International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 09 Issue: 05 | May 2022
p-ISSN: 2395-0072
www.irjet.net
Effects of Hybrid Steel Fibers on the Mechanical Properties of Steel Fiber Reinforced Concrete Mohd Mukaram Ather1, Mohammed Abubakar Siddiq2, Mussab Abdul Raheem3, Kanchala Nanchari4 Students, Department of Civil Engineering 4 HOD Dept of Civil Engineering ISL Engineering College, Hyderabad, Telangana ---------------------------------------------------------------------***--------------------------------------------------------------------1, 2, 3 UG
Abstract - Cement concrete is the most extensively used
construction material in the world. The reason for its extensive use is that it provides good workability and can be moulded to any shape. Ordinary cement concrete possesses a very low tensile strength, limited ductility and little resistance to cracking. Internal micro cracks, leading to brittle failure of concrete. In this modern age, civil engineering constructions have their own structural and durability requirements, every structure has its own intended purpose and hence to meet this purpose, modification in traditional cement concrete has become mandatory. It has been found that different type of fibers added in specific percentage to concrete improves the mechanical properties, durability and serviceability of the structure. It is now established that one of the important properties of Steel Fiber Reinforced Concrete (SFRC) is its superior resistance to cracking and crack propagation. In this project effect of steel fibers on the strength of concrete for M 40 grade will be studied by varying the percentage of fibers in concrete and types of fibers. Compressive strength, Split Tensile Strength & Flexural strength will be compared and tabulated. Fibers addition to concrete results in more closely spaced and improved resistance to the cracks. Improvement observed in mechanical properties of controlled concrete due to present of steel fibers. There is a significant increase in Compressive Strength of concrete with addition of Crimped Steel Fiber when compared to Straight and Hooked Steel Fiber. The percentage increase in Compressive Strengths of Straight Steel Fiber (2%), Hooked Steel Fiber (2%) and Crimped Steel Fiber (2%) are 9.84%, 5.9% & 16.92% respectively. Similar trend is followed for other mechanical properties. Key Words: Crimped Steel Fiber, Straight Steel Fiber, Hooked Steel Fiber, Compressive strength, Split Tensile strength.
1. INTRODUCTION Civil engineers and construction experts are aware of the fact that plain concrete exhibits very low tensile strength, limited ductility and little resistance to cracking, but are forced to use plain concrete due to the exigency. Hence there is an urgent need to reinforce the conventional concrete to cope up with tensile loads and strains suited to our needs. The presence of micro cracks at the mortar-aggregate interface is the inherent weakness of plain concrete. The application of load leads to propagation of cracks and brittle fractures in conventional concrete due to its poor tensile © 2022, IRJET
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strength. Normally micro cracks appear in concrete during hardening stage. When load is applied, micro cracks start developing along the planes which may experience relatively low tensile strains at about 25-30% of the ultimate strength in compression. Further application of load leads to uncontrolled formation of the micro cracks. Concrete mix that contains short, discrete fibers that are uniformly distributed and randomly oriented is called Fiber reinforced concrete. The fibers used are steel fibers, synthetic fibers, glass fibers and natural fibers. The fibers in members resist the opening of the cracks due to micro cracking and increase the ability of the members to withstand loads.
2. LITERATURE REVIEW Ali Amin and Stephen J. Foster [2016], Despite the increased awareness of Steel Fibre Reinforced Concrete (SFRC) in practice and research, SFRC is yet to find common application in load bearing or shear critical building structural elements. Although the far majority of studies on SFRC have focused on members containing fibres only, in most practical applications of SFRC construction, structural members made of SFRC are also reinforced with conventional reinforcing steel for shear ligatures. In this paper, results are presented on shear tests which have been conducted on ten 5 m long by 0.3 m wide by 0.7 m high rectangular simply supported beams with varying transverse and steel fibre reinforcement ratios. The tests have been analysed along with complete material characterisation which quantify the post-cracking behaviour of the SFRC. Rubén Serrano et al; [2016], The decrease in concrete resistance and the expansion generated in reinforced concrete structures by direct exposure to fire at 400 C maximum temperatures serves as the basis for the present research. The aim is to improve these problems by the addition of steel fibers or of polypropylene fibers in concrete. From the results analysis of compression fracture tests on cylindrical concrete specimens, it can be concluded that concrete with addition of polypropylene fibers or steel fibers are a good alternative to traditional concrete, because both its strength, and its behavior in case of fire are improved, delaying the appearance of fissures and explosive concrete spalling. G. Murali, A. S. Santhi and G. Mohan Ganesh[2019], It is well known that concrete is characterized by its high compressive strength, yet its brittle mode of failure is ISO 9001:2008 Certified Journal
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