Innovations in Concrete ConstructionFebruary 26, 2015
There have been some notable innovations concerning concrete in recent years. Among them are self-healing concrete, fibre optic concrete and flexible concrete.
Concrete That Heals Itself
Self-healing concrete may sound like science fiction, but Bath University have come up with an ingenious way in which concrete can heal itself. Namely, utilising bacteria to repair concrete showing signs of decay.
Though concrete is a tough material, especially when in combination with iron rebars, it is a material that can still be very vulnerable in certain conditions. Concrete, particularly reinforced concrete, is vulnerable to water, for instance. Just one small crack can soon become a major issue once water gets into the material’s interior. While, in cold conditions, water inside concrete can turn to ice, which can then expand and increase the size of the crack. Chemicals can also get into the water and cause further problems, with brittleness emerging in the concrete as a result of decalcification. If water gets as far into the concrete as to reach the iron rebar, then rust will affect the iron. This will cause expansion with the concrete then consequently falling apart.
The microbiologist Dr Henk Jonkers, of Delft University, developed self-healing concrete with the aim of revolutionizing civil engineering. Now, the University of Bath, along with Cardiff University and the University of Cambridge, are using bacteria to help heal concrete. The bacteria, which is contained in microcapsules, forms part of a concrete mix. This mix means that if water does enter an opening in the concrete, it is then faced by bacteria that multiplies and produces defensive limestone to seal any crack. The bacteria also protects any iron in concrete too, because of the oxygen-producing process that would otherwise result in metal corrosion.
The success of this type of healing procedure will not only make concrete structures last longer, but it will also lead to repair costs being halved. Man-made carbon dioxide emissions will also fall, because the manufacture of concrete will be reduced.
Transparent/Fibre Optic Concrete
Architect Kengo Kuma’s use of Luccon, which consists of fibre optic strands, is another very innovative way of utilising the possibilities of concrete. The fibre optic strands are embedded into concrete in a layered form, which then makes it possible for light to be transmitted through the concrete blocks.
Impressively, how big any image appears on the other side is down to the thickness of the block itself. Kuma is looking at inventive ways of making use of this technology, including the creation of building facades via projectors.
Engineered Cementitious Composites (ECC) were invented by the University of Michigan’s Vincent Li more than two decades ago. Notably, Polyvinyl Alcohol fibres are used to add 3 to 7% percent in terms of tensile strength that result in no breaks or strength being lost. ECC is now currently being researched for its possible uses worldwide.
ECC is also an inexpensive material, and it is being used in the construction of new, major buildings in Japan. Though the base materials of ECC consist of the typical sand, water and cement there are no big particles regarding the aggregate. The strain capacity of this type of concrete is also optimised to 500 times more than traditional concrete.
Written by Roadmaster Concrete Mixers, the leading providers of volumetric concrete mixers across the UK and Europe.