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Cutting Edge Green Building Methods and Materials (infographic)

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new construction methods - infographic

 

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Smarter and Greener: How cutting edge methods, materials and tech are making the world a more environmentally friendly and productive world.

Cutting Edge Construction Methods

Robot swarm construction

What is it? Researchers at Harvard have built small construction robots programmed to work together as a swarm to build structures.

How it works? The large swarms of robots can use artiificial intelligence to construct buildings, taking inspiration from insect swarm builders such as termites. Being a swarm, if some of the robots for some reason can’t work the others will still be able to complete the job.

What are the benefits? Quicker and safer construction of buildings without the need of human attendance on site. Perfect for constructions in dangerous places or space/colonized planets.

3D Printed Houses

What is it? Using giant 3D printers to build the main structural components of houses and other structures.

How it works? Giant 3D printers take raw materials and fashion them into buildings.

What are the benefits? Quicker construction and less production of waste in the building process. It is also thought that 3D printing may be how we build on the moon and other planets.

Is it being used yet? A small number of teams across the world are pioneering this method, including DUS Architects in the Netherlands, who are building a 3D printed Canal House that is under construction in Amsterdam and the Chinese company WnSun, that have built ten demo houses for $5,000 each.

Innovative Materials

Microalgae

What is it? Uses live micro algae growing in glass to generate renewable energy and provide shade.

How it works? The microalgae are supplied with liquid nutrients and carbon dioxide. They are then harvested to create biogas.

Where it’s being used? Arup have used this technology in the BIQ house as part of the International Building Exhibition in Hamburg, 2013.

Aerogel Insulation

What is it? One of the least dense substances in the world, Aerogel is almost as light as air and has super-insulating properties.

How it works? By removing liquid from gel you are left with the silica structure. This can be spun out to create sheets that have up to four times the insulating power of fiberglass or foam insulation.

What are the benefits? Better insulation in buildings could reduce the environmental burden of heating.

Is it being used yet? Recent reduction in the price of Aerogel has made it viable for usage in construction. Some predict it will soon take over the market in insulation.

Transparent Aluminum

What is it? Aluminum oxynitride or AION is four times harder than fused glass and 85% as hard as sapphire.

How it works? Aluminum oxynitride powder is stuffed into a rubber mourld and compressed in hydraulic fluid to 15,000 psi. It is then fused together by heating for days, then polished until clear.

What are the benefits? Although currently excessively expensive, it could be very useful in the construction of skyscrapers and in providing fire-resistant glass.

It is being used? It’s expense means it is more likely to be found in military tech than in the city.

Features of Smart Buildings

It’s not just materials that are making buildings better, technology is also playing its part

System integration – Systems that interact with each other can better understand, and respond to, the movement of people and resources around a building.

Environmental control – Smart building systems should be able to understand when lights and heating can be altered and turned off. This reduces wasted energy.

Data collection – By collecting data on how your office space is being used, a smart building can help you manage desk and office space more effectively.

Productivity benefits – By monitoring staff productivity through your building, it is possible to see what makes your staff more, and less, productive.

Buildings that Break the Mould

The Edge – Amsterdam

Often called the smartest building in the world, the Edge combines green building techniques with smart building innovation to create a place that’s great to work in and isn’t a burden on the environment.

Rating: Outstanding
BREAM rating : 98.36%

Electricity – 70% less electricity than comparable office buildings
Energy – The solar panels on the roof produce more energy than the building consumes
Heating – Aquifer thermal energy storage system provides all of the energy required
Water – Drained rainwater is used for cleaning and flushing the toilets
Lighting – LED lighting can be regulated via smartphones. Sensors measure occupancy and adjusts energy use.

The Crystal – London
The Crystal showcases state-of-the-art technologies to make buildings more efficient and more sustainable.

BREAM rating: outstanding

Energy – 20% of energy is from solar panels. 70% lower emissions.
Heating – 100% natural heat sources. Has 199 ground source heat pipes
Water – WC water is taken from non-potable sources, 80% of hot water is heated by solar heating and ground source heat pumps
Light – Triple-glazed windows let in 70% of natural light

Source: RubberBond

August 26, 2016 |

Vacuum Glazing: Windows that are Energy Efficient AND Cost Effective

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Energy efficient windows - Triple pane windows

Insulating your home against energy loss is one of the most prominent energy-reduction strategies promoted by governmental agencies and environmental organizations alike. With an estimated 40 percent of heat loss occurring due to poorly insulated walls, floors and windows, this is an effective area to target if you want to decrease your energy bills and reduce your carbon footprint. If you have no large renovation projects on the horizon, opening your walls just to re-insulate is daunting, let alone expensive, but the retrofitting or upgrading of windows is a much easier way to save energy and improve quality of life.

Window insulation is not all the same

In terms of retrofitting and replacing windows, energy savings depend on the current state of your windows, location of your home, direction the windows face and the type of heating and cooling systems installed. The Canada Mortgage and Housing Corporation has estimated average cost savings from better insulated windows to be from $68 in Vancouver, to $198 in Montreal, $203 in Halifax and $337 for Whitehorse, indicating that for Canadian homes location is key to your annual energy savings.

The most common window techniques currently include the use of low emissivity (low-e) coatings, a double-paned window and a gas filling between the two pieces of glass. Typically the gas-fill is argon, as it has the ability to reduce heat loss 30 percent better than air and is not as expensive as alternatives such as krypton, or xenon, all of which are found in the air that we breathe.

