Category Archives: construction

Making better concrete by looking to nature for inspiration

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Researchers from the Masssachusetts Institute of Technology (MIT) are working on a new formula for concrete based on bones, shells, and other such natural materials. From a May 25, 2016 news item on Nanowerk (Note: A link has been removed),

Researchers at MIT are seeking to redesign concrete — the most widely used human-made material in the world — by following nature’s blueprints.

In a paper published online in the journal Construction and Building Materials (“Roadmap across the mesoscale for durable and sustainable cement paste – A bioinspired approach”), the team contrasts cement paste — concrete’s binding ingredient — with the structure and properties of natural materials such as bones, shells, and deep-sea sponges. As the researchers observed, these biological materials are exceptionally strong and durable, thanks in part to their precise assembly of structures at multiple length scales, from the molecular to the macro, or visible, level.

A May 26, 2016 MIT news release (also on EurekAlert), which originated the news item, provides more detail,

From their observations, the team, led by Oral Buyukozturk, a professor in MIT’s Department of Civil and Environmental Engineering (CEE), proposed a new bioinspired, “bottom-up” approach for designing cement paste.

“These materials are assembled in a fascinating fashion, with simple constituents arranging in complex geometric configurations that are beautiful to observe,” Buyukozturk says. “We want to see what kinds of micromechanisms exist within them that provide such superior properties, and how we can adopt a similar building-block-based approach for concrete.”

Ultimately, the team hopes to identify materials in nature that may be used as sustainable and longer-lasting alternatives to Portland cement, which requires a huge amount of energy to manufacture.

“If we can replace cement, partially or totally, with some other materials that may be readily and amply available in nature, we can meet our objectives for sustainability,” Buyukozturk says.

…

“The merger of theory, computation, new synthesis, and characterization methods have enabled a paradigm shift that will likely change the way we produce this ubiquitous material, forever,” Buehler says. “It could lead to more durable roads, bridges, structures, reduce the carbon and energy footprint, and even enable us to sequester carbon dioxide as the material is made. Implementing nanotechnology in concrete is one powerful example [of how] to scale up the power of nanoscience to solve grand engineering challenges.”

From molecules to bridges

Today’s concrete is a random assemblage of crushed rocks and stones, bound together by a cement paste. Concrete’s strength and durability depends partly on its internal structure and configuration of pores. For example, the more porous the material, the more vulnerable it is to cracking. However, there are no techniques available to precisely control concrete’s internal structure and overall properties.

“It’s mostly guesswork,” Buyukozturk says. “We want to change the culture and start controlling the material at the mesoscale.”

As Buyukozturk describes it, the “mesoscale” represents the connection between microscale structures and macroscale properties. For instance, how does cement’s microscopic arrangement affect the overall strength and durability of a tall building or a long bridge? Understanding this connection would help engineers identify features at various length scales that would improve concrete’s overall performance.

“We’re dealing with molecules on the one hand, and building a structure that’s on the order of kilometers in length on the other,” Buyukozturk says. “How do we connect the information we develop at the very small scale, to the information at the large scale? This is the riddle.”

Building from the bottom, up

To start to understand this connection, he and his colleagues looked to biological materials such as bone, deep sea sponges, and nacre (an inner shell layer of mollusks), which have all been studied extensively for their mechanical and microscopic properties. They looked through the scientific literature for information on each biomaterial, and compared their structures and behavior, at the nano-, micro-, and macroscales, with that of cement paste.

They looked for connections between a material’s structure and its mechanical properties. For instance, the researchers found that a deep sea sponge’s onion-like structure of silica layers provides a mechanism for preventing cracks. Nacre has a “brick-and-mortar” arrangement of minerals that generates a strong bond between the mineral layers, making the material extremely tough.

“In this context, there is a wide range of multiscale characterization and computational modeling techniques that are well established for studying the complexities of biological and biomimetic materials, which can be easily translated into the cement community,” says Masic.

Applying the information they learned from investigating biological materials, as well as knowledge they gathered on existing cement paste design tools, the team developed a general, bioinspired framework, or methodology, for engineers to design cement, “from the bottom up.”

The framework is essentially a set of guidelines that engineers can follow, in order to determine how certain additives or ingredients of interest will impact cement’s overall strength and durability. For instance, in a related line of research, Buyukozturk is looking into volcanic ash [emphasis mine] as a cement additive or substitute. To see whether volcanic ash would improve cement paste’s properties, engineers, following the group’s framework, would first use existing experimental techniques, such as nuclear magnetic resonance, scanning electron microscopy, and X-ray diffraction to characterize volcanic ash’s solid and pore configurations over time.

Researchers could then plug these measurements into models that simulate concrete’s long-term evolution, to identify mesoscale relationships between, say, the properties of volcanic ash and the material’s contribution to the strength and durability of an ash-containing concrete bridge. These simulations can then be validated with conventional compression and nanoindentation experiments, to test actual samples of volcanic ash-based concrete.

