Anyone know why fiber reinforced concrete is better then normal concrete?
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When concrete is mixed at the batch plant water is added. This water is a catalyst for the heat of hydration process in which concrete cures and becomes hard. When the water is done reacting with the cement is leaves the concrete. This loss of mass causes the concrete to shrink. This shrinking is one of the reasons concrete cracks. A a 4" slab of concrete normally should crack every 8'-12'. A slab of concrete that is reinforced with fibers will have a tendency to crack less often. How often the concrete cracks will be determined by the quality of fiber you use. Fiber is a three dimensional reinforcing that helps concrete get through its adolescent stage (1-30 days). Some people think that it is so wonder full that it can even take the place of steel reinforcing. This is not true. They protect the concrete, but that is their only similarity. Your concrete is going to crack. When it does your fiber reinforcing stops working (along the crack) and your steel reinforcing goes to work. The steel is going to help the concrete keep from migrating away from itself over time. It will also help prevent heaving and sinking associated with a poor sub grade issues. Long story short- If it were my house I would use them both.
It increases its tensile strength without the need for rebar.
The fibers help to hold the concrete together. Each fiber helps to hold all the concrete that it is in contact with in a solid piece, making it harder to break it apart. Multiply that by millions and you get a chunk of concrete much stronger than un-reinforced concrete.
The fibers are supposed to lock the concrete together for more strength. In a much smaller way, the same as reinforcing rod does. Last I knew, the price was between 5 and $10 per yard more.
The fiber gives the concrete a more strength than standard concrete of the same mix. Does not give it better compressive strength (what you need if you are going to set something really heavy on it), but it is more crack resistant. In a slab application, steel reinforcing is not required as it would be with regular concrete.
Sometimes the fibers in the cement are visible on the surface, like the concrete is growing tiny hairs. Not sure what makes the difference. I have seen the same finisher have the "problem" one time and not the next. Same with different plants. Not a big deal, just looks odd if you pay close attention.
Concrete by itself is not very strong. It's the binding of the sand and the aggragates that give it strength. They put steel, rods, or mesh to keep the concrete from seperating if it cracks. The fibers interweave throughout the mix locking it together, making it stronger than the concrete alone. This is because the fibers lock the sand, grave, and concrete into a uniform mass.
It has the properties of concrete and fiberglass
for two reasons.
1) The fibres are very tiny so that they decrease the permeability of concrete thus makes it better.
2) Concrete is so weak in tension while the fibres are great at tension so placing them somehow in the tension zone of the concrete member will give it a higher performance and longer life time.
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