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This is the Summer 2017 edition of the quarterly BINDER TECHNICIAN NEWS brought to you by the Asphalt Institute.

Ask Mike

Michael T. Beavin
Technical Training Coordinator
Asphalt Institute


Question: Recently, we received a low score on an AASHTO re:source proficiency sample test but was within the limits in the test procedure. Are the results acceptable or not?

Carmen Iglehart
Chemist
Texas Department of Transportation


Answer: Complicated question! There are a few things to keep in mind when comparing your AASHTO re:source proficiency sample results to the maximum allowable variability calculated from the precision and bias estimates in the published test methods.

Think of the precision and bias estimate as a way to grade yourself. For the same reasons your parents wouldn’t be thrilled if you came home with a report card full of Ds, a technician shouldn’t be content with 
two test results that barely fall within the limits.

As an example, a technician produces two test results, 1.32 kPa and 1.40 kPa and calculates the maximum allowable difference between those results based on the single-operator precision for original binder G*/sinδ
. The acceptable range of two test results for d2s is 6.4 percent. 6.4 percent of the average of the two results is 0.09 which is greater than the actual difference. Good news? Not so fast. Yes, the results fall within the limits statistically. They ‘pass’ but they would get a ‘D’ on a report card or the equivalent of a zero, one or two Z score. As you know, a score lower than three requires a response. This is kind of like maintaining a minimum GPA to keep your scholarship. Get a ‘D’ once or twice and it’s not the end of the world but make it a habit and…you get the picture. The actual difference between the two results would result in a very low proficiency sample Z score.

Again, excellent question. The full answer would require more space than we have here, so thank you! You’ve just handed me a future feature article.


Submit your binder question to Mike Beavin for future newsletters.

Need an NBTC class or recertification? Here are our 2017 dates:

November 14-16, 2017

We look forward to seeing you in Lexington!
Mercury falling
    
“You used to be much more… 'muchier'. You’ve lost your muchness.”- Mad Hatter to Alice.



How do you go about losing your muchness? Diet and exercise? Hatter wasn’t complimenting Alice on a slimmer figure; he was referring to what makes her… Alice. Her personality, drive, ambition, social skills. In ‘reality’ it was probably Hatter, not Alice, who was changing. Of course, he would have to be forgiven if this were true because he was being poisoned by something he worked with every day.

Hat makers in the mid-1800s commonly used mercury in the felt making process. It produced a superior felt to that made using, wait for it… camel urine. Yup, I’ll leave it up to the reader to verify that detail. Problem was, mercury is highly toxic and causes tremors, irritability, mental instability, emotional changes and worse. So, let’s climb out of the rabbit hole and take a look around your binder lab. How many little fragile crazy bombs do you have lurking? If your lab has been around for more than a few years, there’s an excellent chance you’ve looked at some of the silver stuff on the wrong side of the thermometer glass. When you did, you performed a by-the-book mercury spill cleanup, I’m sure. Not a speck could have wobbled away and made its home in an out-of-the-way nook in your hood or under a cabinet or in a seldom used drawer, right? Of course not, because over the years that crazy little silver ball would have been slowly vaporizing into your environment.

Over the last several years, the Asphalt Institute binder lab, in an effort to retain our ‘muchness’, has replaced several liquid in-glass thermometers with comparable alternative devices. This was an attempt to reduce potential mercury exposure in the event of a broken thermometer, but, in a few cases like distillation, flash point and softening point, finding an alternative to liquid in-glass was a bit more challenging. The lengths and diameters of the probes weren’t off-the-shelf. Regardless, in 2017 we made the decision to completely eliminate mercury-based thermometry in our labs and we were able to locate acceptable alternatives in every case. I’d like to say that this was entirely proactive but in reality, the final decision came about shortly after we were notified that our calibration company had stopped calibrating them; this after NIST stopped calibrating them in 2011. Mercury was falling and we didn’t want to be there when it landed.