Double-paned windows may already exist in your home, and the option to have a triple-paned window with a double low-e coating is also a possibility. The challenge with these two conventional methods is the width of the window itself and the glass used may be too wide to install into your existing frames (or may change the overall aesthetic of the exterior of your home). However, new research is showing that vacuum glazing may be the most wallet-friendly and environmentally conscious option available commercially.

What is vacuum glazing?

While very similar to a double-paned, gas-filled window, vacuum glazing has one unique difference; there’s no air between the two panes of glass. Instead, the window is designed with a small hole that allows the oxygen to be removed from between the two pieces of glass and then sealed.  By doing so, the conduction and convection processes that normally occur are significantly reduced, as shown in the Pilkington SPACIA brochure here.

The concept originated in 1913 but was not technologically feasible until the late 1980s. By the early 21st Century Nippon Sheet Glass Group made the first commercially available models, which have been implemented in Japan’s architectural designs for homes and businesses for over 10 years.

The vacuum glazing market is dominated by one company, Pilkington, which produces three main vacuum glazing products: the Pilkington SPACIA, the Pilkington SPACIA-21, and the Pilkington SPACIA Shizuka (U-values and other data can be found here).

Each of Pilkington SPACIA’s products utilizes low-e glass and coatings which produce energy performance ratings similar, if not better, than conventional double-glazed windows with low-e coatings but with a significantly thinner frame profile. Ranging from 9mm to 21mm, Pilkington’s SPACIA products are useful for older homes that need refurbishment or for newer homes as their lightweight and thin frames will not sacrifice aesthetics for insulation capabilities.

Additionally, vacuum glazing is a “middle of the road” energy-efficient option when comparing the capital cost to the payback period. A study appearing in the International Journal of Energy Research compared the installation cost and payback of vacuum tube glazing against heat insulation solar glass and solar pond windows—two alternative high performance window technologies. The results showed that vacuum tube glazing has significantly greater thermal reduction properties, increasing annual energy-savings up to $274 CAD (€181), compared to heat insulation solar glass $134 CAD (€89), and solar pond windows $162 CAD (€107).

While the capital cost for vacuum tube windows is in the mid-to-high range for window installations at $3,931 CAD (€2,600), the savings garnered from their installation can reduce the payback period to a little over 14 years. In contrast, heat insulation solar glass windows have a capital cost of $4,536 CAD (€3,000) and solar pond windows ($3,931 CAD (€2,400), but will take 34 years and 22 year respectively, before the payback really begins.

Some conditions apply

While vacuum glazing has financial and aesthetic benefits compared to other energy-efficient alternatives, their availability and feasibility in northern climates has drawn some concerns. Pilkington is the only North American distributor of the product; with less market competition this could increase the cost of vacuum glazed windows. Furthermore, the effectiveness of vacuum glazing in regions with extreme temperature fluctuations could weaken the seals used for vacuum glazed windows, creating a pressure imbalance, which could lead to the windows breaking.

Two American based companies—EverSealed Windows and Guardian Industries—have been working to solve this problem, while increasing the efficiency of their product (EverSealed Windows has demonstrated a prototype vacuum glazing window with a U-value of 0.07). Also, as both companies are headquartered in the United States, vacuum glazing technologies will be made available to the North American market, and decreasing prices.

Overall, vacuum glazing technologies could very well be the future of windows. The use of alternative high-performance windows in retrofitting projects is estimated to have a market of 25.6 million homes in the UK, equivalent to reducing carbon emissions by 12.8 million tonnes or removing 840,000 cars from the road. This number would almost quadruple if vacuum glazing technology is used. As housing codes place a greater emphasis on thermal regulations, vacuum glazing may be the best way to meet new requirements and reduce your carbon footprint without a significant impact on your wallet.

by Maggie O’Brien

image: Vivian Peng (Creative Commons BY-NC-ND)
March 12, 2016 |

Rammed earth

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Rammed earth home - interiorRammed earth, also known as taipa in Portuguese, tapial in Spanish or pisé de terre or simply pisé in French, is a technique used to build walls with earth, chalk, lime and gravel. It’s an ancient building method that has seen a revival in recent years as people seek more sustainable building materials and natural building methods. Rammed earth walls are simple to construct, incombustible, thermally massive, very strong and durable. Conversely, they can be labour-intensive to construct without machinery (powered rammers), and if improperly protected or maintained they are susceptible to water damage. Traditionally, rammed earth buildings are found on every continent except Antarctica. From temperate and wet regions of north Europe to semi-dry deserts, mountain areas and the tropics. The availability of useful soil and building design for the local climatic conditions are factors favouring its use.

Overview of use

Building a rammed earth wall involves compressing a damp mixture of earth that has suitable proportions of sand, gravel and clay (sometimes with an added stabilizer) into an externally supported frame, creating a solid wall of earth. Historically, stabilizers such as lime or animal blood were used to stabilize the material, while modern rammed earth construction uses lime, cement or asphalt emulsions. Some modern builders also add coloured oxides or other items such as bottles or pieces of timber to add variety to the structure.

A temporary frame (formwork) is first built, usually out of wood or plywood, to act as a mould for desired shape and dimensions of each wall section. The frames must be sturdy and well braced, and the two opposing wall faces clamped together, to prevent bulging or deformation from the high compression forces involved. Damp material is poured into a depth of between 100 to 250 mm, and compressed to around 50 per cent of its original height. The compression of material is done iteratively in batches, to gradually build up the wall to the required height, dictated by the top of the frame. Historically, compression was done by hand with a long ramming pole, and was very labour-intensive, but today’s modern construction employs pneumatically powered tampers, which is much more efficient.

