InTrans / Dec 06, 2018
CP Tech issues web series on fiber reinforced concrete
Photo courtesy of Jerod Gross, Snyder & Associates, Inc.
The National Concrete Pavement Technology (CP Tech) Center recently sponsored the presentation of three webinars to explain the most recent findings on macrofiber use in concrete production. The instructors for all three sessions in late 2018 were Jeffery Roesler, Ph.D., P.E., University of Illinois, Urbana-Champaign; and Amanda Bordelon, Ph.D., P.E., Utah Valley University, Orem, Utah.
Overview
The first webinar, Fiber Reinforced Concrete Overview, was presented October 24, 2018. This webinar provided a general overview of the varied types and geometries of fibers used for concrete pavements, with an emphasis on macrofibers. The effect of macrofibers on fresh and hardened concrete properties was discussed, especially when used in concrete paving mixtures. The main concrete test methods required to specify macrofibers for overlays were summarized. Finally, the moderators reviewed the current best practices for constructing concrete overlays with macrofibers from the batching process to the joint sawcutting operations.
Macrofiber Effects
Effects of Macrofibers on Behavior and Performance of Concrete Slabs and Overlays was presented on November 7, 2018. There have been significant recent developments in macrofiber products and complementary research demonstrating their impact on concrete pavements. This webinar reviewed the relevant research findings related to the addition of macrofiber to concrete slabs on grade, which included the increase in plain concrete slab capacity and reduction in crack widths with the use of macrofibers. The presenters also offered a review of studies that have evaluated the increase in pavement performance when macrofibers are added to concrete pavement and overlays. Finally, the increase in load capacity and service life of fiber reinforced concrete overlays was linked to hardened property tests that pavement engineers can specify in their designs.
Macrofiber Software and Guidelines
The third webinar, which aired on December 5, 2018, was Overview of Macrofiber Software and Guidelines for Concrete Overlay Design. It gave viewers a look at the macrofiber software available to determine the recommended fiber reinforced concrete residual strength values for application to concrete overlay design. The inputs and factors affecting the required fiber reinforced concrete content were discussed, as well as integration of the calculated residual strength with the existing concrete pavement overlay design methods. Finally, the instructors offered guidance on how specifications can be adapted to include macrofibers in concrete overlays in order to make sure the designer’s intentions are carried out in the construction phase.
The CP Tech Center now offers the video files and PDFs for all of these webinars in an easily accessible form for interested viewers. See them all on the Recorded Webinars page.