REHABILITATION OF A JOINTED PORTLAND CEMENT CONCRETE PAVEMENT ON I-35 (SOUTHBOUND) IN KAY COUNTY, OKLAHOMA

As part of the SHRP Long Term Pavement Performance (LTPP) Studies, numerous projects are being constructed to study various design strategies for new and rehabilitated pavements. These studies are referred to as Specific Pavement Studies (SPSs). One SPS rehabilitation study specifically targets the rehabilitation of jointed concrete pavements (SPS-6). Specific designs have been prepared and implemented to incorporate seven of the more common concrete pavement rehabilitation strategies, along with a control section. Sixteen such projects are to be constructed around the country. Included in these treatments are asphalt overlays of the jointed concrete both with and without cracking and seating, as well as various other features in an attempt to enhance the performance of these rehabilitation strategies. One of the 16 planned projects was constructed on I-35 in Kay County, Oklahoma, in the fall of 1992. The existing project featured a 0.2-m (8-in.) jointed reinforced concrete pavement, with a 0.1-m (4-in.) sand cushion, over 0.2 m (8 in.) of soil aggregate subbase on a silty clay subgrade. As part of the SHRP LTPP program, performance data have been collected on each test section before and after construction. Although the experimental sections in Oklahoma have not been in service long, distinctions in performance are already apparent. Performance of the sections in Oklahoma appear to indicate that a 0.1-m (4-in.) asphalt overlay of jointed concrete pavement (JCP) can be expected to exhibit reflection cracking within 2 years under typical interstate traffic. Reflective cracking can be controlled to some extent using sawing and sealing of the asphalt cement overlay and can be controlled even more effectively using rubblizing. One must consider, however, that the performance referenced herein may be unique to environment, subgrade type, and traffic levels, to name but a few.