NPA (Neoloy®) Tough-Cells Come out on Top in U.S. Strategic Highway Research Program – SHRP2
Compaction “Roadeo” Field Demonstration: Roller-Integrated Compaction Monitoring and Subgrade Geosynthetic Reinforcement, CEER – Center for Earthworks Engineering Research, Iowa State University, Dec 2012
What’s a ROADEO?
Held on the construction site of State Road 9B in Jacksonville, Florida in May 2011, the contestants in this “Roadeo” field demo were four geosynthetic products, while the large entity in the middle of the ring was a Caterpillar CS74 “Intelligent” compactor with advanced monitoring systems. The sponsors were major transportation bodies, while the judges were leading researchers in the field. The scorecard was comprised of 8 in situ QC / QA test methods. And the winner of the Roadeo was…NPA (Neoloy) Tough-Cells.
Dr. Ofer Kief, Senior Geotechnical Engineer from PRS at the test site, remarked: “This demo project underscores the key role that NPA (Neoloy) Tough-Cells s have in pavement structures, in terms of increased stiffness and lifespan.”
What was Unique about this ROADEO?
The Roadeo was an integrated field test showcasing geosynthetic products with new compaction technology and evaluated with all the conventional QC and QA methods together. NPA (Neoloy) Tough-Cells s (100- and 150-mm height, fabricated from Neoloy® Novel Polymeric Alloy – NPA) squared off against tough competition: BX biaxial geogrids, C30 geogrid/geotextile geocomposites and PPWF polypropylene woven fabrics. The contestants were installed in poorly-graded sand embankments.
Who’s on Top? – NPA (Neoloy) Tough-Cells
NPA (Neoloy) Tough-Cells came out No. 1 in performance. According to the authors, “Sand and gravel are improved more with NPA s than any other geosynthetic.” Cyclical plate loading tests showed that the NPA (Neoloy) Tough-Cells s had the lowest permanent deformation (4.1 mm as opposed to 5.6 mm for the geogrid) and the highest modulus of all the geosynthetics (E = 161 MPa). The modulus improvement factor (MIF) of the sand as a result of NPA (Neoloy) Tough-Cells confinement was consistent with the results of other field tests in the US, India, Holland and Germany, which produced a MIF of 2.5-4.0.
Outstanding Benefits
The benefits of NPA s were noted by the authors – lateral confinement increases stiffness and shear strength of the soils, which distributes wheel loads more widely and reduces rutting. “Confinement technology is applicable to SHRP 2: Element 1 – New embankment and roadway construction over unstable soils; Element 2 – Roadway and embankment widening; and Element 3 – stabilization of pavement working platforms.
SHRP2 Research Program
The objective of SHRP 2 is to achieve highway renewal that is performed rapidly, causes minimum disruption, and produces long-lived facilities consistently throughout the nation’s highway system.
An open house at the end of the Roadeo and in the CEER geotechnical mobile lab, was attended by representatives from the Florida DOT, the National Academy of Sciences (sponsors of the research along with the Federal Highway Administration and the National Research Board) and SHRP 2. The senior researchers at the Roadeo and the report’s authors were a team led by Dr. David White and the Center for Earthworks Engineering Research (CEER) at Iowa State University and Dr. Jie Han who led a team from the University of Kansas.
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