frc-14102n-gateddddddddddddddddde01.pptx

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1. FIBRE REINFORCED CONCRETE (F.R.C) PREPARED BY MOHAMMAD ABDUL ZUBAIR 160423741008 M.E 1 ST SEMESTER STRUCTURAL ENGINEERING

2. Contents 🠶 History. 🠶 Introduction. 🠶 W hy F i ber s ar e used? 🠶 T ou g hen i ng Me c han i sm. 🠶 T y pe of f i bers. 🠶 Mechan i cal proper t i es of FRC. 🠶 S t ru c t ur a l beha v i or of FRC. 🠶 Fac t ors af f ect i ng proper t i es of FRC. 🠶 A d v an t ages an d D i sad v an t ages of FRC. 🠶 A pp l i cat i ons of FRC . CONCLUSION REFERENCES

3. 🠶 T he u s e of f i ber s goes b ac k a t lea s t 350 years , when straw was used to reinforce sun-baked bricks in Mesopotamia. 🠶 Horsehair was used in mortar and straw in mud bricks. 🠶 Abestos fibers were used in concrete in the early 1900. 🠶 In the 1950s, the concept of composite materials came i nto p i cture. 🠶 Steel , Glass and synthetic fibers have been used to improve the properties of concrete for the past 30 or 40 years. 🠶 Research into new fiber-reinforced concretes continues even today. History

4. Introduction 🠶 Concrete conta i n i n g cemen t , wate r , aggrega t e , a n d discontinuous, uniformly dispersed or discrete fibers is called f i be r re i nforced con c rete . 🠶 I t i s a compo s i te obta i ned b y add i n g a s i n gle t y pe or a blen d of f i ber s to the con v ent i onal con c rete m i x . 🠶 Fibers can be in form of steel fibers, glass fibers, natural f i ber s , synthe t i c f i bers , etc .

5. Why Fibres ar e used? 🠶 Main role of fibers is to bridge the cracks that develop in concrete and increase the ductility of concrete elements. 🠶 T here i s cons i derabl e i mpro v ement i n t he pos t - cra c k i ng behavior of concrete containing fibers due to both plastic shr i nkage an d d r y i ng shr i nkage. 🠶 They also reduce the permeability of concrete and thus reduce bleeding of water. 🠶 Som e t y pe s o f f i ber s pro d u c e grea t er abras i on an d sha t t er res i s t anc e i n con c re t e . 🠶 Impar t s more res i s t anc e t o Impac t loa d .

6. WHY ? Concrete: Brittle Weak In Tension

7. M e c hanism OF To u ghening 🠶 Tou g hness i s a b i l i ty of a m ate r i al t o ab s orb e n ergy and plas t i ca l l y defor m w i thou t fractur i n g . 🠶 It can also be defined as resistance to fracture of a m a ter i a l whe n s t res s e d .

8. Contd.

9. Co N d . Source: P.K. Mehta and P.J.M. Monteiro, Concrete: Microstructure, Properties, an d M a t er i a l s , Th i rd Ed i t i o n , F o u rt h Repr i n t 2 11

10. Types of Fibe r s : St e el f i ber s Glas s f i ber s

11. Carbon Fibers C e l l ul o s e F i ber s

12. Syntheti c Fiber s : Nylon F i ber s Polypropy l e n e Fibers

13. Natural Fiber s : Co i r Hay

14. Stee l fibers 🠶 A spect ra t i os of 3 t o 250 . 🠶 D i amet ers v ar y from . 2 5 mm t o . 7 5 mm . 🠶 H i gh s t ru c t ural s t reng t h . 🠶 Reduced crack widths and control the crack widths tightly, thus i mpro v in g d u rab i l i t y . 🠶 Impro v e i mpact an d abras i on res i s t anc e . 🠶 Used in precast and structural applications, highway and airport pavements, refractory and canal linings, industrial flooring, bridge decks, etc.

15. Glas s Fibers 🠶 H i gh t ens i l e s t reng t h, 1 2 t o 40 8 N/mm 2 🠶 Ge n eral l y , f i ber s of l eng t h 2 5 mm ar e used. 🠶 Impro v ement i n i mpact s t rengt h. 🠶 Increased flexural strength, ductility and resistance to thermal shock. 🠶 Used in formwork, swimming pools, ducts and roofs, sewer l i n in g e t c.

