Paper ID#: 148
Paper Title: Development of Roughness Thresholds for Preventive Maintenance of Pavements
Primary Author: K. Chatti
Abstract Text : In this paper, 462 pavement sections from thirty-seven projects in Michigan were analyzed to investigate the interaction between pavement surface roughness and distress. The main hypothesis of this research is that an increase in roughness leads to higher dynamic axle loads, which in turn can lead to a tangible acceleration in pavement distress. If this relationship is established, then it will be possible to plan a preventive maintenance (PM) action to smooth the pavement surface. Such a PM action is bound to extend the service life of the pavement by several years. The objectives of this research were to: 1) test the above hypothesis; 2) develop a roughness threshold; and 3) determine the optimal timing of the PM action. The selected projects include thirteen rigid, fifteen flexible and nine composite pavements. The Ride Quality Index (RQI) and Distress Index (DI) were used as measures of surface roughness and distress, respectively. The analysis showed good relationships between dynamic load-related distress and roughness for rigid and composite pavements (R 2 = 0.739 and 0.624); however for flexible pavements there was significant scatter (R 2 = 0.375). A logistic function was used to fit the data. Roughness thresholds were determined as the RQI-values corresponding to peak acceleration in distress. These were determined to be 64 for rigid pavements and 51 for composite pavements. A model for selecting the optimal timing of PM action was developed based on the reliability concept. The model uses actual RQI growth rates from 1382 rigid-pavement sections.