Ultimately, the researchers hope the framework will help engineers identify ingredients that are structured and evolve in a way, similar to biomaterials, that may improve concrete’s performance and longevity.

“Hopefully this will lead us to some sort of recipe for more sustainable concrete,” Buyukozturk says. “Typically, buildings and bridges are given a certain design life. Can we extend that design life maybe twice or three times? That’s what we aim for. Our framework puts it all on paper, in a very concrete way, for engineers to use.”

This is not the only team looking at new methods for producing the material, my Dec. 24, 2012 posting features a number of ‘concrete’ research projects.

Also, I highlighted the reference to ‘volcanic ash’ as it reminded me of Roman concrete which has lasted for over 2000 years and includes volcanic sand and volcanic rock.  You can read more about it in a Dec. 18, 2014 article by Mark Miller for Ancient Origins where he describes the wonders of the material and what was then a recent discovery of the Romans’ recipe.

I have two links and citations, first, the MIT paper, then the paper on Roman concrete.

Roadmap across the mesoscale for durable and sustainable cement paste – A bioinspired approach by Steven D. Palkovic, Dieter B. Brommer, Kunal Kupwade-Patil, Admir Masic, Markus J. Buehler, Oral Büyüköztürk.Construction and Building Materials Volume 115, 15 July 2016, Pages 13–31.  doi:10.1016/j.conbuildmat.2016.04.020

Mechanical resilience and cementitious processes in Imperial Roman architectural mortar by Marie D. Jackson, Eric N. Landis, Philip F. Brune, Massimo Vitti, Heng Chen, Qinfei Li, Martin Kunz, Hans-Rudolf Wenk, Paulo J. M. Monteiro, and Anthony R. Ingraffea. Proceedings of the National Academy of Sciences  vol. 111 no. 52 18484–18489, doi: 10.1073/pnas.1417456111

The first paper is behind a paywall but the second one appears to be open access.

Winner of Tel Aviv University (Israel) nanoscience and nanotech centre competition

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[downloaded from http://www.e-architect.co.uk/israel/tel-aviv-university-center-for-nanoscience-and-nanotechnology-competition]

[downloaded from http://www.e-architect.co.uk/israel/tel-aviv-university-center-for-nanoscience-and-nanotechnology-competition]

The image above from e-architect shows part of the reason why l’Atelier d’Architecture Michel Rémon was announced as the winner of the international architectural competition for Tel Aviv University’s Nanoscience and Nanotechnology Center. A May 4, 2016 news item on Dexigner provides some explanation,

…

“The final choice of the Nano building reflects the synergy between the technical needs defined by the research teams and our desire to provide an open and welcoming research environment,” commented Joseph Klafter, President of Tel Aviv University. “I have no doubt that the new building will help inspire outstanding research and global collaborations.”

The project for Tel Aviv University presents a matrix of vertical lines creating a “skin” covering the three-storey building. The structure will enable natural light control and balance out the interior-exterior ratio. Visually, the building will not feature windows or doors. [emphasis mine] Among the energy efficiency solutions suggested by the company is special glass to optimize sun energy, natural ventilation, solar panels to cool the building and a rainwater collection system. …

In place of a main door or entry, it seems, according to the image, this building will have an opening. I wonder what they mean ‘special glass’. Are the walls underneath those white strips supposed to be glass? That would explain the lack of obvious windows but how do you cool a ‘transparent’ building and deal with the glare during summer and deal with heat loss in the winter? Presumably the ‘special’ glass will address those issues.

Unfortunately, there isn’t much information available. L’Atelier d’Architecture Michel Rémon doesn’t have an announcement about this latest success on the company website. As for Tel Aviv University’s Center for Nanoscience and Nanotechnology, their website also doesn’t have an announcement.

In any event, it’s a pretty nifty design.

Transparent wood instead of glass for window panes?

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The transparent wood is made by removing the lignin in the wood veneer. (Photo: Peter Larsson

The transparent wood is made by removing the lignin in the wood veneer. (Photo: Peter Larsson

Not quite ready as a replacement for some types of glass window panes, nonetheless, transparent (more like translucent) wood is an impressive achievement. According to a March 30, 2016 news item on ScienceDaily size is what makes this piece of transparent wood newsworthy,

Windows and solar panels in the future could be made from one of the best — and cheapest — construction materials known: wood. Researchers at Stockholm’s KTH Royal Institute of Technology [Sweden] have developed a new transparent wood material that’s suitable for mass production.

Lars Berglund, a professor at Wallenberg Wood Science Center at KTH, says that while optically transparent wood has been developed for microscopic samples in the study of wood anatomy, the KTH project introduces a way to use the material on a large scale. …

A March 31 (?), 2016 KTH Institute of Technology press release, which originated the news item, provides more detail,

“Transparent wood is a good material for solar cells, since it’s a low-cost, readily available and renewable resource,” Berglund says. “This becomes particularly important in covering large surfaces with solar cells.”

