Archive for June, 2011

Ingredients: crushed glass, sand, eco-cement and (wool?) fibers.

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Liquid Granite is a new material developed by Sheffield Hallam University. It utilises groundbreaking technology which will change the way professionals think about structural concrete, engineered stone and all the associated fields within these sectors of the construction industry.

Liquid Granite boasts many technological advances making it an improved alternative to standard concrete. These include…
• Significant ecological benefits
• Improved resistance to fire and heat
• Strength and reinforcement levels
• Moisture resisting properties

As a revolutionary new construction material, Liquid Granite has been the subject of many testing procedures which have all produced favourable results.

Source: Liquid Granite

What do you do with a problem like cement? The cement industry is responsible for 5% of the world’s carbon emissions. Engineers have been working hard on the problem in recent years, with a range of approaches to cutting the environmental impact of the construction industry. The latest on the block is Liquid Granite, a binding material that, according to its inventor, could almost entirely replace cement with a powder made from recycled waste materials.

Liquid Granite replaces the need for more than two-thirds of this Portland cement when making concrete, thereby saving the associated carbon emissions. “One of the biggest culprits of carbon footprint is cement, which we use in making concrete – Liquid Granite does away with most of the use of cement. The amount used is pretty small,” says Prof Pal Mangat of Sheffield Hallam University, who came up with the product. “Potentially, by the time we’re finished with this developmental technology, it’ll be close to zero.”

Liquid Granite is made from an inorganic powder, 30-70% of which is recycled industrial waste materials. Using the same aggregates as normal concrete, it could be used anywhere cement is but with a fraction of the carbon footprint.
“It has good fire-resistant properties, unlike concrete, which explodes upon exposure to high temperatures.”

[Ed.: It doesn’t sound like liquid granite if the aggregates are the same as typical concrete.]

Source: Liquid Granite and the hunt for a carbon-neutral cement

Related articles: Liquid Granite: Building Material of the Future Unveiled
Liquid Granite

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Novacem has developed a new class of cement which will offer performance and cost parity with ordinary Portland cement, but with a carbon negative footprint. It is uniquely positioned to meet the challenge of reducing cement industry carbon emissions.

Our cement is based on magnesium oxide (MgO) and hydrated magnesium carbonates. Our production process uses accelerated carbonation of magnesium silicates under elevated levels of temperature and pressure (i.e. 180oC/150bar). The carbonates produced are heated at low temperatures (700oC) to produce MgO, with the CO2 generated being recycled back in the process. The use of magnesium silicates eliminates the CO2 emissions from raw materials processing. In addition, the low temperatures required allow use of fuels with low energy content or carbon intensity (i.e. biomass), thus further reducing carbon emissions. Additionally, production of the carbonates absorbs CO2; they are produced by carbonating part of the manufactured MgO using atmospheric/industrial CO2. Overall, the production process to make 1 tonne of Novacem cement absorbs up to 100 kg more CO2 than it emits, making it a carbon negative product.

This production process is based on 20 years of research on the mineral carbonation of magnesium silicates. These minerals are widely dispersed with accessible worldwide reserves estimated to significantly exceed 10,000 billion tonnes. Novacem cement demonstrates performance which is already good enough for several significant applications (e.g., masonry products), and which is continually being optimised and improved.

[Should be available 2014-15.]

Source: Novacem

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Calera Inputs and Outputs

Calera Inputs and Outputs

Natural chemical processes in the world’s oceans inspire the Calera’s technology. For millennia these processes have helped to balance the world’s carbon cycle and created massive formations of carbonate deposits, such as the white cliffs of Dover.

Ocean chemistry involves the gradual absorption and mineralization of carbon. Over geologic time, vast amounts of CO2 are naturally absorbed into the oceans and converted into stable minerals, such as limestone. Calera’s technology is based on these processes, and enhances them. In brief, Calera’s technology focuses on two goals:
– Speed. Increasing the speed and scale of gas absorption into solution and then increasing the speed and scale of conversion into minerals so that large volumes of gas can be continuously captured and
– Products. Developing end products that are potentially useful, such as cement and mineral carbonates

Because Calera’s chemistry involves several steps, with each step requiring additional materials and each resulting in a different end product, Calera’s technology is flexible, and has the potential to support a variety of projects and solutions. Among other goals, the technology may be used to capture and store CO2 as bicarbonate, or to develop end products with beneficial commercial uses such as bicarbonate or cement.

Both the conversion of CO2 into bicarbonate, and the subsequent conversion of bicarbonate to carbonate occur more rapidly in solutions with high pH. As the maintenance of a high pH environment is important to Calera’s process, and large volumes of alkalinity are required to support the technology at scale, the availability of alkalinity sources, such as sodium hydroxide, is currently a significant consideration in evaluating projects.

