A PERSPECTIVE OF FLEXIBLE PAVEMENT DESIGN AND CONSTRUCTION PRACTICE

This paper reviews some of the revisions to flexible pavement design and construction practice in many countries worldwide, which have been based on research results and adaptations. These revisions have two common factors. There is a comprehensive approach to design, to consider parameters and factors such as traffic loads, subgrade strength, material properties, environmental aspects, temperatures, moisture, drainage, cross-section elements, and construction and maintenance strategies. This approach allows for the relationship between pavement distress and stress, strain, and deflection caused by traffic loads. There is also an analytical approach to analyse structures, using results from laboratory test and in-situ road tests. Further developments include pavement performance modelling and its use in establishing rational design procedures, and whole-life-cycle cost analysis of structures to support design choice. For example, in India, the pavement design procedure of Standard IRC:37-1984 is being modified and reviewed to meet changing needs, and research projects, such as the Pavement Performance Study, are in progress for modelling pavement performance and validating design procedures. More research and development are needed, for example on Benkelman Beam and FWD deflection measurements and on durable pavements.