30 Apr Fiber mesh reinforcement
General information as recognized within the concrete industry.
Plastic shrinkage occurs as fresh concrete loses its moisture after placement during the
initial strength development stage. This type of shrinkage is affected by environmental
effects of temperature, mostly within the concrete, while ambient temperature, wind and
relative humidity play a smaller combined part. It is a particular problem in hot weather
concreting. At present, there are no specific admixtures developed to handle this type of
Use Fibers for Secondary Reinforcement. Fibers can be added to the concrete mix in
lieu of welded wire mesh. Which Shamrocks applies to all mixes used.
If you could look into a section of concrete poured with fibers you would see millions of
fibers distributed in all directions throughout the concrete mix. As micro cracks begin to
appear due to shrinkage as water evaporates from the concrete (plastic shrinkage), the
cracks intersect with the fibers which block the path and provide higher tensile strength
capacity at this crucial time of initial curing.
All of these facts are subjective to what randomness occurs from project to project. All
concrete will crack, but that is why control joints and fiber mesh are used to reduce the
potential for random cracking.
All concrete continues to strengthen over many years, along with expansion and
contraction from cold to hot seasons, as occurs in the Midwest Region. Water influences
under and around the concrete during months and years also impacts the concrete
performance. Cracking in the short term of days to years is unpredictable.