Integrated Asphalt Mix and Pavement Thickness Design Based on c-Φ Concept

摘要

Due to their empirical basis, the traditional mix design methods such as Marshall and Hveem methods have proven to be inadequate to address current in-service performance problems and pavement thickness design. The Superpave mix design method is a performance-based mix design system, which aims to predict material properties, pavement response, and pavement distress during service. It is theoretically sound, but impractical due to its complexity, lengthy test period, high costs involved, and unsatisfactory performance models. The purpose of this study was to explore the possibility of using c-Φ(cohesion and angle of friction) concept as an analytical tool for asphalt mix and pavement thickness design. The study of applying the c-Φ concept to asphalt paving mix design was once an active research area in the early 1950s. Further research, however, was not pursued subsequently probably due to the complexity and long duration of the laboratory triaxial tests, and difficulties encountered in relating the test results to field behaviour of paving mixtures. Today, with much more advanced test equipment and powerful analytical and computation tools, a re-look at this theoretically sound approach is justified. Finite element analysis was performed to study the stresses of full-depth and multi-layer pavements under load. The computed stresses were then incorporated into appropriate rutting and fatigue models to determine whether the selected asphalt paving materials or pavement thickness could satisfy the design criteria of rutting and fatigue. Finally, a numerical example was given to demonstrate the complete procedure of the proposed integrated mix and thickness design method.