Concrete and Sand: A Complicated Truth

December 23, 2019

Concrete Makes Our Planet a Concrete Jungle

The earliest recordings of concrete buildings date all the way back to 6500BC. Today, 70% of the global population lives in a structure made of concrete. The USA alone has over 55,000 miles of concrete road. It can last for thousands of years and leads to the employment of almost 2 million people in the United States. After water, concrete is the most widely used substance on the planet. You may or may not be surprised that the concrete industry alone is worth $37 million USD.

The future of the concrete industry, however, is in jeopardy. Concrete as a building material has come under scrutiny in recent years. There are two main reasons for this: the environmental impacts of concrete and the global shortage of sand. What is interesting about these two factors is that the ripple effect of these two things touch every single person on the planet, whether they are in the construction industry or not. 

The construction industry will be held responsible to address these impacts and adapt. Already the construction industry is rising to this challenge. Technology has helped the industry to source sustainable building materials, combat the sand shortage, and implement green construction practices to mitigate the environmental impacts of concrete.

The Environmental Impact of Concrete

In a natural world of lush forests, green grass, and colourful plants, the stark contrast of concrete is almost a visual representation of what concrete does to our world. Concrete production is responsible for 4 – 8% of all global CO2 emissions every year. It uses 1/10 of the global industrial water supply, and the mining of limestone and creation of cement in factories is a major contributor to air pollution. 

As more and more studies come to light about the impact of concrete on our environmental wellbeing, building owners, architects, contractors and civilians alike are calling for change. Alternative sustainable building materials like lumber are growing in popularity as technology makes them a viable replacement for concrete. In the past, nothing was as strong or long-lasting as concrete. That simply isn’t the case any more. 

For cases when concrete must be used, there are alternatives such a papercrete or woodcrete which make the material more environmentally friendly. These materials are still new and aren’t necessarily used to build skyscrapers, but they are being recognized as an alternative for small projects or independent buildings.

Example of hempcrete blocks. Hempcrete is created by using the woody part of the hemp plant to make a concrete alternative. Image borrowed from Love Property

The Underbelly of Concrete

A growing concern about concrete use, however, is not the concrete itself. More and more people are growing concerned about the impact of excessive sand use on our planet. 

80% of concrete is made up of an aggregate. More often than not, that aggregate is sand. In the past 20 years or so, the world has boomed in growth. Although much of the US and Canada has been established and are adapting new sustainable building materials into new developments,  developing areas still go right to concrete as their go-to building material. 

The popularity of urban areas is only growing. As more and more people want to live in cities, the demand for concrete rises. Many countries where populations are booming are new to the world of urban development. Since concrete is still the go-to building material for skyscrapers and larger developments, it remains a popular building material for developing countries.  

This growth is also almost completely synonymous with Asian countries as well. They are seeing more growth and development than almost any other global recigon. The use of sand in India has tripled in the past 20 years. It’s estimated that China has used more sand in the past decade than the USA did in all of the 20th century.  In the last 20 year, Shanghai alone has built more high-rises than can be found in all of New York City.

 

More people, more cities, more concrete, more sand. 

 

As sand demand continues, local resources diminish. The introduction of a global sand industry has been created as a result. Some of it is above board and some of it is not. The introduction of illegal harvesting of sand, sand mafias, and blackmarket sales of the material has thrown the world into a global sand crisis. 

Since there are so many factors at play, it’s become almost impossible to monitor. No single government has the power to see the full picture. Noone can really tell when we will be able to figure out how our use of sand has really impacted our world. 

But it’s important to start at the beginning, if understanding is what we really are trying to do.

How Is Sand Harvested?

Sand for construction is harvested from lakes and rivers. Ocean sand is less desirable since it’s infused with salt from the saltwater. If a concrete structure is built with salt in it’s aggregate, it will slowly erode itself from the inside. 

Sand harvesting is often called “sand mining”. This term is misleading, however, because there is not a giant pit in the ground somewhere where sand is being drilled. Giant ships will drive up and down lakes and rivers with a vacuum-like tube sucking up sand as it goes. The sand is collected on these ships, then packaged and shipped across the world.  

It may seem like a relatively harmless task, but sand harvesting is changing the world as we know it.

A dredger pumping sand up. In this particular case, this sand is being directed towards shore. Image bowwed from Oceans Deeply News.

The Environmental Impact of Sand Harvesting

All of the environmental impacts of sand harvesting are apparent before it’s even used for concrete. The simple act of sucking up sand in a giant tube is being felt in ecosystems, in cities and towns, and in the economies of countries across the world.

The Impact on Ecocystems

Sand harvesting pulls the resource from the bottom of lakes and rivers. This sand acts as a home for thousands of microorganisms, for small fish, and other creatures. These organisms would traditionally act as food for other fish, which act as food for bigger fish. Once the sand is sucked up, the home for these microorganisms is as well. This eliminates a food source at the beginning of a river food-chain.

