International Research Journal of Engineering and Technology (IRJET) Volume: 11 Issue: 04 | Apr 2024
www.irjet.net
e-ISSN: 2395-0056 p-ISSN: 2395-0072
“Study on Strength Behaviour of Partial Fibre Reinforced Concrete in Slabs” Bholanath Pal Civil Engineering Department School of Engineering & Technology Maharishi University of Information Technology (Lucknow) M..Tech /Construction Technology & Management Sitapur Road, IIM-By Pass, P.O. Maharishi Vidya Mandir, Lucknow -226013, U.P, India ---------------------------------------------------------------------***---------------------------------------------------------------------
ABSTRACT: In plain concrete, micro-cracks develop even before loading, particularly due to drying shrinkage or other causes of volume changes. These internal micro-cracks are inherently present in the concrete, and its poor tensile strength is due to the propagation of such micro cracks, eventually leading to brittle fracture of the concrete. When loaded, the micro-cracks propagate and open up, and owing to the effect of stress concentration, additional cracks form in places of minor defects. Thus the need for multidirectional and closely spaced reinforcement for concrete arises. It has been recognized that the addition of small, closely spaced and uniformly distributed fibres to concrete would act as crack arrester and would significantly improve its static and dynamic properties. This type of concrete is called Fibre Reinforced Concrete. Partial Fibre Reinforced Concrete (PFRC) is the method of limiting the addition of Fibres in FRC, only to the area subjected to maximum Compressive or Tensile strength when subjected to loading. PFRC will have very similar strength compared to the FRC and have the advantage of lesser fibre quantity which reduces the cost of fibre required. PFRC also have better workability compared to normal FRC. In this project Concrete slabs were selected as the element for the study of strength behavior of Partial Fibre Reinforced Concrete. M20 Concrete with Mix design carried out based on IS 10262-2009 was used to cast the specimen. Steel fibre of 1mm diameter and coconut fibre of 0.45mm diameter were selected to fibre reinforce the concrete. An aspect ratio of 80 is maintained in both the fibres. Various tests like Compressive strength, Split tensile strength, Rebound Hammer, Ultrasonic Pulse Velocity, Ball Impact and Load frame test are done in order to study the strength behavior of Partial Fibre Reinforced Concrete Slabs. Based on the final results obtained from the study, it is concluded that both FRC and PFRC behaves similarly under loading conditions and more than 98% of strength of FRC can be achieved by PFRC with up to 50% reduction of fibre volume and cost. Key words: Partial Fibre Reinforced Concrete (PFRC), Steel Fiber, coconut Fiber, Compressive strength, Split tensile strength, Rebound Hammer, Ultrasonic Pulse Velocity, Ball Impact, Load frame test.
CHAPTER 1 INTRODUCTION 1.1
GENERAL
Concrete is strong in compression, as the aggregate efficiently carries the compression load. However, it is weak in tension as the cement holding the aggregate in place can crack, allowing the structure to fail. This weakness had been adjusted over many decades by using a system of reinforcing bars (rebar) to create reinforced concrete; so that concrete primarily resists compressive stresses and rebar resist tensile and shear stresses. In plain concrete and similar brittle materials, micro-cracks develop even before loading, particularly due to drying shrinkage or other causes of volume changes. These internal micro-cracks are inherently present in the concrete and its poor tensile strength is due to the propagation of such microcracks, eventually leading to brittle fracture of the concrete. When loaded, the micro-cracks propagate and open up, and owing to the effect of stress concentration, additional cracks form in places of minor defects. Thus the need for multidirectional and closely spaced reinforcement for concrete arises.
© 2024, IRJET
|
Impact Factor value: 8.226
|
ISO 9001:2008 Certified Journal
|
Page 1883