Scientists have found a way to turn fine-grained desert sand — long considered useless for construction — into a viable building material by mixing it with wood.
Researchers at the Norwegian University of Science and Technology (NTNU) and the University of Tokyo have developed a prototype for “botanical sand concrete” that could solve one of the construction industry’s biggest resource paradoxes.
While the world is covered in vast deserts, the construction industry is facing a critical shortage of sand. Traditional concrete requires sand with a specific size and shape — usually rough, angular grains found in rivers or produced by crushing rock. Desert sand, by contrast, is too smooth and fine-grained to act as a fastener, meaning concrete made with it is typically too weak for building.
“Researchers have discussed for many years whether desert sand can be used in concrete,” says Ren Wei, a postdoctoral fellow at NTNU. “The challenge is that desert sand is so fine-grained that it is not suitable… In other words, the concrete will not be hard enough.”
Cooking sand and wood
To overcome this, the research team abandoned traditional cement recipes. Instead, they developed a method that combines desert sand with plant-based additives.
The process involves mixing the sand with tiny pieces of wood and subjecting the mixture to heat and pressure. The result is a material known as “botanical sandcrete”.
After testing various temperatures, pressures, and mixing ratios in laboratories at the University of Tokyo, the team found that the new material is surprisingly robust. It achieved enough strength to be used for paving stones, walkways, and pavements.
Solving a global shortage
The implications for the environment are significant. Concrete is the world’s most widely used building material after water, and its production accounts for approximately 8 per cent of global CO₂ emissions.
Currently, the demand for suitable sand leads to the dredging of rivers and the crushing of mountains — processes that cause significant ecological damage. By utilising desert sand, the industry could reduce this strain on natural landscapes.
However, the researchers caution that this does not license the shipment of Sahara sand to construction sites in Northern Europe. For the solution to remain sustainable, the sand must be used in the regions where it is found to avoid the carbon footprint of transport.
“The production process is relatively simple, so in principle the material can be made in many places,” says Wei. “But we need to test more, including how it can withstand cold, before it can be used out in Norway.”
