Behavior of frc under static & impact loads

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BBEHAVIOR EHAVIOR OOF F FRCFRC

BBEAMS EAMS UUNDER NDER

DDIFFERENT IFFERENT LLOADSOADS

By Mohannad M. Abdul-AzizSupervised By Dr. Mazin B. Abdul-Rahman

January 2009

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Fibers in Concrete

• The choice of fibers to use should be made based on what properties are required from the concrete, like:

1.1. Reduce bleedingReduce bleeding

2.2. Improving impact resistanceImproving impact resistance

3.3. Flexural toughness Flexural toughness

4.4. Freeze thaw resistanceFreeze thaw resistance

5.5. Fire resistance Fire resistance

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Range of load versus deflectionRange of load versus deflection

curves for unreinforced matrix curves for unreinforced matrix and fiber reinforced concreteand fiber reinforced concrete

1. Fibers in concrete

Behavior of FRC beams under different Behavior of FRC beams under different loadsloads

Mechanism involved in Mechanism involved in Fiber operationFiber operation

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• Synthetic fibersSynthetic fibers are man-made fibers are man-made fibers resulting from research and resulting from research and development in the petrochemical development in the petrochemical and textile industries.and textile industries.

• SyntheticSynthetic Fiber types Fiber types that have been that have been tried in portland cement concrete tried in portland cement concrete are: carbon, nylon, polyester, are: carbon, nylon, polyester, polyethylene and polyethylene and polypropylenepolypropylene..

2. Using different types of fibers in concrete


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Behavior of FRC beams under different Behavior of FRC beams under different loadsloads2. Using different types of fibers in concrete



Examples of commercially available fibers Examples of commercially available fibers



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cross-sectional geometries of fiberscross-sectional geometries of fibers some typical fiber geometriessome typical fiber geometries

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1.1.Polypropylene FiberPolypropylene Fiber

• PolypropylenePolypropylene fibers, the most popular of the synthetics.

• PolypropylenePolypropylene is hydrophobic, meaning it does not absorb water.




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PolypropylenePolypropylene fibers are produced either as (left) fine fibres with rectangular cross section or (right) cylindrical monofilament.



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2.2. Steel FiberSteel Fiber

• fiber length varies from (12.7 mm) to (63.5 mm). The most common fiber diameters are in the range of (0.45 mm) to (1.0mm).

• steel fibers have shapes which include round, rectangular, and crescent cross sections, depending on the manufacturing process and raw material used.




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Steel fibers with hooked endsSteel fibers with hooked ends



Fracture surface of SFRCFracture surface of SFRC




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- Concrete is a veryConcrete is a very

brittle material.brittle material.

- The role of randomly The role of randomly

distributes discontinuousdistributes discontinuous

fibres is to bridge across fibres is to bridge across

the the crackscracks..



-But why do we need-But why do we need fibers in concretefibers in concrete

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• The real contribution of the fibres is to The real contribution of the fibres is to

increase the increase the flexural toughnessflexural toughness of the of the

concreteconcrete

((defined as defined as

some function of thesome function of the

area under the loadarea under the load

vs. deflection curvevs. deflection curve), ),

under any type ofunder any type of

loading.loading.



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A- Theoretical Part

1. Static Analysis for prepared beam samples.

– (using ANSYS 11.0 (2007) ProgramANSYS 11.0 (2007) Program)

2. Impact Resistance Analysis for prepared

beam samples.

– (using DARC III DARC III Nonlinear transient dynamic Nonlinear transient dynamic

analysis for three dimensional structuresanalysis for three dimensional structures

ProgramProgram)

To compare the result with the experimental works

3. Research working plane

Behavior of FRC beams under different Behavior of FRC beams under different loadsloadsBehavior of FRC beams under different Behavior of FRC beams under different loadsloads

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B- Experimental Works– Material that will be used:

• Cement

• Aggregate

• Sand

• Fiber (PPF) (length 12mm) (SikaFiber)

• Fiber (steel) (length 30mm) (Sika Company)

• Super plasticizer (Water reducer) (Sikament-HRWRA-FFN)

• Silica fume (Sikafume-HR)



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3. Research working plan


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Fiber (PPF) (length 12mm) Fiber (PPF) (length 12mm)

(product by Sika Company)(product by Sika Company)

• Sika FibreSika Fibre is based on high quality monofilament micro polypropylene fibers.

• Appearance/ Colors: White• Packaging: 600g bags at box of 40 bags• Compatibility: Sika FibreSika Fibre can be used with

all Sika® admixtures.

• meeting the requirements of: ACI 544-1& 2RACI 544-1& 2R.



