Western Australia Chapter

Pavement Materials and Design in WA

Geoff Cocks

The talk will outline the different factors to be considered in the design of flexible pavements for Ports, Mine Haul Roads, Airports and low volume Highways and Local Roads. The special case of pavements over highly expansive clay (Gilgai) will be discussed. On solar salt crystallizers, the crystallized salt forms the pavement supporting harvesting and haulage equipment. An approach to assessing the load carrying capacity of crystallized salt pavements will be presented.

The origins of the current Austroads pavement design procedure and its limitations will be examined.

Extensive use is made in Western Australia of low cost marginal quality natural gravels for construction of pavements on low volume roads. An explanation will be given about the origin of WA selection criteria for natural gravels. The reasons why the criteria are different for laterite, ferricrete and calcrete gravel compared to crushed igneous rock, will be outlined. The relationship (where one exists) between the various tests and pavement performance will be discussed. Have you ever wondered whether it really matters if the material being used has a plasticity index or maximum dry compressive strength that is outside the specified range?

Engineers Australia members participating in AGS technical sessions can record attendance on their personal CPD logs. Members should refer to Engineers Australia CPD policy for details on CPD types, requirements and auditing guidelines.