Berglund says transparent wood panels can also be used for windows, and semitransparent facades, when the idea is to let light in but maintain privacy.

The optically transparent wood is a type of wood veneer in which the lignin, a component of the cell walls, is removed chemically.

“When the lignin is removed, the wood becomes beautifully white. But because wood isn’t not naturally transparent, we achieve that effect with some nanoscale tailoring,” he says.

The white porous veneer substrate is impregnated with a transparent polymer and the optical properties of the two are then matched, he says.

“No one has previously considered the possibility of creating larger transparent structures for use as solar cells and in buildings,” he says

Among the work to be done next is enhancing the transparency of the material and scaling up the manufacturing process, Berglund says.

“We also intend to work further with different types of wood,” he adds.

“Wood is by far the most used bio-based material in buildings. It’s attractive that the material comes from renewable sources. It also offers excellent mechanical properties, including strength, toughness, low density and low thermal conductivity.”

The American Chemical Society has a March 30, 2016 news release about the KTH achievement on EurekAlert  highlighting another potential use for transparent wood,

When it comes to indoor lighting, nothing beats the sun’s rays streaming in through windows. Soon, that natural light could be shining through walls, too. Scientists have developed transparent wood that could be used in building materials and could help home and building owners save money on their artificial lighting costs. …

Homeowners often search for ways to brighten up their living space. They opt for light-colored paints, mirrors and lots of lamps and ceiling lights. But if the walls themselves were transparent, this would reduce the need for artificial lighting — and the associated energy costs. Recent work on making transparent paper from wood has led to the potential for making similar but stronger materials. Lars Berglund and colleagues wanted to pursue this possibility.

Here’s a link to and a citation for the paper,

Optically Transparent Wood from a Nanoporous Cellulosic Template: Combining Functional and Structural Performance by Yuanyuan Li, Qiliang Fu, Shun Yu, Min Yan, and Lars Berglund. Biomacromolecules, Article ASAP DOI: 10.1021/acs.biomac.6b00145 Publication Date (Web): March 4, 2016

Copyright © 2016 American Chemical Society

This paper appears to be open access.

Construction and nanotechnology research in Scandinavia

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I keep hearing about the possibilities for better (less polluting, more energy efficient, etc.) building construction materials but there never seems to be much progress.  A June 15, 2015 news item on Nanowerk, which suggests some serious efforts are being made in Scandinavia, may help to explain the delay,

It isn’t cars and vehicle traffic that produce the greatest volumes of climate gas emissions – it’s our own homes. But new research will soon be putting an end to all that!

The building sector is currently responsible for 40% of global energy use and climate gas emissions. This is an under-communicated fact in a world where vehicle traffic and exhaust emissions get far more attention.

In the future, however, we will start to see construction materials and high-tech systems integrated into building shells that are specifically designed to remedy this situation. Such systems will be intelligent and multifunctional. They will consume less energy and generate lower levels of harmful climate gas emissions.

With this objective in mind, researchers at SINTEF are currently testing microscopic nanoparticles as insulation materials, applying voltages to window glass and facades as a means of saving energy, and developing solar cells that prevent the accumulation of snow and ice.

…

Research Director Susie Jahren and Research Manager Petra Rüther are heading SINTEF’s strategic efforts in the field of future construction materials. They say that although there are major commercial opportunities available in the development of green and low carbon building technologies, the construction industry is somewhat bound by tradition and unable to pay for research into future technology development. [emphasis mine]

A June 15, 2015 SINTEF (Scandinavia’s largest independent research organisation) news release on the Alpha Galileo website, which originated the news item, provides an overview of the research being conducted into nanotechnology-enabled construction materials (Note: I have added some heads and ruthlessly trimmed from the text),

[Insulation]

SINTEF researcher Bente Gilbu Tilset is sitting in her office in Forskningsveien 1 in Oslo [Norway]. She and her colleagues are looking into the manufacture of super-insulation materials made up of microscopic nanospheres.

“Our aim is to create a low thermal conductivity construction material “, says Tilset. “When gas molecules collide, energy is transferred between them. If the pores in a given material are small enough, for example less than 100 nanometres in diameter, a molecule will collide more often with the pore walls than with other gas molecules. This will effectively reduce the thermal conductivity of the gas. So, the smaller the pores, the lower the conductivity of the gas”, she says.

…

[Solar cells]

As part of the project “Bygningsintegrerte solceller for Norge” (Building Integrated Photovoltaics, BIPV Norway), researchers from SINTEF, NTNU, the IFE [IFE Group, privately owned company, located in Sweden] and Teknova [company created by the Nordic Institute for Studies in Innovation {NIFU}, located in Norway], are planning to look into how we can utilise solar cells as integral housing construction components, and how they can be adapted to Norwegian daylight and climatic conditions.