One of the more common reasons I hear from techs for keeping mercury thermometers in the lab is that test methods require it. I also frequently hear that an alternative device isn’t available or that AASHTO re:source won’t allow it. I’ll be perfectly clear – there is no asphalt binder standard that requires a liquid in-glass thermometer, there is an acceptable alternative thermometer for every binder standard and AASHTO re:source allows the alternative in every case if it fits the published precision requirements.

The trend of reducing or eliminating mercury from laboratories is picking up momentum with many states either banning or strictly regulating the transport of mercury thermometers. Fewer and fewer calibration companies will standardize them. Accurate, stable and responsive alternative thermometry is readily available and you have AASHTO re:source's blessings to use them.

In the coming weeks, AASHTO 
re:source will be releasing a guidance document detailing approved thermometers and clarifying their stance on laboratory thermometry. In the meantime, feel free to contact me with any questions about our efforts to eliminate mercury in our work environment or for alternative thermometry recommendations.
 

TECH TIP



Ornery o-rings

O-rings being ornery? Need to snip off some of the time it takes to assemble BBR molds? Well, we have the fix for you!

All you need to do is alter the way you go about getting the little rubber rascals in place. Traditionally you use a thumb and index finger, grit your teeth and stretch them over the ends of the mold pieces; a process that ranges from kind-of-uncomfortable to downright painful depending on the newness of the o-rings.

We’ve found a simple, cheap tool that is going to change how you approach the task. At around ten bucks, this farmer’s friend (a band castrator) makes quick work of BBR mold assembly. Slip an o-ring over the prongs, squeeze and voila your o-ring is where it needs to be and your manicure will thank you. No more binder bits under the nails or mystery fingertip pain hours later when you are eating dinner.

So, head over to your local agricultural supply store and grab a new tool for the lab.



- Mike Beavin, Asphalt Institute Technical Training Coordinator
 

Technician Spotlight



Thomas C. Ludlum
HollyFrontier Asphalt Company LLC
Arizona Technical Laboratory Supervisor

 
Thomas has been testing asphalt binder for 10 years and considers himself a "lab rat." He supervises the HollyFrontier lab in Glendale, Arizona. He recently presented on terminal blended asphalt rubber at AAPT.

"NBTC has been able to help me identify areas where variability might occur during testing and how to address it to ensure that I produce quality work," said Thomas. He also said an additional benefit of the course was the opportunity to network with others in the technical community.

Learn more about this program at www.bindertechnician.com




The Asphalt Institute, in cooperation with the North East Transportation Training and Certification Program (NETTCP) and working with the AASHTO Materials Reference Lab (AMRL) and industry leaders, has developed one consistent, national PG binder technician certification. This map indicates the states that have USERS/PRODUCERS (in yellow), PRODUCERS (in green) and USERS (in brown) who have been nationally certified by the Asphalt Institute’s National Binder Technician Certification program.
 
Ultimately, the Asphalt Institute would like to see both certified users and producers in every state. There are now 39 states with users and/or producers who are nationally certified by the AI NBTC and the NETTCP programs. 
FREE TRAINING
Certification: What You Should Know About Training Binder Technicians (free)
Understanding the MSCR Test and its use in the PG Asphalt Binder Specifications (free)

(affordable technology, schedule at your convenience, pause-rewind-understand and email your questions)

 
BUY THE BOOK

Now only $50 in the Asphalt Institute online store. The second printing includes an Appendix on Multiple Stress Creep Recovery (MSCR) testing.
WEBINARS
Asphalt Binder Series
(4 - 2 hour sessions)
Recorded Webinars
Part 1 Intro to Asphalt Binders
Part 2 Asphalt Binder Testing & Specifications
Part 3  Asphalt Binder Testing & Specifications (cont.)
Part 4 Asphalt Binder Modification, Emulsions and Cutbacks

(affordable technology, schedule at your convenience, pause-rewind-understand and email your questions)
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Learn more at www.bindertechnician.com