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Super plasticizer SP (Water reducer) Super plasticizer SP (Water reducer) (Sikament-HRWRA-(Sikament-HRWRA-FFNFFN))


• high-range water-reducing admixture (HRWRA) meeting the requirements of:

• ASTM C494 Type FASTM C494 Type F or GG or ASTM C 1017 Type IASTM C 1017 Type I or IIII.• Chemical Base: Melamine sulphonate polymer based

liquid• Compatibility: Sikament FFN can be used with

Sika Fiber & Sika fume .



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• Why we usedWhy we used

superplasticizersuperplasticizer

- SP can be used in concrete to :

• Get Higher slump without additional water,

• lower w/c at equivalent slumps,

• improved workability,

• increase strength by decreasing (w/cm)



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Silica Fume SF (Sikafume-HR)Silica Fume SF (Sikafume-HR)


• SikaFumeSikaFume is a concrete additive in powder is a concrete additive in powder

form based on silica fume technology.form based on silica fume technology.

• Meeting the requirements of: ACI Committee ACI Committee

234234

• Appearance / Colour: Grey to dark grey powder


Behavior of FRC beams under different Behavior of FRC beams under different loadsloads3. Research working plan


21As-produced powderAs-produced powder



Water-based slurryWater-based slurry

- Silica Fume Product - Silica Fume Product Forms: Forms:



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Premium -- White

Standard -- Grey

- Silica Fume - Silica Fume Colors:Colors:


Behavior of FRC beams under different Behavior of FRC beams under different loadsloads3. Research working plan


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• Why we used silica fumeWhy we used silica fume

• Improve the transition zone wich is represented as a thin layer between the bulk hydrated cement paste and the aggregate particles in concrete. This zone is the weakest component in concrete.

• Provide concrete with very high compressive strength

• Enhancing Mechanical Properties due to its extremely small particle size, and large surface area

• Improving Durability



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• Mix Design: Mix Design: A- Trial Mix: (to get Ref. mix) 1. Fix w/c (to get compressive strength at least 40 Mpa)2. Record slump (200mm ± 5mm) according to slump test (ASTM C 143) 3. Casting:- Cubes (150*150*150)mm- Prisms (100*100*50)mm - Impact rings (152 Dia.*63.5 t)mm

- Beams (ReferenceReference)



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B- Mixes work:1. Mix No. (1)

Ref. + SP (optimum dosage) + SF (optimum

dosage)

- Getting the optimum dosage from SP & SF:- Adding SP (as a percentage by weight of

cement) to reach the same slump of the Ref. mix. - Then adding SF (as a percentage by weight of

cement) to reach the same slump of the Ref. mix.- Record the optimum dosages.- w/c will be reduced due to the effect of SP (as a

chemical ad.) and SF (as a mineral ad.).



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• SPSP used demand:

• Increase workability that has been decreased with the addition of fibers.

( Balling—When fibers entangle into large clumps or balls in a mixture.)

• Silica fume addition usually increases water demand.

• SF SF used demand:

• to improved bond strength in the concrete matrix by increasing the paste to-fiber bond.



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2. Mix No. (2) Mix No.(1) + 0.5 % from PPF (as a VF)3. Mix No. (3) Mix No.(1) + 0.75 % from PPF (as a VF)4. Mix No. (4) Mix No.(1) + 1.5 % from PPF (as a VF)5. Mix No. (5) Mix No.(1) + (50%) 0.5 % from PPF (VF)+(50%) 0.5 % from Steel Fiber (VF)6. Mix No. (6) Mix No.(1) + (50%) 0.75 % from PPF (VF)+(50%) 0.75 % from Steel Fiber (VF)

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7. Mix No. (7) Mix No.(1) + (50%) 1.5 % from PPF (VF)+ (50%) 1.5 % from Steel Fiber (VF)

- For each mix we will cast (at least): ( 33 beams beams ) and ( 33 prisms prisms )



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• Samples Testing:Samples Testing: 1- Static TestStatic Test: by the Universal machine for cubes, prisms and beams.



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2- Impact test:• Improved impact resistance (dynamic energy absorption as well as strength) is one of the important topics of FRC.

• The simplest of the impact tests is the “repeated impact,” drop-weight test.

• The hammer is dropped repeatedly, and the number of blows required to cause the first visible crack on the top and to cause ultimate failure are both recorded.



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Steel frame (impact resistance test) for beam samples

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Thank youThank you

Behavior of frc under static & impact loads

Education

different types of fibers

behavior of frc beams

different loads3

different loads2

concrete concrete

concrete synthetic fibers

concretesteel fibers

concretepolypropylene