|
|
 |
PVA fibers are true structural concrete reinforcement fibers, like steel and glass. Common plastic fibers perform one task in concrete: they restrain plastic shrinkage. But after the first 24 hours, they are largely ineffective in restraining drying shrinkage or other cracking. Why? Their modulus of elasticity is less than that of concrete. That's another way of saying they are stretchier than concrete. To be a true structural fiber, the fiber should be stiffer than the concrete it is reinforcing.
Bond strength between fiber and concrete is another important consideration. Steel has very high tensile strength, but steel fibers have low bond strength with concrete or mortar. When you put the concrete under load, it cracks and the steel fibers tend to slip out without providing significant benefit from their high tensile strength. PVA fibers, on the other hand, form a molecular bond with the concrete during hydration, so you cannot easily pull them out. The net result? In the words of Professor Victor Li from the University of Michigan:
"PVA-ECC provides up to 500 times the tensile strain capacity of fiber-reinforced concrete. The combination of high tensile strength of PVA fibers and controlled interface bond with mortar makes it a true structural fiber."
The PVA-ECC composite has tensile stress-strain behavior more similar to steel than concrete. Give us a call for a sample and try PVA for yourself. We have a family of fibers that are effective from 1/8th inch overlays all the way up to massive pours like bridges and dams.
PVA (polyvinyl alcohol) fibers are manufactured by Kuraray Co. Ltd of Japan. For more about the company, click here.
|
|
|
