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1 Journal home page: INTERNATIONAL JOURNAL OF INNOVATIVE AND APPLIED RESEARCH RESEARCH ARTICLE CHARACTERISTIC PROPERTIES OF STEEL FIBRE REINFORCED CONCRETE WITH VARYING PERCENTAGES OF FIBRE *Er Gulzar Ahmad 1 and Er kshipra kapoor 2 1. M. Tech scholar, Department of civil Engineering, Universal institutions of Engineering and Technology, Lalru, Chandigarh. 2. Assistant Prof. & Head, Department of civil Engineering, Universal institutions of Engineering and Technology, Lalru, Chandigarh. *Corresponding Author Abstract: This paper presents the results of an experimental study investigating the effects of steel fibers on the mechanical properties of concrete. Experimental program consisted of compressive strength test, and workability test on steel fiber reinforced concrete. In this work the strength characteristics of steel fiber reinforced concrete with varying percentages of fibers is found and hence arrived at optimum percentage of steel fibers. M20 grade concrete as per IS: was designed which yielded a proportion of 1:1.86: 2.41 with a w/c ratio of The steel fibers were added at the rate of 0.5%, 1.0%, 1.50%, and 2.0% by volume fraction. Based on the compressive strength and tensile strength it is concluded that the optimum percentage of steel fiber to be added in the concrete mix is 1% by volume fraction. Key Words: Portland cement, concrete, Steel Fiber, Compressive strength, workability. Introduction Fiber reinforced concrete (FRC) is Portland cement concrete reinforced with more or less randomly distributed fibers. In FRC, thousands of small fibers are dispersed and distributed randomly in the concrete during mixing, and thus improve concrete properties in all directions. FRC is cement- based composite material that has been developed in recent years. It has been successfully used in construction with its excellent flexural-tensile strength, resistance to spitting, impact resistance and excellent permeability and frost resistance. It is an effective way to increase toughness, shock resistance and resistance to plastic shrinkage cracking of the mortar. Fiber is a small piece of reinforcing material possessing certain characteristics properties. They can be circular, triangular or flat in cross-section. The fire is often described by a convenient parameter called aspect ratio. The aspect ratio of the fiber is the ratio of its length to its diameter. The principle reason for incorporating fibers into a cement matrix is to increase the toughness and tensile strength and improve the cracking deformation characteristics of the resultant composite. For FRC to be a viable construction material, it must be able to compete economically with existing reinforcing system. FRC composite properties, such as crack resistance, reinforcement and increase in toughness are dependent on the mechanical properties of the fiber, bonding properties of the fiber and matrix, as well as the quantity and distribution within the matrix of the fibers. EXPERIMENTAL PROGRAM 1. MATERIALS AND PROPERTIES The materials selected for this experimental study includes normal natural coarse aggregate, manufactured sand as fine aggregate, cement, Superplasticizer, both end hooked steel fiber and portable drinking water. The physical and chemical properties of each ingredient has considerable role in the desirable properties of concrete like strength and workability. 17

2 CEMENT WATER FINE AGGREGATES STEEL FIBRE COARSE AGGREGATES 1.1 Cement: The cement used for this project work is Portland slag cement. It gives low heat of hydration. Table I : Physical Properties of Cement Brand of cement OPC Standard consistency 35 % Initial setting time (in mins) 142 Final setting time (in mins) 328 Specific gravity Fine aggregates: It should be passed through IS Sieve 4.75 mm. It should have fineness modulus and silt contents should not be more than 4%. Manufacturer s sand has been used for the present investigation; it is also called M sand. Manufactured sand has been regularly used to make quality concrete for decades in India and abroad. M-sand is crushed aggregates produced from hard granite stone which is cubically shaped with grounded edges, washed and graded with consistency to be used as a substitute of river sand.. It confirms to IS which comes under Zone II. Table II : Physical Properties of fine aggregates Specific Gravity 2.54 Water absorption 12 % 1.3 Coarse aggregates: It should be hard, strong, dense, durable and clean. It must be free from vein, adherent coatings and injurious amount of disintegrated pieces, alkalis, vegetable matters and other deleterious substances. It should be roughly cubical in shape. Flaky pieces should be avoided. It should confirm to IS 2838(I). Coarse Aggregate used is of two sizes 20 mm maximum size and 12.5 mm maximum size. Table III : Physical Properties of Coarse aggregates Specific Gravity Water absorption 0.25 % 1.4 Water: Water should be free from acids, oils, alkalies, vegetables or other organic impurities. Soft waters also produce weaker concrete. Water has two functions in a concrete mix. Firstly, it reacts chemically with the cement to form the cement paste in which the inert aggregates are held in suspension until the cement paste has hardened. Secondly, it serves as a lubricant in the mixture of fine aggregates and cement. 1.5 Steel Fiber: Percentage volume fraction of fibers was varied from 0 to 0.38%. Hooked end Steel fibers of 0.75mm diameter with 60mm length is used and its aspect ratio is 80. Density of steel fiber is 7850Kg/m3. 18

