These are the new sustainable materials redefining the urban landscape

Cities are the epicentre of demographic and economic growth, making the need to innovate in urban construction a priority. Traditional construction, dominated by materials like concrete and conventional steel, has significantly contributed to climate change due to its high levels of CO₂ emissions. However, the evolution towards sustainable materials is changing this landscape, offering solutions that not only reduce environmental impact, but also promote resilient and sustainable urban development.

What will I read about in this article?

• The evolution of construction
• Recycled steel
• Green concrete
• Concrete to store energy
• Plastic bricks

The evolution of construction: from traditional to sustainable

Urban construction has come a long way from stone and wood to modern steel and glass skyscrapers. However, this evolution has been a double-edged sword. Traditional materials, although robust and durable, have a considerable ecological footprint. The construction industry is responsible for 37% of all carbon emissions worldwide, according to a report by the United Nations (UN). In fact, concrete alone contributes approximately 8%.

The good news is that, beyond regenerative infrastructures, innovation in sustainable materials is changing the game. These new materials are not only more environmentally friendly but also offer additional benefits such as improved energy efficiency, waste reduction, and the promotion of public health.

Recycled steel to refurbish an airport

Let’s start by talking about the material responsible for supporting the great weight of architecture (or at least building structures). Recycled steel reduces the need to extract new iron ore, thereby decreasing the carbon emissions associated with steel production. Moreover, this material maintains the same structural properties as virgin steel, making it a viable and sustainable option for urban construction.

In fact, it has been chosen by ACCIONA and AENA for the refurbishment and expansion of Palma de Mallorca airport. How will they obtain the 7,000 tonnes of low-emission steel needed for this project?

First, the metallic waste from the old terminal will be managed. Then, the rebar steel will be produced using electric arc furnace technology, powered by renewable energy. Finally, ACCIONA will use this recycled steel in the construction of reinforced concrete structural elements during the refurbishment and expansion of the new terminal.

This approach not only promotes material circularity but also reduces emissions by more than 40% compared to traditional methods. Specifically, more than 1,900 tonnes of CO₂ equivalent emissions will be avoided.

Green concrete to minimise CO₂ emissions

Just as recycled steel is changing the construction landscape, addressing the carbon footprint of concrete could be a crucial breakthrough in the fight against global warming. At the University of California (UCLA), they’re developing an ingenious solution to this problem with their innovative "green" concrete called CO2Concrete. This material is made from two main elements: carbon dioxide from the cement industry and portlandite, a mineral rich in calcium hydroxide, capable of absorbing CO₂ from the atmosphere. When portlandite is mixed with captured CO₂, limestone is formed, an essential component in the production of cement and green concrete.

The UCLA team has perfected a process that completes this transformation in a matter of hours, which is vital for industrial viability. This new method promises to reduce the carbon footprint of concrete by between 50% and 70%, without sacrificing performance or increasing costs compared to traditional concrete.

Moreover, solidification with portlandite mimics natural processes, such as the formation of mollusc shells, demonstrating how nature can inspire innovative solutions to critical environmental challenges. With CO2Concrete, sustainability and economics go hand in hand, offering a viable and eco-friendly alternative for future urban construction.

The concrete that turns your house into a big battery

But innovations with concrete do not end there. In a breakthrough that promises to transform the construction industry and energy management, researchers at the Massachusetts Institute of Technology (MIT) have developed concrete capable of storing energy. This material not only offers the typical structural properties of concrete but also acts as a battery, storing and releasing electricity as needed.

To achieve this, the MIT engineering team started with common materials such as cement, water, and carbon black. Carbon black, a component traditionally used in ink manufacturing, integrates into the cement forming branching fractal structures that exponentially increase the internal conductive surface, enabling rapid charge and discharge of energy.

This technology allows storing up to ten kilowatt-hours per forty-five cubic metres of material, enough for the daily consumption of an average home or to contribute to the stability of the power grid. In this way, buildings could become self-sufficient power plants, capable of storing renewable energy generated by solar panels and releasing it during peak demand periods.

ByBlock, turning plastic waste into bricks

In a world increasingly concerned about sustainability and efficient waste management, a US startup has presented a revolutionary solution: plastic bricks as an alternative to traditional concrete. This innovative technology allows recycling plastics from various sources, transforming them into colourful and versatile construction blocks.

ByBlock plastic bricks have dimensions of 40 cm high by 20 cm wide and deep, with an approximate weight of 10 kg each. These polychromatic blocks offer comparable resistance to traditional concrete. Furthermore, their manufacture helps provide a useful outlet for plastic waste that would otherwise be difficult to recycle.

In conclusion, incorporating sustainable materials in urban construction is not just a passing trend but an opportunity to tackle environmental challenges and promote sustainable development. Adopting these innovations will not only reduce CO₂ emissions but also foster a circular economy and contribute to the creation of healthier and more liveable urban spaces for future generations.