBAO, NEWALL TECH
hile new buildings add to the beauty of a city’s skyline, we must confront the uncomfortable truth: The construction industry also produces a colossal amount of waste. In 2015, for instance, Singapore generated more than 1.4 million tonnes of construction debris.
It is not just construction waste such as concrete, wood and glass that are generated in building projects. The production of cement and bricks, two key construction materials, results in carbon dioxide (CO2) being released. According to non-governmental organisation Carbon War Room, cement production is projected to generate more than 4.8 billion tonnes of CO2 emissions annually by 2020, while brick production in Asia produces more than 359 million tonnes of CO2 every year – almost half the total amount from flights worldwide in 2015.
The good news is that 99 per cent of all construction waste in Singapore is recycled, mostly for use in construction activities, according to Singapore’s National Environment Agency, the public body responsible for ensuring a clean and green environment. For NeWall Tech, a Singaporebased building materials firm, recycling this waste is big business.
It transforms concrete waste into ecofriendly wall panels, thus reducing the amount of waste that would otherwise be disposed.
When construction firms use its wall panels instead of conventional building materials like bricks and cement, they not only lower their carbon footprint but also help to reduce the depletion of natural resources. This means that more buildings can be constructed without severely impacting the environment.
NeWall Tech’s managing director, Dr Tamilselvan Thangayah, and the late Professor Wee Tiong Huan jointly developed the technology to produce the company’s eco-friendly wall at the National University of Singapore in 2005.
To make these walls, concrete waste is first inspected for contamination and then crushed to produce coarse aggregates. The crushed aggregates are then passed through a sieve. The finer materials that pass through the sieve, which are usually discarded because they have little economic value, are used to make the wall panels.
These fine recycled concrete aggregates are mixed with natural sand, cement and water in a concrete mixer to form concrete. The concrete is then fed into a wall extruder, a device that compacts the concrete into wall panels. When the concrete has sufficiently set, usually by the following day, it is cut into prescribed lengths according to the customer’s order and stacked. Delivery takes place about seven days later, when the concrete is strong enough to withstand the stresses generated during transportation, handling and installation.
NeWall Tech’s wall panels have been used in more than one hundred projects in Singapore. They include shopping malls, residential blocks as well as tertiary institutes. Its wall panels have also been used in building projects in Malaysia, particularly the resort town of Desaru, where they have been used to build hostels. However, the availability of concrete recycled aggregates in Malaysia is scarce, says Dr Tamilselvan. So NeWall Tech is exploring the possibility of using other types of recycled materials, such as sawdust, wood chip and oil palm kernel shell, in Malaysia.
Although its wall panels’ overseas use is currently limited to Malaysia, Dr Tamilselvan sees potential for its technology in other markets. He says: “The UK is aggressively promoting demolition waste recycling with the introduction of many programmes and guidelines. And, in light of rapid urbanisation in China, I believe that it may resort to the recycling of demolition waste in the not too distant future.”
“Iʼm certainly proud to be able to contribute towards sustainability in the construction industry and hopefully make a positive difference in the long run.”
Dr Tamilselvan Thangayah, managing director of NeWall Tech
Dr Tamilselvan says that its wall panels are better for the environment and also cost-effective. “The fine recycled concrete aggregates, along with masonry waste, can be used to partially replace sand in the production of wall panels. This translates to less sand and other natural aggregates being required, and hence, a reduction in the exploitation of natural resources,” he says. “The recycled materials used to replace the sand are cheaper, meaning that the price of the wall will also be cheaper.”
Using wall panels, which are prefabricated, can also help construction companies complete their projects at a faster pace and with less manpower, says Dr Tamilselvan. The panels can be tailored to the builder’s required size, thus reducing wastage. They can also be produced on site to lower carbon footprint due to transportation and handling.
He adds that the use of these recycled materials to produce the walls does not compromise quality and performance. The recycled materials are largely made up of sand and other concrete-making materials, so they are not that different from the natural occurring materials usually used to make concrete walls, he says.
“I’m certainly proud to be able to contribute towards sustainability in the construction industry and hopefully make a positive difference in the long run,” says Dr Tamilselvan.
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