Thai professor turns plastic waste into sidewalks

A science professor at Chiang Mai Rajabhat University is turning plastic bags into paving stones for streets and teaching his students to do the same, in the latest example of Thai innovators fighting plastic pollution and embracing the circular economy.

“The paving stones are made of single-use plastic bags. The facility is a workshop for my students to learn how to produce the recycled blocks,” said Assistant Professor Wechsawan Lakas, a lecturer with the Industrial Technology Department of the Science and Technology Faculty at Chiang Mai Rajabhat University, a northern province of Thailand.

The project is a smaller-scale version of a similar endeavor by SCG, the Kingdom’s largest building materials conglomerate that paves roads and highways with a material made in part from recycled plastic, mainly plastic bottles.

Wechsawan said the idea to create paving stones from plastic bags came to him seven years ago on a family vacation in Phuket. “My son had a good time swimming in the sea. I saw not only his happy smile but also plastic waste floating not far from him. I was upset and felt sad. I knew that I must do something so that my child can experience the beauty of nature like the time when I was young,” he said.

Back at the university, he collected plastic waste around the campus. With help from colleagues, he built a “plastic road” on the grounds by mixing shredded bags with asphalt.

He eliminated the asphalt and used sand mixed with plastic bags to produce the paving stones. “I believe that good technology should not be complicated. It must also be easy to implement,” he said. The result is paving stones that are more durable than those currently being used by cities and towns.

Wechsawan said the stones could last as long as it takes for plastic bags to decompose, which is between 100 and 400 years.

“If more people realize the problem and separate their waste properly, plastics can be recycled to new products, thus creating a circular economy,” he said.

His team has traveled to several provinces in central and southern Thailand, teaching communities how to make the paving stones.

Next on his agenda is a project to make roofing tiles from old plastic bags.

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