5 polymer fiber

Fiber Reinforced Concrete:

“FRC is defined as a composite material consisting of concrete reinforced with discrete randomly but uniformly dispersed short length fibers.”

Fibers are generally discontinuous, randomly distributed through out the cement matrices.

Enhances flexural and tensile strength of the concrete.

Fibers may generally be classified into two: organic and inorganic.

Contd. ….

Volume fraction – measure of fiber in concrete.

Typically ranges from 0.1 to 3%.

Aspect ratio - fiber length (l) divided by its diameter (d).

Main categories of F.R.C.

SFRC - Steel Fiber Reinforced Concrete.

GFRC - Glass Fiber Reinforced Concrete.

SNFRC - Synthetic Fiber Reinforced Concrete.

NFRC - Natural Fiber Reinforced Concrete.

POLYMER FIBER REINFORCED CONCRETE (PFRC)

It comes under the category of Synthetic FRC.

Mainly preferred due to its cost effectiveness and zero corrosion risk.

This method has been recognized and approved by BIS, IRC and various national bodies.

Why PFRC for pavements?

Crack arresters-restricting the development of cracks .

Enhanced flexural strength and tensile strength of concrete.

Improved early resistance to plastic shrinkage cracking.

Improved durability and reduced surface water permeability of concrete.

Reduces the risk of plastic settlement cracking over rebar.

Cont. ….

It enables easier and smoother finishing.

Reduced bleeding of water to surface during concrete placement.

Improves the homogeneity of the concrete matrix.

Reduced water absorption.

Greater impact resistance.

The two components of PFRC

Concrete Mix

The code IRC: 44-2008 – For cement concrete mix designs for pavements with fibers.

In presence of fly ash – cement savings upto 35%.

Flexural strength- 40 MPa at 28 days.

2) Polymer fibers

Recron 3S, Polypropylene, Forta ferro, Forta econo net.

Recycled polymer waste from plastic, carpet industry, textile industry, disposed tires.

Size 12mm long and 0.045 mm diameter.

Mixed at the rate of 900gms/m3 of concrete.

Various polymers used in PFRC

PAVEMENT DESIGN

PAVING OPERATION

REQUIREMENTS FOR PAVING OPERATIONS

1) Use of microfilm or antifriction layer of 125 micron in between PFRC and DLC layers.

2) The DLC layer is to be swept clean before applying microfilm .

3) Film is nailed to the DLC layer without wrinkles and holes.

4) Concreting work in hot weather should be carried out in early or later hours.

5) The laying temperature of concrete should always be below 35 degree Celsius.

CURING

Membrane curing is used.

Texture-[censored]-curing machine performs the task.

The resin based curing compound is used at the rate of 300 ml per square meter of the slab area.

After about 1.5 hours moist Hessian cloth is spread, covered with curing compound spray.

Water curing by keeping the Hessian moist by sprinkling water is ensured for 3 days.

Completed PFRC pavement

PROTECTION AND MAINTENANCE

Insert performed neoprene sealant to protect joint groove from dirt .

Test are to be conducted on fine and coarse stone aggregates, water, cement, granular sub base, DLC etc as per standards and specification published by Indian roads congress.

No vehicular traffic until the completion of 28 days of curing, sealing of joints and completion of paved shoulder construction.

POLYESTER FIBER WASTE IN PFRC

The tests resulted in the following inferences:

1. The polyester FRC in thicknesses of 100mm or more can be used.

2. The use of polyester fibers increases the abrasion resistance of concrete by 25%.

3. The polyester fibers are resistant to the strong alkaline conditions in concrete.

4.There is no decrease in long term compressive strength or UPV of PFRC.

5. The results of this study promote effective disposal of these non bio-degradable synthetic fibers.

Advantages of PFRC

PFRC roads are highly impermeable to water.

Implementation of sensors in roads will be easier.

Environmental load of PFRC pavement was found to be significantly lower.

Maintenance activities are reduced.

Impermeable and more durable, skid resistant pavement.

Cont. ….

Fibers reduce plastic shrinkage and substance cracking.

Improved abrasion resistance and impact resistance.

Ductile and flexural toughness of concrete.

Cement saving up to 10%

Improve durability of concrete

Disadvantages of PFRC

Fibers which are too long tend to “ball” in the mix and create workability problems.

