Learn how to be an AASHTO lab 24/7

"“…if you do everything that the AASHTO accreditation requires you to do, if you execute all of the requirements of [AASHTO re:source], you will have a well-run laboratory."

Florida Department of Transportation

Tim Ruelke, P.E., Director, Office of Materials

55+ years of experience
PSP participants
samples shipped per year
laboratory assessments per year
accredited labs

  • Proficiency Sample Ratings: Being Average Has Never Been So Good

    So you opened up your email notification to see that the latest AASHTO re:source proficiency sample ratings were just posted, you log into the website to view your ratings (Figure 1), and you see ratings of **, -5, -3, 5,4. You think to yourself, "I know that 4 and 5 are good, but what about the negative numbers? Those are below 3, so they must be bad... and what are the stars for? I doubt they're like the stars that my elementary school teacher used to give me... and what is this repeatability rating?"
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  • Metrology Musings: Calibration vs. Standardization

    I promised in the inaugural article of Metrology Musings that I'd discuss metrology topics such as calibration, traceability, and measurement uncertainty. Let's use these terms to compare and contrast the two most common, and most commonly misunderstood concepts: calibration and standardization. These terms are prevalent in many testing standards, as well as in AASHTO R 18, Establishing and Implementing a Quality Management System for Construction Materials Testing Laboratories, so it's important to understand the implications of each.
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  • Is Water More Than Just H2O?

    Many common test procedures require special kinds of water, such as tap, distilled, deionized, or deaired. What are the differences among these types of water? Why is it so important to make sure we are using the correct type of water for the correct test?
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  • A Day in the Life of an Assessor

    RING! RING! RING! - The hotel wake-up call abruptly starts my morning routine. In a familiar hotel room, but unfamiliar city, I groggily roll out of bed. So starts another day as an AASHTO re:source Laboratory Assessor on the road. I have to remind myself where I am - I'm just outside of Chicago today. Luckily I got in early enough yesterday to get settled in and this morning is starting off pretty well. Before I head to the laboratory, I grab a quick bite to eat.
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  • Standardizing Timers and Stopwatches

    Whether monitoring strain rates, determining flow speeds, or establishing drying intervals, timing is an important part of laboratory testing. There is a need to ensure that measurements taken with timing devices are meaningful and accurate. Timing is such a critical component of laboratory testing that AASHTO R 18 requires that stopwatches and timers used for testing are standardized at least every six months for some test procedures. By standardizing timers and stopwatches, the user can feel confident in the accuracy of the measurements taken with them.
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  • Quality Corner: What is Quality, Anyway?

    J.M. Juran, affectionately known as the Father of Quality, probably said it best- quality is fitness for use. Quality is defined in many other ways, such as conformance to requirements, a measure of excellence, and meeting customer expectations. No matter how you slice it, quality is always defined by the customer.
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  • The History of the AASHTO Accreditation Program

    The AASHTO Accreditation Program (AAP) was established in 1988 to provide a mechanism for formally recognizing the competency of testing laboratories to perform specific tests on construction materials. Some of you who know the history of the industry may be surprised that the AAP is so young because the AASHTO re:source and CCRL (Cement and Concrete Reference Laboratory) have been around much longer. In fact, the AASHTO re:source was founded in 1965 and the CCRL was established in 1929, as the Cement Reference Laboratory (CRL). The AASHTO re:source and CCRL are collectively known as the Construction Materials Reference Laboratories (CMRL).
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  • Metrology Musings

    Over the course of time I'll explore metrology topics such as calibration, traceability, uncertainty, and measurement standards. As we investigate and unravel some of these metrology mysteries we will determine what makes a good measurement - one that we can trust. We will think together and learn which questions to ask about our measurements. However, with this inaugural article about metrology, I'll keep it simple and fun by providing some interesting facts about metrology history.
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  • Not Just a Box of Rocks: An Introduction to the AASHTO re:source Proficiency Sample Program

    Thousands of laboratories in over 30 countries around the world participate in the AASHTO re:source Proficiency Sample Program (PSP). However, many of us never stop to think about the time, manpower, and logistics needed to produce and distribute these high-quality test samples. This article is intended to provide a better understanding of the complex process involved in proficiency sample production and analysis.
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  • Getting Rid of Mercury: A New Frontier for Temperature Measurement

    These are exciting times in the world of thermometry. Due to the efforts of the Interstate Mercury Education and Reduction Clearing House (IMERC), the way that we take temperature measurements is almost certainly going to change. The initiative has prompted states across the country to reduce the use of mercury and products containing mercury. As concerns over the use of mercury continue to grow, this trend is expected to continue. Several commonly used AASHTO and ASTM standards still require the use of liquid-in-glass thermometers for testing. The recent developments in mercury regulation have caused quite a stir in the construction materials testing community.
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