Evaluation of Fatigue and Toughness of Fiber Reinforced Concrete as a New Highway Pavement Design
Abstract
Concrete pavement design is currently centered on steel reinforcement. Whether that
reinforcement be in the form of dowel bars, as is the case in jointed plain concrete pavement
(JPCP), or in the form of continuous rebar reinforcement, continuously reinforced concrete
pavement (CRCP). The use of steel in concrete pavements presents durability problems due
to the corrodibility of steel. This study evaluates the use of polypropylene fibrillated,
polypropylene macro, and carbon fiber fibers as primary reinforcement in concrete
pavements for the Louisiana DOT. Results showed that fiber reinforcement can be used to
improve both the fatigue and toughness performance of concrete. When post-cracked
strength or toughness is the concern, concrete containing more fibers and fibers with higher
tensile strength are desirable. Carbon fibers maintained greater load-carrying capacity at
lower deflections than the steel fibers, which produced the greatest ductility. However,
toughness and fatigue performance did not correlate for small deflections, suggesting that
polypropylene macro fibers may be adequate for repeated, low stress loading. This study also
found that when repeated low deflections are a concern, such as with pavements, there must
be sufficient fibers across a crack to maintain a tight crack. Conversely, too many fibers
prevent adequate consolidation and aggregate interlock, which negatively influences
performance. When considering the pre-cracked fatigue performance of fiber reinforcement,
the fibers needed to have sufficient length to reach across the crack and bond with the
concrete, and that higher fiber dosages increase the fatigue performance of the concrete. The
resulting pavement design, continuously fiber reinforced concrete pavement (CFRCP), will
provide an alternative to JPCP and CRCP in highway pavement design that is not susceptible
to durability problems associated with corrosion of the reinforcement.
Table of Contents
Introduction -- Literature review -- Methods and instrumentation -- Testing machine and software setup -- Testing results -- Pavement design -- Conclusions and recommendations
Degree
M.S.