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Cement is the most used synthetic material that exists.
However, its strong presence, which helps shape buildings, also has a secondary effect on the climate: its production process is considered a gigantic source of carbon dioxide (
How big is the problem in industry
According to the British research institute Chatham (19659005), one of the gases responsible for global warming
. Possible solutions to minimize the problem are at the l & # 39; House, cement is the source of about 8% of global CO2 emissions.If its industry was a country, it would be the third largest emitter of this gas in the world, behind China and the states. In comparison, its emissions exceed those of aviation fuel (2.5%) and are not far behind those generated by the global agri-food industry (12%), for example. this proportion, the quest ion was one of the topics discussed at the United Nations conference on climate change, COP24, which ended on Saturday in Poland.
During the event, representatives of the industry discussed ways to meet the requirements of the Paris Agreement. – a global commitment to reduce gas emissions into the atmosphere
In order for the agreement to be respected, annual cement emissions should be reduced by at least 16% by the time 2030.
The task is not considered easy [
Cement production involves the extraction and grinding of raw materials, mainly limestone and clay.
They are crushed and mixed with other materials, such as iron ore or ashes. – and, in the next step of the process, introduced into large cylindrical furnaces and heated to about 1450 ° C.
The calcination process – as it is called the chemical decomposition reaction the thermal , used to convert limestone into virgin lime – divides the material into calcium oxide and CO2
. This process gives rise to a new substance called clinker. This is not only the main component of cement, but the material whose production releases the largest amount of CO2 in this industry.
In the form of small grains of grayish tint, the clinker is cooled, crushed and mixed with plaster and limestone.
In 2016, global cement production generated about 2.2 billion tonnes of CO2, or 8% of the global total.
With thermal combustion, 90% of the sector's emissions could be attributed to clinker production.
Essential Material
As the main building material of most apartment buildings, parking lots, bridges and dams, concrete has been used on a large scale by many of the world's leading architects.
In the United Kingdom, he contributed to the wave of post-World War II mbadive development of several of the country's major cities, such as Birmingham, Coventry, Hull and Portsmouth, largely defined by the typical concrete structures of the 'time.
The Sydney Opera House in Australia, the Lotus Temple in India, the Burj Khalifa in Dubai – the largest skyscraper in the world – and the magnificent Rome Pantheon, with the largest unreinforced concrete dome of the world, owe their shape to this material.
Architects, developers and builders have widely adopted concrete and gravel, a cement-water-cement binder, as it is a more affordable building material, but also with other benefits.
"It is economical, can be produced almost anywhere and has all the structural qualities needed to build a building or a sustainable construction site," says Felix Preston, deputy director of research at the Ministry of Energy, Environment and Resources Chatham.
Growth of the cement industry
These attributes of concrete, considered incomparable, have helped boost global cement production since the 1950s, Asia – and especially China – representing the bulk of growth since the 1990s.
Production has been multiplied by more than thirty since 1950 and almost four times since 1990.
2011 and 2013 as the United States throughout the Twentieth century.
But with the stabilization of Chinese consumption, it is expected that future construction growth will occur primarily in the emerging markets of Southeast Asia and Africa. Sub-Saharan Africa – Boosted by Rapid Urbanization and Economic Development
Chatham House researchers predict that the built-up area of the planet is expected to double over the next 40 years, requiring increased cement production by a quarter by 2030.
Long History
For some of us, the presence of concrete in cities may seem recent, but architects and builders have not been able to see it. have been using for millennia.
The first use is thought to have occurred more than 8,000 years ago. with Syrian and Jordanian traders creating concrete floors, buildings and underground cisterns.
Later, the Romans became known as masters of concrete while building the Roman Pantheon in 113-125 AD, with its 43-meter diameter concrete dome, the largest in the world.
The concrete used in our modern environment, however, owes much of its composition to a patented process of the early nineteenth century by the builder Joseph Aspdin of Leeds, England
His innovative technique of burning limestone and limestone. 39, clay in an oven, then to reduce it to powder to make it an "artificial stone" is now known as Portland cement – which continues to be the key ingredient of almost all modern concrete .
