Impact of climate conditions on effectiveness of asphalt pavement preservation techniques

Pavement preservation is practiced by many highway administration agencies throughout the world. Pavement preservation also attracts much attention from agencies that have few or no such programs. How to choose the most effective treatment at a given location, however, remains a question. On the basis of data from the Specific Pavement Study 3 of the Long-Term Pavement Performance program, the study reported in this paper examined the impact of climate conditions on the effectiveness of asphalt pavement preservation techniques. Six climate zones were defined on the bases of number of wet days, freeze-thaw cycles, and number of days below 0C. Within each climate zone, performance differences on graphical representations and paired t-tests were assessed for four types of treatment sections and control sections in terms of the international roughness index (IRI). The magnitudes of the IRI changes caused by these treatments were in general quite noticeable, but the effectiveness varied greatly with climate condition and treatment type. Statistically significant treatments at each climate zone were reported in the study. All four types of treatments significantly reduced IRI growth under two climate conditions: (a) warm and dry and (b) wet and cold. In addition, chip sealing and thin overlay treatments seemed more likely to succeed in different climates.