Tom Burnham, Sr. Research Engineer and ISCP Board Director, the MnDOT–Office of Materials and Road Research, and the NRRA Rigid Pavement Team composed the research overview and goals—Long-Term Research Write-Up—titled “Fiber-Reinforced Concrete Pavement”. The report shows that there is interest in economizing pavement structures while continuing to maintain long-term performance.
In order to quantify the performance of fiber-reinforced concrete pavement, the team designed 9 fiber-reinforced concrete test cells to be constructed at MnROAD. The primary variables of interest include:
• Thickness
• Type of support (base)
• Panel size
• Fiber dosage
The objectives of this study will be to determine:
• Contribution of fibers in reducing panel fatigue cracking
• Contribution of fibers in mitigating joint faulting
• Optimal panel size for designs incorporating fibers
The fiber composition/quantity for the proposed test cells will be determined based on meeting ASTM C1609 residual strength criteria, as well as recent findings from ongoing studies (U of Mn Duluth), and lessons learned from successful field performance in participating states (Illinois). The selection of panel sizes considered a balance of performance and economics (keep longitudinal joints away from wheel paths and reduce number of saw cuts when possible).
To watch the VIDEO with Tom Burnham summarizing the fiber-reinforced cells, titled:
“MnROAD Construction Summer 2017—Concrete with Extra Fiber”, please go to the ISCP VIDEO (article) adjacent to this one: https://www.concretepavements.org/2017/08/07/video-mnroad-construction-summer-2017-concrete-with-extra-fiber-featuring-tom-burnham/
To watch the VIDEO of the paving of the no-, low-, med-, and high-fiber-reinforced concrete test cells “MnROAD Weekly Construction Update—Week of June 26″, please click here:
https://www.youtube.com/watch?v=raMBS5Ww1DA
Past research has demonstrated definite limits to reducing the thickness of conventional joint plain concrete pavement, thus invoking interest in understanding the potential of using fiber-reinforced concrete to allow further slab thickness reductions. Research continues on understanding the mechanisms of joint faulting in thin concrete overlays, and whether fiber-reinforced concrete might mitigate such distress. There is interest in understanding the effects fiber-reinforced concrete might have on panel size, especially for much thinner slabs.
Previous research and field performance have demonstrated that fibers have improved the performance of concrete pavement and overlays by:
- Holding cracks tight
- Transferring the wheel load between adjacent slabs.
Comprehensive quantification of these benefits is still ongoing, including several ongoing laboratory studies.
Potential Benefits for NRRA Members: If a field-validated method can be developed for the selection and dosage rate of structural fibers in thin concrete pavements and overlays, DOTs and local agencies will be able to make educated design decisions about using fibers to reduce thickness without compromising performance, and potential mitigate joint faulting in undoweled concrete overlays. It will address topics of interest in LRRB group (Local street design).
Home photo: CSM Paved Concrete-Fiber Mix-Medium Dosage:
MnDOT–Office of Materials and Road Research
and the NRRA Rigid Pavement Team