In many countries, the traditional heavy-duty pavement type is thick asphaltic concrete (AC) on unbound aggregate and granular subbase courses. This type of flexible pavement structure relies principally on the AC for stiffness, and traffic loading tends to generate high tensile strains in the AC. Consequently, this type of pavement carries a relatively high risk of flexural fatigue in the AC, especially if vehicle overloading is prevalent. When a mechanistic model is used in design, with horizontal tensile strain criteria for flexural fatigue, the benefits of a stiffer subbase become apparent. This approach favours the use of a cement stabilised or lean-mix concrete subbase to support the AC. This composite type of pavement, also called semi-rigid, may be constructed like a flexible pavement without joints, and with compaction by rollers. The paper illustrates the above design principles with examples using the Austroads pavement design method, based on the elastic layered model CIRCLY. (Author/publisher) For the covering entry of this conference, please see ITRD abstract no. E208431.
Samenvatting