Performance of an Unbonded Concrete Overlay on I-74 Physical research rept. (Final) 1995-01

摘要

In Illinois, the typical rehabilitation for a concrete pavement is full-depth patching of the distressed concrete, and overlaying the pavement with 3.25 inches of bituminous concrete. In cases where there are poor joints or extensive durability cracking of the existing concrete pavement, a 5-inch bituminous concrete overlay may be placed. When bituminous concrete overlays reach the end of their service lives, common distresses are reflective longitudinal and transverse cracking, reflective cracks from transverse joints and patches, and reflective D-cracking. Once concrete pavements have deteriorated to the point where the performance of a standard bituminous concrete overlay is questionable, constructing an unbonded concrete overlay may be considered. An unbonded concrete overlay leaves the existing concrete pavement and any bituminous concrete overlays in place. A new concrete pavement is constructed on top of the existing bituminous concrete overlay or a new bituminous concrete interlayer. In 1995, the Illinois Department of Transportation constructed an unbonded concrete overlay on Interstate 74 east of Galesburg. The existing pavement was a 7-inch continuously reinforced concrete pavement, with a 4-inch bituminous aggregate mixture (BAM) base. The existing bituminous concrete overlay ranged from 3 to 4.5 inches thick. The unbonded concrete overlay is 9 inches thick. This report describes the performance of this project through 2001, and the status of unbonded concrete overlays in Illinois.