16. Syntheti c fibers 🠶 Man- made fibers from petrochemical and textile industries. 🠶 Cheap, abundantly available. 🠶 H i gh chemi cal res i s t ance. 🠶 H i gh me l t i n g po i n t . 🠶 Lo w modulus of elas t i c i t y . 🠶 It’s types are acrylic, aramid, carbon, nylon, polyester, pol y e t h y lene , pol y prop y lene , e t c. 🠶 A pp l i cat i ons i n clad d i ng p anel s an d sho t cret e .

17. Natural fibers 🠶 Ob t a i ned a t lo w cost an d lo w le v el of energy us i ng local manpower and technology. 🠶 Jute, co i r a n d bam b oo ar e exam p l es. 🠶 T hey may undergo organ i c de c a y . 🠶 Lo w modulus of elas t i c i t y , h i gh i mpact s t reng t h.

18. Types o f Fibers Types Tensile Strength Young' s Modulus Ultimat e Elongation Specific Gravity ( M p a ) ( 10 3 M p a ) ( % ) Steel 27 5 - 2758 200 . 5 - 35 2.50 Glass 1034 - 3792 69 1 . 5 - 3 . 5 3.20 Asbestos 55 1 - 965 8 9 - 138 0.60 1.50 Rayon 41 3 - 520 6.89 1 - 25 1.50 Cotton 41 3 - 689 4.82 3 - 10 1.10 Nylon 85 8 - 827 4.13 1 6 - 20 0.50 Polypropylene 55 1 - 758 3.45 24 1.10 Acrylic 20 6 - 413 2.06 2 5 - 45 0.90

19. Mechanical Proper ties of FRC 🠶 Co m press i v e S t reng t h The presence of fibers may alter the failure mode of cylinders, but the fiber effect will be minor on the improvement of compressive strength values (0 to 15 percent). 🠶 Modulus of Elasticity Modulus of elasticity of FRC increases slightly with an increase in the fibers content. It was found that for each 1 percent increase in fiber content by volume, there is an increase of 3 percent in t he modulus of elas t i ci t y . 🠶 Flexure The flexural strength was reported to be increased by 2.5 times us i ng 4 p e rce n t f i ber s .

20. 🠶 Spli tt i n g T ensi l e S t reng t h The presence of 3 percent fiber by volume was reported to increase the splitting tensile strength of mortar about 2.5 times t hat of t he unre i nforced o n e . 🠶 Toughness For FRC, toughness is about 10 to 40 times that of plain concrete. 🠶 Fa t igu e S t reng t h The addition of fibers increases fatigue strength of about 90 percent. 🠶 I mpact Resis t ance The impact strength for fibrous concrete is generally 5 to 10 times that of plain concrete depending on the volume of fiber.

21. Stru c tural behaviou r of FRC 🠶 Flexure The use of fibers in reinforced concrete flexure members increases ductility, tensile strength, moment capacity, and stiffness. The fibers improve crack control and preserve post cracking structural i n t egrity of mem bers. 🠶 Torsion The use of fibers eliminate the sudden failure characteristic of plain concrete beams. It increases stiffness, torsional strength, ductility, rotational capacity, and the number of cracks with less crack width. 🠶 Hig h S t reng t h Concre t e Fibers increases the ductility of high strength concrete. Fiber addition will help in controlling cracks and deflections.

22. 🠶 Shear Addition of fibers increases shear capacity of reinforced concrete beams up to 100 percent. Addition of randomly distributed fibers increases shear-friction strength and ultimate strength. 🠶 Column The increase of fiber content slightly increases the ductility of axially loaded specimen. The use of fibers helps in reducing the exp l os i v e t y pe fa i lur e for column s . 🠶 Cracking and Deflection Tests have shown that fiber reinforcement effectively controls cracking and deflection, in addition to strength improvement. In conventionally reinforced concrete beams, fiber addition increases stiffness, and reduces deflection.

