ASPHALTopics | Fall 2015 | VOL 28 | NO 3

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The results of the testing showed that the mixing and compaction temperature is significantly lower using either of the two recommended testing procedure – sometimes by as much as 15°C for heavily modified asphalt cement (refer to figure right). Why is this significant? When we raise the temperature in the lab, the volumetric properties of the mix are changed. Because the mix is easier to compact, it is likely that the asphalt cement content will be lower at four per cent air void content required for Superpave mix design. The difference will be even greater with Marshall mix design. Remember why the equiviscous concept was introduced – for any particular aggregate blend, the air void and asphalt cement content should be the same regardless of the asphalt cement chosen. This does not seem to be the case anymore. Many of our premium mixes using more highly modified asphalt cement appear to have much lower asphalt cement contents than the same mix made with a PG 58-<strong>28</strong> which is not modified. It’s time for a change. Up to this point, I have been talking about laboratory mixing and compaction temperatures. Remember, we need the temp-vis chart so that two labs get the same volumetric results. But how does this apply to plant mix production and field placement? In August 2011, the Asphalt Institute’s Technical Advisory Committee issued a guidance document titled Determination of Laboratory Mixing and Compaction Temperatures for Hot-Mix Asphalt. Here is a quote from that document: PROJECT MIXING AND COMPACTION TEMPERATURES The Asphalt Institute reminds the reader that laboratory mixing and compaction temperatures are intended for determining design volumetric properties of the asphalt mixture and are not intended to represent actual mixing and compaction temperatures at the project level. In a hot mix asphalt (HMA) facility, the mixing temperature can best be defined as the temperature at which the aggregate can be sufficiently and uniformly coated. As with the lab temperatures, the mixing temperature should not exceed 177°C (350°F). The compaction temperature for HMA is usually in the range of 135-155°C (275-310°F) and is based solely on the ability of the compaction equipment available for the project to achieve adequate in-place density. It is hoped that the move to a different methodology for measuring the temperature and viscosity will not only go back to the original intent of the making the asphalt cement content independent of the asphalt cement modification, but also make the laboratory mixing and compaction temperature similar to those used in the HMA production process. The Ontario asphalt binder suppliers have chosen to study this issue this winter by evaluating the Steady Shear Flow procedure performed in the Dynamic Shear Rheometer (DSR) against the standard rotational viscosity procedure. Samples will be collected and evaluated and hopefully suppliers will agree on a procedure to be used in the 2016 paving season. This will likely also include some mix testing of typical Ontario mixes. Stay tuned – this should be interesting. 38 OHMPA | ASPHALTOPICS
ENVIRONMENTAL ESSENTIALS by Christina Wright Higher fees coming to HWIN: A good time to review your hazardous waste The Hazardous Waste Information Network (HWIN) website is where generators, carriers and receivers of subject waste (as defined under Regulation 347 of the Environmental Protection Act) are required to register their subject waste activities with the Ontario Ministry of the Environment and Climate Change (MOECC). Examples of subject waste from an asphalt plant may include: chemicals from labs, wet scrubber sludge, used oil from maintenance activities, spilled asphalt cement, or contaminated soil. All facilities that generate subject waste must identify their appropriate waste codes and register these waste codes on their HWIN account. Annually this “generator registration” must be reviewed and renewed by February 15. The MOECC is proposing increases in the HWIN waste tonnage fee from the current $10/tonne to $20/tonne starting in 2016 and $30/tonne starting in 2017. This is a significant cost increase if your facility generates a lot of subject waste. The manifest fee of $5/manifest and the annual registration fee of $50 will remain the same. How can you reduce your waste costs? Confirm you are using the appropriate waste characterization codes. The more hazardous the waste characterization code, the higher the waste disposal costs. If you are relying solely on your waste carrier to determine your waste characterization codes, consider getting a second opinion. Further, if you or your waste carrier are relying on old waste characterization testing data (e.g. a leachate toxic test), consider getting new test data. Don’t over characterize your waste! Don’t mix your wastes together or with other materials. Not only does this increase the total waste tonnage requiring disposal, but the mixed waste may now have a more hazardous waste characterization code. Remember, intentional waste mixing at your site (such as “diluting” your waste) is considered waste processing by the MOECC – this activity is permissible, but it requires a specific waste ECA permit. For more information on HWIN visit the HWIN homepage at https://www.hwin.ca/hwin/index.jsp Christina Wright is Environmental Compliance Specialist at BCX Environmental Consulting, a Canadian environmental engineering company specializing in providing expert environmental consulting services. FALL <strong>2015</strong> 39
Page 1: FALL 2015 | VOL28 | NO3 Asphalt Inn
Page 5 and 6: PRESIDENTIAL POINTS by Steve Smith
Page 7 and 8: LETTERS FROM THE ED by Vince Aurili
Page 9 and 10: MARCOM MATTERS by Abigail Wright Pe
Page 11 and 12: of asphalt innovation by Lisa Fatto
Page 13 and 14: “One of the fastest ways to stimu
Page 15 and 16: “Asphalt is 100 per cent recyclab
Page 17 and 18: Twenty years ago Louisiana had an i
Page 19 and 20: 5 yr Safety Record for OGFC:I - (Di
Page 21 and 22: Better education and awareness abou
Page 23 and 24: ERATURE CONTROL SYSTEM “The V-Pac
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Page 27 and 28: questions about the effect of binde
Page 29 and 30: Outside influences, including acces
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Page 35 and 36: Aurilio... again Shortly afterward
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Page 41 and 42: COOLING ASPHALT BURNS DVD NOW AVAIL
Page 43 and 44: It’s All About Relationships

ASPHALTopics | Fall 2015 | VOL 28 | NO 3

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