PERFORMANCE OF RESURFACING OF JRCP AND CRCP ON THE ILLINOIS INTERSTATE HIGHWAY SYSTEM. CIVIL ENGINEERING STUDIES. INTERIM REPORT

A study was conducted on the survival of asphalt concrete (AC) overlays on the Illinois Interstate highway system. Data were obtained from the Illinois Pavement Feedback Database (IPFS) for 410 AC overlay construction sections placed on continuously reinforced concrete pavement (CRCP) and jointed reinforced concrete pavement (JRCP) between 1964 and 1989. The overlays range in thickness from 1.5 to 6.0 in. Both in-service life and 18-kip equivalent single-axle loads (ESALs) carried to rehabilitation of the overlay were analyzed through the use of survival curves. The mean age and accumulated 18-kip ESALs at the time of overlay rehabilitation were estimated for each category of overlay thickness (thin and thick), pavement type (JRCP and CRCP) and PCC durability (with and without "D" cracking). Not quite enough data are yet available for CRCP sections to estimate means reliably. Results showed that each of the factors considered, along with traffic level, had a significant effect on the life of the overlays. The information will be very useful in improving the design of AC overlays in the future.