Once complete, the wall is strong enough that the frames can be immediately removed. This is necessary if a surface texture (e.g. by wire brushing) is desired, since walls become too hard to work after about an hour. The walls are best constructed in warm weather so that they can dry and harden. Walls take some time to dry out completely, and may take up to two years to completely cure. Compression strength increases with increased curing time, and exposed walls should be sealed to prevent water damage.

In modern variations of the method, rammed earth walls are constructed on top of conventional footings or a reinforced concrete slab base.

Features and benefits

The compression strength of rammed earth can be up to 4.3 MPa. This is less than the value of a similar thickness of concrete, but more than strong enough for use in domestic buildings. Indeed, properly built rammed earth can withstand loads for thousands of years, as many still-standing ancient rammed earth structures around the world attest. Rammed earth using rebar, wood or bamboo reinforcement can prevent failure caused by earthquakes or heavy storms. Mixing cement with the soil mixture can also increase the structure’s load bearing capacity but can only be used in clay-poor mixtures. The USDA observed that rammed earth structures last indefinitely and could be built for no more than two-thirds the cost of standard frame houses.

Soil is a locally available, low cost and sustainable resource, and harvesting it for use in construction has minimal environmental impact. This makes rammed earth construction highly affordable and viable for low-income builders. Unskilled labour (often friends and family) are able to provide most of the necessary labour, and today more than 30 per cent of the world’s population uses earth as a building material.

While the cost of material is low, constructing rammed earth without mechanical tools can be a very time consuming project; however with a mechanical tamper and prefabricated formwork it can take as little as two to three days to construct the walls for a 2000 to 2200 ft2 house.

One of the significant benefits of rammed earth is its excellent thermal mass; like brick or concrete construction, it can absorb heat during the day and release it at night. This can even out daily temperature variations and reduce the need for air conditioning and heating. But, rammed earth, also like brick and concrete, often requires insulation in colder climates. It must also be protected from heavy rain and insulated with vapour barriers.

When finished and without paint or other finish, the walls have the colour and texture of natural earth. Blemishes can also be patched up using the soil mixture as a plaster and sanded smooth. Care needs to be taken to avoid moisture-impermeable finishes such as cement render, as these will impair the ability of the wall to desorb (rid itself of) moisture, leading to a loss of compressive strength.

The thickness and density of rammed earth walls, typically 300 to 350mm thick, lends itself naturally to soundproofing. Rammed earth walls are also termite-resistant, non-toxic, inherently fireproof and ultimately biodegradable.

The material mass and clay content of rammed earth allows the building to “breathe” more than concrete structures, avoiding condensation issues without significant heat loss.

Nails or screws can be driven easily into well-cured walls, and they can be effectively patched with the same material used to build them.

What makes it sustainable?

Because rammed earth structures use locally available materials, they typically have low embodied energy and generate very little waste. The soils used are generally subsoils low in clay, between 5 per cent and 15 per cent with the topsoil retained for agricultural use. Ideally, the soil removed to prepare the building foundation can be used, further reducing cost and energy used for transportation.

Rammed earth buildings reduce the need for lumber because the formwork used is removable and can be continually reused.

Rammed earth can effectively control humidity where unclad walls containing clay are exposed to an internal space. Humidity is held between 40 per cent and 60 per cent which is the ideal humidity range for asthma sufferers and the storage of susceptible items, such as books.

When cement is used in the earth mixture, sustainable benefits such as low embodied energy and humidity control will not be realized. Manufacture of the cement itself adds to the global carbon dioxide burden at a rate of 1.25 tonnes per tonne of cement produced. Partial substitution of cement with alternatives such as ground granulated blast furnace slag hasn’t been proven effective and brings other sustainability questions with it.

Rammed earth can contribute to the overall energy efficiency of buildings. The density, thickness and thermal conductivity of rammed earth makes it a particularly suitable material for passive solar heating. Warmth takes almost 12 hours to work its way through a 350mm thick wall.

Rammed earth housing has been shown to resolve problems with homelessness caused by otherwise high building costs, as well as to help address the ecological dilemma of deforestation and toxic building materials associated with conventional construction methods.

History

Rammed earth has been used around the world in a wide range of climatic conditions, from wet northern Europe to dry regions in Africa. And it has been used for a long time.

Evidence of the early use of rammed earth has been seen in Neolithic archaeological sites of the Yangshao and Longshan in China along the Yellow River, dating back to 5000 BCE. By 2000 BCE, the use of rammed earth architectural techniques was commonly used for walls and foundations in China. The Great Wall of China used the “hang tu”-method which utilized layers of 10-15 cm loose earth (between formwork), which was then rammed with poles. Thickness: up to 10.6 m (which is much thicker than what is optimal).

In the 1800s in the United States, rammed earth was popularized by a book Rural Economy by S. W. Johnson. It was used to construct Borough House Plantation and Church of the Holy Cross in South Carolina, which are two National Historic Landmarks of the United States:

“Constructed in 1821, the Borough House Plantation complex contains the oldest and largest collection of ‘high style’ pise de terre (rammed earth) buildings in the United States. Six of the 27 dependencies and portions of the main house were constructed using this ancient technique, which was introduced to this country in 1806 through the book Rural Economy, by S.W. Johnson.” An outstanding example of rammed earth construction in Canada is St. Thomas Anglican Church (Shanty Bay, Ontario) built between 1838 and 1841.