The use of PFRC, being a relatively new technology poses a threat of a high initial cost of construction.

In case the road breaks, the whole concrete slab needs to be replaced.

COMPARISONS BETWEEN PFRC AND NORMAL CONCRETE

APPLICATIONS OF PFRC

Slab On Grade.

Structural Concrete.

Water retaining Structures.

Water proofing in rooftops, sunken toilets, etc.

Kerala based projects using PFRC

CIAL Airports: Turning Pad Concrete, New Arrival Bldg, Cargo storage complex.

ICTT Vallarpadam: Jetty Construction 8000 cubic mtr slab/Simplex infra.

Cochin Port Trust: Mattancherry Warf, NCB, UTL etc.

MES: GE Air Force – Tvm Projects, DGMAPs Projects Cochin

Southern Railway: Platforms at Quilon, Kochuveli, etc.

Harbour Engineering Dept: Vipin Jetty wearing coat.

CONCLUSION

PFRC can be used advantageously over normal concrete pavement.

PFRC requires specific design considerations and construction procedures to obtain optimum performance.

Reduction in maintenance and rehabilitation operations, makes PFRC cheaper than flexible pavement by 30-35%.

Promote effective disposal of non bio-degradable synthetic fibers.

A new hope to developing and globalizing the quality and reshaping the face of the “True Indian Roads”.

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4. Natural fiber

Information on mechanical properties of unprocessed natural fibers is available. In this section, a brief summary of the results of research to determine the mechanical properties of various types of unprocessed natural fibers is presented. The types of fibers for which the mechanical properties have been evaluated are given in the table below. A brief description for some of the more commonly found natural fibers is presented:

a. Coconut fiber: A mature coconut has an outer covering made of fibrous material. This part of the coconut, called the husk, consists of a hard skin and a large amount of fibers embedded in a soft material. The fibers can be extracted simply by soaking the husk in water to decompose the soft material surrounding the fibers. This process, called retting, is widely used in the less developed countries. Alternatively, a mechanical process can be used to separate the fibers. Coconut cultivation is restricted to the tropical regions of Africa, Asia, and Central America.

b. Sisal fiber: In Australia, sisal fibers have been successfully used for making gypsum plaster sheets. A considerable amount of research has been carried out in Sweden for developing good quality concrete products reinforced with sisal fibers. These fibers are stronger than most of the other natural fibers, as can be seen from the table below.

c. Sugar cane bagasse fiber. Sugar cane is cultivated in both tropical and sub-tropical regions. Sugar cane bagasse is the residue remaining after the extraction of the juice and contains about 50 percent fiber and 30 percent pith with moisture and soluble solids constituting the remaining 20 %. In order to obtain good quality fibers, the pith and other solids are removed from the fibers. The properties of bagasse fibers depend, to a very large extent, on the variety of the sugar cane, its maturity, and on the efficiency of the milling plant. The properties given in the table below are considered to be typical.

d. Bamboo fiber: Bamboo belongs to the grass family and can grow to a height of 15 m with diameters varying within the range of 25 to 100 mm. It grows naturally in tropical and sub-tropical regions. Dried bamboo stems are commonly used for building temporary structures such as scaffolding. They may also be fabricated to form a continuous reinforcing material for concrete. Bamboo fibers are strong in tension (table below) and can be used as a reinforcing material. However, they have a high water absorption capacity, low modulus of elasticity, and special equipment may be needed to extract them from the stems.

e. Jute fiber: Jute is grown mainly in India, Bangladesh, China, and Thailand. It is grown solely for its fiber, which is traditionally used for making ropes and bags to transport grains and other materials ranging from cement to sugar. Strong in tension (table below), jute fiber can also be used in a cement matrix. The process of obtaining jute fibers is very simple. Mature plants are cut and soaked in water for about four weeks, which completely decomposes the bark. The fibers thus exposed are then stripped from the stem, washed, and dried.

f. Flax: Flax is a slender and erect plant grown mainly for its fiber. Both the tensile strength and the modulus of elasticity of flax are extremely high compared to those of other natural fibers, as may be seen from the table below.

g. Other vegetable fibers: Of the various vegetable fibers, only a few have been found to be potentially suitable as reinforcing materials. The mechanical properties of the more promising fibers, namely elephant grass, water reed, plantain, and musamba, are listed. Investigations have also been carried out to explore the possibility of using other natural fibers such as palm fiber and akwara fiber as reinforcing materials for concrete. These fibers are usually removed manually from the stem of the plant.

