ABSTRACT
Pavement preservation provides a means for maintaining and improving the functional condition of an existing pavement through application of a set of treatments that prevent the intrusion of moisture, slow deterioration or correct localized defects. It also means, in simpler terms, deferring costly pavement rehabilitation or reconstruction to a later time. While pavement preservation is not expected to increase the structural capacity of pavements, it can lead to improved performance, longer service lives, and reduced life cycle costs. Often anecdotal information has been used to incorporate preservation treatments into the pavement management decision-making process. There are, however, plenty of data to assess the effects of preservation treatments on pavement performance. For example, data from the U.S. Long-Term Pavement Performance (LTPP) program, or highway agency data typically stored in pavement management system databases are both excellent sources. There is also a wealth of information available from research studies carried out throughout the world. This paper shows the use of the referenced data to model the effects of thin overlays on pavement performance, both immediately after placement and long-term. The performance measures selected for use in this analysis are rutting and roughness. It was found that the LTPP data provided much more detail than State data, although both sources resulted in similar conclusions. Mainly, thin overlays reduce rutting and roughness in terms of immediate condition and improve long term performance.