23. Facto rs affe c ting t he Pr o perties of FRC 🠶 Volum e of f i bers 🠶 Aspect ra t i o of f i ber 🠶 Or i enta t io n of f i b e r 🠶 Relat i v e f i be r m a tr i x s t i ffne s s

24. Volume of fiber 🠶 Low v ol u me fract i on( l ess th a n 1 % ) 🠶 Used in slab and pavement that have large exposed s u rface lead i ng to h i gh shr i nkage cra c k i n g . 🠶 Moderate volume fraction(between 1 and 2 percent) 🠶 Used in Construction method such as Shortcrete & in Structures which requires improved capacity against delam i n a t ion , spall i ng & fat i g u e . 🠶 H i gh v olu m e fract i on( g reater th a n 2 % ) 🠶 Used in making high performance fiber reinforced composites.

25. Aspect R a tio of fiber 🠶 It is defined as ratio of length of fiber to it’s diameter (L/d). 🠶 I ncrease i n the a s pe c t rat i o upto 75 , t here i s i ncrease i n relat i v e s t rength an d tou ghne s s. 🠶 Beyond 75 of aspect ratio, there is decrease in aspect rat i o an d toughnes s . Type of concrete Aspect ratio Rel a tive str e ngth Relative toughness P l a i n co n cr e t e with randomly D i s pe r s e d f i b e rs 1.0 1.0 25 1.50 2.0 50 1.60 8.0 75 1.70 10.50 100 1.50 8.50

26. Orientatio n of fibers 🠶 Al i g n ed i n the d i re c t i on of load 🠶 Aligned in the direction perpendicular to load 🠶 Rand o mly d i st r i bu t i on of f i b e rs 🠶 It is observed that fibers aligned parallel to applied loa d o ffered more tens i l e strengt h an d toughness than randomly distributed or perpendicular fibers.

27. Lo L a o d ad d D i i r re e c c t t io i n on Par a ll e l Pe r p e n d icu l a r Random

28. Relative fiber m atrix 🠶 Modulus of elasticity of matrix must be less than of fibers for eff i c i ent s t ress t rans f er. 🠶 Low modulus of fibers imparts more energy absorption while high modulus fibers imparts strength and stiffness. 🠶 Low modulus fibers e.g. Nylons and Polypropylene fibers. 🠶 H i gh modu lu s f i ber s e. g. S t eel, Glas s , an d C a rb o n f i bers.

29. Advantages of FRC 🠶 High modulus of elasticity for effective long-term re i n force m e n t , e v en i n t h e ha r de n ed co n cre t e. 🠶 Does not rust nor corrode and requires no minimum cover. 🠶 Ideal aspect ratio (i.e. relationship between Fiber diameter a n d l e n g t h ) wh i ch m a ke s t h em excel l e n t for ear l y - age performance. 🠶 Easily placed, Cast, Sprayed and less labour intensive than p l ac i n g re b ar. 🠶 Greater retained toughness in conventional concrete mixes. 🠶 Higher flexural strength, depending on addition rate. 🠶 Ca n be m a de i n t o t h i n s h eet s or i rregu l a r shap es. 🠶 FR C p o ss e ss e s en o ugh p l as t i c i ty t o go under large deform a t i on once t he peak loa d has bee n rea c he d .

30. Disadvantages of FRC 🠶 Greater reduction of workability. 🠶 H i gh cost of ma t er i als . 🠶 Generally fibers do not increase the flexural strength of concrete, and so cannot replace moment resisting or s t ru c t ural s t eel re i nforcemen t .

31. Applications of FRC 🠶 R u nway, Air c ra f t P a rking, an d P a v emen t s . For the same wheel load FRC slabs could be about one half the t h i ckness of p l a i n concret e sla b . FRC pa v emen t s of f ers good resistance even in severe and mild environments. It can be used in runways, taxiways, aprons, seawalls, dock areas, park i ng an d l oad i ng ramps. 🠶 T unnel L i n i ng an d Slo p e S t ab i l i za t ion Steel fiber reinforced concrete are being used to line underground openings and rock slope stabilization. It eliminates the need for mesh reinforcement and scaffolding. 🠶 Dam s an d Hydra u l i c S t ruc t ure FRC is being used for the construction and repair of dams and other hydraulic structures to provide resistance to cavitation and severe erosion caused by the impact of large debris.

