FLEXIBLE PAVEMENTS - RESULTS OF VICROADS PAVEMENT PERFORMANCE MONITORING PROGRAM

In the late 1990's, VicRoads reestablished its long term Strategic Pavement Monitoring Program with the principal objective of reporting general trends in pavement condition using roughness, rutting, pavement deflection and visual condition as the principle indicators of pavement performance. This information can then be used to develop pavement performance prediction models suitable for inclusion in HDM4, recently implemented by VicRoads. In addition, it is anticipated that the monitoring data will also enable Austroads pavement design and overlay design procedures to be further refined. The program incorporates monitoring of heavily trafficked unbound granular pavements at 9 sites varying in age from 10 - 23 years with cumulative in-service traffic loadings as high as 2 x 10 7 ESAs. These pavements are surfaced with a sprayed seal and typically incorporate up to 400 mm of high quality crushed rock placed over lower quality crushed rock and select fill materials. Considerable data is now available which clearly confirms the excellent performance of these pavements, particularly in relation to pavement roughness and rutting. Trends in the data confirm that these pavements will continue to provide satisfactory long-term performance. Also included within the program are 5 deep strength asphalt pavement sites that were established initially under the Strategic Highway Research Program (SHRP) long term pavement performance (LTPP) studies. Monitoring of the 5 sites, which are all located along the Western Ring Road, began in 1994. Deep strength asphalt pavements in Victoria typically consist of not less than 175 mm of asphalt overlying a high quality cement treated subbase. In expansive subgrade environments, a thick non-expansive capping layer is placed beneath the cement treated subbase. Trends in roughness, rutting and pavement deflection are now available and this data may ultimately assist with establishing performance based specification criteria. The pavement monitoring program also now incorporates assessment of the performance of pavement rehabilitation and surfacing treatments in various locations throughout Victoria. The treatments include cementitious stabilization, granular resheets, and asphalt regulation combined with geotextile reinforced seals. This new focus is a significant expansion from past pavement monitoring programs that concentrated largely on newly constructed pavements.