Concrete Highway Pavement Load Capacity for Possible Future Increases in Permissible Axle Loads

From time to time there is discussion within Government and industry about measures to improve freight transport efficiency. These discussions often include increasing permissible axle loads. If this was to happen it may also be limited to major road transport corridors. This paper neither supports nor sets out a case for such increases. However, it would be informative from an engineering perspective to assess the effect of such increases on future thickness requirements and the load carrying capacity of the existing inventory of concrete highway pavements either in service or under construction totalling approximately 850km. Using the current Australian national pavement design guide, related concrete highway pavement design criteria and contemporary weigh in motion axle load data, future thickness requirements and the load capacities of existing pavements for a possible range of increases in axle loads are discussed. Although thickness design includes some consideration of load transfer across joints, and cracks in CRCP pavements, this paper deals primarily with the effects of axle loads on thickness design and not detailed issues associated with joint and reinforcement design that would largely remain unaffected

This presentation looks at the issues around theoretical future increases in permissible axle loads. Two main topics include:

1. Thickness requirements new concrete pavements
2. Load capacity of existing concrete pavements

Furthermore, the included presentation looks into four principal factors:

• Major road transport corridors considered
• Pavement structure
• Traffic loads
• Design procedure