The main objective of this study is to control restrained plastic shrinkage cracking through the addition of
natural and PVA fibers in a cement-based composite. Two types of natural fibers (flax and agave lechuguilla)
as well as synthetic fibers (PVA) were investigated at volume fractions of 0.1% and 0.7%. 38 prismatic
mortar specimens were freshly cast on top of a grooved and hard concrete substrate, providing a
bottom restraint; this resulted in cracking in the freshly placed overlay, which was detected as a function
of time. The effectiveness of the fibers was evaluated by considering reducing the number of cracks and
total crack area under these conditions. The results obtained show that both natural fibers were effective
in controlling restrained plastic shrinkage cracking like the commercially available PVA fibers; the total
crack areas were also reduced by at least 93% compared with plain mortar specimens.