Performance based approach for evaluating the optimal timing of preventive maintenance strategies

Historically, transportation departments concentrate resources on building new roads, but in the last few decades the focus has moved towards maintaining and preserving existing pavement surfaces. Starting from the 1990’s many studies showed the importance of maintenance for pavement performance, and in particular they focused on preventive maintenance. It was demonstrated that maintenance, if applied at the right time, not only can extended the service life of an existing road but also, if the treatment is done when the pavement is still in good condition, it can be more effective. It is now understood that preventive maintenance has a critical effect on pavement management, not only from the point of view of the quality of road surfaces, but it is also cost-saving, since it allows the pavement to last longer. The effectiveness of preventive maintenance is linked to the timing of its application. In fact, late intervention can prove to be useless and cause only a loss of money. A problem that affects preventive maintenance is the lack of knowledge and guidelines for the staff that deals with maintenance on a day-to-day basis. In common practice, pre-established treatments are often applied regardless of the type of distress, traffic, and timing of the intervention, thus wasting resources without guaranteeing any substantial improvement in pavement performance. This thesis focused on these problems and specifically on the optimal timing to establish the specific treatment that, if applied at the right time, guarantees the best benefit/cost ratio depending on the road system, type of pavement and traffic. To accomplish the objectives, the following tasks were performed: - Analysis of pavement deterioration data to establish performance curves that describe how the pavement performs without maintenance depending on the road system and the traffic. - Analysis of the preventive maintenance treatments to determine their adequate range of application and their performance over the years. - Identification of the optimal timing for application of preventive maintenance treatment considering the cost-effectiveness and performance of each treatment with sensitivity analysis on roads, traffic and costs. This work focuses on a Virginia case study and it uses data that reflects the transportation conditions of this State. Although this is a very specific case study, the research methodology and the conclusions can be generalized to apply to a variety of pavement maintenance situations encountered by highway agencies. This work shall represent a first attempt to achieve complete analytic comprehension of preventive maintenance treatments in order to develop guidelines that optimize the performance of the selected preventive maintenance treatment. Future research should be focused on the development of models that describe the performance of the treatments over a long-term period.