Seeing the built world in a grain of sand

A quiet crisis is slowly but steadily threatening an aspect of the construction industry

In October of last year, global designers came together at Dutch Design Week in Eindhoven, the Netherlands, to discuss the rapid depletion of one of the most consumed natural resources on earth: sand.

It is said that there is five hundred quadrillion grains of sand on planet Earth. This granular material is one of those things we rarely consider. Every year, we remove billions of tons of sand from beaches, rivers and oceans and lock it away in our infrastructure, commodities and technologies, resulting in global sand scarcity. Environmental scientists estimate that the rapid depletion of the world’s sand reserves could leave the industries that rely on it searching elsewhere within 20 years.

High-quality, fine white silica sand is used in the global glassmaking and concrete industries — with the latter using an estimated 25 billion tons of sand and gravel every year — as well as being a critical ingredient in computer chips and used in the controversial process of fracking to produce oil and gas. Even golf course developers demand sand with specific qualities for their bunkers.

While once widely considered to be a limitless material, we may not run out of sand entirely but it will become increasingly scarce and expensive as our modern world continues to urbanize and expand. Sand is excavated at a rate faster than it can renew itself, disappearing from shorelines, rivers and sea beds. Illegal sand mining destroys fragile landscapes around the world that rely on this substance to help avert environmental disasters, and an estimated 50 billion tons of sand per year gets trapped behind the growing number of dams around the world, which prevent rivers from carrying new deposits downstream and potentially causing dam failure.

More than 196 million tons of sand were mined around the world last year — a market valued at $8.3 billion in the United States — according to the U.S. Geological Survey (USGS). In the U.S., 230 companies have 335 sand operations across 35 states, according to the USGS. Within the past few years, four U.S. sand companies have even started selling shares on the New York Stock Exchange.

Concrete cannot be created with just any type of sand; it needs to be course and “gritty” with a chemical composition of silicon dioxide (SiO2), which makes the grain very hard because it contains quartz. The individual sand grain particles must range in diameter from 0.0625 to 2 millimeters. This type of sand — referred to as fine aggregate — typically makes up about 25 percent of a wet concrete mixture. Sand from natural gravel deposits or crushed rocks can be used as a fine aggregate in concrete production to produce a structural concrete, but requires production as it does not occur naturally.

Wind-formed sand grains that are found in deserts are too smooth to be useful for concrete. Dubai has had to import sand from Australia for its mega construction projects; last year they imported $456 million worth of sand. Tamil Nadu, a South Indian state, purchased 55,443 metric tons of sand from Malaysia for construction projects last year. Even China, which accounts for a fifth of the world’s sand imports, according to the Trade Statistics Branch of the United Nations, has felt the pinch. Because of the frenzied development of new dams, buildings and factories the country has used more sand in the last four years than the United States has in the last century. China has even been piling huge amounts of sand onto reefs to create new islands and expand its foothold in the South China Sea.

And where there is a scarcity or rarity of materials, there is inevitably crime. Criminal mafias have sprung up globally, creating a sand-smuggling underworld, and stealing and illegally transporting sand on an epic scale. Illegal sand-mining has become a multi-billion dollar industry. Scientists researching beach erosion in Negril, Jamaica, discovered that local armed mafias were to blame for much of the damage: men came to the beach in the middle of night, hauled away bags of sand and sold them for the construction of beach-front developments. In India, gangs strip beaches and river beds of sand and sell it to illegal dealers. Police officers are now routinely assigned to stand guard in quarries in Bogota, Colombia, due to the emergence of illegal mining. Even where sand mining and dredging regulations exist they are often impossible to enforce.

To combat this looming issue, scientists from Imperial College London have developed a composite material that binds desert sand and other fine powders to create a concrete-like material, which they claim is as strong as traditional bricks and concrete, yet biodegradable with half the carbon footprint of concrete. In light of the billions of tons of sand used by the construction industry every year, maybe this is the breakthrough we’ve been waiting for.