Development of a Preventive Maintenance Strategy for Minimizing Roughness-Related Pavement Damage

Abstract

The Michigan Department of Transportation (MDOT) uses several measures of pavement performance in managing its pavement network, including the distress index (DI) and the ride quality index (RQI). Currently, decisions on when and where to take rehabilitation or preventive maintenance action are mainly based on the DI. The RQI is used only in a passive or reactive fashion: When DI reaches the threshold for poor ride quality, a decision to rehabilitate the road is made. MDOT is currently funding a research study to develop RQI thresholds for each pavement type (rigid, flexible, or composite) aimed at retarding pavement damage caused by roughness-generated, dynamic (impact) loading. These thresholds correspond to the RQI value at which pavement damage is accelerated by high dynamic loads. Given these new RQI thresholds, extending the service life of the pavement by taking preventive maintenance action in the form of smoothing of the pavement surface (by way of milling, grinding, or adding a thin overlay) becomes possible. New RQI thresholds are proposed in a proactive fashion in the context of preventive maintenance: The objective is to determine the opportune time and locations for applying relatively light maintenance to smooth the pavement surface, thereby minimizing dynamic (impact) loads and extending the pavement service life at minimal cost. For this purpose, a reliability-based model for selecting the optimal timing (or planning period) for such preventive maintenance action was developed using the new RQI-threshold and actual RQI-growth rates from in-service pavements. This model can be an effective tool to use in the context of preventive maintenance of pavements.