Performance monitoring of heavily trafficked flexible pavements

A monitoring program was established in 1980 to evaluate the performance of a number of heavily trafficked flexible pavements in Vi#toria. The objectives of the program was to provide feedback on pavement design, construction methods and guidance for maintenance planning. Currently twenty-six pavement sections having a total test length of 613 lane kilometres are being monitored. Most of these pavements have been constructed in the last ten years, and deflection testing shows that they will not need reshaping due to excessive rutting within the design period. However, the program has highlighted road sections where the deflections have increased to or above the design level. By early detection of these sections, ameliorative maintenance treatments have been undertaken to inhibit the rate of pavement deflection increase. About half of the asphalt surfaced pavements are showing significant areas where the pavement stiffness is insufficient to resist premature cracking of the asphalt. These pavements were constructed before 1980. They had a lower asphalt thickness than required by current design standards and were constructed without a cement treated crushed rock sub-base, whereas a cement treated crushed rock sub-base would now be used to stiffen the pavement. The ride quality of all pavements is good. The monitoring program is providing feedback on the 1987 NAASRA pavement design guide, providing appropriate design deflection and curvature values. The results to date tend to suggest that the Shell fatigue relationship underestimates the fatigue life of asphalt surfaced pavements (A).