Fiber Reinforced Concrete

What we know about Fiber Reinforced Concrete:

Macro Synthetic Fiber may be added to the concrete either at the ready mixed plant or to the mixer truck on the site. The addition of the fibers to the concrete should be in accordance with an agreed method statement, to ensure that the fibers are adequately distributed throughout the concrete.
Fibers are usually used in concrete to control cracking due to plastic shrinkage and to drying shrinkage. All fibers don't increase the flexural strength of concrete and so cannot replace movement resisting or structural steel reinforcement. In addition, the character of fiber reinforced concrete changes with varying concretes, fiber material, geometric, distribution, orientation, and densities.
Some research in the late 2000's indicated that using fibers in concrete has limited effect on the impact resistance of the material.

But when proper material and amount of fibers are used they can benefit in:

Improving mix cohesion, improving pumpability over long distance,
Improve impact and abrasion resistance,
Improve structural strength,
Reduces crack widths and control the crack width lightly, thus improving durability,
Improve freeze thaw resistance.

Blend of both steel and polymer fibers are often used in construction projects in order to combine the benefits of both products, structural improvements provided by the steel fibers and the resistance to plastic shrinkage is improved by polymer fibers.

Also the new fiber reinforced concrete claims 500 times more resistance to cracking and 40% lighter than traditional concrete.

 Addition of fibers also improved in cracking problem where cracks were small and less, the could be overcome by the self healing concrete technology.
 Other idea show that recycled materials are used to make it environmental friendly concrete.