AAPA explains national harmonisation of asphalt test methods

Test methods for asphalt process control and product acceptance have been streamlined. AAPA explains why.

The Australian Asphalt Pavement Association (AAPA) has succeeded to harmonising key test methods used for asphalt process control and product acceptance across the country. For historical reasons, a range of local test methods exist used in different parts of the country. Although the differences between procedures in test methods are usually modest, they do impact test results and introduce uncertainty when comparing results between test methods.

Based on information from the AAPA National Proficiency Testing Scheme, and in close consultation with industry and road agencies, preferred national test methods were identified.

By eliminating local and less used methods, the industry can focus its efforts on the continual improvement of a much-reduced number of selected national test methods. Improvement of test accuracy, precision and reproducibility is of critical importance for the robustness of process control, product acceptance and pavement design. Other benefits of harmonisation include:

• Increased confidence in test methods

• Increased ease of knowledge sharing and technology transfer between jurisdictions and fields of practice (e.g. airports and roads)

• Streamlined testing process, less duplication in test equipment

• Lower test accreditation burden and transferability of materials testers across jurisdictions

• Increased transparency of differences between specifications

• Facilitate the gradual harmonisation of asphalt delivery across Australia

“AAPA members are committed to the continual improvement of the products delivered by our industry,” said Dr Erik Denneman, the Director of Technology and Leadership at the AAPA.

“As part of this drive, AAPA encourages stakeholders to coordinate their efforts and converge on a harmonised framework for the delivery of asphalt and sprayed seals in Australia.

“A prerequisite for achieving this goal is ensuring that test results and performance properties can be meaningfully compared between jurisdictions and product specifications.

“Clear direction for change is evident from the results of the AAPA 2017 National Proficiency Testing Round. Laboratories from all states and territories where part if this initiative. The proficiency testing round included various routine asphalt and aggregate tests. The results indicated that a single dominant national test method already exists for most tests. A large majority of results – about 80 per cent –  were reported against a single test method, while the remainder was reported against a range of alternative test methods. The results for maximum density testing are provided in the table below as an example. For this test a total of 97 results were submitted, 75 of those tests were performed in accordance with AS/NZS2891.7.1, with a small number of tests performed using other test methods. A similar distribution in the use of test methods can be observed for most other tests.”

AAPA has written to asphalt specifiers to request that all references to test methods in specifications are checked against this list. State Road agencies have stated their support for the harmonisation of these test methods.

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