Green Concrete

Concrete is the most widely used man-made substance on the Planet. At current rates, three tonnes of concrete are used every year for every person in the World. Notwithstanding the relatively low cost, ubiquity and utility of concrete, it has one major problem: the production of concrete produces large amounts of CO2 – the industry as a whole producing 2.8 billion tonnes of CO2 annually (more than, for example, the entire CO2 output of the USA or China – equivalent to 8% of planetary Carbon production).

Typically, Green concrete is made of different raw materials from cement-based concrete - namely fly ash (a waste product from coal power plants and is commonly disposed of in ponds and sent to landfills), recycled concrete aggregates and aluminium can fibres.

There are a number of alternative environmental requirements with which green concrete structures must comply (see: https://theconstructor.org/concrete/green-concrete/5566/): 

• CO2 emissions shall be reduced by at least 30 %.
• At least 20 % of the concrete shall be residual products used as aggregate.
• Use of concrete industries own residual products.
• Use of new types of residual products, previously land filled or disposed of in other ways.
• CO2-neutral, waste-derived fuels shall substitute fossil fuels in the cement production by at least 10 %.
  

Assessment

The development of Green Concrete remains in its fairly early stages (having only been conceived of in the last 25 years). As with all things ESG, green and sustainable, there are #nostraightlines. Some, for example, endorse the use of recycled or waste materials as sustainable because of their low cost and reduced use of landfill – undoubtably preferable to traditional cement-based concrete, but hardly sustainable. On the other hand, new forms of green concrete are being developed which are less harmful (even beneficial) to marine environments. If the future is green, it has to be Green Concrete.