Mono and Fibril Brand Microsynthetic Fibres for Industrial Floors

MONO AND FIBRIL FIBRESPP Microfibers in terms of concrete durability and industrial concrete floors

CİHAN ERDOĞAN Sales Engineer

CONTEXT• BRIEF HISTORY

• MICRO SYNTHETIC FIBRES

• CONCRETE FIBRES

• POLYPROPYLENE

• DURABILITY

• SHRINKAGE AND PERMEABILITY

• CONCRETE FLOOR DURABILITY

• MONO FIBRES AND FIBRIL FIBERS

• FIBER REINFORCED CONCRETE (FRC)

• BENEFITS

• ADDING FIBERS

• CONCLUSION

• Q/A

BRIEF HISTORY

• In 1960s, fiber reinforced concrete comes into life with the

publication of Romualdi, Batson and Mandel. It was an era for

concrete technology.

• 1980s polypropylene fibers has been started to use as an cost

effective alternative in terms of crack controlling. Until that

moment alkali resistant fibers were used for crack controlling.

• All this time lots of fiber reinforcement fibers have been

developed and their usage depends on the intended purpose of

concrete.

WHAT IS MICRO SYNTHETIC FIBRES?

The European standard for polymer fibres is EN 14889-2.Part 2 covers fibre manufactured from polymeric materials.It divides polymer fibres into two classes:

• Class I: micro-fibres, < 0,30mm in diameter. These caneither be monofilament or fibrillated.

• Class II: macro-fibres, ≥ 0,30mm in diameter. These havethe same dimensions as steel fibres.

WHAT IS MICRO SYNTHETIC FIBRES?

Typical properties of microsynthetic fibres include;

• Generally made of polypropylene;

• The cross section can be circular, rectangular or elliptical; The crosssection, together with the surface characteristics, Young´s modulusand the tensile strength, determine the bond between the fibres andthe concrete;

• Polymer fibres are resistant to the high alkalinity of concrete;

• Micro-polymer fibres can contribute to fire resistance, and resistanceto plastic shrinkage depending on the length and the fibre content.These are selected according to the maximum size of aggregate and tothe specified engineering requirements.

CHARACTERISTICS OF ALL CONCRETE FIBRES

• Alkali resistance

• Sufficient Fiber Count

• Homogeneous Distribution

• Lower dosage

• Cost Effectiveness

WHY POLYPROPYLENE?Table. Physical properties of commonly used fibers in concrete materials*

WHY POLYPROPYLENE?

Lowest specific gravity in all synthetic fiber types. This

means highest fiber counts comparing to other synthetic

fibers.

Enough young modulus for crack controlling.

Best elongation capacity by %25.

Lowest price per kg.

DURABILITY

• Durability - the ability of a material to resistweathering action, chemical attack, abrasion, andother conditions of service (ACI Terminology).

• Physical factors effects to durability are Creep,shrinkage, permeability, rheology and electricalproperties.

SHRINKAGE AND PERMEABILITY

• Shrinkage and permeability are important factors to beconsidered in the design process.

• Shrinkage and permeability properties of concrete wouldcause cracking results.

• Cracking reduces service life of concrete. This service lifechange depends on the concrete structure environment. Ex.A chemical company floor would have a short service lifebecause of cracks. Harmful chemicals would penetratedeeper parts of the concrete structure.

SHRINKAGE

• Shrinkage: Decrease in either length or volume of amaterial resulting from changes in moisture content orchemical changes. (ACI Concrete Terminology)

• Shrinkage can cause cracks related to the stress composed.

• Mainly two types of shrinkage cracks in Concrete; Plastic Shrinkage Cracking: It happens on the surface of fresh

Concrete.

Restrained shrinkage cracking: It happens in Hardened State ofConcrete.

PLASTIC SHRINKAGE CRACKING

• Plastic shrinkage cracking is caused by moisture loss aftercasting.

• Generally if the moisture evaporation rate exceeds 0,5 kg/m².h,it causes negative capillarity pressure inside the concrete,resulting in internal strain. This means there is a risk to haveplastic shrinkage crack on the surface of concrete structure.

• It is very important for high temperature climates and stormyweathers.

PLASTIC SHRINKAGE CRACKING

Factors effects the moisture loss on the concrete surface;

• Concrete Temperature• Relative humidity rate• High wind speed• Ambient Temperature

SHRINKAGE

Uşaklıgil Factory Concrete Floor, Dilovası/ Kocaeli

SHRINKAGE

• This graphic was publishedby Portland CementAssocaition. It can be usedfor prediction of moistureloss of the Concrete withdifferent weatherconditions.

PERMEABILITY• Permeability- the ability of a given concrete to permit

liquids or gases to pass through. (ACI Terminology)

• Concrete is susceptible to degradation through corrosion,alkali-silica reaction, sulfate attack, freezing-and-thawingdamage, and other mechanisms that results from theingress of water.

• Concrete durability is intimately related to the rate atwhich water is enable to penetrate it. We call it waterpermeability.