The Impact of Erosion

As sand is harvested, the shore of lakes and rivers gradually fall in to fill the space left by extracting the sand or gravel holding it in place. Think of it as the river itself trying to fill the gap created from sand harvesting. This “falling in” of shore sand and land into the river is called erosion.

Visual representation of land erosion from sand harvesting. Image borrowed from Three Issues

As river and lake-bed erosion happens, it drops off out-of-water ecosystems down into the water. As the shores of lakes and rivers fall into the water to fill the gap, the waterways expand and grow. Shorelines and coastlines are being changed by this process and it’s effectively bringing water close to our towns. Flooding is already an issue in many of the world cities and this is not helping the situation. 

For many coastal regions, tourists play a large part in local economies. As beaches fall into the water and shrink up, tourism will slow down.  It is estimated that 67% of Southern California beaches will be gone by 2100. For small cities, the loss of tourism dollars could drastically impact the wellbeing of anyone living there.

Satellite images from 1995 and 2013 show the impact of sand mining on the waterway connecting China’s Poyang Lake and the Yangtze River. Image borrowed from Yale Environment 360.

The Global Sand Shortage

The simple way of putting it is that we are running out of sand. 

As explored above, sand from water sources like lakes and rivers are often harvested for construction. When first hearing about a sand shortage, your mind may have gone to the vast deserts of the Sahara Desert or to all the sand in the deserts of the USA. Unfortunately, that sand doesn’t count.

Desert sand is often a very fine sand – the blowing wind and constant friction between the grains create a very fine, round sand. It’s so round, in fact, that it cannot be used as an aggregate.

It is estimated that the world goes through about 50 billion tons of sand in a year. The problem with this is that only about half of that is produced in the same amount of time. Humans have sucked up sand from riverbeds and lake bottoms years without thinking much of it. It’s only now that we are starting to realize what this means.

Black Market and Sand Mafia

The demand for sand as sand resources become more and more depleted have created an underground, black market for the material. This includes the creation of sand mafias

Governments have attempted to regulate the use and harvesting of sand but the addition of regulations means that the worth of sand goes up. As with everything in the world, the creation of laws results in the creation of law breakers. As soon as sand was labeled a commodity worth controlling, people started harvesting it and selling it on the black market. A “Sand Mafia” has been created as a result.

In India, over 300 trucks fill up every day on the Sone River. Image borrowed from National Geographic.

Sand mafia members actually steal sand from lakes and rivers to sell behind closed doors. Some go to beaches in the middle of the night. Some dive down with buckets to haul up sand from the depths of the water. People have been killed in their quest for sand because of this black market demand.

At the same time that this is going on, legal demand of sand continues. Both markets pull from the same stockpile of sand which is constantly growing smaller. It’s a battle that seems to have no winner; in the end, we will all loose.

A Demand For Change

It’s clear that something needs to change. Our earth, our cities, our economies, and our lives depend on it. But as the sand shortage begins to make headlines, it falls once again to the men and women who build our world to set the new standard for global building practises. 

It’s clear that it’s a challenge the industry is up for.

The Adaptation of the Construction Industry

The construction industry itself has already been adapting to the changing reputation of concrete by adopting new technologies and sourcing new building methods. These adaptations include everything from recycling concrete to sourcing man-made sand for an aggregate. 

The use of other sustainable building materials like lumber, and concrete-like alternative building materials like papercrete or woodcrete are helping to move the industry away from concrete as a whole. Green building practises like green roofs, grey water recycling programs, and alternative energy sources installed in buildings may help to make the finished product of a concrete building better for the environment.

In terms of the sand shortage, the use of manmade manufactured sand – called M-Sand – is empowering contractors to make both environmentally and budget friendly decisions for concrete production. This is important since even concrete alternatives like papercrete and woodcrete still use some sand as an aggregate.

The output of M-Sand. Image borrowed from The Constructor.

M-Sand is created by grounding up hard rock to create sand. It’s budget friendly for contractors because hard rock can often be found in local areas by a project instead of having to transport the material in. Concrete recycling is also helping to battle sand use by using old concrete as an aggregate for new concrete. Other aggregate alternatives include quarry dust, copper slag, broken bottles and even shells are helping to battle our obsession with sand.

As technology continues to drive the industry into the future, building and material alternatives will help us to adapt to growing environmental concerns. The real challenge is how we as human beings can change our own psychological connection of concrete to growth, prosperity and development.

Kevin Forestell

Kevin Forestell is CEO of DOZR and one of the co-founders. Kevin first got started as an entrepreneur when he founded Forestell Landscaping right after graduating from University. His love and passion for the industry and desire to help solve an equipment problem that contractors faced every day is what brought the founding team to start DOZR. Kevin is proud of the level of efficiency brought to the industry through DOZR and hopes that DOZR will help change the standard way equipment is rented.

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