The effects of reflective cracking on the performance of recycled asphaltic pavement overlays were investigated. Two 1/2-mi sections for full removal of the existing asphaltic pavement and replacement with recycled material on the existing crushed gravel base course were selected. The pavement performance after partial removal of the existing asphaltic pavement and placement of a recycled overlay was compared with the performance after complete removal and replacement with recycled asphaltic pavement. Severe tenting (called tenting because of the tent-like structure produced at transverse cracks) developed during the freeze months of January, February, and March. The present serviceability index (PSI), an indicator of ride quality, deteriorated from 3.4 In october 1985 to 1.7 In february 1986 (on a scale of 0 to 5, 5 being the best). In an attempt to solve this serious tenting problem, three different treatments were applied to the pavement. Retrofit edge drains were installed in 1987 to remove infiltrated water from the pavement structure. Retrofit transverse drains or transverse interchannel flow (TIC) drains were installed in 1988 directly under the transverse cracks to remove the infiltrated water. Crack sealing was performed in 1988 to prevent water from entering the pavement through the transverse cracks. Reflective crack study results in the 7-year period 1981 to 1988 indicate 58% more transverse (reflective) cracks occurred in the partial removal and recycled overlay sections than in the full removal and replacement sections. The performance, as measured by psi, deteriorated at a faster-than-normal rate, which appeared to be increasing. The retrofit edge drains and retrofit tic drains were found to be ineffective in solving the tenting problem. Transverse crack sealing appeared to be somewhat successful.
Abstract