Performance of Polyethylene Parting Strips in PCC Pavements

There are two techniques for constructing longitudinal joints allowed by the Wisconsin Department of Transportation (WISDOT): (1) sawing; and (2) insertion of polyethylene parting strips during construction. Secondary cracks parallel to the longitudinal joint and concrete spalling have been observed in several portland cement concrete (PCC) pavement projects constructed using parting strips. To evaluate the performance of parting strips in the formation of longitudinal joints in PCC pavements, an extensive database was developed. This database involved visual observation and laboratory analysis of cores taken from distressed and nondistressed areas. Visual observation involves collecting data regarding traffic condition and the distress type and severity. Laboratory analysis involves the collection of cores and their analysis to determine the possible causes of distress. An investigation of 60 core samples taken from 20 sites, a positive statistical correlation was found between the amount of spalling and parting strip installation variables including depth, angle, and variance. A statistical model developed verifies the assumption that an improperly installed parting strip leads to spalling along the longitudinal joint.