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"“…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

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50 years of experience
3,000+
PSP participants
23,000+
samples shipped per year
1,000
laboratory assessments per year
1,900+
accredited labs







  • Changes to the AASHTO Accreditation Program

    You may have noticed that our program has undergone quite a few changes over the last year. We have modified some of our operations in an attempt to keep up with customer expectations and to ensure we remain a trusted and reliable source of accreditation services in the construction materials industry.
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  • I Received A Low PSP Score, What Next?

    You just received an e-mail notifying you of low PSP ratings. This means that at least one of your scores was more than two standard deviations from the grand average, or that your laboratory did not submit data. (If you want more information on what ratings mean and how we calculate them, please review Proficiency Sample Ratings: Being Average Has Never Been So Good).
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  • Maintaining AASHTO Accreditation, Maintaining Quality

    Being AASHTO accredited shows that your laboratory is serious about quality. However, the process isn’t over after AASHTO accreditation is initially granted. By maintaining accreditation, you are showing your continued commitment to excellence.
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  • Top 6 Uses of the AASHTO re:source Proficiency Sample Program

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  • A Beginner’s Guide to AASHTO Accreditation

    I get asked a lot of questions about all of our programs. Some of the most commonly asked questions are regarding the AASHTO Accreditation Program (AAP). This is understandable, as it can seem like a daunting task for a new laboratory to get the accreditation process started.
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  • The Last Guy Didn’t Write Me Up On That!

    Gigs and dings and bones to pick…oh my! We at AASHTO re:source refer to these things by their proper name… “nonconformities.” So what’s the story behind why the last assessor didn’t “write you up” on something? That depends on lots of things – the test methods, the laboratory’s personnel, random sampling, our learning curve, miscommunication, and just plain human behavior. Let’s dig a little deeper into why two assessments of the same laboratory most likely will never be identical.
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  • Reality Calibration

    I have a confession to make. Although I’ve been an outspoken critic of “Reality TV,” there is one show that I sometimes watch with my wife. It’s called “Married at First Sight” and in each season six people agree to participate in an extreme experiment: Each pledges to legally marry a complete stranger. No dating, no talking, no getting-to-know-you period. It’s not just that they have never met; they don’t know a thing about their future spouse, haven’t even seen a glimpse of them, until the actual marriage ceremony. (I’m not sure how this actually resembles reality, although my wife sometimes thinks that I’m an alien.) You can probably guess how these marriages work out: they usually don’t. The couples struggle because they don’t know how each other will respond to certain situations. How many of us would agree to that type of arrangement?
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  • Evaluating Competency: How do you measure up?

    Raise your hand if you’ve received a nonconformity related to training and competency evaluations. Good. The first step is admitting it. Whether the finding has been minor and easily resolved, or it has required you to revamp your entire training and competency evaluation program, just about everyone has been there before. When it comes to the array of requirements, options, and best practices, there can be a lot of confusion about what you are supposed to be doing. AASHTO R 18 and ASTM quality system standards such as, C1077, D3666, and E329 can all have differently worded requirements, which can add more confusion to the issue. This article will help hone your understanding of documenting competence and interpreting the requirements of quality system standards.
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  • Ask AASHTO re:source!

    Why doesn’t AASHTO re:source provide enough soil to properly perform ASTM D698 and D1557 on the proficiency samples? Why aren’t extra proficiency samples (XPS) available for emulsified asphalt and paint?
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  • A Series on Safety - Eyewear

    As an employer in the United States, you have the legal responsibility to provide a safe workplace. The specific requirements that apply to your company or laboratory are not as simple as black and white. While the Occupational Safety and Health Administration (OSHA) does have requirements, the uniqueness of the hazards to each workplace situation leave the ball in your court to determine your hazards and use the OSHA requirements to protect your employees. For this first article, I’d like to go over protective eyewear requirements. This is a great example of an issue that seems like it should be really easy to decipher. The further we investigate the requirements, the more gray areas appear.
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  • What's the Difference? Accreditation, Certification, and Related Terms

    As we look back on 50 years of contributions to quality and excellence in materials testing at AASHTO re:source, we reflect on the largest turning points that have led to the program’s success. One such event that marks a proud moment in AASHTO re:source history occurred in 1988 when the AASHTO Accreditation Program (AAP) was established. The program was developed to provide a mechanism to formally recognize the competency of construction materials testing laboratories. (Check out The History of the AASHTO Accreditation Program for more information.) As we look back on this historic occasion, we reflect on the term “accreditation” and its essential role in construction materials testing.
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  • Soil Classification – The Bigger Picture

    The names Atterberg, Casagrande and Terzaghi are well versed in the soil mechanics industry. Back in the fall of 2014, Tracy Barnhart wrote a wonderful article on the ‘Three Musketeers in Soils Testing: Atterberg, Casagrande, and Terzaghi’. This summer, we have decided to expand on the works of one individual in particular, Casagrande, and his development of the Unified Soil Classification System (USCS).
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  • Did You Know?

    Some tips, tricks, and interesting facts to make life in the testing laboratory just a little bit easier.
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  • AASHTO re:source and CCRL: Two Organizations, One Mission

    The AASHTO re:source and the Cement and Concrete Reference Laboratory (CCRL). At first glance their relationship can be difficult to understand. To be fair, it’s pretty complicated.
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  • Top 5 Findings of Moisture-Density Relations of Soils

    Here are the most common findings AASHTO re:source assessors observe while laboratories are demonstrating AASHTO T 99, ASTM D698, AASHTO T 180, and ASTM D1557 test methods and some tips on how to prevent them.
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  • The Importance of Aggregate Correction Factors in Air Content of Freshly Mixed Concrete (ASTM C231 and AASHTO T 152)

    Of the approximately 1,200 laboratories that performed ASTM C231 during the 35th CCRL inspection tour, about 20 percent received at least one finding for this test. Of those findings, about 85 percent were a result of aggregate correction factors not being determined. Another common nonconformity is using the factor incorrectly in the calculation of the actual air content.
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  • Did You Know?

    Some tips, tricks, and interesting facts to make life in the testing laboratory just a little bit easier.
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  • Debunking Myths about the AASHTO re:source Proficiency Sample Program

    The AASHTO re:source Proficiency Sample Program (PSP) was created in March 1966 as a mechanism to evaluate testing competency by comparing the results of each participating laboratory to a large body of laboratories that are testing the same material. The program also provides laboratories with the means to check both the testing apparatus and the operator under actual testing conditions. Originally there were only four basic material types in our program. The program has grown extensively over the years and we now distribute fifteen different sample types each year.
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  • Balances 101

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  • Three Musketeers in Soils Testing: Atterberg, Casagrande, and Terzaghi

    Who in their right mind invented a test that involves making “worms” out of soil? Albert Atterberg, that’s who! The Atterberg limit tests, commonly known as liquid and plastic limit of soils, are named for Albert Mauritz Atterberg, a Swedish chemist and agricultural scientist. Atterberg was born in 1846. In 1872, he earned his Ph.D. in chemistry from Uppsala University in Sweden. Atterberg taught analytical chemistry at Uppsala for several years before becoming a principal of the Chemical Station and Seed Control Institute in Kalmar, Sweden.
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