The 1920s through the 1940s was an active research period for rammed earth construction in the U.S. South Dakota State College carried out extensive research and built almost 100 weathering walls of rammed earth. Over a period of thirty years the college researched the use of paints and plasters in relation to colloids in soil. In 1945 Clemson Agricultural College of South Carolina published their results on rammed earth research in a pamphlet called “Rammed Earth Building Construction.” In 1936 on a homestead near Gardendale, Alabama, the United States Department of Agriculture constructed an experimental community of rammed earth buildings with architect Thomas Hibben. The houses were built inexpensively and sold to the public, along with land sufficient for a garden and small livestock plots. The project was a success and provided valuable homes to low-income families.

USAID is working with undeveloped countries to improve the building science around rammed earth houses. They also financed the writing of the “Handbook of Rammed Earth” by Texas A&M University and the Texas Transportation Institute. The handbook was never available for purchase by the public until the Rammed Earth Institute International gained permission to reprint it.

Interest in rammed earth fell after World War II when the prices of modern building materials dropped. Rammed earth began to be viewed as substandard, and today it often meets opposition from contractors, engineers and tradesmen who are unfamiliar with earth construction techniques.

 


This article originally appeared on Appropedia.

image: Lsbentz (Creative Commons BY-NC-ND)

September 23, 2013 |

Steel: the world’s most recycled metal [infographic]

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Steel: the most recycled metal

Screen reader version:

Has been used for over 1000 years

Is the only common metal that will stick to a magnet

Is the most recycled material on Earth

Steel is extremely economical to recycle because of its magnetic qualities and because it doesn’t lose any of its inherent strength qualities, no matter how many times it is recycled.

What is steel?

Steel is an alloy material made of iron and other elements including carbon.

You will also find the following elements present in steel

Manganese
Phosphorus
Sulphur
Silicon
Oxygen
Nitrogen
Aluminum

Hard facts

25 million – number of tonnes of steel products produced each year

2 million – the number of people the world steel industry employs

200 – the number of steel cans of food produced

Nicolas Appert – invented the steel can in 1810 as a way to preserve food for Napoleon’s army

2/3 – amount of cans on supermarket shelves made of steel

The lifecylce of recycled steel

Purchased – consumables are bought from the supermarket

Consumed – product is consumed or used

Disposed in recycling – waste steel is put in recycling

Collected – recycling is collected

Sorted – then sorted

Baled & compacted – products are baled and compacted for ease of transport and handling

Melted – the recovered materials are melted in a furnace

Iron added – molten iron is added

Heated – oxygen is blasted into the furnace, which is heated to 1700 degrees centigrade

Cooled & rolled – the melted metal is poured into slab moulds and rolled into coils and flat sheets

Remoulded – these sheets are used to manufacture new products

Shipped – products are shipped to shops and supermarkets

Recycled steel statistics

Recycling 1 tonne of steel saves 1.5 tonnes of iron ore, 0.5 tonnes of coal

86% saved in air pollution

40%saved in water use

76% saved in water pollution

42% – new metals made using recycled steel

62 – 74% energy saving

200 million tonnes – recycling raw materials cuts CO2 emissions by this amount every year

100% – amount of steel cans that are recyclable

2.5 billion – the number of cans recycled each year

18,000 – the weight equivalent in double-decker buses

25% – percentage of steel cans made from recycled steel

26 hours – how long you can power a 60-watt light bulb for with the energy saved from recycling seven steel cans

94% – the percentage of steel recycled when a building is demolished

Steel is an essential materials that is pivotal to our way of life and to the products we will demand for a sustainable future.

It is a unique material that can be used forever once made; it has a unique ability to be truly recycled through a closed-loop system, which will lead to the further preservation of Earth’s precious resources.

infographic courtesy http://www.colorcoat-online.com

August 17, 2013 |

Durable and sustainable concrete inspired by the ancient Romans

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 IMAGE: Chris Brandon of the ROMACON project collects a sample of ancient Roman concrete drilled from a breakwater in Pozzuoli Bay, near Naples, Italy. The breakwater dates back to around 37…
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Berkeley — In a quest to make concrete more durable and sustainable, an international team of geologists and engineers has found inspiration in the ancient Romans, whose massive concrete structures have withstood the elements for more than 2,000 years.

Using the Advanced Light Source at Lawrence Berkeley National Laboratory (Berkeley Lab), a research team from the University of California, Berkeley, examined the fine-scale structure of Roman concrete. It described for the first time how the extraordinarily stable compound—calcium-aluminum-silicate-hydrate (C-A-S-H)—binds the material used to build some of the most enduring structures in Western civilization.

The discovery could help improve the durability of modern concrete that within 50 years often shows signs of degradation, particularly in ocean environments.

The manufacturing of Roman concrete also leaves a smaller carbon footprint than does its modern counterpart. The process for creating Portland cement, a key ingredient in modern concrete, requires fossil fuels to burn calcium carbonate (limestone) and clays at about 1,450 degrees Celsius (2,642 degrees Fahrenheit). Seven per cent of global carbon dioxide emissions every year comes from this activity. The production of lime for Roman concrete, however, is much cleaner, requiring temperatures that are two-thirds of that required for making Portland cement.

The researchers’ findings are published in two papers, the Journal of the American Ceramic Society and the journal American Mineralogist.

