A natural resource used to produce concrete for construction and other industries, sand is in short supply, leading researchers to explore alternatives.
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Sand is the second-most consumed natural resource on the planet after water. The building sector alone uses up to 50 billion tonnes a year worldwide, mostly for concrete production. The world’s vast deserts and beaches may create the illusion of unlimited supply; but desert sand is too smooth and beach sand too salty to use. Instead, sand is typically dredged from rivers. The environmental impact of river dredging is serious – so much so that the export of river sand has been banned in countries such as India, Cambodia and Vietnam, where it has been especially damaging to the environment.
Mining sand from rivers is seen as unsustainable, at least with current dredging methods, but efforts to curb it exacerbate supply chain issues. The problem is especially acute in countries with building booms, notably China and India, home to the world’s largest and second-largest construction sectors. “The issue is construction,” says Shobha Bhatia, Professor of Civil & Environmental Engineering at Syracuse University. “But many of us also don't realize that sand is used for things like smartphone and TV screens, solar panels and other electric items,” she adds.
Some researchers are turning to technology and innovation in search of alternatives to sand, according to the BBC. Among them is Dr John Orr, University Lecturer in Concrete Structures at Cambridge University, whose research has found a way to process plastic waste for use in concrete. Orr points to the potential impact of this solution in India, which is grappling with both the exorbitant cost of sand and a plague of plastic. While plastic can only replace 10% of concrete’s raw materials, Orr adds that “in nations with a construction boom, using plastic in concrete could grow in popularity.”
Similar research has looked at replacing the sand in concrete with other waste materials like glass, but Orr and other experts warn against over-reliance on these types of solutions. They emphasise the deeper issue of concrete’s overuse. This could be remedied through design and architectural innovation. “Often, structures are overdesigned – they use too much concrete,” says Orr. “Savings in concrete in the order of 30-50% are possible.”
Vince Beiser, author of The World in a Grain: The Story of Sand and How It Transformed Civilization, says that sand is just a symptom of a larger problem. The main problem is the overconsumption of natural resources overall. Beiser suggests the creation of an international certification body for sand to help lower demand and encourage sustainable mining practices. In a 2019 report, the United Nations also argued for improved governance and a more transparent sand supply chain, saying the demand for sand poses “one of the major sustainability challenges of the 21st century.”