PLASTIC SHRINKAGE CRACKING OF POLYPROPYLENE FIBER-REINFORCED CONCRETE SLABS

The effects of polypropylene fibers and construction operations on the plastic shrinkage cracking of concrete slabs were investigated. Statistical methods of experimental design and analysis were used to derive statistically reliable conclusions. Polypropylene fibers, at relatively low fiber volume fractions, were observed to reduce substantially the total area and maximum crack width of slab surfaces subjected to restrained plastic shrinkage movements. The rate of screeding of the fresh concrete surface was also a critical factor (particularly in plain concrete). Slower screeding rates led to reduced plastic shrinkage cracking.