A holistic approach to flexible pavement design improves performance

The purpose of the paper is to share knowledge, stimulate discussion about a number of existing pavement design issues, and discuss a practical methodology for translating materials knowledge and research into design and construction to achieve client expectations of pavement performance. The Austroads Pavement Design Guide provides a wealth of background and theory for a design practitioner to design a pavement that will satisfy the road ownerrs expected performance. However, it is the authorrs view that the final output from the mechanistic design process has to be based not only on the design guide and CIRCLY analysis but also incorporate engineering judgement, experience and practicalities of construction. Pavement performance can only be guaranteed by both a sound pavement design strategy and ensuring the design parameters are achieved by a construction process which requires direct communication between the designer and the construction crews, in terms of the construction methodology, materials and testing. The paper reviews a number of concepts, such as subgrade and asphalt strain criteria, design modulus, terminal condition and performance indicators, and brings together a range of information, research and developments, and in-service case studies of achieving quality, performance and value for money with a pragmatic design approach.