POLYMER FIBRE REINFORCED CONCRETE PAVEMENTS.pptx (Size: 9.92 MB / Downloads: 2683)
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.
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.
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
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
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.
Membrane curing is used.
Texture-cum-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.
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.
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.
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”.