From bridges and buildings to tunnels, concrete is a vital cog in modern infrastructure projects. And while it may have become indispensable to major developments, concrete also has a significant impact on the environment.
Concrete is made by combining water, a material like sand or crushed gravel – known as aggregate – and, importantly, cement, and it's this component that has a considerable environmental impact.
According to a 2018 report from Chatham House, over 4 billion metric tons of cement are produced annually. This, the policy institute said, accounts "for around 8 per cent of global CO2 emissions."
Around the world, efforts are being made to develop new techniques and processes to reduce the environmental effects of our reliance on concrete.
Earlier this month Boral – an Australian firm that specializes in building and construction materials – announced the launch of a five-year partnership with the University of Technology Sydney (UTS).
In a statement, the company said that the partnership would look to "accelerate product innovation, and the research, development and commercialisation of low carbon concrete."
The partnership between Boral and UTS represents one of many efforts currently underway to develop novel, interesting and sustainable building materials.
These include Netherlands-based StoneCycling. The firm says its "WasteBasedBricks" are produced "from a minimum of 60% waste" and "suitable for interiors and exteriors."
In the U.K., the DB Group has developed Cemfree, which it describes as a "totally cement-free alternative to conventional concrete." To date, the material has been used in a number of settings, including part of the M25, a major motorway in the south of England.
Traditional materials such as bamboo and timber represent other options for the sustainably minded, while major firms such as Bouygues Construction U.K. are looking to deploy interesting concepts such as paints that can help to boost air quality.
Another firm working in the area of sustainable building products is Kenoteq, a start-up spun out from research carried out at Heriot-Watt University, Edinburgh.
The university says the firm has developed a brick produced from what it describes as "90% recycled construction and demolition waste."
In an interview with CNBC in March, Kenoteq's Technical Director Gabriela Medero explained that the material used in the 'K-briq' could be a combination of things such as gravel, plaster board and bricks.
On the subject of finding more sustainable solutions and using different materials and processes in the years ahead, Medero – a professor at Heriot-Watt's School of Energy, Geoscience, Infrastructure and Society – explained that such a shift was "the only way forward. The way we are doing (things) as a construction sector … is not sustainable long term."
"It's the exploitation of natural resources, it's the… massive volumes of waste, together with the massive volumes of carbon emissions," she added. "We need to change."