 IMAGE: Sample of ancient Roman maritime concrete from Pozzuoli Bay near Naples, Italy. Its diameter is 9 centimeters, and it is composed of mortar formulated from lime, volcanic ash and chunks…
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“Roman concrete has remained coherent and well consolidated for 2,000 years in aggressive maritime environments,” said Marie Jackson, lead author of both papers. “It is one of the most durable construction materials on the planet, and that was no accident. Shipping was the lifeline of political, economic and military stability for the Roman Empire, so constructing harbours that would last was critical.”

The research team was led by Paulo Monteiro, a UC Berkeley professor of civil and environmental engineering and a faculty scientist at Berkeley Lab, and Jackson, a UC Berkeley research engineer in civil and environmental engineering. They characterized samples of Roman concrete taken from a breakwater in Pozzuoli Bay, near Naples, Italy.

Building the Empire

Concrete was the Roman Empire’s construction material of choice. It was used in monuments such as the Pantheon in Rome as well as in wharves, breakwaters and other harbour structures. Of particular interest to the research team was how Roman’s underwater concrete endured the unforgiving saltwater environment.

The recipe for Roman concrete was described around 30 B.C. by Marcus Vitruvius Pollio, an engineer for Octavian, who became Emperor Augustus. The not-so-secret ingredient is volcanic ash, which Romans combined with lime to form mortar. They packed this mortar and rock chunks into wooden moulds immersed in seawater. Rather than battle the marine elements, Romans harnessed saltwater and made it an integral part of the concrete.

 IMAGE: This scanning electron microscope image shows crystals of a rare mineral, Al-tobermorite, magnified about 25,000 times. UC Berkeley researchers characterized Al-tobermorite in samples of Roman concrete.
Click here for more information.

The researchers also described a very rare hydrothermal mineral called aluminum tobermorite (Al-tobermorite) that formed in the concrete. “Our study provided the first experimental determination of the mechanical properties of the mineral,” said Jackson.

So why did the use of Roman concrete decrease? “As the Roman Empire declined, and shipping declined, the need for the seawater concrete declined,” said Jackson. “You could also argue that the original structures were built so well that, once they were in place, they didn’t need to be replaced.”

An earth-friendly alternative

While Roman concrete is durable, Monteiro said it is unlikely to replace modern concrete because it’s not ideal for construction where faster hardening is needed.

But the researchers are now finding ways to apply their discoveries about Roman concrete to the development of more earth-friendly and durable modern concrete. They’re investigating whether volcanic ash would be a good, large-volume substitute in countries without easy access to fly ash, an industrial waste product from the burning of coal that’s commonly used to produce modern, green concrete.

“There’s not enough fly ash in this world to replace half of the Portland cement being used,” said Monteiro. “Many countries don’t have fly ash, so the idea is to find alternative, local materials that will work, including the kind of volcanic ash that Romans used. Using these alternatives could replace 40 per cent of the world’s demand for Portland cement.”

The research began with initial funding from King Abdullah University of Science and Technology in Saudi Arabia (KAUST), which launched a research partnership with UC Berkeley in 2008. Monteiro noted that Saudi Arabia has “mountains of volcanic ash” that could potentially be used in concrete.

In addition to KAUST, funding from the Loeb Classical Library Foundation, Harvard University and the Department of Energy’s Office of Science helped support this research. Samples were provided by Marie Jackson and the Roman Maritime Concrete Study (ROMACONS), sponsored by CTG Italcementi, a research center based in Bergamo, Italy. The researchers also used the Berlin Electron Storage Ring Society for Synchrotron Radiation, or BESSY, for their analyses.

Source: Eurekalert!

July 25, 2013 |

A comparison of straw bale versus papercrete

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In this article we present the outcome of our research into straw bale versus papercrete as alternatives to the most common types of building materials based on criteria such as R-value, cost of production and pollution concerns. The purpose is to see how appropriate these materials are for application depending on location and personal choice.

Background

Even though we might be accustomed to only a few different types of building materials in the United States, many alternatives to the typical wood and sheet rock or red brick buildings exist. Some alternatives are more environmentally friendly than others and better suited to certain locations, but by what factors can these decisions be made? How can they be compared? We had the opportunity to research papercrete and straw bale building materials as alternatives to the typical and most common building materials and develop a materials evaluator spreadsheet to compare the two.

Straw bale houses were very popular among settlers in the plains areas for the abundance of straw and the insulative properties, useful during long cold winters. Once the mass production of construction materials in the 1950s started, straw bale construction started losing popularity. Straw bale could not compete with the cheapness and quickness of application of mass produced materials, but due to the appropriate technologies movement in the 1970s there was a resurgence of people interested in the application of straw bale as a building material. It’s a byproduct of grain harvesting and usually becomes waste. It has an amazing R-value, which reduces the need for heating in the winter and air conditioning in the summer and can withstand strong seismic activity because of its compressive strength and flexibility.

Papercrete is a building material made from cement, shredded paper and sand. Waste paper can be used–and should be used–and the ratios of the component materials can be adjusted to meet the needs of the builder. The application of papercrete is versatile because it can be shaped into many different forms. Different size bricks can be formed to meet the specifications of particular projects and they can be made and stored on site over a period of time.

Problem statement

The Campus Center for Appropriate Technologies (CCAT) at Humboldt State University has asked us, as students of Engineering, to research different building materials for a tool shed that they will be building on site. The shed will not only be functional but will be a teaching tool and demonstration piece for the community.

