Concrete is an integral part of any construction project, it can be roads, tall structures, irrigation canals, reservoir dams, tunnels, industrial floorings, precast segments etc. This is because concrete is more durable than any other material. Even though concrete is more durable, it is naturally subjected to cracking due to the effect of change in temperature, humidity, wind, and corrosion of steel bars. The cracks can give a way to repair and maintenance or the structure may collapse at service load conditions.
Synthetic Fiber Reinforced Concrete (SFRC) is a type of concrete which contains short discrete synthetic fibers that are uniformly distributed and randomly oriented in the concrete matrix and provides 3-Dimensional Reinforcement for concrete structures.
Role of Synthetic Fibers in Concrete
The two forces, one in top layer and other in bottom layer of freshly laid concrete, develops tensile stresses in the top layer. This leads to the development of early tensile strength in top layer of concrete and creates cracks. The fibers intercept the cracks and act like internal band-aids. Fibers will ‘elongate’ or ‘stretch’ before they are able to transfer significant amounts of stress across the cracks and allow it to carry more load. It’s an interlocking mechanism.
Synthetic Fiber Reinforced Concrete projects have proven that synthetic fibers do increase the longevity of constructed projects and have been found to contribute to a number of durability properties, which translates into longer concrete life at a reasonable additional cost.
These Synthetic Fibers have the potential to enhance specific properties of the fresh and hardened concrete such as workability, segregation, bleeding, plastic shrinkage, compressive strength, flexural strength, impact resistance, toughness or energy absorption, abrasion resistance, durability etc.
Based on the cross-sectional size, shape, and intendant applications, Synthetic Fibers are categorized into 2 groups:
Micro Fibers: These fibers are used in concrete to reduce Plastic Shrinkage Cracks. These shrinkage cracks occur mainly due to moisture loss in concrete within first 24 hours after placing. During this plastic state, Young’s Modulus of Micro Fibers is greater than Young’s Modulus of Fresh Concrete. Thus, Polymer Micro Fibers act as a Plastic Shrinkage Reinforcement during the first 24 hours and later mechanical properties of the concrete will add up and result in no shrinkage cracks at a dry state.
Figure 1: Young’s Modulus (E) of Polymer Fibers at an early age of Concrete“Greater the Young’s Modulus of Fiber, better will be the crack control in terms of crack length and width. The Young’s Modulus of Fiber is the only key parameter to resolve crack issues by bridging the cracks by millions of dense network of Synthetic Fibers.”
In case of any fire accidents, these micro fibers act as capillaries or ducts. Fibers get liquefied and create pores in the concrete to ventilate the accumulated smoke/steam from the inner area to the outer atmosphere, which, in turn, reduces the internal pressure of the building and offers high resistance to spalling of concrete.
Macro Fibers: These fibers are designed to infuse the concrete with high added levels of energy absorption, flexural toughness, durability and increase the post-cracking residual strength of concrete, without the risk of corrosion associated with steel. They also help to mitigate the formation of shrinkage cracking in concrete. These macro fibers play a vital role in transferring structural loads and are a 100% substitute for steel fibers and steel reinforcements in some areas of applications such as tunnel lining, shotcrete, industrial floorings, mezzanine deck slabs, and many more.
| Table1: Peak Loads, Crack Loads & Energy absorbed values recorded from panels | |||
| Panel #1 5 Kgs Dosage |
Panel #2 6 Kgs Dosage |
Panel #3 7 Kgs Dosage |
|
| Energy Absorption up to 25 mm (Joules) | 855 | 883 | 928 |
| First Crack Load (KN) | 56.1 | 44.8 | 51.5 |
| Peak Load (KN) | 60.2 | 69.8 | 59.7 |
Synthetic Fibers play a vital role in the design and construction of Ground Supported Slabs, Mezzanine Deck Slabs, Precast Concrete, PQC Roads, White Topping, Driveway, Industrial Flooring, Tunnel Lining, Shotcrete, Plastering Mortar, Refractory Bricks, Paver Blocks, Thermal Power Plants, Soil Stabilization, Paints, Waterproofing, Cement Boards and many other applications.
FIBERCRETE® offers world-class made-in-India Synthetic Micro & Macro Concrete Fiber Products for the Construction Industry; they carry a valid CE (European conformity) mark.Kalyani Polymers is a leading manufacturer and supplier of Synthetic Micro & Macro Concrete Fibers to the Indian and International Markets under the brand name FIBERCRETE®. These Fibers are Tri-Component Polymeric-based engineered fibers produced by state-of-the-art European machineries from the pellets to fibers and they comply with the standard specifications of Fiber Reinforced Concrete such as EFNARC, ASTM, IRC, MORTH, RVNL, MES, IS standards.
FIBERCRETE® Fibers are Certified and Approved by the following Organizations:
- Indian Institute of Technology Madras, Chennai
- Indian Institute of Technology, Hyderabad
- SKG Project and Engineering, Mumbai
- Kalinda Technical Services & Consultancy, Pune
- Stedrant Technoclinic, Bangalore
- Academy of Concrete Technology, Bangalore
- CIPET, Mysore and Hyderabad
- SHRIRAM Institute for Industrial Research, New Delhi
- The Bombay Textile Research Association, Mumbai
- High Tensile Strength
- Greater Elastic Modulus
- Non-Corrosive
- Acid & Alkali Resistance
- Chemically Inert
- Hydrophobic (do not absorb water)
- High fiber count
- Reduces the dead weight of concrete element
- Uniform Dispersion in concrete
- EN 14889-2, 2006
- ASTM C 1116-03
- ASTM C 1116M – 06
- IRC SP 46, 2013
- IRC SP 76, 2016
