The Queensland Department of Transport and Main Roads is set to publish a Technical Note to allow thinner asphalt pavement design in Queensland, opening the way for cost savings and more innovative asphalt mixes.
Heavy duty asphalt pavements like those typically used on south east Queensland motorways could realise significant savings using the new Technical Note (TN167), particularly in combination with the department’s Pavement Design Supplement.
Recent research by the department, undertaken in partnership with the Australian Road Research Board through the National Asset Centre of Excellence (NACoE), has demonstrated that thinner asphalt pavements can be adopted in Queensland’s warm climate without detracting from pavement performance.
TN167 brings this research, and research outcomes from Austroads and the Australian Asphalt Pavement Association (AAPA), into a single practical guide for design engineers and asphalt producers.
Through the Technical Note this research can be put into practice on ‘real world’ projects, where real cost savings will occur. Initial reductions in pavement thickness of 7% are expected using conventional asphalt mixes, and is possible to make further reductions through the use of more highly engineered (optimised) or innovative mixes.
Implementing all options in the TN167 would realise (indicative) savings of around $850,000 per kilometre for a typical six lane motorway in south east Queensland.
Perhaps most significantly, the option to develop mix-specific flexural modulus master curves and fatigue models is expected to reduce the barriers to innovative, high performance asphalt mixes such as high modulus asphalt (EME2) and mixes with (innovative) polymer modified binders.
TN167 has been consulted widely with industry stakeholders and is due for online release in February 2017. Once published it will be available free from the Transport and Main Roads website, with background research reports and training webinars available from the NACoE website in the future.