Plastic waste can be crushed and used as an ingredient for structural concrete, researchers at the University of Bath in the UK have concluded.
The academics say that using plastic scrap in the mix is a viable ingredient for the construction industry. The research focussed on India, which is currently facing a national sand shortage as well as the problem of waste plastic becoming litter. Collaborating researchers at Goa University have confirmed the breakthrough offers a two-fold solution.
Too much plastic, too little sand
Sand traditionally makes up about 30% of concrete but, by using 10% of fine plastic residue, the researchers believe India could save 820 million tonnes of sand a year. This is great news for a nation experiencing a rapidly growing urban population and ‘booming’ construction sector. In 2014 alone, an estimated 280 000 tonnes of cement was manufactured in India.
The sand shortage is said to be so acute that it has sparked unregulated sand extraction from riverbeds, a practice that has recently been banned in many Indian states.
Dr John Orr, who led the research project, says India currently produces 15 000 tonnes of plastic waste daily and the lack of recycling facilities is a major challenge.
Making it worthwhile
‘Typically, when you put an inert, man-made material like plastic into concrete, you lose strength,’ Dr Orr points out. ‘This is because the plastic material doesn’t bond to the cement paste in the material in the same way that sand particle does.’
The key success in the research was to balance a small loss in strength with the appropriate amount of plastic to make its use worthwhile. Dr Orr adds: ‘It really is a viable material for use in some areas of construction that might help us tackle the issues of not recycling the plastic and meeting the demand for sand.’