3 Fig. 1 Steel fiber 1.6 Super Plasticizer: Super plasticizers, also known as high range water reducers, are chemical admixtures used where well-dispersed particle suspension is required. In my study Master Rebuild was used as super plasticizer. This was obtained from BASF Construction Chemicals (India) Pvt. Ltd 2. TESTING PROCEDURE Concrete test specimen consists of 150x150x150mm cubes, Concrete cube specimen were tested at 7 and 28 days to obtain the compressive strength of concrete. Fig 2: Compressive strength machine 19

4 RESULTS AND DISCUSSION The compressive strength of the cubes at different days and Steel fiber combination are given in table 4. And the slump value and compaction factor is given in table 5. Table 4: Compressive strength of concrete Mix Compressive strength(mpa) 3 Days 7 Days 28 days Normal Concrete % SF % SF % SF % SF The slump and the compaction factor are given in table 5 Table 5: Slump and compaction factor test Mix Slump (mm) Compaction Factor Normal Concrete % SF % SF % SF % SF Conclusion The study on the introduction of effect of steel fibers can be still promising as steel fiber reinforced concrete is used for sustainable and long-lasting concrete structures. Steel fibers are widely used as a fiber reinforced concrete all over the world. Lot of research work had been done on steel fiber reinforced concrete and lot of researchers work prominently over it. Addition of 1% steel fibers result in higher compressive strength and use of more than 1% steel fibers will bring down the compressive strength. Load carrying capacity of the joints also increased with the increasing fiber content. Acknowledgement The research work described in this paper was a part of M-Tech research work at Universal institutions of Engineering and Technology, Lalru, Chandigarh. Authors are also highly thankful to Civil engineering department for cooperation and facilities. References 1. Milind V. Mohod, Performance of Steel Fiber Reinforced Concrete IJCS ISSN: , Vol. 1, Issue 12 (December 2012), PP AHSANA FATHIMA K M & SHIBI VARGHESE, BEHAVIOURAL STUDY OF STEEL FIBER AND POLYPROPYLENE FIBER REINFORCED CONCRETE ISSN(E): ; ISSN(P): ,Vol. 2, Issue 10, Oct 2014, N. Ganesan, P.V. Indira and Ruby Abraham, STEEL FIBRE REINFORCED HIGH PERFORMANCE CONCRETE BEAM-COLUMN JOINTS SUBJECTED TO CYCLIC LOADING 20

5 4. N. Janesan, P. V. Indira and S. Rajendra Prasad, 2010: Structural behaviour of steel fibre reinforced concrete wall panels in two-way is plane action. Indian concrete journal. 5. Rui D. Neves and Joao C. O. Fernandes de Almeida, Compressive behaviour of steel fibre reinforced concrete, structural concrete No Jiuru, T., Chaobin, H., Kaijian, Y. and Yongcheng, Y. (1992). Seismic Behaviour and Shear Strength of Framed Joint Using Steel-Fiber Reinforced Concrete, Journal of Structural Engineering, ASCE, Vol. 118, No. 2, pp Kumar, V., Nautiyalil, B.D. and Kumar, S. (1991). A Study of Exterior Beam-Column Joints, The Indian Concrete Journal, Vol. 65, No. 1, pp Oh, B.H. (1992). Flexural Analysis of Reinforced Concrete Beams Containing Steel Fibres, Journal of Structural Engineering, ASCE, Vol. 118, No. 10, pp Shamim, M. and Kumar, V. (1999). Behaviour of Reinforced Concrete Beam-Column Joint A Review, Journal of Structural Engineering, ASCE, Vol. 26, No. 3, pp Shannag, M.J., Abu-Dyya, N. and Abu-Farsakh, G. (2005). Lateral Load Response of High Performance Fiber Reinforced Concrete Beam-Column Joints, Construction and Building Materials. 11. Indian standard code of practice for specification for coarse and fine aggregate from natural sources for concrete, IS 383: (1970), Bureau of Indian standards, New Delhi. 12. Indian standard code of practice for recommended guidelines for concrete mix design, IS 10262: 2009, Bureau of Indian standards, New Delhi. 13. Indian standard code of practice for plain and reinforced concrete IS 456: 2000, Bureau of Indian standards, New Delhi. 14. Shetty M.S- Concrete Technology; S Chand publications. 21