One of the challenges is to develop a solar cell which prevents the accumulation of snow and ice. The cells must be robust enough to withstand harsh wind and weather conditions and have lifetimes that enable them to function as electricity generators.

…

[Energy]

Today, we spend 90 per cent of our time indoors. This is as much as three times more than in the 1950s. We are also letting less daylight into our buildings as a result of energy considerations and construction engineering requirements. Research shows that daylight is very important to our health, well-being and biological rhythms. It also promotes productivity and learning. So the question is – is it possible to save energy and get the benefits of greater exposure to daylight?

Technologies involving thermochromic, photochromic and electrochromic pigments can help us to control how sunlight enters our buildings, all according to our requirements for daylight and warmth from the sun.

…

Self-healing concrete

Every year, between 40 and 120 million Euros are spent in Europe on the maintenance of bridges, tunnels and construction walls. These time-consuming and costly activities have to be reduced, and the project CAPDESIGN is aiming to make a contribution in this field.

The objective of the project is to produce concrete that can be ‘restored’ after being exposed to loads and stresses by means of self-healing agents that prevent the formation of cracks. The method involves mixing small capsules into the wet concrete before it hardens. These remain in the matrix until loads or other factors threaten to crack it. The capsules then burst and the self-healing agents are released to repair the structure.

At SINTEF, researchers are working with the material that makes up the capsule shells. The shell has to be able to protect the self-healing agent in the capsules for an extended period and then, under the right conditions, break down and release the agents in response to the formation of cracks caused by temperature, pH, or a load or stress resulting from an impact or shaking. At the same time, the capsules must not impair the ductility or the mechanical properties of the newly-mixed concrete.

…

You’ll notice most of the research seems to be taking place in Norway. I suspect that is due to the story having come from a joint Norwegian Norwegian University of Science and Technology (NTNU)/SINTEF, website, Gemini.no/en. Anyone wishing to test their Norwegian readings skills need only omit ‘/en’ from the URL.

Foam glass manufacturing facility commissioned in Russia’s Kaluga region

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A Dec. 27, 2013 news item on Azlonano features RUSNANO and a foam glass facility in Russia,

On December 20 [2013], Russia’s first and Europe’s major technological complex for the production of foam glass ICM Glass Kaluga, of the project company Rusnano, was commissioned in the industrial park Borovskoye. The ceremony was attended by the Kaluga Region’s Governor Anatoly Artamonov and chairman of Rusnano’s board Anatoly Chubais.

The facility is aimed at hi-tech production of construction materials from foam glass. Broken glass is used as the raw material, which enables effective recycling of solid household rubbish. The complex’s planned capacity is 300,000 cubic metres a year to be achieved by the facility’s 50 employees. The agreed total budget exceeds 1.8 billion roubles ($54 million).

I found more information about the new facility in a Dec.20, 2013 press release (machine translation of Russian into English) here: http://www.newportal.admoblkaluga.ru/main/news/events/detail.php?ID=153747, (I think this is a portal for the Kaluga region)

December 20 [2013] in the industrial park “Vorsino” Borovsky District hosted a ceremony industrial launch of the first in Russia and the largest in Europe and technological complex for the production of crushed stone penostekolnogo LLC “AySiEm Glass Kaluga” – the project company “RUSNANO”. It was attended by Governor Anatoly Artamonov and delegation “RUSNANO” headed by the chairman of the state corporation Anatoly Chubais.

Taken at the enterprise high-tech production of construction material of foamed glass. Feedstock is usual broken glass that facilitates efficient processing of municipal solid waste. The design capacity of the complex is 300 thousand cubic meters per year, the staff – 50 people. The total budget of the project is determined in the amount of more than 1.8 billion rubles.

Talking about the significance of the event, Anatoly Artamonov emphasized perspective of further business cooperation with the State Corporation “Rusnano”. “Our cooperation – an important milestone in the economic development of the Kaluga region, because we have chosen an innovative way and are committed to increase the share of high-tech products”, – assured the governor.

Chairman of the Board of the Civil Code “RUSNANO” Anatoly Chubais also expressed readiness to support the business activities of the Kaluga region. “Today, in the region we run two joint projects. The plans of two more – in the production of innovative pharmaceuticals – with a complete cycle from design to sales. They invested 8 billion rubles, plan – and another 10 billion, “- he said.

On the same day in the office «Freight Village Kaluga» held a meeting at which the parties discussed the details of future cooperation. In order to continue business contacts “RUSNANO” Fund for Infrastructure and Educational Programs with Government organizations and the Kaluga region Anatoly Chubais Anatoly Artamonov and signed the final protocol. The main outcome of the meeting was a joint decision on the establishment of nanotechnology center in Obninsk, which will bring together teams of scientists and professionals working in the field of nanotechnology. Thus, according to Anatoly Chubais, “Kaluga region will be the region, opening a” second wave “nanocenters.”

