From bamboo concrete to facades made of pollution to mushroom columns, the future of building is looking bright. CN visited a new exhibition — SuperMaterial — showing off innovations that could redefine the construction industry.
From materials that generate their own energy to those that tread more lightly on the planet, these inventions are designed to improve performance and reduce environmental impact.
1. Wood
Wood has been used as a building material since prehistory, but it took a back seat to steel and concrete during the industrialization of the 20th century. It has recently been rediscovered, however, as architects and builders look for new ways to reduce the carbon footprint of buildings and make them more sustainable.
One of the key benefits of wooden structures is that they absorb and store carbon dioxide from the air during their lifetimes. By contrast, steel and concrete buildings release significant amounts of carbon during the production and construction process. Wood is also more environmentally friendly than other common building materials, requiring significantly less embodied energy.
A new technology called cross-laminated timber (CLT) is causing a big buzz in the green building world. CLT combines pieces of lumber — generally conifers like pine, spruce, and fir, but occasionally deciduous species such as birch, beech, or ash — into larger panels that can then be used to build walls, floors, and roofs.
As the panels are assembled, they form an extremely strong structural system. And because the panels can be built to much greater heights than conventional lumber, they can provide the framework for a more environmentally and economically sustainable building.
The technology can be adapted to meet the needs of any structure, but it is being especially well received in the US, where there is a great need for more green office buildings, and where telecommuting is becoming more popular. And because the technology allows for larger homes, which are often constructed with wood, it can also help to reduce sprawl and increase the efficiency of land use.
Other inventions in wood construction aim to improve the performance of existing wood buildings, and even create entirely new types of building. For example, scientists in Sweden have discovered that by modifying the lignin in wood, they can turn it transparent. The resulting material could be used in facades and skylights, with the added benefit that it would release or absorb heat much more effectively than glass.
2. Stone
Stone is a common building material, but what makes it unique are the inventions that came along with it. Humans developed a wide range of stone tools that allowed them to survive and thrive as they hunted large game, broke bones for marrow, and prepared animal hides. This period of time is called the Stone Age and is characterized by stone artifacts like hand axes, spear points, scrapers and more.
When people began using stones as tools, they needed to find types of stone that could be shaped to meet their specific needs. Initially they relied on flint, a type of rock that is soft enough to be split with a sharp edge, and began to shape it into blades for cutting or scraping. Later, they began to find other materials that could be used to create tools as well.
As building techniques improved, walls began to be built with the stones facing each other rather than side by side. These are referred to as face stones and make up the majority of the volume and structure of a wall. Walls were also built in courses, which are layers of face stones stacked on top of each other. If a wall is not built in courses, it is referred to as a random wall.
In the late Stone Age, humans discovered ways to build stone walls with mortar. This was made by mixing burnt gypsum or lime with water to make a paste that has slight bonding ability. This allowed walls to be built more quickly, but still required a great deal of skill and attention.
In the modern world, most of us build with concrete or cement block walls. However, many of the same construction techniques that were developed in the Stone Age are still used today to build homes, buildings and other structures.
3. Steel
Steel may be supplanted by polymers and ceramics in certain areas, but it isn’t going away anytime soon. We use it for buildings, railroads, cars, trucks, tools and armour. The modern steel industry has come a long way since its early days. One of the biggest changes came about in the 1800s with the invention of the Bessemer process for manufacturing cheap, high-quality steel. The availability of this steel enabled innovations like steam engines, railroads and internal combustion engines to be developed. It also made skyscrapers and other massive construction projects possible.
Historically, iron and steel were expensive to make. But the open-hearth steelmaking method invented in the mid-1800s drastically reduced that cost, making it more affordable and more available. This was a major factor in fueling the Industrial Revolution.
Although blacksmiths began experimenting with steel in the 6th Century BC, it wasn’t until the 11th century that this metal alloy reached the level of mass production. Damascus Steel, which is still used for sword blades today because of its ability to take on a razor sharp edge, was produced in the Middle East at that time.
The next milestone was achieved in 1912 with the introduction of stainless steel. This allowed architects to create stronger, more beautiful and longer-lasting structures. Today, most steel is produced by melting down scrap and using recycled material. This is called secondary steel production and has helped reduce energy consumption. It also contributes to lower emissions. However, it would be a huge step forward if we could make zero-emissions steel to help reach our global goal of keeping temperatures below 2°C. (Source: Allwood et al, 2019). This isn’t likely in the near future but it is an important goal to strive for.
4. Brick
Bricks have been a staple in construction since time immemorial. They're one of the most durable materials available. However, new inventions are changing how we build with them.
For instance, builders now use hollow clay bricks that are perforated and lined with insulating material. These bricks are much lighter than traditional bricks, reducing costs and increasing speed of construction. They also don't require mortar to hold them together, making them more environmentally friendly.
Until recently, brickmakers had to go through the long and laborious process of mixing clay with water, driving oxen over it to trample it into a thick paste, scooping it into standardised wooden frames (each producing a brick roughly 42 cm long, 20 cm wide and 10 cm thick), stamping each side with a wire-strung bow, burning the edges, loading the kilns, removing the hot bricks for cooling, stacking them to dry, and bundling them for transportation. It was a dirty and laborious job, but a necessary one for creating buildings that could last for decades.
Nowadays, bricks are made in a variety of ways, including extrusion and molding. A brick's colour, surface texture, density, weight, absorption and pore structure, thermal characteristics, moisture movement and fire resistance can be controlled through these variations. They can even be customised for specific climates, for example, by increasing the size of a brick to make it more effective in colder regions.
Another innovative way of using bricks is by incorporating them into a wall's ventilation system. Known as Breathe Brick, this type of brick is designed to absorb air pollutants by absorbing them from the surface of a building's exterior. The result is a clean and healthy environment inside the structure.
5. Concrete
Concrete is a building material that offers strength, durability and energy efficiency. It is resistant to fire, moisture, and termites and is not as prone to cracking as wood. It is also a good choice for houses in hurricane-prone areas as it can withstand the high winds. However, it does require a great deal of energy to make and transport, which makes it more costly to use than steel.
Throughout the decades, concrete has become an architectural staple. It spawned brutalist structures such as Owen Luder's Tricorn Centre, but it also gave rise to the sleek curves of Oscar Niemeyer and Tadao Ando. Today, China uses half the world's concrete, pouring it into roads, railways, cities and megamalls at a staggering rate. But the monstrous scale of production has a dark side, requiring mountains of cement and beaches of sand and sucking up a 10th of all industrial water in arid and water-stressed regions. Concrete also contributes to the global heat island effect and traps air pollution.
Scientists are now working on giving concrete a modern upgrade. One project involves incorporating nanoscale reinforcements to boost its flexural strength. Another aims to reduce its environmental footprint by replacing the traditional Portland cement with an alternative such as fly ash or geopolymer composites that can be produced from waste materials. Scientists have also developed self-healing concrete, which uses bacteria to fill in cracks. The Bacillus bacteria are mixed into the concrete before it is poured, and when a crack forms, the bacteria produce calcite to fill the hole.
Some companies have even turned concrete into a green material. The company Builtd created a tower with an air-purifying facade, using Neolith sintered stone slabs that were treated with Pureti, a photocatalytic coating that can remove nitrogen oxide from the air.
