It’s rare that the opportunity to preserve resources, recycle resources, enhance quality, and improve cost efficiency all come together to deliver an important, improved product that the world uses in abundance every day.

We live on a finite planet with a finite atmosphere, and we have a finite quantity of resources at our disposal. At certain points in history, our human capabilities scale past the point of reason, where our busy work begins to take an excessive toll on planet Earth.

That’s exactly what’s happening in the concrete industry. But there’s a very good story is percolating to the top of the construction world.

Traditional concrete, the building material made from a geopolymer known as Portland cement, isn’t glamorous. It’s not high-tech. It’s not taking us to space. It’s not forming the metaverse – it’s quite the opposite of the metaverse, in fact! Instead, concrete is literally providing the foundation for our real world and for virtually every finished, hardened structure we need to build – our roads, buildings, bridges, and more.

Contrary to popular belief, Portland cement doesn’t owe its name to the beautiful port city in Oregon. Two hundred years ago, the inventor of an earlier version of the material named it after Portland stone, a similar-looking product that was quarried on the Isle of Portland in England.

Today’s concrete has evolved over the years to include lime/clay cement combined with aggregates like clay, shale, sand, iron ore, bauxite, fly ash, and/or slag. Concrete, in the end, is essential that Portland aggregate cement product + water + sand + gravel … all natural resources.

As of 2021, 4.4 billion tons of concrete were produced worldwide, and that number is projected to increase by 25% by 2050.

Researchers are perfecting a variety of eco-friendly, green concrete alternatives made from unique combinations of geopolymer cement components. What makes the resulting concrete “green” compared to traditional concrete products is the fact that each, to one degree or another in the manufacturing process:

1. Uses recyclable material
2. Utilizes a less energy-intensive manufacturing process
3. Generates a lower amount of carbon dioxide (CO2) and wastewater

In addition to those benefits, many varieties of green concrete are proving to be more durable, stronger, and less expensive. They can also be set up quicker with less shrinkage.

All of these are positive attributes, so what’s not to love?

A Better Recipe of Raw Materials

Natural sand is a critical material used in traditional concrete. Natural sand, though, is a limited resource, and it’s also used in the fracking process. This material is mined from open pits, inland dunes, river beds, and other geologically fragile environments. There’s a similar story with gravel, which is another aggregate and another critical component of Portland cement-based concrete.

In contrast, many varieties of geopolymers that make up green concrete use natural fibers and industrial waste products like waste glass sand, fly ash from coal-fired power plants, and blast furnace slag, a by-product of iron and steel production.

Additional research is being done on integrating aggregate from demolition waste and other recycled concrete, forming a closed loop for this important construction material.

A Better Use of Our Energy Resources

At the risk of getting into the weeds and dredging up more detail than you ever wanted to know, green concrete also reduces energy consumption.

First of all, sand mining is very energy-intensive, and any reduction in that activity is a big step in the right direction. Second, the heating process for making traditional Portland cement requires massive amounts of energy. But formulating green cement with fly ash, for example, reduces that significantly.

Reducing Greenhouse Gases

Due to its chemical processes, Portland cement manufacturing accounts for 7% of the global release of CO2, according to the International Energy Agency. If the concrete industry were a country, it would be the third-largest CO2 emitter, right behind the U.S. and China.

Alternatively, green geopolymer cement production can reduce this by 90%. That’s pretty stark, not to mention compelling.

Making A Better Cement Product

As a result, these new green processes and formulations are not only making concrete in a better way, they’re making concrete better.

• Using natural fibers like hemp or bamboo for reinforcement instead of synthetic or steel fibers is not only cheaper but also adds tensile strength and reduces corrosion.
• Lead slag is proving to be an ideal additive to green concrete to reduce drying shrinkage.
• Green concrete containing waste glass sand (as opposed to natural sand) has been shown to be stronger and less porous than other varieties.
• Finally, thanks to many of the features mentioned above, green concrete promises to be less expensive than traditional Portland cement-based concrete.

The next step for this technology is to incorporate it into 3D-printed buildings and other structures, reducing waste during construction. It’s too early to say if construction will ever be considered a “green industry,” but it’s definitely taking major steps in that direction.

Focusing on the Positive

This is one of the best good-news stories I’ve had a chance to talk about in a long time. Futurists tend to spend a lot of time exploring new frontiers and breakthrough industries and less time exploring the implications of advances in current practices that can be just as or even more impactful in the long run.

And too many observers and pundits tend to focus on the seemingly insurmountable challenges all around us instead of rolling up their sleeves and picking away at today’s problems.

