Monitoring Pavement Changes in a Rehabilitation Project with Continuous Rolling Dynamic Deflectometer Profiles (05-2545)
Jeffrey Lik-Yeung Lee, Consultant, Australia
Kenneth H. Stokoe, University of Texas, Austin
Dar-Hao Chen, Texas Department of Transportation
Miles Ralph Garrison, Texas Department of Transportation
Boo Hyun Nam, University of Central Florida

The success of a rehabilitation project which involves replacing the AC overlay on a concrete pavement often depends on assessing the existing conditions and repairing critically weak locations. A case study is presented where the Rolling Dynamic Deflectometer (RDD) was used to collect continuous deflection profiles at different stages in such a project. The project, conducted by TxDOT, was located in the Atlanta District. The condition of the pavement was monitored in each stage using the RDD. The stages ranged from before milling the original AC overlay to 22 months after the new overlay was placed. Deflection profiles measured after milling were used to identify locations with a high potential for reflection cracking. After the overlay was placed, profiling was repeated at three different times to: (1) monitor changes at locations of previously high deflections, (2) evaluate the effectiveness of full-depth repairs, and (3) group the new overlay, which consisted of different AC test sections within the project, according to the condition of the underlying concrete pavement. It was found that continuous deflection profiles performed at the start of a rehabilitation project can be used to identify high-deflection locations that, if not repaired, will likely deteriorate rapidly after the new overlay is placed. The continuous deflection profile measured on the concrete pavement after milling was particularly helpful in identifying high-deflection locations that are irregularly spaced. Continuous deflection profiles, measured at various times after placement of the new overlay effectively tracked the zones of deterioration.