Reference: In the current year, the regional government in conjunction with the Fund for Infrastructure and Educational Programs of the state corporation “RUSNANO” program was launched to stimulate demand for nanotech products. It provides for the inclusion of 10 per cent of innovation, including nanotechnology products in state and municipal orders. In 2014, with the support of the corporation “RUSNANO” in the region plans to build the center positron emission tomography, “PET-Center”, which will bring a new level not only a primary diagnosis of cancer, but also to monitor the dynamics of the disease, to evaluate the effectiveness of the treatment.

For the curious, here’s more information about foam glass on the ENCO Engineering website,

Foamed glass grain as described in the following is an excellent bulk material for civil construction and insulation purposes. It is a lightweight, extremely fine-pored expanded glass with millions of hermetically sealed pores. Since no diffusion can take place, the material is watertight and achieves an efficient barrier against soil humidity.

Besides the outstanding mechanical and thermal properties of the product, foamed glass manufacture is an exemplary process for waste recycling on an industrial basis. Foam glass can be manufactured fully out of waste glass, with only a minimum of virgin additives.

Foamed glass grain is the product of choice wherever a finely grained, free-flowing bulk material is required. It is especially suitable for thin-walled thermal insulations, such as for window frames, cement bricks and insulating plasters.

ENCO Engineering is a Swiss chemical engineering and consultancy according to the information on the company website’s homepage.

Cement and concrete festival

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Over the last week or so there’ve been a number of articles and publications about cement and concrete and nanotechnology. The Dec. 17, 2012 Nanowerk Spotlight article by (Mohammed) Shakeel Iqbal and Yashwant Mahajan for India’s Centre for Knowledge Management of Nanoscience & Technology (CKMNT, an ARCI [International Advanced Research Centre for Powder Metallurgy and New Materials] project, Dept.of Science & Technology) seemed to kick off the trend with a patent analysis of nanotechnology-enabled cement innovations,

China is the world leader of patent filings, their 154 patent applications contributing 41% of overall filings, representing the major and active R&D player in the area of nano-based cementitious materials. South Korea is the second leading country with 55 patents (15% of patent filings) on nano-enabled cement, closely followed by United States with 51 patents. Russia, Germany, Japan, France and India are the other leading patent filing countries with 37, 18, 11, 9 and 5 patents respectively, while the remaining patents represent a minor contribution from rest of the world.

….

Dagestan State University (Russia) is the leading assignee with 15-patents to its credit, which are mainly focussed on the development of heat resistant and high compression strength concrete materials. Halliburton Energy Services Inc (USA) comes second with 14-patents that are directed towards well bore cementing for the gas, oil or water wells using nano-cementitious materials.

This is another teaser article from the CKMNT (see my Dec. 13, 2012 posting about their bio-pharmaceutical teaser article) that highlights the findings from a forthcoming report,

A comprehensive Market Research Report on “Nanotechnology in Cement Industry” is proposed to be released by CKMNT in the near future. Interested readers may please contact Dr. Y. R. Mahajan, Technical Adviser and Editor, Nanotech Insights or Mr. H. Purushotham, Team Leader purushotham@ckmnt.com.

Regardless of one’s feelings about patents and patent systems, the article also provides a  good technology overview of the various nanomaterials used as fillers in cement, courtesy of the information in the filed patents.

A December 20, 2012 news item on Azonano points to at least of the reasons cement is occasioning research interest,

Cement production is responsible for 5% of carbon dioxide emissions. If we are to invent a “green” cement, we need to understand in more detail the legendary qualities of traditional Portland cement. A research group partly financed by the Swiss National Science Foundation (SNSF) is tackling this task.

The Dec. 20, 2012 Swiss National Science Foundation (SNSF) news release, which originated the news item on Azonano, goes on to describe the research into exactly how Portland cement’s qualities are derived,

The researchers first developed a packing model of hydrated calcium silicate nanoparticles. They then devised a method for observing their precipitation based on numerical simulations. This approach has proven successful (*). “We were able to show that the different densities on the nano scale can be explained by the packing of nanoparticles of varying sizes. At this crucial level, the result is greater material hardness than if the particles were of the same size and it corresponds to the established knowledge that, at macroscopic level, aggregates of different sizes form a harder concrete.” [said Emanuela Del Gado, SNSF professor at the Institute for Building Materials of the ETH Zurich]

Until today, all attempts to reduce or partially replace burnt calcium carbonate in the production of cement have resulted in less material hardness. By gaining a better understanding of the mechanisms at the nano level, it is possible to identify physical and chemical parameters and to improve the carbon footprint of concrete without reducing its hardness.

