Monitoring Pavement Changes in a Rehabilitation Project with Continuous Rolling Dynamic Deflectometer Profiles

The success of a rehabilitation project that involves replacement of the asphalt concrete (AC) overlay on a concrete pavement often depends on the assessment of the existing conditions and the repair of critically weak locations. In a case study, a rolling dynamic deflectometer (RDD) was used to collect continuous deflection profiles at different stages in such a project. The project, conducted by the Texas Department of Transportation, was located in the Atlanta District. The condition of the pavement was monitored with an RDD in each stage. The stages ranged from before milling of the original AC overlay to 22 months after the placement of a new overlay. The deflection profiles measured after milling were used to identify locations with a high potential for reflection cracking. After the new overlay was placed, profiling was repeated at three different times to ( a) monitor changes at locations of previously high deflections, ( b) evaluate the effectiveness of full-depth repairs, and ( c) group different AC test sections of the new overlay according to the condition of the underlying concrete pavement. It was found that the continuous deflection profiles obtained 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 were irregularly spaced. Continuous deflection profiles, measured at various times after placement of the new overlay, effectively tracked the zones of deterioration.