Non-Destructive Measurement of Pavement Layer Thickness

摘要

The overall objective of the reported work has been to rapidly determine the average pavement thickness on a newly constructed pavement section to within 0.1 inch of the true value, without extensive reliance on cores. The project has been divided into two tasks--0ne for asphalt pavement and one for concrete pavement. The asphalt task has focused on two adaptations of ground penetrating radar (GPR), one involving the use of an air-launch horn antenna, and one using dual ground-coupled antennas in a common midpoint (CMP) measurement mode. The concrete task has included the CMP method and conventional Impact-Echo methods. The work has involved theoretical analyses, laboratory testing on small slabs and simulated pavement materials, testing at full scale pavement test facilities, and testing on I I newly constructed pavement sections in California. The California test sites included full depth asphalt, asphalt overlays, and full depth concrete pavements. The thickness data collected with the tested devices has been correlated with thickness results obtained from over 170 cores taken at points in the test areas. For the asphalt pavements, both GPR methods have been shown to be capable of measuring the average. section thickness to within 0.1 inches of the average core value. The CMP method. however, appears to be limited to asphalt thickness greater than 3 inches. For the concrete pavements, the two impact-echo methods tested were shown to be able to measure the average section thickness to within 0.16 and 0.24 inches of average core value. All of the methods required the use of a single calibration core per site to achieve the reported accuracy.