National Concrete Pavement Technology Center

Project description

Fiber-reinforcement can improve the performance of concrete overlays in several ways. The best-understood benefits are increased fracture toughness and post-cracking resilience. Fibers can also benefit overlays through other methods, such as enhancing aggregate interlock/load transfer and reducing curling stresses, but these effects are not as well-understood and have not been studied extensively in the field. While cracking is the primary failure mode considered in concrete overlay design, load transfer and smoothness are also important to long-term performance. Concrete overlay test sections in Mitchell, Worth, and Buchanan Counties were constructed from 2017-19 with varying thickness, joint spacing, underlying structure, and both with and without fiber-reinforcement. Previous analysis of those sections focused on early-age joint activation behavior and the feasibility of extending joint spacing when using fibers. This study proposes further testing and analysis, including falling weight deflectometer (FWD) and pavement profile measurements (laser profile and LIDAR), to characterize how fibers affect load transfer efficiency, curling and warping, and smoothness in these sections. Results for the fiber-reinforced test sections can be compared to the control sections placed without fibers. The primary deliverable for this project will be a report that details results and analysis of FWD testing and profile measurements to characterize the impact of fibers on joint load transfer efficiency, slab curling, and pavement smoothness. The data will also be studied to analyze the relationships between those properties and design parameters such as overlay type, thickness, and joint spacing. These results will also be compared with performance predictions from concrete overlay design software to investigate how the additional performance impacts of fibers that are found in this study can improve and supplement existing design procedures.