{"id":151676,"date":"2025-06-04T09:17:13","date_gmt":"2025-06-04T08:17:13","guid":{"rendered":"https:\/\/www.pbctoday.co.uk\/news\/?p=151676"},"modified":"2025-06-04T10:55:17","modified_gmt":"2025-06-04T09:55:17","slug":"concretes-carbon-footprint-problem-and-what-you-can-do-about-it","status":"publish","type":"post","link":"https:\/\/www.pbctoday.co.uk\/news\/energy-news\/concretes-carbon-footprint-problem-and-what-you-can-do-about-it\/151676\/","title":{"rendered":"Concrete\u2019s carbon footprint problem and what you can do about it"},"content":{"rendered":"

Concrete is the most consumed material on Earth after water. It shapes our cities, infrastructure and homes – but at a significant environmental cost, writes Sarah Walker, senior architect product specialist at Vectorworks<\/h2>\n

Concrete production is responsible for over 7% of annual global anthropogenic CO\u2082 emissions. Most of these emissions \u2014 about 90% \u2014 come from Portland cement, the binding agent that gives concrete its strength.<\/p>\n

Reducing concrete\u2019s carbon footprint is critical in the fight against climate change.\u00a0 Fortunately, there are strategies to achieve this, from supplementing or replacing Portland cement to rethinking how we design and use concrete in construction<\/a>.<\/p>\n

Why Portland cement is the problem<\/h3>\n

Portland cement is the key ingredient in concrete, but its production is highly carbon intensive. The emissions come from two main sources.<\/p>\n

First, burning fossil fuels is necessary to manufacture cement, as limestone must be heated to over 1,400C, a process that relies on coal, natural gas or other fossil fuels.<\/p>\n

Second, limestone calcination \u2014 a chemical reaction that breaks down limestone (CaCO\u2083) into lime (CaO) \u2014 releases CO\u2082 as a byproduct.<\/p>\n

Since Portland cement is the main driver of concrete\u2019s carbon footprint, reducing its use is the most effective way to cut emissions.<\/p>\n

Supplementary cementitious materials (SCMs)<\/h3>\n

One of the simplest ways to lower concrete\u2019s embodied carbon is by replacing a percentage of Portland cement with supplementary cementitious materials (SCMs).<\/p>\n

SCMs are industrial byproducts that improve concrete\u2019s performance while reducing its carbon footprint. Fly ash, a byproduct of coal-fired power plants, improves workability and durability. Slag, a byproduct of steel production, enhances strength and reduces heat generation during curing.<\/p>\n

Up to 40% of Portland cement in a concrete mix can be replaced with SCMs, significantly cutting emissions.<\/p>\n

The ideal ratio of cement to SCMs depends on the strength and durability requirements for a given project.<\/p>\n

Cement alternatives and carbon sequestration<\/h3>\n

While SCMs help reduce emissions, new cement alternatives and carbon sequestration technologies offer even greater potential for a low-carbon future.<\/p>\n