3. Synthetic fiber

Synthetic fibers specifically engineered for concrete are manufactured from man-made materials that can withstand the long-term alkaline environment of concrete. Synthetic fibers are added to concrete before or during the mixing operation. The use of synthetic fibers at typical addition rates does not require any mix design change.

Why use?

Synthetic fibers benefit concrete in both the plastic and hardened states. Some of the benefits include:

® Reduced plastic settlement cracks

® Reduced plastic shrinkage cracks

® Lowered permeability

® Increased impact and abrasion resistance

® Increased shatter resistance

Some synthetic fibers may be used as secondary reinforcement (Hardened Concrete Performance Documentation required).

2. Glass fiber

Definition: A family of reinforcing materials for reinforced plastics based on single filaments of glass ranging in diameter from 3 to 19 micrometers (0.00012 inch to 0.00075 inch). Single filaments are produced by mechanically drawing molten glass streams. Next, the filaments are usually gathered into bundles called strands or rovings. The strands may be used in continuous form for filament winding; chopped into short lengths for incorporation into molding compounds or use in spray-up processes; or formed into fabrics and mats of various types for use in hand coatings with a material known as a coupling agent, which serves to promote adhesion of the glass to the specific resin being used. Glass fiber reinforcements are classified according to their properties. At present there are five major types of glass used to make fibers. The letter designation is taken from a characteristic property: 1) A-glass is a high-alkali glass containing 25% soda and lime, which offers very good resistance to chemicals, but lower electrical properties. 2) C-glass is chemical glass, a special mixture with extremely high chemical resistance. 3) E-glass is electrical grade with low alkali content. It manifests better electrical insulation and strongly resists attack by water. More than 50% of the glass fibers used for reinforcement is E-glass. 4) S-glass is a high-strength glass with a 33% higher tensile strength than E-glass. 5) D-glass has a low dielectric constant with superior electrical properties. However, its mechanical properties are not so good as E-or S-glass. It is available in limited quantities. Glass fibers coated with nickel, by the electron beam deposition process, are used in molding compounds and as reinforcements for electrically conductive parts. The major disadvantage of glass fiber is its unidirectional reinforcement which leads to uneven shrinkage and warpage.

1. Steel fiber details

Harde provides stainless steel and galvanized steel engineering fiber for construction in various types and sizes. For over a decade, we have been concentrating on development and manufacture of steel fiber and steel band products.

Choose from the following list to learn more about our commodities. A more complete description of these products is also available.

Steel Fiber General Description

Supplying concrete fibres, mainly Metallic fibres. Metallic fibres include low carbon cold drawing steel fibres, stainless steel fibre, and sheet steel fibres etc. We have types of Hooked Ends, Corrugation, Flat Ends and Micro steel fiber etc.

Steel Fiber

Description:

Steel fibres are filaments of wire, deformed and cut to lengths, for reinforcement of concrete, mortar and other composite materials. It is a cold drawn wire fibre with corrugated and flatted shape. It is often used to instead of Xorex steel fiber.

Applications:

- cellar walls - slabs on

vibrocompacted piles - pavements

- liquid tight floors - jointless floors

- jointless floors on - industrial floors

vibrocompacted piles - overlays

- outdoor slabs - piles

- foundation slabs - segmental linings

- suspended ground slabs

- composite slabs

Specification:

Fiber length (mm): 38 (1.5”)

Equivalent Diameter (mm): 1.0±0.03

Tensile strength: (Mpa ±5%): 850

The thickness of fiber is 0.5mm and width is 1.4mm

Fiber length (mm): 50(2”)

Equivalent Diameter (mm): 1.0±0.03

Tensile strength: (Mpa ±5%): 850

The thickness of fiber is 0.5mm and width is 1.4mm

Steel fiber specification can be made according to requirement.

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Major Product Index:

Straight Steel Fiber

Product Description:

The cold-rolled strip steel products are made from cutting. Stainless steel fiber has high tensile strength and it can be easily dispersed, and can be easily integrated with the concrete.