For those of a more technical turn of mind, here’s a citation for the paper (from the SNSF press release),

E. Masoero, E. Del Gado, R. J.-M. Pellenq, F.-J. Ulm, and S. Yip (2012). Nanostructure and Nanomechanics of Cement: Polydisperse Colloidal Packing. Physical Review Letters. DOI: 10.1103/PhysRevLett.109.155503

Meanwhile, there’s a technical group in Spain working on ‘biological’ concrete. From the Dec. 20, 2012 news item on ScienceDaily,

In studying this concrete, the researchers at the Structural Technology Group of the Universitat Politècnica de Catalunya • BarcelonaTech (UPC) have focused on two cement-based materials. The first of these is conventional carbonated concrete (based on Portland cement), with which they can obtain a material with a pH of around 8. The second material is manufactured with a magnesium phosphate cement (MPC), a hydraulic conglomerate that does not require any treatment to reduce its pH, since it is slightly acidic.

On account of its quick setting properties, magnesium phosphate cement has been used in the past as a repair material. It has also been employed as a biocement in the field of medicine and dentistry, indicating that it does not have an additional environmental impact.

The innovative feature of this new (vertical multilayer) concrete is that it acts as a natural biological support for the growth and development of certain biological organisms, to be specific, certain families of microalgae, fungi, lichens and mosses.

Here’s a description of the ‘biological’ concrete and its layers,

In order to obtain the biological concrete, besides the pH, other parameters that influence the bioreceptivity of the material have been modified, such as porosity and surface roughness. The result obtained is a multilayer element in the form of a panel which, in addition to a structural layer, consists of three other layers: the first of these is a waterproofing layer situated on top of the structural layer, protecting the latter from possible damage caused by water seeping through.

The next layer is the biological layer, which supports colonisation and allows water to accumulate inside it. It acts as an internal microstructure, aiding retention and expelling moisture; since it has the capacity to capture and store rainwater, this layer facilitates the development of biological organisms.

The final layer is a discontinuous coating layer with a reverse waterproofing function. [emphasis mine] This layer permits the entry of rainwater and prevents it from escaping; in this way, the outflow of water is redirected to where it is aimed to obtain biological growth

This work is designed for a Mediterranean climate and definitely not for rain forests such as the Pacific Northwest which, climatologically, is a temperate rainforest.

The ScienceDaily news item ends with this information about future research and commercialization,

The research has led to a doctoral thesis, which Sandra Manso is writing. At present, the experimental campaign corresponding to the phase of biological growth is being conducted, and this will be completed at the UPC and the University of Ghent (Belgium). This research has received support from Antonio Gómez Bolea, a lecturer in the Faculty of Biology at the University of Barcelona, who has made contributions in the field of biological growth on construction materials.

At present, a patent is in the process of being obtained for this innovative product, and the Catalan company ESCOFET 1886 S.A., a manufacturer of concrete panels for architectural and urban furniture purposes, has already shown an interest in commercialising the material.

Almost at the same time, the US Transport Research Board (a division of the US National Research Council) released this Dec. 19, 2012 announcement about their latest circular,

TRB Transportation Research Circular E-C170: Nanotechnology in Concrete Materials: A Synopsis explore promising new research and innovations using nanotechnology that have the potential to result in improved mechanical properties, volume change properties, durability, and sustainability in concrete materials.

The report is 44 pp (PDF version) and provides an in-depth look (featuring some case studies) at the research not just of nanomaterials but also nanoelectronics and sensors as features in nanotechoology-enabled concrete and cement products.

There you have it, a festival of cement and concrete.

Smart wall or smart window? Ravenbrick brings one to the market in 2013

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Alex Davies posted a July 10, 2012 article on the Treehugger website about a smart window/wall system from RavenBrick. From the article (Note: I have removed links),

The RavenWindow from RavenBrick changes its tint in response to temperature, so it blocks sunlight entering a building after a set temperature has been reached. Combine it with a layer of insulating materials that store heat during the day and release it at night, and you’ve got the RavenSkin Smart Wall System.

Here’s a little more about the RavenWindow from the company’s Project Portfolio page,

RavenBrick has installed their RavenWindow product at the [US] Department of Energy’s National Renewable Energy Lab in Golden Colorado. This LEED platinum building was designed to use the most energy efficient products available. This installation, on the executive floor, is the first of three installations that will be done at NREL.

RavenWindow at NREL in the clear state viewed from the inside (from the RavenBrick website)

 

RavenWindow at NREL in the tinted state viewed from the inside (from the RavenBrick website)

Then, here is the view of the tinted windows from the outside,

RavenWindow at NREL in the tinted state viewed from outside (from the RavenBrick website)

They do give a fairly simple explanation of the technology, from the company’s The Technology page,

RavenBrick’s smart window systems are changing the rules of energy efficent design by doing something that previous generations of building materials simply couldn’t: letting the sun’s heat into the building when you need it, and keeping it out when you don’t.

Our thermochromic filters utilize advances in nanotechnology, pioneered and patented by RavenBrick, to transition from a transparent to a reflective state in response to changes in the outside temperature. This transition allows a building to use the sun as a source of free heat on cold days and block solar heat effectively on hot days.

