How Well Do Polypropylene Fibers Control Cracking.pdf
How well do polypropylene
fibers control cracking?
A survey of concrete slab performance
W. R. MALISCH
Abstract:
Polypropylene fibers have been suggested as an alternative to using welded fabric wire for crack control purposes in concrete slabs. It’s easier to add fibers to the concrete than it is to place wire mesh in a slab. And because wire mesh won’t function properly if it’s lying on the subgrade or has bowed up near the surface, advocates of fiber reinforcement argue that uniformly distributed fibers will more reliably control cracking. Reductions in plastic shrinkage, plastic shrinkage cracking and in drying shrinkage are also claimed. The effectiveness of crack control with polypropylene fibers, though, has been questioned. Under the same stress, polypropylene stretches much more than steel and it has a lower tensile strength. Because of this, critics contend, polypropylene fibers can’t control the distribution of cracks in hardened concrete.