The 'living concrete' that can heal itself
By Andrew Stewart, for CNN
Updated 9:58 AM ET, Thu May 14, 2015

http://www.cnn.com/2015/05/14/tech/bioconcrete-delft-jonkers/

(CNN)It's the world's most popular building material, and ever since the Romans built the pantheon from it some 2,000 years ago, we've been trying to find ways to make concrete more durable.

No matter how carefully it is mixed or reinforced, all concrete eventually cracks, and under some conditions, those cracks can lead to collapse.

"The problem with cracks in concrete is leakage," explains professor Henk Jonkers, of Delft University of Technology, in the Netherlands.

"If you have cracks, water comes through -- in your basements, in a parking garage. Secondly, if this water gets to the steel reinforcements -- in concrete we have all these steel rebars -- if they corrode, the structure collapses."

But Jonkers has come up with an entirely new way of giving concrete a longer life.

"We have invented bioconcrete -- that's concrete that heals itself using bacteria," he says.

The bioconcrete is mixed just like regular concrete, but with an extra ingredient -- the "healing agent." It remains intact during mixing, only dissolving and becoming active if the concrete cracks and water gets in.

Jonkers, a microbiologist, began working on it in 2006, when a concrete technologist asked him if it would be possible to use bacteria to make self-healing concrete.

It took Jonkers three years to crack the problem -- but there were some tricky challenges to overcome.

"You need bacteria that can survive the harsh environment of concrete," says Jonkers. "It's a rock-like, stone-like material, very dry."

Concrete is extremely alkaline and the "healing" bacteria must wait dormant for years before being activated by water.

Jonkers chose bacillus bacteria for the job, because they thrive in alkaline conditions and produce spores that can survive for decades without food or oxygen.

"The next challenge was not only to have the bacteria active in concrete, but also to make them produce repair material for the concrete -- and that is limestone," Jonkers explains.

In order to produce limestone the bacilli need a food source. Sugar was one option, but adding sugar to the mix would create soft, weak, concrete.

In the end, Jonkers chose calcium lactate, setting the bacteria and calcium lactate into capsules made from biodegradable plastic and adding the capsules to the wet concrete mix.

"We are combining nature with construction materials" Henk Jonkers, Delft University

When cracks eventually begin to form in the concrete, water enters and open the capsules.

The bacteria then germinate, multiply and feed on the lactate, and in doing so they combine the calcium with carbonate ions to form calcite, or limestone, which closes up the cracks.

Now Jonkers hopes his concrete could be the start of a new age of biological buildings.

"It is combining nature with construction materials," he says. "Nature is supplying us a lot of functionality for free -- in this case, limestone-producing bacteria.

If we can implement it in materials, we can really benefit from it, so I think it's a really nice example of tying nature and the built environments together in one new concept."





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http://weburbanist.com/2015/05/10/urban-algae-canopy-produces-a-forests-worth-of-oxygen-daily/


New Articles Daily on Urban Architecture, Art, Design, Travel, & Technology
Urban Algae Canopy Produces a Forest’s Worth of Oxygen Daily
Article by Urbanist, filed under Cities & Urbanism in the Architecture category.

urban algae prototype system
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Generating as much oxygen per day as 400,000 square feet of natural woodland, the Urban Algae Canopy combines architecture, biology and digital technology to create a structure that generates energy, responds to and enhances its environment.

urban algae exterior shelter

Created by EcoLogics Studio and demonstrated in Milan, Italy, this “world’s first bio-digital canopy integrates micro-algal cultures and real time digital cultivation protocols on a unique architectural system,” with flows of water and energy regulated by weather patterns and visitor usage. Sun increases photosynthesis, for example, causing the structure to generate organic shade in realtime. In addition to CO2 reduction, the canopy as a whole can produce over 300 pounds of biomass daily, all through a relatively passive system that requires far less space and upkeep than conventional civic greenery.

urban canopy

A hybrid of architectural and ecosystem design, the canopy is made to adapt its features based on manual as well as environmental inputs, letting users exert control (via a digital interface) within a larger dynamic system. “This process is driven by the biology of mico-algae is inherently responsive and adaptive; visitors will benefit from this natural shading property while being able to influence it in real-time.”

For EcoLogics, this is only a step toward a larger vision – organic systems tied to high-tech ones in current and future buildings and infrastructure, as well as a breakdown of the differentiation between urban and rural, cities and nature. Indeed, the Canopy is just the latest of many projects the EcoLogics team has executed around similar themes, though it combines a series of construction techniques and materials they have been developing: “The exceptional properties of microalgae organisms are enhanced by their cultivation within a custom designed 3 layers ETFE cladding system. A special CNC welding technology is at the core of it and enables ecoLogicStudio to design and control the morphology of the cushions under stress as well as the fluid dynamic behaviour of the water medium as it travels through it.”

urban algae water system

Integrating organic and artificial systems opens up sustainable possibilities for everything from temperature control to power generation methods using advantages of both natural and digital parts. It is also conceivable that the organic inputs and outputs of such systems could eventually be integrated into the production cycle of urban vertical farms. For now, the canopy will remain a working prototype and proof of concept as well as a chance to experiment with refining the constituent technologies. Meanwhile, others are taking different approaches to the use of algae in urban objects, including a design for smog-eating algae street lamps and this bio-voltaic table.

urban algae canopy project

More from its creators: “In ecoLogicStudio we believe that it is now time to overcome the segregation between technology and nature typical of the mechanical age, to embrace a systemic understanding of architecture. In this prototype the boundaries between the material, spatial and technological dimensions have been carefully articulated to achieve efficiency, resilience and beauty.” For an active application on a permanent building exterior with additional scientific details, be sure to take a look at the world’s first bio-adaptive facade in Germany.

"All the world's a stage,
And all the men and women merely players:
They have their exits and their entrances;
And one man in his time plays many parts..." -The Bard

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