The company is developing proprietary technology that is expected to substantially reduce the cost to produce sodium hydroxide: internal targets exceed a 75% reduction in associated energy needs and cost. But in the near-term the possibility of abundant and relatively low-cost sodium hydroxide are significant considerations in the selection of projects and could provide considerable economic advantages at select locations.

Additionally, if the desired end product of the company’s process is cement, the process requires large volumes of divalent calcium cations, most readily available from materials such as “hard” water sources containing calcium or by adding calcium chloride.
Calera’s technology may be suitable for a variety of facilities, including both retrofits and new plants. We have successfully retrofitted our technology at the demonstration level to an existing gas plant in Moss Landing, California.

Source: Calera
Good article in Scientific American — Cement from CO2: A Concrete Cure for Global Warming?

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Our modern world is largely built with Portland cement. It’s the most traded commodity in the world after water. Portland cement is said to be the most destructive man-made material in the world. Portland cement is the biggest source of carbon emissions in the world, producing around 5-8% of global carbon emissions. Even more alarming, demand continues to increase. It is imperative to switch to more sustainable building materials, and that’s one reason for this blog – to learn about affordable, stone-like materials that can last hundreds of years.

The following companies offer sustainable cement made with fly ash, slag, magnesium based cement, geopolymer.
Ashram Ecocements
Blue World Crete, Inc.
(60% recycled glass added to Portland… but same idea could be used with geopolymer)
Recycled timber and eco-cement blocks
Ecobrique (clay with waste treatment plant residue)
Asia Mortar R-crete Eco Render
Eco Bricks (Hydraulically compressed fly ash, cement, gypsum and stone dust)
AfriSam Eco Building Cement
Ecolite Concrete Blocks
ECOCEM Low Carbon Concrete
Micro (pre-made slabs with up to 74% recycled content)
Siloxo Pty. Ltd. (no products for sale yet)

(Please send us other resources and I’ll add them here.)

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This is a type of geo-polymer cement (Trademark of an American Company) giving very high & very early strength of concrete. This is blended hydraulic cement in which no chlorides are added during manufacturing process. The cement is being used for rapid repair of airfields. US Air Force used this type of cement to build and equip temporary military airports in very short time.

The Pyrament® blended-cement is the ideal material for repairing runways made of concrete, industrial pavements, and highway roads. In the case of a runway, 4-6 hours hardening is enough to allow the landing of an Airbus or a Boeing. The geo-polymeric cement reaches a compression strength of 20 Mpa after 4 hours, whereas plain concrete gets to this strength after several days.

If we compare in a microscope the structure of concrete made of regular cement with another sample made of geopolymer cement, we notice that the regular cement is a coarse stacking of grains of matter. This causes cracks and weaknesses. Whereas concrete made of geo-polymer cement (in black) is smooth and homogeneous. This provides, in fact, superior assets.

Source: ConcreBasics.org

Construction Productivity Advancement Research (CPAR) Program. Performance of Concretes Proportioned with Pyrament Blended Cement

Pyrament Blended Cement (PBC) is known in the construction industry for its ability to gain strength rapidly and achieve very high early strength. The Waterways Experiment Station (WES) conducted a laboratory evaluation of concretes made with PBC to determine if these concretes perform better than concretes made with ordinary portland cement (OPC) in tests of various aspects of concrete durability. For this study, six concretes based on PBC-XT were proportioned with three cement contents and two aggregate types. The objective was to determine if the cement, advertised as giving high early strength and marketed initially as a rapid-construction material, is durable enough to justify its use for long-term performance in addition to shorter construction time. Concretes prepared from PBC-XT cement were subjected to analyses of its resistance to damage during cycles of freezing and thawing, expansion in a high- sulfate environment, damage from underwater abrasion, penetration of dissolved chlorides, scaling from deicing chemicals, and expansion from chemical interaction between alkalies in the cement and silica in aggregate. In all categories, the PBC-XT cement concretes achieved or exceeded expected performance based on the manufacturer’s product literature. In all but the last category, PBC-XT concretes performed better than is generally expected of high- quality OPC concretes. Concrete permeability, High-early strength, Rapid-setting concrete. Blended hydraulic cement, High-performance concrete, Durability, Rapid chloride permeability,

Source (106 page free report): Storming Media

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Maltese concrete

Maltese concrete

The temples on Malta are claimed to be some of the oldest free-standing temples in the world. A. Service (6), mentions the ‘contemporary cement of the floor’ in the pavement of the Ggantija temple on Gozo, Malta, and although the idea was not accepted for a long time, Maltese archaeologists are now of the opinion that Torba (as it is called on Malta), was formed by compacting crumbled rock and rock dust then adding water (7), creating a tough and durable rock-like material on-par with the best and strongest concrete used today.

Source: Prehistoric Malta http://www.ancient-wisdom.co.uk/malta.htm

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