When it comes to sustainable architecture, timber usually gets all the attention. But concrete is more than catching up, some viewing latest developments around the product so groundbreaking as to trigger a “second industrial revolution”.

That’s how Scott Shell, an architect with environmental philanthropic organisation ClimateWorks Foundation recently described the advancements in reducing damage caused by concrete manufacturing. Methods developed in the past few years are even receiving financial backing from the likes of Amazon and Microsoft who see the potential for ‘green’ concrete to become the next big thing.

Stopping pollutants at the pass

There is good reason for the enthusiasm. Concrete is the world’s number one construction material (followed by steel, wood, stone, brick and masonry). It is also the most widely used substance on the planet after water.

Yet concrete is also one of the world’s leading pollutants. Estimates put concrete manufacture’s contribution to global CO2 emissions at 8%. One of The Guardian’s most popular articles of 2019 branded concrete “the most destructive material on Earth” and deduced that if the cement industry were a country it would be the third largest carbon dioxide emitter in the world – belching out 2.8 billion tonnes to come in third place after China and the US.

As a result, the development of methods to combat this damage are hitting their stride both here and internationally. In the US, CarbonCure Technologies limits concrete’s carbon pollution by wrangling directly with the carbon dioxide, injecting it straight into the concrete where it reacts with calcium ions. This forms an extremely hard substance called calcium carbonate which both reduces the amount of cement required for a job while trapping carbon instead of allowing it to flow out into the atmosphere.

Like several other innovators CarbonCure is calling its product ‘green concrete’, its invention deemed so progressive it has financial backing from Amazon and Microsoft.

Australia has been no slouch in the area either. The Australian arm of Holcim, (holcim.com.au), a global leader in innovative and sustainable building solutions, uses ECOPact the world’s broadest range of low carbon concrete throughout its work. This product emits on average 30% lower CO2 emissions without comprising the integrity of the concrete, helping builders and building owners reduce their carbon footprints.

ECOPact is currently being employed for in the construction of a home in Waverly in Sydney’s Eastern Suburbs. Builder Akira Barzaghi from Mindful Building says ECOPact has reduced the structure’s carbon footprint by up to 70%.

Delving into the detail

Australian researchers and academics have also been busy looking into the creation of environmentally friendly ways to manufacture concrete. Last year a team from RMIT made headlines here and in the US, with The Washington Post taking great interest in their efforts to utilise ground coffee and chaff - the byproducts of roasting and brewing coffee – to make ‘green concrete’. Adding coffee grounds to concrete, the RMIT team found, made their product 30% stronger while acting as a sustainable alternative to mined sand. Importantly, in results published in the Journal of Cleaner Production, Transforming spent coffee grounds into a valuable resource for the enhancement of concrete strength - ScienceDirect this method also prevents coffee waste becoming landfill and transforming itself into another environmental vandal, one that produces methane and other greenhouse gases as it decomposes. Other projects by RMIT researchers include producing concrete partially made with used rubber tyres, while at the University of Sydney, academics are experimenting with embedding their version with ground glass.

Not to be outdone, Japanese researchers recently utilised not only coffee grounds but also Chinese cabbage, orange rinds, pumpkins, banana peels, seaweed and onions to create sustainable concrete. A report by Nicole James in the Epoch Times this week states that the Japanese product is four times stronger than conventional concrete. But while it may sound as edible as it is green, the lacquer and waterproofing alone would take this new type of concrete firmly off the menu.