FIBER REINFORCED CONCRETE FIBER REINFORCED CONCRETE ABSTRACT Concrete is weak in tension and strong in compression .Even though reinforcement is provided in tension zone micro cracks are developed in the tension and compression zone. The propagation of these cracks can be arrested by using fiber reinforcement in concrete. The fiber reinforcement is provided using different materials like steel carbon, glass fibers and polypropylene fibers. The fibers are very small which are distributed over the whole area of concrete .because of this we can not only arrest crack formation but also we can increase flexural ,shear ,torsion, strength, freezing &thawing resistance. INTRODUCTION In all countries, the construction industry is rapidly developing based on the invention of different materials and products in engineering fields. Engineers have attempted various types of materials in order to make the task more efficient reducing time, cost, improving durability, quality and performance of structures during their lifetime. 1
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FIBER REINFORCED CONCRETE
FIBER REINFORCED CONCRETE
ABSTRACT
Concrete is weak in tension and strong in compression .Even though reinforcement is
provided in tension zone micro cracks are developed in the tension and compression zone.
The propagation of these cracks can be arrested by using fiber reinforcement in concrete. The
fiber reinforcement is provided using different materials like steel carbon, glass fibers and
polypropylene fibers. The fibers are very small which are distributed over the whole area of
concrete .because of this we can not only arrest crack formation but also we can increase
Asbestos is a naturally occurring silicate minerals used commercially for their desirable
physical properties. They all have in common their eponymous, asbesti form habit: long,
(1:20) thin fibrous crystals. Asbestos became increasingly popular among manufacturers and
builders in the late 19th century because of its sound absorption, average tensile strength, its
resistance to fire, heat, electrical and chemical damage, and affordability. It was used in such
applications as electrical insulation for hotplate wiring and in building insulation. When
asbestos is used for its resistance to fire or heat, the fibers are often mixed with cement
(resulting in fiber cement) or woven into fabric or mats. Commercial asbestos mining began
in the Eastern Townships of Quebec, Canada and the world's largest asbestos mine is located
in the town of Asbestos, Quebec.
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FIBER REINFORCED CONCRETE
HEALTH HAZARD OF ASBESTOS
The inhalation of asbestos fibers can cause serious illnesses, including malignant lung cancer,
mesothelioma (a formerly rare cancer strongly associated with exposure to amphibole
asbestos), and asbestosis (a type of pneumoconiosis). Long exposure to high concentrations
of asbestos fibers is more likely to cause health problems. This is most common among the
miners of asbestos, since they have the longest exposure to it. The European Union has
banned all use of asbestos and extraction, manufacture and processing of asbestos products.
CARBON FIBER REINFORCED CONCRETE
Carbon fibers are the most recent & probably the most spectacular addition to the range of
fiber available for commercial use. Carbon fiber comes under the very high modulus of
elasticity and flexural strength. These are expansive. Their strength & stiffness characteristics
have been found to be superior even to those of steel. But they are more vulnerable to damage
than even glass fiber, and hence are generally treated with resign coating.
BENEFITS OF CFRC
· High strength lightweight concrete cabe achieved.
· More durable in hot weather & less shrinkage value
· Increased freezing - thawing resistances
Uses
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FIBER REINFORCED CONCRETE
Where the lightweight concreting is required.
Precast thin sections with lightweight concreting (up to Specific Gravity 1.0)
Suitable for high temperature and low humidity areas
COMPARISION OF DIFFERENT PROPERTIES AMONG DIFFERENT TYPES OF
CONCRETE
SOME DEVELOPMENTS IN FIBER-REINFORCED CONCRETE
An FRC sub-category named Engineered Cementitious Composite (ECC) claims 500 times
more resistance to cracking and 40 percent lighter than traditional concrete.ECC claims it can
sustain strain-hardening up to several percent strain, resulting in a material ductility of at least
two orders of magnitude higher when compared to normal concrete or standard fiber-
reinforced concrete. ECC also claims a unique cracking behavior. When loaded to beyond the
elastic range, ECC maintains crack width to below 100 µm, even when deformed to several
percent tensile strains. Field results with ECC and The Michigan Department of
Transportation resulted in early-age cracking
Recent studies performed on a high-performance fiber-reinforced concrete in a bridge deck
found that adding fibers provided residual strength and controlled cracking. A new kind of
natural fiber-reinforced concrete (NFRC) made of cellulose fibers processed from genetically
modified slash pine trees is giving good results. The cellulose fibers are longer and greater in
diameter than other timber sources. Some studies were performed using waste carpet fibers in
concrete as an environmentally friendly use of recycled carpet waste. A carpet typically
consists of two layers of backing (usually fabric from polypropylene tape yarns), joined by
CaCO3 filled styrene-butadiene latex rubber (SBR), and face fibers (majority being nylon 6
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2-3300-4000.5-1.01.7-2.07.5Carbon
32002.32.5-3.40.02-20Asbestos
0.25170--2.90.01-200Mica Fl
0.5520.00.97.5Polypropylene
2-3802-3.52.69-15Glass
1-32003-47.85-500Steel
Tensile Strength, GPaModulus of Elasticity, GPa
Failure Srain, %
Specific Gravity
Diameter µm
Fiber
FIBER REINFORCED CONCRETE
and nylon 66 textured yarns). Such nylon and polypropylene fibers can be used for concrete
reinforcement. Other ideas are emerging to use recycled materials as fibers.
CONCLUDING REMARKS
Innovations in engineering design, which often establish the need for new building materials,
have made fibre-reinforced cements very popular. The possibility of increased tensile
strength and impact resistance offers potential reductions in the weight and thickness of
building components and should also cut down on damage resulting from shipping and
handling. Although ASTM C440-74a describes the use of asbestos-cement and related
products, there are, at this time, no general ASTM standards for fibre-reinforced cement,
mortar and concrete. Until these standards become available, it will be necessary to rely on
the experience and judgment of both the designer and the fibre manufacturer. The onus is
thus on the designer to be aware of the limitations presently inherent in some of these
composites, particularly the durability of glass-fibre-reinforced products
REFERENCES
Building Research Station (1976), A Study of the Properties of Cem-Fil/OPC Composites, Building Research Establishment Current Paper, CP38/76, Garston, England.
Cheetham, C.J. and P. Maguire, (1979), Coating of Glass Fibres, U.S. Patent 4,173,486.
Majumdar. A.J. and J.F. Ryder, (1968), Glass Fibre Reinforcement of Cement Products, Glass Technology, Vol. 9 (3), pp. 78-84.
Ramachandran, V.S.,(1979), Superplasticizers in concrete, National Research Council of Canada, Division of Building Research, Canadian Building Digest pp. 203