Effect of PG XX-34 on Transverse Cracking in Minnesota

The Minnesota Department of Transportation (DOT) adopted the use of performance-graded (PG) asphalt binders in 1997. In 1999 the Minnesota DOT required PG XX-34 binders for all new (not overlay) bituminous construction with the objective of reducing the amount of transverse cracking. Pavement management data were used to track the development of transverse cracking on PG XX-34 projects. The transverse cracking rate of the PG XX-34 projects was then compared with the cracking rates for similar projects from the pre-PG era. The comparison found that after 7 years of service, transverse cracks on the PG projects were developing at approximately 1/10th the rate experienced before performance grading was implemented.