Eximo vs act concrete5/17/2023 ![]() The drawback of the iron and steel industry is its CO 2 emissions, which account for 6.7% of the global total, but as with cement, work is currently underway to reduce them. Although it is still only 85% reused, it is the most recycled industrial material in the world. ![]() Stainless steel, a building material often considered an example of sustainability because of its durability and because it is 100% recyclable without loss of properties, especially stands out. Image: WikimediaĬoncrete is not the only source of recycled building materials. The process of concrete recycling involves machines capable of crushing large pieces into small lumps. Although most member states still only recycle 50%, in some EU countries the rate is already as high as 90%. In the EU there has been a directive in place since 2008 that called on countries to recycle 70% of construction and demolition waste by 2020. Construction rubble can be broken down and crushed to different sizes, allowing it to be used as building blocks, in breakwaters or retaining walls, as gravel for roads and landscaping, or as aggregate for making new concrete. ![]() Traditionally, demolition debris is dumped in landfills, but increasingly it is being reused. Recycling is also an essential way to reduce the consumption of cement. The cement thus becomes a carbon sink that can even improve the properties of the resulting concrete. One cement-specific process involves using CO 2 as a curing agent, so that the carbon is trapped in a solid state, mineralised in the form of calcium carbonate. However, these technologies are still in experimental or pilot project phases, and some experts are sceptical. There are a variety of proposals for carbon capture and storage, ranging from burying CO 2 to using it as a raw material in the manufacture of materials. Using CO 2 to cure cement can avoid carbon emissions as it remains trapped in solid state. Therefore, apart from reducing the amount of CO 2 in concrete mixes, proposals to decarbonise cement production focus on capturing CO 2 so that it is not released into the atmosphere. It is thus impossible to manufacture cement without producing CO 2. Carbonising cement to decarbonise itĪlthough the bulk of CO 2 emissions generally come from burning fossil fuels, in the case of the cement industry this only accounts for 50% of the carbon emitted the other half cannot be eliminated either by improving efficiency or by substituting energy sources, as it is inherent in the chemical reaction that gives rise to the main ingredient in cement: the calcination of limestone, or calcium carbonate (CaCO 3 ), results in lime (calcium oxide, CaO) and CO 2. This is why both research and industry are exploring ways to reduce these emissions or to find substitute materials. And while it seems clear that in the future concrete will continue to be the basic resource it has been since it was invented in its modern form in the 19th century, today we have a problem: cement, the glue that binds the components of concrete together, is responsible for 8% of global emissions of CO 2, the main greenhouse gas provoking climate change. And yet, unless you are standing in the middle of a natural setting, you only have to look in almost any direction to find it: three tonnes of concrete per year is used for every person on the planet, which is twice that of all other building materials combined. If you ask people what the second most consumed material in the world is after water, most will likely draw a blank.
0 Comments
Leave a Reply. |