A team of researchers from Sona College of Technology, Salem has patented a unique method of replacing up to 70 per cent sand in concrete with shredded plastic in the process cracking two of the biggest environmental issues faced by the world in the 21st century. The technology will help save the second most used natural resource—Sand–while simultaneously helping cut down the landfills from growing taller with waste plastic bottles.
India consumes nearly 70 million tons of sand annually to meet its infrastructure demands and this usage is growing at 7 per cent per annum. At the same time, over 5 million tons of plastic are consumed each year, with only about a quarter being recycled and the rest ending up in landfills. Surprising though it may sound, sand is the basic building block of construction and forms a big chunk of the concrete used in the structures we see in modern cities – be it malls, offices or residences.
The invention converting plastic waste into useable construction material can be used to partially replace the traditional concrete ingredient. “Our invention successfully utilizes recycled plastic waste as partial replacement for fine aggregate or natural sand in making paver blocks and precast bricks,” says Dr R. Malathy, Dean (R&D) and Professor, Department of Civil Engineering and lead inventor of the technology that has just been awarded the patent by India’s Patent Office.
Waste PET (poly ethylene terephthalate) bottles collected from Salem and around are crushed to less than 4.75 mm size in large machines. Sona College’s inventors from department of civil engineering achieved 70 per cent replacement of natural sand while matching the strength of tri-arc shaped paver blocks as per IS 15658-2006 codal.
The Sona College team of inventors — Dr R Malathy, Dr SRR Senthil Kumar, N Karuppasamy and K Dhinesh Babu — worked on the invention that earned them the patent “Effect of recycled plastic wastes as partial replacement for fine aggregate in manufacturing paver blocks” in 2019. The final patent was assigned in early 2022.
Environment friendly
“By utilizing plastic waste and dramatically reducing use of natural sand our patented technology offers significant environmental and cost advantage,” said Dr SRR Senthil Kumar, Principal, Sona College of Technology. Chocko Valliappa, Vice Chairman, Sona Group of Education Institutions said, “We at the Sona Group have inspired the faculty and students to continuously raise the bar in harnessing technology for commercial use for greater societal benefit. Our recent breakthrough invention will hopefully check depletion of global sand stock as well as limit plastic waste.”
