
Coffee grounds could be used as an ingredient to make concrete stronger and greener, according to researchers at RMIT University in Melbourne, Australia. Look through the gallery to see other technologies that could make the construction sector more eco-friendly.

Indian company Carbon Craft Design produces floor tiles made with black carbon extracted from dirty air, could help to combat India's air pollution crisis.

StoneyCycling's WasteBasedBricks® use 91 kilograms of waste in every square meter, ensuring each brick is made of at least 60% recycled materials.

StoneyCycling's customized bricks are used for high-end architecture projects around the globe, like this wasabi-colored facade for a private residence in The Netherlands.

StoneCycling isn't the only company turning waste into bricks. Kenoteq's K-Briq -- which can be manufactured in any color, shape or size -- is made of 90% recycled construction waste. Compared to a regular clay brick, it produces 10 times less carbon emissions. By installing its technology close to recycling plants, Kenoteq hopes to reduce carbon emissions from transporting the bricks, too.

Regular bricks can help combat climate change, too. A technology developed at Washington University, Missouri, allows bricks to be transformed into energy storage devices powerful enough to turn on LED lights. When gases are pumped into the brick's pores, they react with the brick's chemical components, coating them in a web of plastic nanofiber, which is a good conductor of electricity.

A student in India had another brick-based brainwave. Along with three classmates from Jadavpur University, India, Abhishek Banerjee started the Plastiqube project in 2017 in response to human rights abuses in traditional brick kilns. The startup's bricks are made from recycled plastic and don't use any mortar -- a huge benefit when cement production accounts for up to 8% of global CO2 emissions.

It's bad for the planet but concrete is everywhere in our built environment. What if it grew greenery instead of paving over it? ECOncrete's bio-enhanced concrete does just that -- supporting vegetation like lichen, moss and climbing plants. Encouraging plant growth on building is about more than just aesthetics: ECOncrete says plant coverage can help to improve air quality and energy efficiency, and reduce noise pollution.

Italian architect Stefano Boeri wants us to think beyond a single green wall, though: his vertical forest erected in Milan in 2014 (pictured) was the first of many projects aiming to regenerate urban environments while reducing carbon emissions and providing natural shade for residents.

Boeri's smart, green city designs incorporate clean energy and transport into the infrastructure: sustainable solutions like solar panels and electric, semi-automatic transport networks are just a few ideas in the proposal for the Forest City of Cancun.

Research indicates that green roofs are a brilliant solution for naturally cooling buildings and managing water in storms and floods. With the right foliage, they can also act as urban carbon stores. Boeri's project in Tirana, Albania, combines nature and technology in plans for a self-sufficient smart city for 12,000 residents, which can house as many plants as people.

Texas-based construction tech innovators ICON are pioneering a low-waste solution to building: 3D printing. The company's giant printer, Vulcan, runs on a parallel gantry frame and can print up to 500 square-feet in just 24 hours.

In 2019, ICON broke ground on the first 3D-printed community in Mexico, and earlier this year, completed several homes in Austin, Texas (pictured). Alongside these social housing projects, ICON is developing and testing technology with NASA: they hope to 3D print the first-ever moon base as part of the Artemis lunar missions.

A common challenge for architects working in tropical climates is designing buildings that keep cool. India-based design studio Ant came up with an old-school solution, inspired by beehives, that could reduce the need for air conditioning. CoolAnt uses a honeycomb-like network of terracotta tubes, which circulate water with an electric pump. The water evaporates from the terracotta surface as air passes through, cooling the air.