KTC Test Site’s Pavements, Materials and Geotechnology research project to be featured in the NCHRP publication “Research Makes the Difference 2012”
Lexington – KTC Test Site reserach will be featured in the National Cooperative Highway Research Program (NCHRP) executive brochure “Research Makes the Difference 2012”. The project, “Use of Ground Penetrating Radar for Void Detection and Hydro-Geochemical Water Testing Results at the Cumberland Gap Tunnel” was conducted by the Center’s Pavements, Materials, and Geotechnology Program to determine why the tunnel’s continuously reinforced concrete pavement had settled in various areas.
Principal Investigator Brad Rister P.E., Program Manager Clark Graves P.E.; and hydro-geochemist, Dr. James Dinger, alongside their team, conducted Ground Penetrating Radar (GPR) surveys and Hydro-Geochemical Water Testing (HGWT) and found that approximately 0.75 to 1.5 cubic yards of limestone sub-base material left the tunnel, in solution form, every month due to calcium deficient ground water beneath it. As a result, approximately 7,300 total square feet of pavement surface had voids beneath it that ranged from 0.5 to 40 inches in depth. The project summary states that if the pavement were to fail, its impact would impose an approximate 1.1 million dollars of daily users cost to the travelling public.
“The use of GPR provided a means to evaluate the extent of the problems associated with the pavement settlement,” Graves said. “Using this information, along with the information gained from the water chemistry, [crews] were able to isolate the repairs to specific areas instead of replacing an entire section of the tunnel roadway.”
The study determined that the best remediation strategy was to replace the existing limestone sub-base material with granite and rebuild the continuously reinforced pavement. The initial proposal was to replace approximately 2,800 feet of pavement in each tunnel at an approximate cost of $10,000,000. The GPR and HGWT results, however, reduced costs in excess of $5,000,000.
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For more information contact: Brad W. Rister, P.E.; (859) 257-7331, brad.rister@uky.edu
Amy I. Terry, Communications and Marketing Specialist, (859) 257-7466, amy.terry@uky.edu