Posted on August 10, 2016 at 07:05 AM
Advantages & Benefits of Synthetic Fibres in Concrete Flooring & Plastering Applications
Use fibres in concrete or concreting materials as an additive, dates back to Romans & Egyptians period. Romans included bits of horse hair in the construction of Roman Colosseum which was built in 80BC and the Egyptians used straw in their bricks for constructions. There are other historical places like Tipu Palace at Sriranganapatna, where fibers were used in mortar.
Drawbacks of use of Concrete in Flooring Works
Plain concrete is prone to plastic shrinkage and settlement cracks. Usually, these floors will have very less abrasion resistance and impact resistance. Construction joints are often left as weak joints after casting. All these issues leads to periodic maintenance of floors due to less durability and earlier wearing of top floor surface.
Drawbacks of using Plain Plastering
Plastic shrinkage cracks are often developed in the initial stage of plastering. Segregation, High rebound loss of mortar & High water and moisture absorption from the atmosphere are other issues. Thermal and drying shrinkage cracks can be developed in the hardened surface of plastering. It demands more maintenance in terms of periodic waterproofing and painting of the buildings.
Development of Fiber Reinforcement
In olden days vegetable Fibers, Straws, Jute and Cotton, Coconut Fiber known as coir were widely used as fibre. Later Horse hair, Sheep’s Wool replaced the demand. In current industrial and construction practices Glass, Polyester, Nylon, Polypropylene and Steel fibres are used as additive in the concrete.
Comparison with Various Types of Fibers
Glass fibres are expensive, unsafe and unprotected use causes itching is hazardous to human health. Steel fibres are prone to Corrosion and it increases Dead Weight of the structure which is not favorable. Steel is also expensive compared to other fibres. Mixing of steel can be another problem. Nylon fibres on the other had are Very Expensive
Working of Fibres in Concrete
Fibre holds the aggregates and prevents separation of coarse aggregate due to vibration /gravity ensuring better bonding within the matrix. This provides a uniform mixture of concrete and fiber allows slow transfer of water to surface thereby reducing cracks in the concrete.
Nowadays, synthetic fibers widely are added to concrete to reduce plastic shrinkage cracking of reinforced and structural plain concrete and to reduce shrinkage and temperature cracking in structural plain concrete slabs on grade. Consideration to be given to the volume, size and type of fibers used for mixing. These fibers are considered as admixtures and are used in addition to any structural reinforcement, shrinkage and temperature reinforcement and joints. The fibers may be used in concrete over steel deck construction. In addition to this, fibers may be used in fire resistant construction on steel decks.
Advantages & Benefits of Using Synthetic Fibres in Plastering
- Fibers reduced shrinkage cracks
- Rebound loss of the mortar has been reduced to 10 % instead of 30 to 40 % without fibers in the mortar
- No Dampness and leakage of plastered walls
- Better finish of wall surface
- Increased durability due to Increased strength of mortar and thus longer life of constructions
- Savings due to economic mix designs and more durable plastered surface
- Compressive strength of plaster was increased by over 15-20%
- Results in Cement savings up to 3%
- Increase in labor productivity by over 5%
Advantages of Using Synthetic Fibres in Concrete Flooring Works
- The use of fibers has improved the abrasion resistance of concrete floors to moving loads.
- No appearance of plastic shrinkage and plastic settlement cracks on the concrete floor surface.
- Service life of the floor is enhanced due to high durable concrete produced with synthetic fibers.
- Improved impact resistance of floors to point loads.
- Concrete mix with fibers was cohesive with better workability.
- Compressive strength of plaster was increased by over 8-10%.
Synthetic Fibers can be used in all construction applications, different types of fibers should be developed to address each specific construction applications. Construction industry should encourage new technologies like fibers reinforcement in construction to a larger extent for improving the durability and serviceability of the building and structures.