But, despite its unequivocal presence, the environmental references of concrete have been further examined over the past two decades. involves quarrying – causing air pollution by dust – but also requires the use of huge furnaces, which require large amounts of energy.
The sector has made progress: the improvement of the energy efficiency of new installations and the combustion of waste instead of fossil fuels have reduced emissions by 18%. According to the Chatham House, the average CO2 emissions per ton of product over the last decades,
The new Global Association of Cement and Concrete (GCCA), which currently accounts for about 35% of global production. cement and focused on sustainable development, participated in the COP24 environmental summit
Benjamin Sporton, chief executive officer of the organization, said that the organization now existed "demonstrates the commitment of industry in sustainable development, including: adopting measures to combat climate change. "
The GCCA should publish a set of sustainable development guidelines that its members will need to follow.
"Gather the act to direct and guide the movement, as well as to set up a detailed work program, we can help ensure a sustainable future for cement and concrete, as well as the needs future generations, "said Sporton.
But despite the promise, Chatham House says the industry is reaching the limits of what it can do with the current measures.
If it has any hope of meeting the commitments made in the Paris Agreement in 2015, it will have to take into account the review of the process of manufacturing the cement itself, not only to reduce 39, use of fossil fuels.
Solutions
Preston, Department of Energy, Environment and Resources at Chatham House, as well as colleagues, claim that the industry needs to urgently seek a series of CO2 reduction strategies.
Additional efforts for energy efficiency, replacement of fossil fuels by alternative sources, at the latest.
"We have a long way to go to close this gap," said Preston.
What the industry really needs to do is develop its efforts to produce new types
New Cements
One of those who are trying to get more support for the production of alternative cements, Ginger Krieg Dosier, co-founder and CEO of BioMason – the North American start-up implanted in United States, uses billions of bacteria to produce "bioconcrete" bricks.
This technique involves placing sand in molds, injecting microorganisms, a process similar to that created by coral is triggered
"I am fascinated by cements and marine structures," explains Krieg Dosier, an architect surprised at finding no alternative – a real logic for bricks and masonry when she began her research in a law firm. 39 architects p More than 10 years ago
This discovery led to the creation of his own solution – which, after years of development, only takes four days to prepare.
The process takes place at room temperature, without the need for fossil fuels or calcination, two of the main sources of CO2 emissions from the cement industry.
Krieg Dosier believes that "green cements" and technologies of this type a solution to the problem of emissions from the industry.
"Traditional Portland cement production practices will continue to release CO2 due to their basic chemical composition," she said, adding that instead of using capture and storage carbon, it is necessary to invest more in techniques that effectively remove carbon from the atmosphere.
"Alternative Cements and Fixing Technologies Go Beyond the"
Other Forces
"This slow and hard-to-change area begins to clash with these deep (patterns) breaks that We are starting to see in the however, as very little low-carbon cement is coming onto the market and that no one has been applied on a large scale, it seems likely that continued government support
Without government pressure on timely delivery, it may not be possible to obtain from laboratories the next generation of low-carbon cements in laboratories.
And the delay begins to shrink
The Intergovernmental Panel on Climate Change is leading international body in the field of global warming – said last month that rising average global temperature was to be kept below 1.5 ° C – rather than 2 ° C as stated in the Paris Agreement. This means that CO2 emissions must decrease by 45% compared to 2010 levels. And that, until 2030.
Like other young companies, Krieg Dosier describes the difficulties encountered in simultaneously developing and marketing their products and their development.
"I think the construction industry is about to become more widely used for substitute materials." She says. "This is partly due to market demand, other innovative technologies and a broader concern about climate change."
Preston believes that it is crucial that governments and the industry act swiftly.
"There is an urgent need for affordable and quality housing," she says. "We need new infrastructure, we can only be part of this circle if we are able to radically improve the way we build, so that these buildings are usually built with net emissions as close as possible from scratch. "
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