Investigation of a million tonnes of Ontario hot mix asphalt (2015-2018)

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Since 2011, Laboratory Standard 299 - Asphalt Cement's Resistance to Ductile Failure and Laboratory Standard 308 - Performance Grade of Physically Aged Asphalt Cement have been implemented for acceptance of over 1.5 million tonnes of hot mix asphalt (HMA) for the Ontario Ministry of Transportation and various municipalities (Durham, Kingston, Niagara, Peel, Timmins, Waterloo, York). The Ministry's objective has been to provide contractors with an opportunity to improve their ability to specify asphalt cement (AC) that meets performance warranties while municipalities have implemented in an attempt to stave off more premature cracking. Imperial Oil supports the research because it produces top-quality AC from Cold Lake, Alberta, at its refineries in Edmonton and Nanticoke, Ontario, and it therefore has a vested interest to see improved specifications implemented. It is possible, or even likely, that samples from the AC implementation initiatives since 2011 were mixed up or contaminated and that HMA was mixed with too much recycled pavement (RAP) or shingles (RAS) and/or overheated during production. It is also recognized that current acceptance criteria for LS-299 and LS-308 are likely too permissive and need tightening. Finally, a third method, LS-228 Accelerated Aging Using Modified Pressure Aging Vessel, is needed in addition to LS-299 and LS-308, to effectively deal with the early cracking. These issues need to be investigated in order to provide the best advice to stakeholders on how to construct pavements that provide value for money. This proposal requests matching funds to develop and validate methods that help ensure that future roads last longer. The research deliverables include: (1) an extraction and recovery protocol for AC; (2) a standard for detecting waste engine oils in AC; (3) a standard for detecting polymers in AC and HMA; (4) LS-228, LS-299 and LS-308 test results for up to 100 AC and HMA samples; (5) additional validation of LS-299, LS-308 and LS-228; and (6) a rheological quality assurance test for small quantities of recovered AC. Once the results of this research are obtained, the knowhow will be transferred to stakeholders for the betterment of the asphalt industry.