Evaluation of strength characteristics of recycled asphalt pavement materials

Neumann, Philip M. and Somasundaraswaran, Kathirgamalingam (2014) Evaluation of strength characteristics of recycled asphalt pavement materials. In: 26th Australian Road Research Board Conference (ARRB 2014): Research Driving Efficiency, 19-22 Oct 2014, Sydney, Australia.

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Use of recycled asphalt pavement (RAP) can reduce the cost of pavement materials significantly. In Queensland, the Department of Transport and Main Roads is reluctant to increase RAP usages and has placed stricter limits, allowing a maximum RAP content of only 15% by mass of mix. This is due to the fact that the presence of aged and stiffer binder can increase the resilient modulus of the mixtures and reduce fatigue life if no allowance is made. Researchers' suggest adapting a low grade binder as an option when using higher percentage of RAP. This research was to assess whether using a softer binder could help to improve the fatigue life of high percentile RAP mixtures. The mix design tested was a dense grade 20mm base course. Experiments were carried out to find the mechanical properties of batches comprised of 0, 15% RAP with same binder and 30%, 45% and 60% of RAP with one step lower level binder. During batching all possible efforts were taken to maintain homogeneity between the samples, and effective binder volume was adjusted for air voids before estimating the actual modulus. The results were used to estimate the fatigue life using the Austroads' fatigue model. It was found that mixing higher percentile RAP together with the binder one grade lower than usual can be effective in reducing residual modulus and improving fatigue life of the pavement. However, there is also potential to overcompensate, yielding softer mixes which may be more susceptible to rutting. It was also found that 60% mix could give similar mechanical performance to a conventional mix. In summary, using the softer binder had the greatest impact on blended binder fatigue life so Australian guidelines can be improved to make the most effective use of recycled asphalts where further studies are required.

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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Paper)
Refereed: Yes
Item Status: Live Archive
Additional Information: © ARRB Group Ltd and Authors 2014. Permanent restricted access to published version due to publisher copyright policy.
Faculty/School / Institute/Centre: Current - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying
Date Deposited: 13 Apr 2015 06:21
Last Modified: 19 Jun 2017 04:09
Uncontrolled Keywords: recycled asphalt; road materials; asphalt pavement
Fields of Research : 09 Engineering > 0912 Materials Engineering > 091299 Materials Engineering not elsewhere classified
09 Engineering > 0905 Civil Engineering > 090503 Construction Materials
09 Engineering > 0905 Civil Engineering > 090507 Transport Engineering
Socio-Economic Objective: B Economic Development > 88 Transport > 8801 Ground Transport > 880106 Road Infrastructure and Networks
URI: http://eprints.usq.edu.au/id/eprint/26935

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