32. 🠶 T h i n She l l , Wa l ls , P i pes , an d Manh ole s F i brou s co n cre t e p e r m i t s t h e use of t h i n ner flat a n d cur v ed structural elements. Steel fibrous shortcrete is used in the construct i on of hem i sphe r ica l domes. 🠶 Agriculture It is used in animal storage structures, walls, silos, paving, etc. 🠶 Precast Concrete and Products It is used in architectural panels, tilt-up construction, walls, fencing, septic tanks, grease trap structures, vaults and sculptures.

33. 🠶 Commercial It is used for exterior and interior floors, slabs and parking areas, roadways, etc. 🠶 W arehous e / Ind u s t r i al It is used in light to heavy duty loaded floors. 🠶 Residential I t i ncludes app l i cat i on i n dr i v ewa y s , s i dewalks , poo l cons t ru c t i on, basements, colored concrete, foundations, drainage, etc.

34. Fi b e r Reinfo r ce d Conc r ete N o rmal Reinf o rced concrete H i gh Durab i l i ty Protect st e el from Corros i on L i ghter mater i als More expensive W i th the sam e vo l u m e, the str e ngth i s great e r Less workability Lower Durability Ste e l potent i al to corro s i on He a v i er mater i al Economical W i th the sam e vo l u m e, the str e ngth i s less H i gh w o rkab i l i ty a s c o m pared to FRC.

35. Application of FRC i n Indi a & Abr o ad 🠶 More than 400 tones of Steel Fibers have been used in the construction of a road overlay for a project at Mathura (UP). 🠶 A 4 km long district heating tunnel, caring heating pipelines f r om a p ower plan t on t h e i slan d A mager i n t o t he c e n t er of Cop en h agen , i s l i ned w i t h SF C segme n t s w i t hout any con v en t iona l s t eel bar re i nforcemen t . 🠶 Steel fibers are used without rebars to carry flexural loads at a parking garage at Heathrow Airport. It is a structure with 10 cm t h i ck sla b . 🠶 Precast fiber reinforced concrete manhole covers and frames ar e be i ng w i dely used i n Ind i a.

36. Pa v e me n t w it h s t ee l f i br e r e i n for c e d con cr e t e

37. 🠶 In c rease i n compre s s i v e s t rengt h of con c re t e: ⦿ Spec i me n s w i t hout any f i ber s a f t er compress i on test Spec i me n s w i t h f i bers aft e r compress i on t est

38. 🠶 Increase in tensile strength of concrete: ⦿ Spec i me n s w i t hout any f i ber s a f t er sp l i t t ens i l e test. Spec i me ns w i t h f i bers a f t er sl i p t ens i l e t es t .

39. 🠶 Increase in impact strength of concrete: ⦿ Spec i me n s w i t hout any f i ber s a f t er compress i on test Spec i me n s w i t h f i bers aft e r compress i on t est

40. 🠶 In c rease i n shea r s t rengt h of con c re t e: ⦿ Spec i me n s w i t hout any f i ber s a f t er shea r t es t . Spec i me n s w i t h f i bers aft e r s h ear t es t .

41. GFRC project at Trillium Building Woodland Hills, California

42. Footbridge in Fredrikstad, Norway

43. SFRC used at Tehri Dam, Uttarakhand

44. Con c lu s ion 🠶 The total energy absorbed in fiber as measured by the area under the load-deflection curve is at least 10 to 40 times higher for fiber-reinforced concrete than that of plain concrete. 🠶 Addition of fiber to conventionally reinforced beams increased the fatigue life and decreased the crack width under fat i gue load in g . 🠶 At elevated temperature SFRC have more strength both in compress i on an d t ens i o n . 🠶 Cost savings of 10% - 30% over conventional concrete flooring systems.

45. Refe r ences 🠶 K . Sr i n i v as a Ra o , S.Rakesh kumar, A.Laxmi Narayana, Comparison of Performance of Standard Concrete and Fibre Reinforced Standard Concrete Exposed To Elevated Temperatures , American Journal of Engineering Research (AJER), e-ISSN: 2320-0847 p-ISSN : 2320-0936, Volume-02, Issue- 03 , 201 3 , pp - 20 - 26 🠶 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, A mer i c a n Concrete Ins t i t ute, Detro i t , MI , 2 2 pp