RavenBrick’s technology diagram (from the RavenBrick website)

Davies’ Treehugger article offers some figures regarding savings (and another illustration),

The RavenSkin Smart Wall System promises to cut energy bills by as much as 30 percent, so it’s sure to offset the costs of installation (not listed on the RavenBrick website). The “infrared power system” doesn’t involve electricity, moving parts or wires, so it’s low maintenance, [sic]

I would have liked a little more detail. How did they derive the savings number, i.e.,  “by as much as 30%”? Also, is there any data from the US Dept. of Energy? At any rate, this product is due to reach the marketplace sometime in 2013.

I last mentioned RavenBrick and their windows in my Aug. 5, 2009 posting. In my Sept. 7, 2011 posting about the US Dept. of Energy, I focussed on smart window research being done at their Lawrence Berkeley National Laboratory (Berkeley Lab).

Nano-enhanced marine products make boats and ships lighter

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A leader in marine closures? Apparently this is Pacific Coast Marine’s claim to fame and they are now announcing a new line of products with nano-enhanced (?) carbon fibers. (I’ve not come across the term ‘nano-enhanced’ before. Is this a new marketing term?) According to the June 25, 2012 news item on Nanowerk,

Zyvex Marine, a division of Zyvex Technologies, and Pacific Coast Marine announced a partnership to make the industry’s lightest and most durable doors, hatches, and other marine closures using nano-composites. …

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Zyvex Marine, the pioneer of the 54′ boat Piranha that weighs 8,000 pounds yet would have weighed 40,000 pounds with traditional materials, is a leader in watercraft and component manufacturing using carbon nanotube-enhanced carbon fiber materials.

Pacific Coast Marine, a leader in marine closures for nearly 30 years, worked with Zyvex during the last year to develop doors, hatches and closures for current watercraft produced by Zyvex Marine. Now recognizing greater commercial opportunities for lightweight doors and hatches on its boats, Pacific Coast Marine and Zyvex are unveiling a door that weighs 66% less than a traditional door – from 150 pounds to just 50 pounds each – and is more durable.

Both Zyvex Marine and Pacific Coast Marine are nearby neighbours being just a few hours south of Vancouver (Canada) in Washington State.

Here’s a little more about Zyvex Marine from the company’s About page,

Zyvex is the premier provider of carbon fiber nano-composites vessels and specializes in manned and unmanned variants for an array of operating conditions using the most advanced materials science available.

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Zyvex Marine formally became a division of Zyvex Technologies in November 2011 and has a storied history dating back to 2009. In early 2009, the world’s first commercialized carbon nanotube enhanced (CNTe) carbon fiber material, Arovex, enabled the design of a prototype vessel called the 540SE. Setting new standards for fuel efficiency and performance, the lightweight 540SE hull offered a 75% reduction in fuel consumption costs, translating to increased range and lower operating costs.

In 2010, Zyvex Marine manufactured its first prototype craft, the Piranha USV Concept, taking it from the drawing board and into the water in under one year. Setting new standards in range, speed, sea keeping and payload for unmanned vessels, the Piranha USV Concept is a generational leap beyond boats built out of traditional materials like fiberglass or aluminum.

In 2011 Zyvex Marine shipped the first production nano-composite vessel, a lightweight 54′ boat. It set new standards for an unmanned vessel in the areas of range, speed, sea keeping and payload, fulfilling the promises made by the original Piranha USV Concept.

As for Pacific Coast Marine, from the Home page,

Pacific Coast Marine began building its reputation for nearly 30 years by supplying rugged and very high quality marine closures for the North Pacific and worldwide work boat fleets. PCM now is the largest supplier of high quality marine doors, windows and hatches in the world. Applications include superyachts, cruise ships, ocean tugs, ocean crew boats, offshore oil platforms, military vessels, fast ferries and merchant ships. The marine environment demands the very best, and that is PCM.

Given how much traffic there is on the seas, more fuel efficiency seems like a good step forward to using fewer resources. I am assuming, of course, that it doesn’t encourage yet more traffic. I notice that these products can also be used for offshore oil platforms, a topic of some interest in the province of British Columbia where I live.

Anti-fogging, self-cleaning, and glare-free: glass

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They raise my hopes then dash them to the ground; still, this is very exciting news for anyone wanting self-cleaning windows. The April 26, 2012 news item on Nanowerk features some of the latest work from MIT (Massachusetts Institute of Technology) on nanotextures and ‘multifunctional’ glass,

One of the most instantly recognizable features of glass is the way it reflects light. But a new way of creating surface textures on glass, developed by researchers at MIT, virtually eliminates reflections, producing glass that is almost unrecognizable because of its absence of glare — and whose surface causes water droplets to bounce right off, like tiny rubber balls.

The new “multifunctional” glass, based on surface nanotextures that produce an array of conical features, is self-cleaning and resists fogging and glare, the researchers say. Ultimately, they hope it can be made using an inexpensive manufacturing process that could be applied to optical devices, the screens of smartphones and televisions, solar panels, car windshields and even windows in buildings.

