Recently, a contractor submitted a concrete slab on grade mix design
proposing the use of polypropylene multi-filament fibers as a substitute
for the specified reinforcing steel. The manufacturer's guidelines clearly
stated some conditions where the use of the fiber mix was not appropriate.
1. Control of cracking as a result of external stresses.
2. Elimination or reduction in curling or creep.
3. Decreasing the thickness of slabs on grade.
4. Increasing the structural number of Portland cement in pavement or slabs
5. Replacement of any steel used for bending moment resistance.
6. Increasing ACI and PCA control joint guidelines.
The proposal was rejected.
This manufacturer also stated some conditions where the use of the fiber
mix might be appropriate.
1. For greater impact, abrasion and shatter resistance in concrete.
2. Placements where all materials must be non-metallic.
3. Reduction in the permeability of concrete.
Michael Krakower SE