From Fragile Sand to Strong Foundations: Scientists Develop Green Technology for Island Construction
Building roads, runways and other critical infrastructure on islands and coral reefs has long presented engineers with a difficult challenge: how to transform fragile local soil into a foundation capable of withstanding heavy loads and harsh environmental conditions.
Now, scientists from South Ural State University (SUSU), Russia, and Zhejiang University, China, have developed a potentially sustainable answer — a technology that strengthens calcareous sand with enzymes, coconut fibre and calcium carbonate.
According to a report by TV BRICS, a partner of the News Agency of Nigeria (NAN), the new material can be up to five times stronger under dynamic loads than untreated sand, while avoiding some of the environmental drawbacks associated with conventional soil-stabilisation techniques.
The innovation addresses a problem common to construction in island and coastal environments. Calcareous sand, which is largely composed of fragments of marine organisms and limestone, is highly porous and brittle. Under pressure or repeated impact, its grains can easily break down, making it unsuitable for supporting heavy infrastructure without significant treatment.
Importing conventional construction sand from the mainland is often costly and logistically difficult, particularly for remote islands. Engineers have traditionally relied on cement and chemical resins to stabilise weak soils, but those approaches can carry significant environmental costs.
The Russian-Chinese research team has instead turned to a biological process known as enzymatically induced calcium carbonate precipitation.
The process begins with urease, an enzyme extracted from soybeans. The enzyme is mixed with urea and calcium chloride in a solution. At room temperature, a chemical reaction produces calcium carbonate — the same mineral found in limestone.
The calcium carbonate forms around and between the sand grains, effectively binding them together and creating a stronger, more stable structure without the need for high-temperature processing.
But the researchers discovered that mineral bonding alone was not enough to withstand severe impact. To address this, they introduced coconut fibre into the mixture.
The natural fibre acts as reinforcement, helping the material maintain its structural integrity when subjected to sudden or repeated loads.
“Coconut fibre plays a key role: it reinforces the material, much like steel reinforcement in concrete,” said Tamara Chernykh, professor in the Department of Building Materials and Products at South Ural State University.
She explained that the reinforcement becomes particularly important when the material is exposed to dynamic forces such as waves striking coastal structures or aircraft landing on a runway.
In laboratory tests, samples without coconut fibre were completely destroyed under dynamic loading, while samples containing the fibre remained intact.
“This is of fundamental importance for island airfields and jetties,” Chernykh said.
The researchers tested different compositions of the reinforced sand for both static strength, measured through compression, and dynamic strength, which assesses its ability to withstand sudden impacts.
The experiments showed that increasing the amount of calcium carbonate generally increased the strength of the material. The most effective formulation consisted of equal proportions of fine and coarse sand combined with 0.4 per cent coconut fibre.
The resulting material demonstrated significant resistance to heavy impact, suggesting that the technology could have applications well beyond laboratory experiments.
Potential uses include stabilising the ground beneath airport runways, reinforcing foundations for jetties and breakwaters, and supporting other infrastructure exposed to coastal conditions.
One of the most significant features of the technology is its emphasis on locally available and environmentally friendly materials.
Rather than transporting large quantities of conventional construction materials to remote islands, the approach could allow engineers to strengthen sand already available at the construction site. Coconut fibre, an agricultural by-product widely available in many tropical countries, provides an additional locally sourced component.
The process also avoids the high-temperature firing required in cement production. By operating at room temperature and producing no harmful emissions during the calcium-carbonate precipitation process, the researchers say the method can reduce the environmental footprint associated with soil stabilisation.
The development therefore represents more than a new method of strengthening weak sand. It points towards a broader approach to construction in environmentally sensitive and geographically isolated locations — using biological processes and locally available materials to create stronger foundations without relying entirely on conventional, carbon-intensive construction methods.
For island nations and coastal communities facing the twin pressures of infrastructure deficits and environmental vulnerability, such technologies could offer a pathway towards building stronger infrastructure while reducing the ecological cost of construction.
