How to Cure our Concrete Dependency | The B1M

How to Cure our Concrete Dependency | The B1M

With the ability to be formed into almost
any shape, concrete is the most widely used material in the world and shapes nearly every
part of our built environment from bridges and tunnels to countless building types and vast dams. While no other material comes close to offering
the strength and adaptability of concrete, the process of creating its core ingredient,
cement, is one of the largest contributors of greenhouse gases on our planet, producing
some 8% of total emissions. For every 1,000 kilograms of cement produced, approximately 900 kilograms of carbon dioxide arises as a by-product. In 2016 alone, over
2.2 billion tonnes of carbon dioxide were released through cement manufacture. Now, in an effort to cure our dependence on
this material and reduce the environmental impact of construction activity, innovative
new solutions are being pioneered. BioMason in the United States has developed
a way of creating concrete bricks without the need for heat or the use of traditional
Portland cement. During their “living” manufacturing process,
sand is placed into moulds after being mixed with bacteria which are fed an aqueous solution.
This causes the bacteria to harden, binding the mixture together in much the same way
that coral grows in our oceans. While this process is slow under the sea,
here artificial manipulation of the solution accelerates the hardening process to just
four days. By replacing traditional binding agents with
biologically controlled structural cement and relying on natural processes, the need
for heat during manufacturing is eliminated. Though only applicable to concrete bricks
at the present time, further advancements could see this method adapted and scaled to
larger forms in the near future. While cement has long been the go-to binding
agent for concrete, a failed experiment at the University of Arizona unintentionally
created a material five times stronger than concrete, with a recycled content of 95%. Ferrock – or iron-rich ferrous rock – is
made primarily from steel dust, a waste product from various industrial processes, and silica
made from ground-up recycled glass. When mixed together, the iron in the steel
dust reacts with CO2 and rusts to form iron-carbonate fusing the components together. Like concrete,
Ferrock cannot return to its liquid state once hardened. However, unlike the manufacturing of cement
which creates large amounts of carbon dioxide, the hardening process of Ferrock actually
absorbs and traps CO2, creating a carbon-negative product. While advantageous as a concept, the large-scale
implementation of Ferrock does have limitations. While the materials used to create Ferrock
are currently cheaper than cement, the price of large-scale adoption could become uneconomical
if demand for steel dust and recycled glass creates a lucrative new resource market for
waste products. Researchers at CarbonCure in the United States
have developed a way of converting the CO2 arising from cement manufacture into a valuable
commodity for the industry. Working as a bolt-on technology which can
be scaled to suit plants of any size, CarbonCure’s technique sees carbon dioxide injected into
concrete mixes while they are still wet – resulting in CO2 becoming trapped in the material as
it cures. In addition, chemical reactions within the
mix cause limestone nanoparticles to be formed, strengthening the final product and allowing
contractors to achieve their required concrete strengths while using less cement. While over 100 concrete plants across North
America are already employing this technique, mainstream adoption of the technology has
been relatively slow – principally because contractors and engineers, who are generally
liable for the strength and quality of concrete on projects, greet the innovation with caution. Despite this, large projects like this scheme
in Atlanta have acted as strong case studies, highlighting the benefits of carbon capture
to our wider industry. In time, CarbonCure estimate that full-scale
worldwide adoption of their technique would save 700 megatons of CO2 a year – the equivalent
of taking 150 million vehicles off of our roads. With the effects of human activity on the
environment now under closer scrutiny than ever before – and a growing recognition
of the impact of the construction sector – these innovations could make a solid difference
in helping to cut CO2 emissions, protecting the planet that we all call home. If you enjoyed this video and would like to get more from the definitive video channel for construction, subscribe to The B1M.

Comments (3)

  1. We just need a new material just as strong or stronger than concrete, last longer at a similar price tag, while being less harsh on the environment. Carbon nanotubes, maybe?

  2. The issue is less with the carbon emissions and more with the fact that we are running out of sand to make it with

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