Pavement distress considerations: Bannister Road, Canning Vale, Western Australia

Pavement was widened both sides using 200 mm limestone or recycled pavement sub-base and the existing pavement reconstructed using a conventional granular overlay approach. The existing asphalt was removed, followed by placement of 150 mm minimum thickness of crushed rock followed by application of a prime 10 mm seal and 30 mm of dense graded asphalt. Within a few months, crocodile cracking of the asphalt surfacing was observed despite what was considered to have been a very well prepared and controlled construction programme. This paper describes the approach that was used to investigate the early onset of surface cracking. Thorough measurements of the composition, condition and stiffness of the pavement layers were undertaken. Movement of water, derived from rainfall and irrigation sprays, into the asphalt surface and then the upper zones of the base course early in the life of the pavement together with a lower than expected quality base course material, are identified as the most likely causes of the distress. (a) For the covering entry of this conference, please see ITRD abstract no. E213488.