Our goal in researching these two materials is to determine which one is more suitable for our location based on a number of different comparable criteria such as transportation costs, CO2 emissions and R-Value. Just because there’s an alternative building material doesn’t necessarily make it the best choice. If one material takes more fuel, creates more pollution and uses up more natural resources than another it might be wise to take another look before any decision is made.

Example of a Papercrete Shed

Instructions

Our materials evaluator spreadsheet, Media: Straw_bale_vs_papercrete.xls, is dynamic and user friendly. This spreadsheet allows the user to change values in the red cells to determine which material is best suited for their project. On page two of the spreadsheet is the calculations page for the “winner.” On this sheet the red cells contain weights on a scale of 1-10. These weights reflect how important each characteristic is to the user and may be adjusted. For example, cost may be extremely important to one user and assigned a weight of “10,” while another user may not be as concerned with cost and may assign it a weight of “5.” After all of the input has been adjusted in the red cells and the user hits enter, the new “winner” will appear in the “winner” box. There’s a ruby red scale bar in the “winner” box that displays by how much the “winner” won. In addition, if the “winner” is straw bale the “winner” box will turn yellow. If the “winner” is papercrete the “winner” box will turn gray.

Strawbale home under construction

Justifications

Average straw yields for the 2003-2004 growing season were found at the University of Kentucky Spindletop Farm, Lexington, KY. This provided us the information on what the average price per bale should be. [1]

Farming information including average fuel usage per acre. From this site we gathered part of the equation needed in figuring out carbon emissions. [2]

Strawbale weight and dimensions, this allowed us to calculate how many bales needed per shed. [3]

John Deere 8030 Series Tractors: Record-setting fuel efficiency!(15.13Hp*hr/gal. Data we used in determining carbon emissions. [4]

The most comprehensive straw bale site we’ve found (Great References)- Canada based site that addresses history, method, load bearing capacity, applications, and common concerns (i.e. height limitations, rot, fire, longevity…). These became most of the characteristics used to compare straw bale to papercrete –[5]

We found the prices of straw bale from a local distributor in our town. This source also helped us factor in the distance that the straw travels from the harvesting site to the construction site. There was also a project in central California that got their straw from the same area. This transport distance provided more information to calculate carbon emissions- [6][7]

Papercrete can be made using various ratios of materials. We tried to match our information with the some of the most common forms and mixtures used for load bearing construction. This standardization allowed us to compare it to strawbale–we found a lot of information through living paper.com that provided how to’s, mixes and instructions.[8]

We also found a lot of information concerning statistics on the CO2 emissions of cement as well as graphs for analysis on papercrete. We used this information to compare cement CO2 emissions with straw bale CO2 emissions.-[9]

Results

We were able to determine which material is most appropriate for the CCAT shed project by entering collected data and stated assumptions in our dynamic materials evaluator spreadsheet. Initially we had thought that straw bale would be our material of choice because it consists almost entirely of natural and recycled material and the cement used in papercrete is energy intensive. But once we put the weights to what we valued most and considered why we were building the shed our results showed that papercrete is more appropriate. The results of each characteristic evaluation can be viewed on the Media:Straw_bale_vs_papercrete.xls spreadsheet.

Conclusions

Even though straw bale is much less energy intensive in extraction than the cement used in papercrete, we chose papercrete as our building material based on our spreadsheet analysis. We valued and weighted the various categories and papercrete came out as the “winner” in our materials evaluator spreadsheet. Detailed results can be viewed on the Media:Straw_bale_vs_papercrete.xls spreadsheet.

Discussion and next steps

This project and analysis could be improved and expanded upon in many ways. We only researched and analyzed two materials, straw bale and papercrete, and more materials can be evaluated based on our selected characteristics. One way in which we would like to improve this project is by adding common, conventional building materials used in stick frame, timber frame, and concrete block construction to display how alternative building materials compare. We believe that it’s important to add these materials to our comparison since the purpose of determining which materials are most “appropriate” is to reduce consumption and pollution resulting from the use of conventional building materials.

References

  1.  http://www.uky.edu/Ag/GrainCrops/Research/Research_pdf/SmallGrains_StrawYields2005.pdf
  2.  http://www.precisiontillage.com/assets/uploads/Costs%20and%20Fuel%20Use.pdf
  3.  http://www.buildinggreen.com/auth/image.cfm?imageName=images/0403/baledimensions.jpg&fileName=040301a.xml
  4.  http://www.deere.com/en_US/ag/feature/2008/8030_fuel_efficiency.html
  5.  – http://harvesthomes.ca/building/straw_bale_primer.pdf
  6.  3G’s Hay and Grain, Arcata California
  7.  http://www.presentationcenter.org/Environment/Welcome_Center/WC_Construction/straw_bale.html
  8.  http://www.livinginpaper.com
  9.  http://www.buildingforafuture.co.uk/autumn05/ordinary_portland_cement.pdf

by Sean GavlasJessica FowlerBrandon BarlowGraham Felsenthal (Humboldt State University – Arcata, CA)

June 26, 2013 |

5 sustainable building materials for your next building project

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As the world population increases, the need for accommodation will inevitably increase. Unfortunately, current mainstream building methods are unsustainable, producing large amounts of CO2 both during construction and throughout a building’s life. Thankfully, sustainability is becoming a priority for developers, and with many exciting innovations happening in the construction industry, sustainably addressing global accommodation needs seems possible. Here’s five materials that could help:

Wool bricks

Developed by Spanish and Scottish researchers with an aim to “obtain a composite that was more sustainable, non-toxic, using abundant local materials that would mechanically improve the bricks’ strength,” these wool bricks are exactly what the name suggests. Simply by adding wool and a natural polymer found in seaweed to the clay of the brick, the brick is 37% stronger than other bricks, and more resistant to the cold wet climate often found in Britain. They also dry hard, reducing the embodied energy as they don’t need to be fired like traditional bricks.

