International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 04 Issue: 07 | July -2017
p-ISSN: 2395-0072
www.irjet.net
Study of Fiber Reinforced Concrete Subjected to Elevated Temperature Mr. Nisarg Shankar1, DR Y.M Manjunath2, Ritesh L3 1Assistant
Professor, Department of Civil Engineering, SJB Institute of Technology, Bengaluru, Karnataka, India Professor, Department of Civil Engineering, National Institute of Engineering, Mysuru, Karnataka, India 3PG Student, Department of Civil Engineering, SJB Institute of Technology, Bengaluru, Karnataka, India ---------------------------------------------------------------------***--------------------------------------------------------------------2
Abstract - Fiber reinforced concrete is increasingly being
compression but very weak in tension. The cracks gradually propagate to the compression end of the member and finally, the member breaks. This shortcomings are traditionally overcome by adding reinforcing bars or pre stressing steel. Fibers are discontinuous are generally distributed randomly throughout the concrete matrix. Fibers are being used in structural applications with conventional reinforcement, because of the flexibility in methods of fabrication. Fiber reinforced concrete can be an economic and useful construction materials.
used for various civil infrastructure applications worldwide. With the introduction of fiber materials in concrete, the knowledge about the effect of fiber percentage on the residual strength of concrete after subjecting to elevated temperature is less. Fire represents one of the most severe exposure conditions in structures. Hence provisions for appropriate fire resistance for structural members are major safety requirements for any building design. This project aims at studying the performance of steel fiber and polyester fiber reinforced concrete with varying percentage subjected to elevated temperatures. Totally 48 beams of size (0.5*0.1*0.1m) have casted with 0% fiber, 1% steel fiber. Flexural strength test have been conducted on these casted beams using universal testing machine and results compared with residual strength with different temperature of varied percentage of fibers.
1.2 Polyester Fibers Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term polyester, as a specific material most commonly refers to polyethylene terephthalate (pET). Natural polyesters and a few synthetic ones are biodegradable, but most synthetic polyesters are not' Depending on the chemical structure, polyester can be a thermoplastic or thermo set; however, the most common polyesters are thermoplastics till Liquid crystalline polyesters are among the first industrially used liquid crystal polymers.
Key Words: Fibre reinforced, Polyesters, Steel fibres, Flexural strength, Deflection, Elevated temperature etc
1. INTRODUCTION Since ancient times, fibers have been used to reinforce brittle materials. Straw was used to reinforce sun-baked bricks and horse hair was used to reinforce masonry mortar and plaster. In modern times, a wide range of engineering materials (including ceramics, plastics, and cement and gypsum products) incorporate fibers to enhance composite properties. The enhanced properties include tensile strength, compressive strength, elastic modules, crack resistance, crack control, durability, fatigue life, resistance to impact and abrasion, shrinkage, expansion, thermal characteristics and fire resistance. Concrete also have remarkable fire resisting properties. In most of the cases of accidental fire, it is found that concrete failure depends on the intensity and duration of fire. Exposure of concrete to fire may result in cracking, spalling during heating and disintegration during cooling. To reduce cracking, spalling and disintegration of concrete many attempts have been made. One of the attempts is the introduction of fibers in concrete.
1.3 Steel Fibers Concrete is the most widely used structural material in the world with an annual production of over seven billion tons. For a variety of reasons, much of this concrete is cracked. It is now well established that steel fiber reinforcement offers a solution to the problem of cracking by making concrete tougher and more ductile. It has also been proved by extensive research and field trials carried out over the past three decades, that addition of steel fibers to conventional plain or reinforced and pre stressed concrete members at the time of mixing/production imparts improvements to several properties of concrete, particularly those related to strength, performance and durability. The efficiency of steel fibers as concrete macro-reinforcement is in proportion to increasing fiber content, fiber strength, aspect ratio and bonding efficiency of the fibers in the concrete matrix.
1.1 Fiber Reinforced Concrete Concrete is a composite material containing hydraulic cement, water, coarse aggregate and fine aggregate. This stone like material is a brittle material which is strong in
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