PERMEABILITY• The most well known permeability related cracks are

corrosion cracks.

• Corrosion produces rusts on the steel reinforcement.

• A rust can be 10 times bigger of the corroded area. Itcauses additional stress in every direction in the concrete.

Schema of the rust attacked area on the rebar

Factors Related to Industrial Concrete Floor Durability• High humidity and rain

• Freezing and Thawing Resistance

• Chemical Resistance

• Resistance to Sulfate Attack

• Chloride Resistance and Corrosion

• Resistance to Alkali-Silica Reaction

• Abrasion Resistance

MONO FIBRES

• Composition 100% virgin polypropylene

• Type Monofilament• Cross section Round• Tensile strength (TS) 600-700 MPa• Young’s modul (TS/E) 3000-3500

Mpa• Elongation (E) 20-25%• Specific density 0.91 g/cm3

• Alkali resistance Excellent

MONO FIBRES

Available Lengths Areas of Usage

Mono 3 (3mm length) Repair Mortars, Plasters

Mono 6 (6mm length) Repair Mortars, Plasters, Various construction

chemicals

Mono 12 (12mm length) Screed concrete, Shotcrete Application, Tunnelling,

Residential Building Projects, Coating Concrete

Mono 18 (18mm length) Industrial Floor Applications, Field Concrete, Precast

Applications

FIBRIL FIBERS

• Composition 100% virgin

polypropylene

• Type Fibrillated Form

• Cross section Rectangular

• Tensile strength (TS) 300-400 MPa

• Young’s modul (TS/E) 1.000-2.500

MPa

• Elongation (E) 20-25%

• Specific density 0.91 g/cm3

• Alkali resistance Excellent

FIBRIL FIBERS

Available Lengths Areas of Usage

Fibril 6 (6mm length) Construction Chemicals, Refractory Applications

Fibril 12 (12mm length) Industrial Floor Applications, Field Concrete and Parking

Lots, Precast Applications, Shotcrete Applications,

Tunnel-Dam Projects, Refractory Applications

Fibril 18 (18mm length) Industrial Floor Applications, Field Concrete and Parking

Lots, Precast Applications, Shotcrete Applications,

Tunnel-Dam Projects, Refractory Applications

Fiber Reinforced Concrete (FRC)

• Concrete containing dispersed, randomly oriented fibers (ACITerminology).

Benefits of synthetic fibre reinforced FRC;

• Improve mix cohesion, improving pumpability over long distances

• Improve freeze-thaw resistance

• Improve resistance to explosive spalling in case of a severe fire

• Improve impact resistance– and abrasion–resistance

• Increase resistance to plastic shrinkage

• Reduce crack widths and control the crack widths tightly, thus improvingdurability

BENEFITS• Microfibers provide the best solution in concrete technology to

prevent plastic shrinkage cracking.

• Polypropylene microfibers make bridges between the aggregates.

• Additional tensile forces will occur in the concrete due to thenegative capillarity pressure.

• These bridges bear tensile stress that is related to plasticshrinkage.

• Researches show that 0,2% volume fraction of polypropylenemicrofibers provide reasonable control of plastic shrinkagecracking (reducing to 10%).

BENEFITS

• Fiber reinforcement influences the way cracks developin concrete and improves surface roughness ofindividual cracks.

• Fiber initiates crack branching, a lower waterpermeability would be resulted.

• This prevents corrosion of the conventional steel inthe concrete structure.

BENEFITS• To directly investigate the effects of fibers have on the durability of

concrete structures, Sanjuan et al. (1997) included PP fibers in the coverover conventional steel reinforcement.

• Mortar was cast around steel bars in specimens that were then exposedto restraint shrinkage conditions immediately after casting.

• The specimens were ponded with a chloride ion-rich solution while therate of corrosion in the steel was monitored.

• As a result fiber-reinforced matrixes cracked less and demonstratedlower corrosion rates showing the direct impact of fibers onpermeability-related deterioration mechanisms.

ADDING FIBERS• Fibres can be added directly into the truck mixer, or, to optimise

dispersion, into the plant mixer.

• A minimum mixing time of five minutes (or one minute per m³) at the maximum speed of the drum is required.

• Microfibers effects the slump of the FRC. Advised levels vary from 50 to 125 mm slump.

CONCLUSION

• Microsynthetic fibers has diameter lower than 0,30mm.

• Important features such as tensile strength, Young’s modulus,elongation, density, alkali resistance.

• Important characteristics for all types of concrete fibers are alkaliresistance, sufficient fiber count, homogenous distribution, lowerdosage rate and cost effectiveness.

• Polypropylene has the best physical features in order to controlcracking.

CONCLUSION

• Durability is a phenomenon which defines the quality andservice life of concrete material.

• Shrinkage and permeability are important factors toenhance concrete durability.

• Microsynthetic fibers are the best solution to preventshrinkage and permeability related cracks.

• Mono and Fibril fibers provide most of the industrialconcrete floor durability requirements.

Mono Fibers reinforced concrete floor- Friterm Factory