Plastic bottles could be used as building materials for India’s booming construction industry, according to a study.
Research has shown replacing sand in concrete with plastic waste could solve a national sand shortage and also reduce growing amounts of rubbish on its streets.
The University of Bath-led project has been selected to receive the 2018 Atlas Award in recognition of its potential impact on developing societies around the world.
The research found small particles made completely from plastic bottles could replace 10% of the sand in a concrete mixture, potentially saving 820 million tonnes of sand a year.
Other materials including plastic bags were trialled, but bottles, which were ground and graded to match sand particles, were found to perform the best.
India is one of the world’s fastest growing economies, and a booming construction sector has led to a surge in the cost of and demand for sand.
Unregulated sand extraction from riverbeds has become so widespread that it is now banned in many Indian states, after fears it could lead to coastal erosion and an unstable fishing industry.
The rapid growth in India’s urban population also means plastic waste has become a significant problem, with 15,000 tons of it dumped on the streets daily due to a lack of recycling facilities.
Cambridge University lecturer in concrete structures, John Orr, who completed the research while working at the University of Bath, said the findings could help tackle both problems.
He said: “Typically, when you put an inert, man-made material like plastic into concrete, you lose a bit of strength because the plastic material doesn’t bond to the cement paste in the material in the same way that a sand particle would.
“The key challenge here was to have a limit between a small reduction in strengths, which we achieved, and using an appropriate amount of plastic to make it worthwhile.
“It is really a viable material for use in some areas of construction that might help us to tackle issues of not being able to recycle the plastic and meeting a demand for sand.”
The research, in partnership with Goa Engineering College, India, has been published in the journal Construction and Building Materials.