Concrete alternatives to… concrete

By Mariusz Bogacki, Researcher and Science Communicator, Edinburgh

While concrete remains the most popular building material on the planet, there are many concrete alternatives to concrete!

In the past we have written about Cross-Laminated Timber (CLT) technology as a sustainable alternative to concrete-based construction materials. However, its current global application is limited as not many countries maintain a well-managed forestry policy and lack professional expertise in how to design and built with it effectively. Not to mention that CLT is much more expensive when compared with concrete. Keeping these challenges in mind let’s take a look at other contemporary, as well as long established, alternatives to concrete.

Rammed Earth

Rammed earth is an ancient building technique that has been used for thousands of years. Its origins date back to ancient China and Romans used it for construction of their famous roads! The technology involves compacting layers of earth and other materials, such as gravel, sand and clay, into a solid structure. Rammed earth structures are incredibly strong, durable, and energy-efficient, making them an excellent alternative to concrete. What’s more – its texture and warm, natural colour results in a distinctive artisanal look.

Hempcrete

This is a more contemporary alternative to concentre. Hempcrete is a lightweight and breathable material that’s made from a mix of hemp fibres, lime and water. Its production actually resembles production of concrete blocks. However, Hempcrete is fire-resistant and highly sustainable, with hemp fibres being a renewable resource, and lime a low-carbon material. This combination makes it perfect for insulation, and it can be used for walls, floors, and roofs.

Ferrock

Arguably the most environmentally friendly building solution comes from Ferrock. Ferrock is a modern construction material that's made from recycled materials such as steel dust – which is a waste product of steel production– and silica from ground up glass, making it much stronger and way more sustainable than concrete. Ferrock is not only made from waste materials but its production results in absorbing carbon dioxide, which means that it actually has a negative carbon footprint.

Geopolymer

This is another innovative construction material that relies on recycling. Geopolymer is a type of cement that's made from industrial waste such as fly ash, which is a by-product of coal-fired power plants. Geopolymer has a much lower carbon footprint than traditional cement, and it's also highly durable and resistant to corrosion. It's an excellent alternative to concrete for building foundations, walls, and floors.

Concrete is undoubtedly a valuable construction material. Its durability, versatility and relative cost-effectiveness make it a ubiquitous material used in everything from buildings to roads and bridges. However, the construction industry generates around 11% of global gas emissions – so, if we are to combat climate change, we need new alternatives to how we build and construct things.