Concrete is one of the most widely used construction materials in the world, but producing it comes with an environmental cost.
A significant part of that impact comes from cement, the ingredient that binds concrete together. Cement production requires high temperatures and releases carbon dioxide during manufacturing, which has encouraged the construction industry to explore lower-carbon alternatives.
So, can concrete become greener?
Reducing the Carbon Content of Concrete
One of the main approaches is reducing the amount of traditional cement required in a concrete mix.
Alternative materials such as ground granulated blast-furnace slag and pulverised fuel ash have long been used as partial cement replacements. Newer materials and manufacturing techniques are also being developed to lower the carbon footprint of concrete while maintaining the strength and durability required for construction.
Rather than replacing concrete altogether, the focus is increasingly on producing it more efficiently.
Using Recycled Materials
Recycling is another important part of the shift towards more sustainable construction.
Where appropriate, crushed concrete from demolished buildings can be processed and reused as aggregate in new construction projects.
This reduces demand for newly extracted materials while also helping to keep construction waste out of landfill.
However, the suitability of recycled materials depends on the type of project and the performance required from the finished concrete.
Reducing Waste on Construction Sites
Sustainability isn’t only about changing the ingredients.
Ordering too much concrete creates unnecessary waste, while ordering too little can result in additional deliveries, delays and further transport emissions.
Modern concrete supply methods can help reduce this problem.
Volumetric mixing, for example, allows concrete to be produced on-site in the quantity required rather than arriving as a predetermined load. This can help contractors reduce unused material and respond more easily when project requirements change.
Could Concrete Ever Become Truly Sustainable?
Concrete is unlikely to disappear from construction anytime soon. It remains valued because of its strength, versatility and long service life.
The more realistic goal is therefore to continually reduce its environmental impact.
Lower-carbon cement, recycled materials, more efficient production and better control over the quantities being used all have a role to play.
The future of sustainable construction may not involve abandoning concrete. Instead, it may depend on finding smarter ways to produce, deliver and use it.