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Appendix E 2 Specimen Requirements

Wheel tracking specimens are normally prismatic with a plan area of 300 x 300 mm. The depth of the specimens in the Australian test will probably be in the range 50 to 100 mm. Procedures for the manufacture of slabs suitable for wheel tracking are described in Austroads test method AGPT/T220. Specimens cut from a pavement can also be wheel tracked, although a method of taking into account the effect of the (uncontrolled) thickness of these specimens still has to be developed. It has also been agreed that cylindrical specimens can be accommodated in the test method but these should be at least 200 mm in diameter.

The wheel tracking rate is dependent upon the air voids content of the specimens (although not to the same extent as dynamic creep) and, for standardised testing, an air voids content of 5% is usually specified. Specimens need to be brought up to the testing temperature and conditioned for a period at the test temperature to disperse any stresses due to handling.