Evaluation of Design Techniques for Extra Heavy-duty Flexible Pavements and Other Critical Considerations

The design of heavy-duty flexible pavements for highways is well-established in the United States, Europe, and Australia. However, a standardised design methodology for extra heavy-duty flexible pavements–specifically tailored for ports and intermodal container terminals–remains lacking. These pavements present unique challenges due to significant variations in several load repetitions, load magnitudes, long-term static loads, tyre pressures, wheel and axle configurations, and loading characteristics, with axle loads reaching up to 120 tonnes. Existing design methods are often influenced by industry interests, such as concrete interlocking pavers, concrete, and asphalt, leaving pavement practitioners with limited tools to optimise designs for the extreme load conditions encountered over the pavement’s design life. Traditionally, extra heavy-duty pavements are considered high-risk areas due to their high failure rates and the substantial costs associated with such failures. This study provides a comprehensive review of existing design methodologies and software available internationally, critically compares these methods, and discusses other critical considerations to mitigate the risks of extra heavy-duty pavement failure. The literature review reveals that the development of develop unified design guidelines for extra heavy-duty flexible pavements intended to withstand severe axle loads up to 120 tonnes or more would require further research in this area.