The emergence of green concrete demonstrates that doing the right thing from a sustainability perspective doesn’t mean we have to compromise the quality of life or, in this case, the quality of building.

We need more of these kinds of breakthroughs and more researchers working in big areas like this to help ensure our world is on the best possible trajectory into the future.

Challenges in the construction industry, including a declining workforce and the cost of materials, combined with some incredible technology and manufacturing breakthroughs, are changing today’s construction sites in ways that will make them unrecognizable in the future. The three trends making the most impact are: modular construction, 3D printing construction, and robotic bricklaying.

Modular Construction

Prefabrication is a broad term that describes the practice of building all or portions of a home or commercial building off-site – maybe even in another state or country. The components are transported to the construction site for incorporation into the structure or to make up the structure itself.

The most intriguing of these prefab options is “permanent modular construction,” or PMC. Specialized prefabrication companies can build rooms or entire suites offsite, complete with pipes, fixtures, wiring, tile, and countertops. They’re shipped to the construction site by truck and off-loaded with massive cranes. The modules are held in place while workers scramble to connect them with other elements of the structure or stack them on top of or next to another module.

It’s not quite snap in place but it’s not too far off.

While modular construction represents around 4% of commercial and residential projects in the U.S., that number is already significantly higher in China, Japan, and some European countries.

Modular projects offer incredible efficiencies and implications for quality. Fabricating modules at a climate-controlled indoor site transforms the work into more of a repeatable factory job than a craftsman task. Plus, in order to withstand the rigors of the transporting and off-loading steps, modules tend to be built to sturdier specifications, which make the resulting buildings better able to survive the worst that nature can throw at them.

A recent industry analysis found that developers see the most promise for the modular technique with healthcare facilities, hotels/motels, multifamily residences, schools and colleges, and low-rise offices.

3D Printing Construction

Before dismissing the idea of a “concrete house,” check out this one by a builder in New York. The company’s robotic construction system built 40% of the structure – the windows and walls – before finish workers came in to take care of the rest. The final cost of the house was approximately 20% less than a comparable, traditionally built home.

The technical term for 3-D printing is “additive manufacturing”. Framing a 2,000 square foot house using this technology can take as little as three days. 3-D builders are moving beyond the use of normal concrete to reinforced composites that can further reduce the price and make the homes even more secure from fire, pests, water damage, and mold.

The overall cost reduction of 10-50%, faster construction speed, and increased durability makes 3-D printed homes very attractive as affordable starter homes.

Even greater efficiencies are possible when the printing is combined with modular construction. This planned community in California will have 3-D printed homes that are built in a fabrication facility and then shipped to their new neighborhood.

Printed homes can be designed and constructed in all styles, from traditional to downright space age, as with these futuristic-looking styles.

From an environmental perspective, additive manufacture of homes is a win as well, since the process doesn’t produce any scrap.

3-D homes could be ideal in remote, impoverished locations around the world. If the truck and supplies can be brought in, there’s little need for too many more construction
specialists, especially if the designs are quite simple.

Robotic Bricklaying Construction

What would be more futuristic than a competition between a robotic arm that’s printing a wall vs. a robotic arm that’s building a brick wall? The concepts are similar – the layer-by-layer construction of the interior and exterior framing guided by pre-programmed design plans.

Today’s truck-based, robotic arms can load, cut, route, and place bricks, framing a house in as little as two days. Human bricklayers lay 300-500 pieces per day on average. In contrast, the leading robotics alternatives can place 200 much larger bricks per hour – and that’s expected to increase to 1,000 in future models. These robots also apply a special mortar or adhesive that dries faster than standard mortar.

Just like the other construction technology solutions, robotic bricklaying is evolving and making tremendous strides in improved speed, safety, and quality. The benefits and economies related to this approach to bricklaying are even greater when the technique is applied to multi-story structures.

The Future of Housing

Residential and commercial construction in the U.S. is a $1.6 trillion industry. Hundreds of thousands of construction workers were laid off during COVID and the Census Bureau estimates that 60% of them won’t return, in spite of the expected resurgence of the industry in 2021.

In the U.S., state and local budgets have been squeezed thanks to COVID economic impacts, so less funding is available to subsidize affordable housing projects. And with the hot housing market, more and more people are being priced out of starter homes.

Modular assembled, 3D printed, and robot built homes can bring down housing costs and help address both of those pressing societal issues as we move into the future, leaving plenty of room and demand for all three of these technologies.