Five students of Universitas Gadjah Mada (UGM) made an innovation in the form of concrete composite from plastic waste.
“Concrete composite is made from melted plastic mixed with sand,” said Putra Makmur Boangmanalu to reporters in a press conference on Tuesday (29/10) in Public Relations and Protocol Office UGM.
Putra developed the product together with fellow students Stephanus Satria Wira Waskitha, Vidiskiu Fortino Kurniawan, Nicolaus Elka Yudhatama, and Reza Yustika Bayuardi, who were concerned by the large amount of plastic waste in the country. The number of plastic production has increased twentyfold between 1964 and 2015 and reached 322,000 million tonnes
“Concerned by the plastic waste problems, we thought of making concrete composite as an effort to reduce plastic waste which could be applied directly applied to the community,” said the Chemistry student.
Putra explained that to get the concrete composite, they used polyethylene terephthalate (PET) plastic bottles. The plastic was shredded with a plastic shredder and then heated at 410-580° Celcius for 30 minutes. The melted plastic was then mixed with fine sand and later formed in a mould measuring 5cm x 5cm x 5cm. The material was dried for seven days.
“The melted plastic is used to replace cement,” he said.
Elka added the concrete composite product had higher compressive strength than of those sold in the market, which is 15,52 MPa. Meanwhile, the compressive strength of M15 concrete or products on the market is 15 MPa after being dried for 28 days. “This means that the plastic concrete composite is stronger than the average concrete,” he said.
People can make this composite by themselves as it does not require complex heavy tools. The concrete composite can also be used as paving blocks.
“What is still homework for us is how to produce the composite in a more competitive price,” said Vidiskiu.
He explained regular concrete brick costs Rp2,500 each while the plastic concrete composite ranges between Rp3,500-Rp4,000,” he said.
This product has been applied in Sepanjang village, Karanganyar city, Central Java, during the Student Community Service program. The students also won a gold medal during the 2nd World Innovation Technology Expo (WINTEX) 2019 international competition, organized by the Indonesian Invention and Innovation Promotion Association (INNOPA) from 9-12 October 2019 in Jakarta.
Source: https://www.ugm.ac.id/id/berita/18641-mahasiswa-ugm-sulap-sampah-plastik-menjadi-komposit-beton
