Toward the development of pavement-specific structural synthetic fibers

Thin fiber reinforced concrete (FRC) pavements and overlays can be economical for low- and moderate-traffic volume roads. Due to insufficient concrete cover thickness, thin concrete pavements or overlays cannot accommodate dowel bars that are typically used in conventional thick concrete pavements. The critical distress for such applications is the transverse joint faulting because of the lack of joint load transfer between the concrete slabs. The currently available synthetic structural fibers can contribute to joint performance to a certain extent. However, as pavements experience significant slab contraction and expansion and carry both wheel and environmental loads, there is a need to design and develop fibers that will provide high joint performance and help mitigate transverse joint faulting when used at an affordable dosage. The overall goal of this study is to develop pavement-specific fibers that will yield the needed joint performance benefits to achieve the intended design life. The study is being conducted in two phases. This report is written for Phase 1 of the study. The study started with a literature review, followed by a finite element analysis, falling weight deflectometer (FWD) data analysis, and laboratory testing of fiber reinforced concrete and individual fibers embedded in concrete. The finite element results and FWD data were amalgamated to quantify the possible joint load transfer of the base layer and foundation, aggregate interlocking, and the needed contribution from the structural fibers. A procedure was established to account for the contribution of the fibers. A new parameter, namely, modulus of fiber support, was introduced to evaluate the stiffness of the fibers that participate in joint load transfer. Notably, a laboratory approach is identified to determine the modulus of fiber support, which can help determine the optimum fiber dosages as well as design and test the pavement-specific fibers in the future phase of the study.