It’s a big contributor to global warming with every tonne of Ordinary Portland Cement releasing 1 tonne of CO2 into the atmosphere.
Breakthroughs in the Last 20 Years Have Seen Dust Emissions Reduced by 70%, Oxides of Nitrogen Reduced by 50% and Sulphur Dioxide Emissions a Massive 75% Down
The material that builds our buildings, paves our roads and spans our bridges is the most widely produced and consumed material on earth apart from water. By 2030, urban growth in China and India will place global cement output at 5bn metric tons per year, with current output already responsible for 8% of the global emissions total, according to a WWF report.
There are many different types of concrete: compact, strong, skinny, cement free and one you probably didn’t know about self-healing and its UK born and still in its infancy and could revolutionize the construction industry.
1. Smog Cleaning Buildings
But first, smog cleaning buildings: The Manuel Gea González a newly constructed hospital in Mexico city, has a 2,500-square-meter facade constructed from ‘Prosolve’ modules. These are coated with a special pigment which, when hit by ambient ultraviolet light, reacts with urban air pollutants, breaking them down into less noxious compounds like carbon dioxide and water. The pigment itself remains unchanged, which means the modules can keep purifying the air for up to a decade, or until their coating wears off.
2. Strong Concrete
Strong concrete (one world trade centre New York): the perimeter frame is built of steel, creating column free large floor plates that can be more easily subdivided for letting purposes. The major concrete innovation at the new One World Trade Centre also known as the ‘Freedom Tower’ was the strength of the actual material specially developed to build the tower. The supporting columns on the first 40 floors of the 110 storey building are made from concrete that can withstand loads of 12,000 – 14,000 pounds per square inch (psi) – the strongest ever used.
3. Compact Concrete
Compact concrete (240 Blackfriars London): concrete’s inherent strength can win developers extra floor space. The extra space at Blackfriars was created using concrete floor-plates that still permitted spacious floor to ceiling heights but was much more compact than steel beams.
4. Slip Form
Slip form (the Shard London): the method is used to build tall structures by continuously pouring concrete from a moving crane. Below the surface of the Shard was the biggest job, constructing the raft, which forms the towers foundations. The 3 metre deep slab was created in a single pour and set a record for the biggest concrete pour in UK construction history.
5. Skinny Concrete
Skinny concrete (Park Avenue, New York): the skyscraper is regarded as the tallest residential building in the western hemisphere and has an exposed concrete structural frame, which enables column-free interiors. 432 Park Avenue is one of several skinny skyscrapers now rising in central Manhattan and casting shadows over New York’s beloved Central Park.
Skinny concrete is also popular in furniture design. You can now get a 3mm concrete panel for interior design. Concrete furniture has been around for as long as concrete countertops have. In the early days the furniture was primarily made out of precast concrete.
Since it needed to be reinforced with steel, the concrete tended to be thick, massive and heavy. This made large, thin and delicate pieces impractical or impossible. The current trend towards using glass-fiber reinforced concrete (GFRC) has changed that. GFRC is a form of concrete that has inherently high flex strength. It can be easily shaped into complex, three-dimensional shapes that do not need to be thick to be strong.
6. Cement Free Concrete
Cement free concrete (Global Change Institute Brisbane): the Australian building opted for an earth friendly concrete. The project contains no Portland cement – the traditional binding agent in concrete. Instead, it is bound together with a geopolymer created by the chemical reaction that takes place when blast furnace slag from iron production is mixed with ash fly ash, itself a byproduct of coal fired power stations. The use of the material has, the institute says, cut carbon emissions by 80% – 90% and created what is believed to be the world’s first cement free concrete building. It is a very exciting product, not only because of its extremely low carbon emission, but also because of the improved structural and durability properties compared to conventional concrete.
7. Geopolymer Cement
Geopolymer cement: is being developed and utilised as an alternative to conventional Portland cement for use in transportation, infrastructure, construction and offshore applications. Geopolymer relies on minimally processed natural materials or industrial byproducts to significantly reduce its carbon footprint, while also being resistant to many common concrete durability issues.
Such cements can be formulated to cure more rapidly than Portland-based cements with some mixes gaining most of their ultimate strength within 24 hours. Although geopolymerization does not rely on toxic organic solvents, but on water, it needs chemical ingredients that may be dangerous and therefore requires some safety procedures.