MINIMUM MAINTENANCE APPROACH FOR THE DESIGN OF FLEXIBLE PAVEMENT IN THE TROPICS

For pavements subjected to moderate and heavy traffic, the most prevalent treatment is to place an overlay on the existing pavement. In Hong Kong, in mid 1993, the Highways Department implemented a pilot pavement management system (PMS) with the objective of studying the practicality of full scale introduction. The pilot PMS generated life cycle cost analysis of pavements using the World Bank's Highways Design and Maintenance Standard (HDM-3) to optimize maintenance investment decision-making. The low cost automated data collection systems introduced during the Pilot Scheme were versatile, powerful and adaptable to network surveys for pavement management purposes. This system is different in comparison with the SAMP, System Analysis and Management of Pavement, because it considers urban pavement management only. However, SAMP can be used to analyze the pavement management for urban and rural area by indicating it in the input. In addition, this system puts more stress on structural maintenance than on the economic design of the pavement. A computer model (known as PAVENET-R) based on genetic algorithms, was developed with the aim of solving the pavement maintenance-rehabilitation trade-off problem at the network level. An integer-coding scheme is selected for parameter representation in the model. Four numerical examples of road networks of 30 pavement segments, each with different relative costs of rehabilitation and maintenance activities, are analyzed. The solution of the analysis provided the complete program of repair activities by year and by pavement segment for four cases. All solutions satisfy the pavement performance requirements, that distress conditions and pavement serviceability are kept above their respective warning levels throughout the 20-year analysis period. The analysis of the convergence characteristics and other details of the solutions to the four different cases of the problem suggest the genetic algorithm approach is effective. (a) For the covering entry of this conference, please see ITRD abstract no. E204151.