Europe / Middle East / Africa
Impressive new concrete technology
Mar, 12 2010
There’s been a stir in the British construction industry lately over the development of a new building material that holds out the promise of greatly reducing cement use while delivering high fire ratings and great load-bearing strength.
It was developed by Pal Mangat, director of the Centre for Infrastructure Management at Sheffield Hallam University, and despite early successes in the application of his material, he’s keeping pretty quiet about what’s in it.
From what we know so far, the product, dubbed Liquid Granite, is a powder made up of between 30 and 70 per cent industrial waste. It also contains less than one-third of the cement usually used for precast concrete. And, no, that isn’t a typographical error. Liquid Granite is a powder.
“It replaces most of the cement in standard concrete with a secret formula of products to change the basic properties of the material,” Mangat says. “I believe it has great potential for the future.”
Concrete made with the material has high compressive strength and a high level of fire resistance.
So far, it’s available only in the United Kingdom, supplied by a firm called Liquid Granite Ltd. But, despite the name, it is not related to the “liquid granite” used in North America as a sealant with a wide range of applications, from industrial floors to kitchen countertops. That means there will be a name change somewhere along the way before the new British product is available over here.
In England it is being used, so far, for fire-resistant members in construction of the Olympic Village which is being built for the London Summer Olympics in 2012, and in a shopping mall, also in London.
Mangat says that, so far, he’s been able to replace more than two-thirds of the Portland cement when making concrete, thus saving the associated carbon emissions.
“One of the biggest culprits of carbon footprint is cement, which we use in making concrete,” he says. “Liquid Granite does away with most of the use of cement. The amount used is pretty small.”
“Potentially, by the time we’re finished with this developmental technology, it’ll be close to zero.”
He’s especially keen on the material’s fire-resistant properties. It can withstand temperatures of up to 1,100°C while maintaining its structural properties. Thus, it has already been granted a four-hour fire rating.
That means, Mangat says, that it should find uses wherever fire safety is crucial, “such as around power stations, and in domestic and commercial buildings, where it can offer added time for evacuation in case of emergency.”
Beyond that, he won’t say much — with good reason.
The world uses about two billion tonnes of cement every year, and there are estimates that by 2020, demand will be 50 per cent higher than it is today.
Each tonne of cement manufactured results in the release of about 400 kg of carbon dioxide, and the industry is responsible for roughly five per cent of the world’s carbon emissions, so huge rewards await anyone who can come up with a carbon-free material to replace it.
Indeed, a British firm called Novacem has created a new cement that has a negative carbon footprint over its lifetime. It uses magnesium silicates, which emit no carbon dioxide when heated, and the process is carried out at much lower temperatures than used in the manufacture of Portland cement. As well, the magnesium-based product absorbs carbon dioxide as it hardens. It has been estimated that over its lifetime, a tonne of the material could remove about 600 kg of the gas.
As climate agreements are written, and begin to bite, it’s a safe bet that the race to reduce carbon emissions will get tighter and tighter.
The payoff for the winner will be immense.
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Maybe new to him
This is old news as this is exactly what PowerCem does with it's ConcreCem additives, check it out at www.powercem.com . The professor might be surprised when he gets around to doing a patent search as PCT has patents on this technology in GB, Europe and the USA with patent filed and pending elsewhere.
Posted By : George Clark
Posted On : 3/12/2010 5:51:52 PM
Wrong figures-right concept
As an average, 1T Ordinairy Portland Cement = 1 T CO2 = 1.6 T raw material, mainly Calcium Carbonate. Of this, 600 kg dissapears by the calcining process as CO2 in the air, the 400 kg CO2 comes from the thermal process.
At this moment the best figure we have is globally 2.4 Billion tons of CO2 comes from "cement".
Most confusion from figures comes from what one calls cement. If it is the definition of "what the cement industry delivers" it can be OPC and blended cements, while when the blending is done by the concrete producer it is not!? So mostly a market guided definition.
That is why so called Water Binder Ratio's all differ from country to country and that is why the industry has a hard time to evolve towards the high tech level it can get.
Acc. to http://www.thefreedictionary.com/cement,
1. A building material made by grinding calcined limestone and clay to a fine powder, which can be mixed with water and poured to set as a solid mass or used as an ingredient in making mortar or concrete.
2. A substance that hardens to act as an adhesive; glue.
3. Something that serves to bind or unite: "Custom was in early days the cement of society" (Walter Bagehot).
4. Geology A chemically precipitated substance that binds particles of clastic rocks.
Once we can, like most progressive industries, judge concrete not on HOW but WHAT has been produced, we will advance. Performance over Prescription!
So the new concrete technology presented is another promising step to maturity of the industry. Bravo!
Posted By : Boudewijn Piscaer
Posted On : 3/13/2010 6:06:24 AM
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