Solar tiles

Traditional roof tiles are either mined from the ground or set from concrete or clay—all energy intensive methods. Once installed, they exist to simply protect a building from the elements despite the fact that they spend a large portion of the day absorbing energy from the sun. With this in mind, many companies are now developing solar tiles. Unlike most solar units which are fixed on top of existing roofing, solar tiles are fully integrated into the building, protecting it from the weather and generating power for its inhabitants.

Sustainable concrete

While 95 percent of a building’s CO2 emissions are a result of the energy consumed during its life, there’s much that can be done to reduce that five percent associated with construction. Concrete is an ideal place to start, partly because almost every building uses it, but mostly due to the fact that concrete is responsible for a staggering 7-10% of global CO2 emissions. More sustainable forms of concrete exist that use recycled materials in the mix. Crushed glass can be added, as can wood chips or slag—a byproduct of steel manufacturing. While these changes aren’t radically transforming concrete, by simply using a material that would have otherwise gone to waste, the CO2 emissions associated with concrete are reduced.

Paper insulation

Made from recycled newspapers and cardboard, paper-based insulation is a superior alternative to chemical foams. Both insect resistant and fire retardant thanks to the inclusion of borax, boric acid, and calcium carbonate (all completely natural materials that have no associations with health problems), paper insulation can be blown into cavity walls, filling every crack and creating an almost draft-free space.

Triple-glazed windows

The three layers of glass do a better job of stopping heat from leaving the building than standard windows, with fully insulated window frames contributing further. In most double-glazed windows, gas argon is injected between each layer of glass to aid insulation, but in these super-efficient windows, krypton—a better, but more expensive insulator—is used. In addition to this, low-emissivity coatings are applied to the glass, further preventing heat from escaping.

A building that combines all five of these methods would make for a great sustainable housing option. While the construction industry tends to progress at a slow pace, the importance of sustainability is a high profile issue, and one that’s only likely to increase. With sustainable building materials already fully developed, it’s now up to consumers to actively demand their use and building developers to respond promptly.

[box]By Joe Peach at This Big City. This article originally appeared on the sustainable cities website This Big City.[/box]

May 9, 2013 |

CARBON REDUCED CONCRETE: Using biofuel byproducts to build stronger, greener concrete

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Balconies - concrete buildingK2TMEVQV4U72 MANHATTAN, KAN. — Kansas State University civil engineers are developing the right mix to reduce concrete’s carbon footprint and make it stronger. Their innovative ingredient: biofuel byproducts. 

“The idea is to use bioethanol production byproducts to produce a material to use in concrete as a partial replacement of cement,” said Feraidon Ataie, doctoral student in civil engineering, Kabul, Afghanistan. “By using these materials we can reduce the carbon footprint of concrete materials.”

Concrete is made from three major components: portland cement, water and aggregate. The world uses nearly 7 billion cubic meters of concrete a year, making concrete the most-used industrial material after water, said Kyle Riding, assistant professor of civil engineering and Ataie’s faculty mentor.

“Even though making concrete is less energy intensive than making steel or other building materials, we use so much of it that concrete production accounts for between 3 to 8 per cent of global carbon dioxide emissions,” Riding said.

To reduce carbon dioxide emissions from concrete production, the researchers are studying environmentally friendly materials that can replace part of the portland cement used in concrete. They are finding success using the byproducts of biofuels made from corn stover, wheat straw and rice straw.

“It is predicted that bioethanol production will increase in the future because of sustainability,” Ataie said. “As bioethanol production increases, the amount of the byproduct produced also increases. This byproduct can be used in concrete.”

The researchers are specifically looking at byproducts from production of cellulosic ethanol, which is biofuel produced from inedible material such as wood chips, wheat straw or other agricultural residue. Cellulosic ethanol is different from traditional bioethanol, which uses corn and grain to make biofuel. Corn ethanol’s byproduct (called distiller’s dried grains) can be used as cattle feed, but cellulosic ethanol’s byproduct (called high-lignin residue) is often perceived as less valuable.

“With the cellulosic ethanol process, you have leftover material that has lignin and some cellulose in it, but it’s not really a feed material anymore,” Riding said. “Your choices of how to use it are a lot lower. The most common choices would be to either burn it for electricity or dispose of the ash.”

When the researchers added the high-lignin ash byproduct to cement, the ash reacted chemically with the cement to make it stronger. The researchers tested the finished concrete material and found that replacing 20 per cent of the cement with cellulosic material after burning increased the strength of the concrete by 32 per cent.

“We have been working on applying viable biofuel pretreatments to materials to see if we can improve the behaviour and use of ash and concrete,” Riding said. “This has the potential to make biofuel manufacture more cost effective by better using all of the resources that are being wasted and getting value from otherwise wasteful material and leftover materials. It has the potential to improve the strength and durability of concrete. It benefits both industries.”

