What we don’t know about pavement preservation

Any economical extension of pavement service life has a significant benefit for long-term life-cycle costs. Preventive maintenance activities can substantially extend the pavement service life (or keep it from prematurely failing). The simple concept of higher costs for deferred maintenance becomes more difficult when the objective is quantifying the cost tradeoffs, and selecting among maintenance alternatives. The focus of this paper is to examine why this task is difficult, and to evaluate what we need to learn in order to improve the procedures for analyzing maintenance tradeoffs. The paper will be limited to asphalt concrete pavements (ACP), but the concepts are very similar for portland cement concrete pavements (PCCP). Current budget constraints in Washington State necessitate the development of new strategies with regard to preventive maintenance. Even if the optimum long-term rehabilitation plan for a particular section of roadway calls for a capital construction rehabilitation project, there may not be funds available to complete the construction. This situation has resulted in the development of preventive maintenance strategies for the purpose of delaying or avoiding capital construction spending. These strategies include: (1) addressing early distress, (2) correcting short distressed sections, (3) maintaining and “holding” sections that are currently due for rehabilitation, and (4) integrating preventive maintenance with rehabilitation strategies.