Stainless steel fiber is widely used and the main parameters as follows:

Fiber length: 25-35mm

Fiber diameter: 0.3-0.7mm

Tensile strength:≥650MPa

Stainless steel fiber is made in accordance to the country standard YB/T151-1999 Standard for Steel Fibers for Concrete Uses, and the JG/T3064-1999 Standard of Steel Fiber for Concrete Building Industry.

Packing: We can provide package according to our customers’ specifications. Stainless steel fiber can be packed in one-layer of plastic and two-layer paper bags or boxes. The weight is 20kg per bag, or per customers request.

Indentation Steel Fiber

We offer steel fiber for concrete mixing to enhance the strength.

Indentation steel fiber is widely used and the main parameters as follows:

Fiber length: 25-35mm

Fiber diameter: 0.3-0.7mm

Tensile strength:≥650MPa

Steel fiber is made in accordance to the country standard YB/T151-1999 Standard for Steel Fibers for Concrete Uses, and the JG/T3064-1999 Standard of Steel Fiber for Concrete Building Industry.

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Hooked Ends Steel Fiber

Steel fiber with hooked ends is made using high-quality low-carbon steel wire. A kind of high-performance steel fiber, with the characteristics of the high tensile strength, good toughness, low prices, etc. The product is widely used in concrete strengthening.

Hooked ends steel fiber is made in accordance to the country standard YB/T151-1999 Standard for Steel Fibers for Concrete Uses, and the JG/T3064-1999 Standard of Steel Fiber for Concrete Building Industry.

Classify your order for hooked ends steel fiber:

Wire Diameter (mm)

Fiber Length (mm)

Tensile Strength(Mpa) of Steel Fiber

Types of fiber used in concrete

There are many types of fibers that can be used in concrete including steel fibers, glass fibers, synthetic fibers and natural fibers. The characteristics of the fiber reinforced concrete depend on the fiber material, amount, geometry, distribution, orientation, and densities of the fibers used. Fibers are added to fresh concrete during the batching and mixing process to allow them to be equally distributed throughout the concrete.

Basics Of Fiber Reinforced Concrete

What Is Fiber Reinforced Concrete

Fiber reinforced concrete is a type of concrete that includes fibrous substance that increases its structural strength and cohesion. Fiber reinforced concrete has small distinct that are homogeneously dispersed and oriented haphazardly. used are s, synthetic , glass , and natural . The characteristics of fiber reinforced concrete are changed by the alteration of quantities of concretes, fiber substances, geometric configuration, dispersal, direction and concentration.

Why Fiber Reinforced Concrete Is Used

Portland cement concrete is believed to be a comparatively brittle substance. When un-reinforced concrete is exposed to tensile stresses, it is likely to fracture and fail. Since the beginning of the nineteenth century, studies were conducted to reinforce concrete by using steel. After the reinforcement of concrete by steel, it becomes a composite group in which the steel endures the tensile stresses. When concrete is reinforced by using fiber in the mixture, it further increases the tensile strength of the composite system. Research has revealed that the strength of concrete may be improved tremendously by the addition of fiber reinforcing. Since the stretching ability under load of reinforcing fiber is greater than concrete, initially the composite system will function as un-reinforced concrete. However, with additional loading the fiber reinforcing will be activated, to hold the concrete mix together.

Characteristics Of Fiber Reinforced Concrete

The characteristics of concrete depend upon the kind of fiber utilized, volume proportion of the fiber, and the ratio of length and diameter of the fiber. These conditions will improve the mechanical properties, including toughness, ductility, tensile strength, shear resistance and loading limit of the fiber reinforced concrete. Materials used for fiber reinforcement include steel, glass, polyester, rayon, cotton, and polythene. Most commonly used materials are steel and glass that are acid resisting. Natural being vulnerable to alkali attack are not much popular. Similarly, plastic have recently been introduced in the field of reinforcement and are still in the development phase. It is considered that the contribution of plastic to increase the static strength of concrete is limited. Nylons have the characteristics of a plastic material, and presently have a limited application in the slab technology. It is generally believed that nylon possess strength that is greater than the welded wire fabric in such slabs.