The research could greatly affect Kansas and other agricultural states that produce crops such as wheat and corn. After harvesting these crops, the leftover wheat straw and corn stover can be used for making cellulosic ethanol. Cellulosic ethanol byproducts then can be added to cement to strengthen concrete.

“The utilization of this byproduct is important in both concrete materials and biofuel production,” Ataie said. “If you use this in concrete to increase strength and quality, then you add value to this byproduct rather than just landfilling it. If you add value to this byproduct, then it is a positive factor for the industry. It can help to reduce the cost of bioethanol production.”

 


The researchers have published some of their work in the American Society of Civil Engineer’s Journal of Materials in Civil Engineering and are preparing several other publications. Ataie also was one of two Kansas State University graduate students named a winner at the 2013 Capitol Graduate Research Summit in Topeka. His poster was titled “Utilization of high lignin residue ash (HLRA) in concrete materials.”

The research at Kansas State University was funded by more than $210,000 from the National Science Foundation. The researchers collaborated with the University of Texas, North Carolina State University and the National Renewable Energy Laboratory in Golden, Colo. The research also involved Antoine Borden, senior in civil engineering, Colorado Springs, Colo.

image: Mazwebs

March 28, 2013 |

NANORODS: Harvesting the sun’s energy in a totally different way

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(Santa Barbara, Calif.) — A new method of harvesting the Sun’s energy is emerging, thanks to scientists at UC Santa Barbara’s Departments of Chemistry, Chemical Engineering, and Materials. Though still in its infancy, the research promises to convert sunlight into energy using a process based on metals that are more robust than many of the semiconductors used in conventional methods. The researchers’ findings are published in the latest issue of the journal Nature Nanotechnology.

 

“It is the first radically new and potentially workable alternative to semiconductor-based solar conversion devices to be developed in the past 70 years or so,” said Martin Moskovits, professor of chemistry at UCSB.

In conventional photoprocesses, a technology developed and used over the last century, sunlight hits the surface of semiconductor material, one side of which is electron-rich, while the other side is not. The photon, or light particle, excites the electrons, causing them to leave their postions, and create positively-charged “holes.” The result is a current of charged particles that can be captured and delivered for various uses, including powering lightbulbs, charging batteries, or facilitating chemical reactions.

“For example, the electrons might cause hydrogen ions in water to be converted into hydrogen, a fuel, while the holes produce oxygen,” said Moskovits.

In the technology developed by Moskovits and his team, it is not semiconductor materials that provide the electrons and venue for the conversion of solar energy, but nanostructured metals — a “forest” of gold nanorods, to be specific.

For this experiment, gold nanorods were capped with a layer of crystalline titanium dioxide decorated with platinum nanoparticles, and set in water. A cobalt-based oxidation catalyst was deposited on the lower portion of the array.

“When nanostructures, such as nanorods, of certain metals are exposed to visible light, the conduction electrons of the metal can be caused to oscillate collectively, absorbing a great deal of the light,” said Moskovits. “This excitation is called a surface plasmon.”

As the “hot” electrons in these plasmonic waves are excited by light particles, some travel up the nanorod, through a filter layer of crystalline titanium dioxide, and are captured by platinum particles. This causes the reaction that splits hydrogen ions from the bond that forms water. Meanwhile, the holes left behind by the excited electrons head toward the cobalt-based catalyst on the lower part of the rod to form oxygen.

According to the study, hydrogen production was clearly observable after about two hours. Additionally, the nanorods were not subject to the photocorrosion that often causes traditional semiconductor material to fail in minutes.

“The device operated with no hint of failure for many weeks,” Moskovits said.

The plasmonic method of splitting water is currently less efficient and more costly than conventional photoprocesses, but if the last century of photovoltaic technology has shown anything, it is that continued research will improve on the cost and efficiency of this new method — and likely in far less time than it took for the semiconductor-based technology, said Moskovits.

“Despite the recentness of the discovery, we have already attained ‘respectable’ efficiencies. More importantly, we can imagine achievable strategies for improving the efficiencies radically,” he said.

Research in this study was also performed by postdoctoral researchers Syed Mubeen and Joun Lee; grad student Nirala Singh; materials engineer Stephan Kraemer; and chemistry professor Galen Stucky.

March 6, 2013 |

JUTE: Sustainable reinforcement for concrete has newly discovered benefits

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ball of string

Cheap fibre used to make burlap, gunny sacks and twine could inexpensively reinforce mortar and concrete. (photo courtesy iStockphoto/Thinkstock)

Fashionable people may turn up their noses at jute—the cheap fibre used to make burlap, gunny sacks, twine and other common products—but new research is enhancing jute’s appeal as an inexpensive, sustainable reinforcement for mortar and concrete. The study appears in ACS’ journal Industrial & Engineering Chemistry Research.

Subhasish B. Majumder and colleagues note that there has been a resurgence of interest in using economical, sustainable natural fibres, rather than steel or synthetic fibres, to reinforce the cement compositions used to make concrete and mortar, the world’s most widely used building materials. That reinforcement makes cement compositions stronger and more resistant to cracks. Their previous research showed that jute works as a reinforcement fibre.

The new study discovered another advantage of jute, which is second only to cotton as the most widely used natural fibre. The addition of jute fibers also delays the hardening of concrete and mortar, which must be trucked to construction sites. “The prolonged setting of these fibre-reinforced cement composites would be beneficial for applications where the pre-mixed cement aggregates are required to be transported from a distant place to construction site,” the report states.

Source: American Chemical Society

January 17, 2013 |
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