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If there is something that you’ve been dying to ask us, please let us know! We welcome any questions related to AASHTO re:source’s programs and services, and I will answer questions here in future newsletters. We may even use your questions as topics for future newsletter articles or webinars! For the inaugural column, here are some questions that we commonly receive about the AASHTO re:source Proficiency Sample Program.

Falling-weight deflectometers (FWDs) are used to collect important data that is used to characterize layer stiffness, and for planning maintenance and rehabilitation activities on highways and other major roads. Accurate data collection leads to a better prediction of maintenance and rehabilitation needs, which in turn leads to more effective planning and budgeting of these activities. Unfortunately, it is estimated that at this time only about half of the FWDs in use in the United States are regularly calibrated. This article will describe the primary sources of measurement error in FWD data collection and how the calibration protocol is used to effectively minimize these errors.

A frequently overlooked technical requirement of AASHTO R 18 and ISO/IEC 17025 is the implementation of an equipment maintenance program. Proper equipment maintenance helps to ensure that the most-used and valuable pieces of equipment in your laboratory are in good working order and ready for use whenever you need them. This, in turn, provides peace of mind and fewer headaches in day-to-day laboratory operations. This article will focus on how regular equipment maintenance can benefit your laboratory, as well as provide guidance on the elements of an effective maintenance program.

It’s tax time, so hearing the word “audit” may strike some fear in you today. No worries – I’m not with the IRS! That being said, AASHTO R 18, ISO/IEC 17025, and various other quality management system standards do require that construction materials testing and inspection agencies perform internal audits. R 18 states the following: “Internal audits shall verify that the laboratory’s operations continue to comply with its policies and procedures and the requirements of this standard (i.e. R 18).” R 18 also requires that internal audits be conducted at least every 12 months.

Some tips, tricks, and interesting facts to make life in the testing laboratory just a little bit easier.

We get a lot of questions from laboratories that are looking for a thermometer that they can use to replace their mercury thermometers. Unfortunately, there is no simple answer to that question, and folks tend to get a little frustrated when we don’t have the straightforward response they were looking for. Okay, okay, so I’ve never run into a customer quite as grumpy as this little green fella’ here, but I do understand peoples’ frustration. Why don’t we just get to the point already?

Our previous article examined precision and its importance in materials testing. This is the follow-up article in which we will address bias, which is the other component of the precision and bias statements frequently found at the end of AASHTO and ASTM test methods.

​Before we end this journey, let’s go over the road we’ve traveled thus far. In Part 1, you learned what a QMS is and some of the many benefits of having an effective QMS. I also discussed developing a quality policy statement and goals, and how a quality manual is the handbook to a QMS. In Part 2, I taught you how to get started with developing your QMS documentation, and you learned some tips to help ensure your documentation is effective. Now it’s time to head for the finish line! Along the way, I will be taking some U-turns to elaborate on a few things previously mentioned in my series, such as maintaining your QMS, getting buy-in from others, and document control.

Now that you have had plenty of time to read ”Making the Grade Part 1” and familiarize yourselves with sieve-related terminology, literature, and requirements, we will explore sieves a bit more in depth. In this article, I will explore the values in Table 1 of ASTM E11, Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves, explain the check requirements, and discuss sieve use in conjunction with mechanical shakers. I will also share some creative tips for repurposing your out-of-service sieves.

Some tips, tricks, and interesting facts to make life in the testing laboratory just a little bit easier.

Ever wonder what is actually behind the all of the AASHTO re:source proficiency samples you receive? How long it takes to process them, or where samples are shipped? Previous articles on this topic include: "Not Just a Box of Rocks: An Introduction to the AMRL Proficiency Sample Program," "Proficiency Sample Ratings: Being Average Has Never Been So Good," and "Getting the Most Out of the Proficiency Sample Program: A Guide to Our Online Features and Tools." These articles can give you a great understanding of the program, but they only tell you what you need to know. Check out this infographic for a visual representation of our proficiency sample program.

