Why is concrete so bad for the environment?

Cement production is the leading industrial cause of carbon pollution in the world, responsible for 8% of global emissions. The key raw material for Portland cement is limestone, which releases carbon dioxide as it is heated in a cement kiln. This process accounts for more than 55% of cement-related emissions. One reason why carbon emissions are so high is because cement has to be heated to very high temperatures for clinker to form.

One of the main culprits for this is alite (Ca3SiO), a mineral in concrete that cures within a few hours of pouring and is therefore responsible for much of its initial strength. However, the wing must also be heated to 1,500 °C in the clinker formation process. Some research suggests that alite can be replaced by a different mineral, such as belite (Ca2SiO). Belite is also a mineral that is already used in concrete.

It has a roasting temperature of 1,200 °C, which is significantly lower than that of the wing. In addition, the belite is actually stronger once the concrete is cured. However, it takes on the order of days or months for the belite to fully set, which leaves the concrete weak for a longer time. Current research focuses on finding potential impurity additives, such as magnesium, that could speed up the curing process.

It is also worth considering that belite needs more energy to grind, which can make its full impact life similar or even longer than that of the wing. If the cement industry were a country, it would be the third largest emitter in the world, behind China and the US. UU. It provides more CO2 than aviation fuel (2.5%) and is not far behind the global agricultural business (12%).

What explains this impressive carbon footprint? To make cement, you have to heat the limestone to almost 1,500 degrees C. Unfortunately, the most efficient way to heat a cement kiln is to burn a lot of coal, which, along with other fossil fuel energy sources, accounts for 40 percent of industry emissions. Eventually, limestone breaks down into calcium oxide (also known as lime) and releases CO2, which goes directly into the atmosphere, accounting for 60 percent more of industry emissions. When it comes to thinking about climate change and playing our part in slowing things down, we naturally think about things like the way we travel, the products we use at home, how we heat our homes, etc.

We don't usually look at the four walls around us and think they might be contributing to the problem. When, in fact, concrete is said to be responsible for around 4 to 8% of the world's CO2 emissions. Coal, oil and gas are the only materials that emit higher levels of greenhouse gases. Concrete contributes significantly to the climate crisis because its production releases huge amounts of carbon dioxide into the atmosphere.

Carbon dioxide and methane are the two greenhouse gases most responsible for global warming. They created a configuration that uses an electric crane surrounded by piles of 35-ton concrete blocks, which can be produced from waste products, to store energy by using excess power generation to power the crane to lift and stack the concrete blocks. The road construction and maintenance industry consumes tons of high-carbon concrete every day to protect urban and road infrastructure. This is achieved by directly injecting recycled liquid carbon dioxide from third-party industrial emitters, into the wet concrete mixing stage during the manufacturing process.

In the time it takes you to read this sentence, the global construction industry will have poured more than 19,000 concrete tubs. In the UK, it helped the massive wave of post-World War II development, largely still dividing opinion, with several of the country's major cities, such as Birmingham, Coventry, Hull and Portsmouth, largely defined by the concrete structures of that construction push. As elsewhere, the concrete craze in the largest nation of South America began quite benign as a means of social development, then transformed into an economic necessity and eventually became a tool for political expediency and individual greed. A mixture of sand and gravel, a binder of cement and water, concrete is widely accepted by architects, structural engineers, developers and builders because it is a remarkably good building material.

Concrete currently accounts for about 8 percent of the carbon dioxide emitted into the atmosphere, overshadowing the aviation industry's contribution of 2.5 percent. In addition, concrete production requires large amounts of water, and world production accounts for nearly one-tenth of the world's industrial water use. However, concrete structures have a large mass, so this comparison is not always directly relevant for decision making. Half of the CO2 emissions in concrete production come from the reaction that breaks down calcium carbonate and the other half from the fossil fuels needed to heat furnaces and transport materials.

It is worth noting that this value is based on mixing proportions for concrete of no more than 20% fly ash. Despite the known durability problems with the use of steel reinforcements, which can crack concrete from the inside, it is still the reference material worldwide. So a chemical reaction, CO2 becomes a mineral, sequestering the greenhouse gas pollutant in concrete infrastructures, buildings, roads, etc. for long periods of time.

According to the National Ready Concrete Association, every pound of concrete releases 0.93 pounds of carbon dioxide. Concrete is used to create hard surfaces that contribute to surface runoff that can lead to soil erosion, water pollution and flooding. . .

Chloe Robinson
Chloe Robinson

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