Minnesota Department of Transportation
Structural fibers improve the long-term performance of concrete pavements and overlays and potentially are useful to reduce the slab thickness. These fibers are available in different parent material compositions; stiffness; shapes; and aspect ratios. The main objective of this study was to characterize the post-crack flexural and joint performance of fiber reinforced concrete to develop a specification for the selection of structural fibers for concrete overlays and/or pavements. The study included a literature review; an online survey; and a large-scale laboratory testing. It was found that the majority (almost 94%) of the FRC overlays in this country were constructed with structural synthetic fibers; which provided equal or better performance than projects using the steel fibers. In the laboratory study; a total of 43 different mixes were prepared with 11 different types of fibers. Fiber dosage; stiffness; and geometry significantly influenced the residual strength ratio (RSR) and residual strength (RS). In general; embossed; twisted; and crimped fibers performed better on average than straight-flat synthetic fibers when the comparison was made in terms of RSR or RS. From the joint performance testing; it was found that fibers can greatly improve the performance of the pavement with respect to load transfer efficiency (LTE); differential displacement; and differential joint energy dissipation. The findings from this were used to recommend the target ranges post-crack flexural performance; and joint performance parameters.
Object File Name