Precision and bias statements are those often skimmed-over sections at the end of the AASHTO and ASTM test methods. You know - the section after the “Report” and before the “Keywords” sections. Although these statements are easy to overlook, without precision and bias statements, test methods would have no merit. These statements are the evidence that proves that the test method works.

It's time to hit the road and get this QMS thing started! The first part of my series (Part 1 – Why Bother?) focused on the many benefits of developing and implementing an effective QMS. Let’s see where this road will take us next.

The dynamic shear rheometer (DSR), as described by AASHTO T 315, is arguably the most important apparatus used in the performance-graded (PG) binder system. The DSR is utilized in several instances as part of the binder grading specification, AASHTO M 320, and the provisional specification, AASHTO MP 19, which includes AASHTO TP 70, The Multiple Stress Creep Recovery (MSCR) Test. The MSCR test is performed on the DSR, and refers to AASHTO T 315 for calibration and standardization requirements of the apparatus.

It has been over a year since we started to request technician certification information during a laboratory’s annual review for AASHTO accreditation rather than during the on-site assessment if the laboratory is accredited for ASTM C1077, D3666, D3740, or E329. This change was made to improve the consistency of our assessment of laboratory conformance to the ASTM quality system standards that require technician certifications. A consistent evaluation ensures that all AASHTO-accredited laboratories throughout the country are treated fairly and that our program can better meet the needs of the agencies that specify accreditation for these standards.

Sieves come in many shapes and sizes and are used for a variety of materials. The purpose of putting a sieve to good use is always the same; separating particles into size fractions. You are probably familiar with sieving in some capacity – we use the process every day, sometimes without even realizing it! Whether you are sifting flour for a cake, panning for gold, drying your laundry, making coffee, or even checking to see if your carry-on luggage will fit in an overhead storage bin, you are sieving. Congratulations. Even your fingers can act as a sieve! Have you ever filtered through a handful of sand to find a sea shell or a lost piece of jewelry? Your fingers act as particle barriers, letting the smaller pieces of sand pass through, leaving the precious shells in your hand.

In my last article ("Uncertainty? There’s An App For That") I promised that we would further explore the numbers and the math that goes into estimating measurement uncertainty. As Churchill Eisenhart once said, “A quantitative result without any kind of uncertainty estimate is not only useless, it is dangerous because it can be misused.” Unlike bias, or systematic error, measurement uncertainty is always there and can never be eliminated. You have to know what it is and then deal with it. If you calibrate any of your own measurement equipment then you should be familiar with the process of estimating uncertainty. Even if you don’t calibrate any equipment, it helps to understand the development of measurement uncertainty estimates so you can evaluate calibration certificates from your service providers.

Some tips, tricks, and interesting facts to make life in the testing laboratory just a little bit easier.

​I've said it myself: without calibration, we have no confidence in the measurements that we take. And if a measurement isn’t meaningful, why even bother? Nevertheless, if you’ve read my previous articles, "The Anatomy of a Liquid-in-Glass Thermometer" and "Let’s Get Digital," you know that, up to this point, I have (intentionally) avoided the subject of thermometer calibration. So, if calibration is such an important subject, why have I been avoiding it for so long? The answer is simple: I’ve been procrastinating.

We experience pressure every day. Feeling the wind on your face, drinking through a straw, even sitting in your chair all give you sensations of pressure. So why can pressure be such a confusing concept to apply to laboratory testing? There are several factors. Pressure is measured in several different units – kilopascals, millimeters of mercury, pounds per square inch, and many others. Pressure can also be measured from several different perspectives, depending on the kind of equipment used. In addition, laboratory work may require the application of either a partial vacuum (also called negative pressure), or a positive pressure. Finally, there are terms for specific kinds of pressure (residual, partial, barometric, etc.) used in laboratory testing that can add to the confusion.