Over the past few decades the construction field has developed in a way which cannot be explained to a normal person. It is due to the fact that with new findings and new technology scientists have been able to invent new types of materials that were never thought of. Carbon fiber is one such type of versatile material. In this article we are going to talk about how Carbon fiber has helped to develop the construction sector of the world.
First it will be useful to identify what factors help Carbon fibers of these new accomplishments. The versatile properties of carbon fiber include high stiffness, high tensile strength, high chemical resistance, high temperature tolerance and low thermal expansion. These make them one of the most popular and used material in Civil engineering possessing strength up to five times that of steel and being lighter in weight, we might as well call it ‘the superhero’ of the material world. Indeed it is the “Superhero”. It is also called graphite fiber or carbon graphite. Carbon fiber is made of very thin strands of the element Carbon.
Carbon fibers have high tensile strength and are very strong for their size. In fact, carbon fiber can be the strongest material. Carbon fibers consist of a high elastic modulus and fatigue strength when compared to glass fibers, making them ideal for the construction industry. Considering service life, it has been suggested that carbon fiber reinforced polymers have more potential than agamid and glass fibers. Carbon fiber reinforced polymers also are highly chemically resistant and have high temperature tolerance with low thermal expansion and corrosion resistance. So what else to talk about its application when it comes to the Construction industry? So let us see now how carbon Fiber is used in Construction.
In the case of reinforced (RC) or pre stressed concrete (PC) structures, a new repair technology involves the use of externally bonded FRP (Fiber reinforced plastics) laminates. Similar to steel plate bonding, the FRP laminate bonding involves adhere a thin, flexible fiber sheet to the concrete surface with a thermos set resin. This technique is used to increase the shear and flexural capacity of beams and slabs and to increase confinement in columns. The system does not add significant dead load to the structure, suffers less from corrosion, and may be installed in a relatively short period of time.
The uses of near surface mounted (NSM) FRP rods is another promising new technology for increasing flexural and shear strength. Benefits of using near surface mounted FRP rods, when compared to superficially bonded FRP laminates are the possibility of anchoring the rods into adjacent members and less installation time. Another benefit of this method is the particularly attractive nature for flexural strengthening in the negative moment regions of slabs and decks, where external strengthening will be subjected to mechanical and environmental damage and would require protective cover which could interfere with the presence of floor finishes.
The above mentioned technique can also be used to repair bridges.
Current trends in construction toward repair and rehabilitation have emphasized the need to provide additional strength to such existing structures. Structures that experience a change in use or a degradation problem, or a design/construction defect normally require some degree of strengthening.
This field is relatively new and rapidly in progress. Carbon fibers in precast concrete started to appear in quantity-production from 2003. Now it is a very common material for precast elements in the North America. A carbon fiber grid is used in the panel faces to replace steel mesh reinforcement, and as a mechanical link to the outer and inner sections of a concrete wall. Non-corrosive carbon fiber grid strengthening in the wall panel face allows less use of concrete, which reduces weight and raw material used. The wall panels with carbon fiber grid reinforcement weighs about 40% less than conventional precast panels.
It is used as a shear grid to connect the inner and outer concrete exterior of sandwich wall panels, creating a fully structurally compound, thermally efficient unit. Carbon fiber grid is integrated as reinforcing in the double tee slab to replace conventional steel mesh. Replacing welded gird with carbon fiber grid in the slabs reduces weight and the need of protection from chemicals.
Another field of applying carbon fiber is bridge construction. Since 1992 there have been built many footbridges were constructed mostly from fiber reinforced compounds. The main purpose for application of carbon fiber reinforced plastic was to provide bridge weight reduction and economy of lifting equipment.
When tornadoes tore across the Midwest, they set their fury against buildings made from wood, steel and concrete architectural components which were used to construct homes a hundred years ago. For the people looking for a new start, new types of materials might be able to provide the resistance to weather disasters those century-old housing technologies could not provide. Originally designed for building military bases, Concrete Cloth is a cement-impregnated fabric that functions same way as a plaster cast, except on a much bigger scale. Giant rolls of this clothe spool the fabric out across uneven ground of hastily made frames. Spraying the material with water begins a chemical reaction that, after some drying, results in a low profile structure strong enough to resist whatever Mother Nature can throw at it. Concrete Cloth is easy enough to work with and costs cheap enough to provide communal shelters for the residents of trailer parks and houses without storm cellars.
Carbon fiber is a good substitute of steel filaments in fiber-concrete. The fibers, used for fiber concrete are usually cheap cellulose or PAN-based fibers that gave less thermal conductivity when compared with steel and also provide good cohesion when use with concrete. This solution is good for high loaded floors and roads. In fiber-cement, carbon fibers replace asbestos, because carbon fiber does not provoke any inhalation problems.