Here’s what they mean by ‘conical features’,

Through a process involving thin layers of material deposited on a surface and then selectively etched away, the MIT team produced a surface covered with tiny cones, each five times taller than their width. This pattern prevents reflections, while at the same time repelling water from the surface. Image: Hyungryul Choi and Kyoo-Chul Park

David Chandler in his April 26, 2012 news release for MIT explains,

The surface pattern — consisting of an array of nanoscale cones that are five times as tall as their base width of 200 nanometers — is based on a new fabrication approach the MIT team developed using coating and etching techniques adapted from the semiconductor industry. Fabrication begins by coating a glass surface with several thin layers, including a photoresist layer, which is then illuminated with a grid pattern and etched away; successive etchings produce the conical shapes. The team has already applied for a patent on the process.

Since it is the shape of the nanotextured surface — rather than any particular method of achieving that shape — that provides the unique characteristics, Park and Choi [MIT mechanical engineering graduate students Kyoo-Chul Park and Hyungryul Choi] say that in the future glass or transparent polymer films might be manufactured with such surface features simply by passing them through a pair of textured rollers while still partially molten; such a process would add minimally to the cost of manufacture.

If you’re guessing that nature inspired some of this, read on (from Chandler’s MIT news release),

The researchers say they drew their inspiration from nature, where textured surfaces ranging from lotus leaves to desert-beetle carapaces and moth eyes have developed in ways that often fulfill multiple purposes at once. Although the arrays of pointed nanocones on the surface appear fragile when viewed microscopically, the researchers say their calculations show they should be resistant to a wide range of forces, ranging from impact by raindrops in a strong downpour or wind-driven pollen and grit to direct poking with a finger. Further testing will be needed to demonstrate how well the nanotextured surfaces hold up over time in practical applications.

The chief excitement seems to centre around applications with solar panels (from Chandler’s MIT news release),

Photovoltaic panels, Park explains, can lose as much as 40 percent of their efficiency within six months as dust and dirt accumulate on their surfaces. But a solar panel protected by the new self-cleaning glass, he says, would have much less of a problem. In addition, the panel would be more efficient because more light would be transmitted through its surface, instead of being reflected away — especially when the sun’s rays are inclined at a sharp angle to the panel. At such times, such as early mornings and late afternoons, conventional glass might reflect away more than 50 percent of the light, whereas an anti-reflection surface would reduce the reflection to a negligible level.

While some earlier work has treated solar panels with hydrophobic coatings, the new multifunctional surfaces created by the MIT team are even more effective at repelling water, keeping the panels clean longer, the researchers say. In addition, existing hydrophobic coatings do not prevent reflective losses, giving the new system yet another advantage.

More testing is needed and while they do fantasize about wider applications (car windows, microscopes, cameras, smartphones, building windows, etc. mentioned earlier in this posting)  for this technology there are no immediate plans to fulfill my dream of self-cleaning apartment windows and mirrors.

Construction materials and a McGill University physicist

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At the Construction Specifications Canada (CSC) conference, May 25 – 29, 2011 in Montréal, PeterGrutter, a physics professor at McGill University (located in Montréal, Québec) noted that nanotechnology will have a huge impact on the construction industry. From  Greg Meckbach’s June 7, 2011 article for the online version of the Daily Commercial News and Construction Record,

“Fundamentally, you can change a lot of the properties, curing times, energy consumption in major building materials by using various types of nano materials” he said.

Grutter made his remarks during a presentation at the CSC annual conference at Montreal’s Delta Centre Ville.

He said silicon dioxide has a “huge potential benefit” because if you reduce the size of the silicon particles to nanometer-scale, you could form concrete with fewer pores.

“It will stop infiltration of water and that infiltration of water is what leads to degradation of concrete.”

Grutter added iron oxide can increase tensile strength and abrasion resistance of materials but he stressed he cannot predict how quickly advances in nanotechnology will be widely used in construction.

Grutter did go on to comment about possible health issues in a way that suggests his investigation of the topic has been hasty,

In addition to cost, there are concerns about contamination and the health effects on people exposed to nanomaterials, he said.

“In the construction industry, if you use nanoparticles, the workers can be exposed to these particles and someone might live there,” he said. “We might not see these potential benefits implemented in society that quickly.”

Assessing health risks is time consuming, Grutter said. [emphases mine]

“… workers can be exposed to [nano]particles and someone might live there,” seems a little sketchy doesn’t it? As for the time it takes to assess health risks, I’m not sure what point Grutter is making with that comment. Still I have to say that I’m thrilled about this next bit,

Another potential application is self-cleaning walls, where the material emulates the properties of hydrophobic leaves.

Instead of sliding off, water rolls off, and with surface tension the water brings dirt off with it, so it remains self cleaning.

“It would be really cool, because essentially what that means is that to clean off sides of buildings you would just have to wait for it to rain.”

Self-cleaning buildings? Does this mean there’ll also be self-cleaning windows? I hope so.