INSPIRING SUCCESS STORY

SamWoh paves the way to more eco-friendly roads

Key Highlights:

New bitumen recipe with AMTC uses recycled plastic and requires less crude oil to produce
40% more durable than current bitumen
Improved lifespan of roads means lower maintenance costs

Enterprise profile

Since 1975, SamWoh Corporation Pte Ltd has been behind many of Singapore’s civil engineering and infrastructure constructions. Some of its key developments include the Mandai Wildlife Bridge across Mandai Lake Road and the Sentosa Gateway Tunnel. The company also resurfaces runways at Changi Airport, among other projects. It was the first recipient of the Building and Construction Authority Green Mark Platinum Award, demonstrating its commitment to sustainability and innovation.

Problem statement

Roads are often constructed using bitumen, a form of sticky black by-product of petroleum that binds together a mixture of crushed stone, sand, and gravel. Bitumen deteriorates from prolonged use, resulting in the need for roads to be repaved every few years.

“Every time a car tyre comes in contact with the road, bitumen stretches like a rubber band. Over time, the elasticity weakens and will need to be replaced,” explained Dr Lim Zheng Bang, Manager at Singapore Polytechnic’s Advanced Materials Technology Centre (AMTC).

To find a more sustainable solution to road construction, SamWoh worked with the team at AMTC. The plan was to use recycled plastic to replace a percentage of bitumen in the overall material composition.

_{Dr Lim Zheng Bang, Manager at SP’s Advanced Materials Technology Centre operating machinery at the lab}

_{Dr Lim Zheng Bang, Manager at SP’s Advanced Materials Technology Centre, showing a sample of the new bitumen recipe that is at least 40% more durable than existing ones.}

Impact achieved

With the guidance of Dr Lim, student interns at AMTC conducted numerous experiments between 2019 and 2021 before the ideal mixture of bitumen and recycled plastic was found. This new recipe, which replaces 5 to 10 percent of bitumen with recycled plastic, is at least 40 percent more durable than the existing composition.

The new bitumen mixture was then put through rigorous testing by the Land Transport Authority, National Environment Agency, and the Public Utilities Board before it was approved for trial in a real-life environment from Q4 2021 to Q1 2023.

“We received grants from these organisations to secure a section of the road near the Pandan Reservoir, which has now been paved with this new version of bitumen, and the results have been promising,” said Dr Lim. He added that by increasing the use of plastics, less crude oil is needed to create the bitumen, which makes it a greener alternative.

SamWoh, which has invested time and resources to support the project, plans to use the new mixture for its upcoming projects. Dr Kelvin Lee, Senior Technical Manager at SamWoh Innovation Centre, said: “We are hopeful that this research can help to promote sustainable construction through the recycling of plastic waste.”

“We received grants from these organisations to secure a section of the road near the Pandan Reservoir, which has now been paved with this new version of bitumen, and the results have been promising,” said Dr Lim.

_{A sample of the new bitumen recipe that’s at least 40% more durable than existing ones}

_{Dr Lim Zheng Bang, Manager at SP’s Advanced Materials Technology Centre (left) talking to colleagues in the lab}

_{The new bitumen mixture being laid out near Pandan Reservoir for testing.}

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