Case Study: Measuring Thickness of Concrete Pavement in New Highway Test Section, Arizona

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Problem: Determine thickness of new highway pavements placed on different sub-bases, including aggregate, permeable asphalt, and lean concrete.

Results: Independent measurements of wave speed were used with impact-echo tests to measure thickness at eight locations.

Verification: Cores.

Outcome: Uncertainties in measured thickness were 1% for pavement on lean concrete sub-base, 2% for asphalt sub-base, and 3% for aggregate sub-base. Results contributed to preparation of new ASTM Standard, C 1383 98a, entitled, "Standard Test Method for Measuring the P-Wave Speed and the Thickness of Concrete Plates Using the Impact-Echo Method", approved by ASTM in December 1997.