Steel fibre reinforced_concrete

Steel fibre reinforced concrete

1. PRESENTED BY SIDDHARTH 1DS13CV139 STEEL FIBRE REINFORCED CONCRETE GUIDED BY DINESH B.R DEPT. OF CIVIL ENGINEERING Dayananda sagar of engineering college

2. CONTENTS Introduction Why to use FRC Classification of FRC Steel fibre reinforced concrete(SFRC) Types of SFRC Composition of SFRC Solution Mixing Properties of concrete improved by steel fibres Limitation of SFRC Application of SFRC Conclusion References

3. INTRODUCTION Fibre Reinforced concrete Fibre reinforced concrete is a composite material consisting of mixtures of cement, mortar and discontinuous, discrete, uniformly dispersed suitable fibres .

4. Why to use FRC Plain concrete - brittle material with limited ductility low tensile strength and strain capacity i nternal micro-cracks are present in that concrete. The role of randomly distributed fibres - to build bridge across the cracks and to provide some post-cracking ductile m ore tougher m ore impact resistance m ore load carrying load

5. CLASSIFICATION OF FRC STEEL FIBRE REINFORCED CONCRETE(SFRC) GLASS FIBRE REINFORCED CONCRETE(GFRC) SYNTHETIC FIBRE REINFORCED CONCRETE(SNFRC) NATURAL FIBRE REINFORCED CONCRETE(NFRC ) Recently some new FRC named High Performance Fibre Reinforced Concrete (HPFRC) and Ultra High Performance Fibre Reinforced Concrete (UHPFRC ) have introduced which shows significant changes over plain concrete.

6. DIFFERENT TYPES OF FRC STEEL FIBRE GLASS FIBRE SYNTHETIC FIBRE NATURAL FIBRE

7. STEEL FIBRE REINFORCED CONCRETE IN steel fibre reinforced concrete we use steel as the fibre for reinforcing so it is called as steel fibre reinforced concrete (SFRC)

8. TYPES OF STEEL FIBRE STRAIGHT STEEL FIBRE CRIMPED STEEL FIBRE STRANDED STEEL FIBRE HOOKED STEEL FIBRE TWISTED STEEL FIBRE

9. COMPOSTION OF STEEL FIBRE G enerally includes carbon steel or stainless steel. T he length dimension ranges from 6.4mm to 76mm while the diameter ranges 0.25mm to 0.75mm. T he steel fibres are described by a convenient parameter “aspect ratio”. The aspect ratio is determined by length to diameter ratio. It varies from 20 to 100 .

10. STEEL FIBRE

11. SOLUTION: STEEL FIBRE REINFORCED CONCRETE

12. MIXING Water, cement, aggregates and sand were mixed for 2 minutes, then steel fibres slowly added. Internal vibration was used for the compaction of concrete or prismatic specimens. Slabs used external vibrations. Covered with wet cloths. Kept at 65% humidity.

13. PROPERTIES OF CONCRETE IMPROVED BY STEEL FIBRES Compressive strength Ultimate strength is only slightly affected by the presence of steel fibres. Increases compressive strength from 0 to 15%.

14. SFRC:PROPRETIES Tensile strength In direct tension, the improvement in strength from 30-40% In split tensile strength increase from 10-45%.

15. SFRC:PROPERTIES FLEXURAL STRENGTH Much greater than in tension or compression because of ductile behaviour. It changes from 20-100% for addition up to 3% by total volume of fibres .

16. FLEXURAL

17. SFRC:PROPERTIES IMPACT Under flexural impact loading the peak load for SFRC is 40% higher than the normal concrete .

18. LIMITATION OF SFRC More precise compared to normal concrete. Unless SF are added in adequate quantity, the desired improvement cannot be obtained. Massive change in the total cost of the construction. Corrosion of the surface. Proper proportion of steel fibres not used having a problem in finishing with fibres coming out.

19. APPLICATION OF SFRC Industrial flooring Canal linings Highway and airport pavements Precast applications- wall and roofs panels, pipe, boats, staircase & manhole covers Structural applications

20. CONCLUSION The efficient utilization of fibrous concrete involves improved static and dynamic properties like tensile strength, energy absorbing characteristic , impact strength and flexural strength . At elevated temperature SFRC have more strength both in compression and tension . Cost savings of 10% - 30% over conventional concrete flooring systems.

21. REFERENCES Abid A. Shah, Y. Ribakov , Recent trends in steel fibered high-strength concrete , Elsevier, Materials and Design 32 (2011), pp 4122–4151 ACI Committee 544. 1990. State-of-the-Art Report on Fiber Reinforced Concrete .ACI Manual of Concrete Practice, Part 5, American Concrete Institute, Detroit,MI , 22 pp C.H. Henager , “Steel fibrous shotcrete ”. A summary of the State – of – the art concrete Int. : Design and construction 1981. J. Endgington , D.J. Hannant & R.I.T. Williams, “Steel fiber reinforced concrete” Current paper CP 69/74 Building research establishment Garston Watford 1974. C.D . Johnston, “Steel fiber reinforced mortar and concrete”, A review of mechanical properties. In fiber reinforced concrete ACI – SP 44 – Detroit 1974. R.J . Craig, “Structural applications of reinforced steel fibrous concrete”. Concrete Int. Design and Construction 1984.