Learn how to be an AASHTO lab 24/7

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.

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.

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.

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

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.

We all know that AASHTO R 18 requires balances be calibrated at least every 12 months; however, there are additional factors that need to be considered in order to ensure that balances are kept in the best possible working condition. Knowledge of proper calibration procedures and balance maintenance is the responsibility of the laboratory. The handling and care of balances can change based on the use of the balance, so this article will address factors to consider when using a top-loading direct reading lab scale or balance.

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.

The objective of any standards development organization is to promote uniformity in their field. In regards to construction materials testing, the goal of organizations like AASHTO and ASTM is to promote uniformity and improvement of testing procedures. Even with uniformity in mind, differences in the wording presented in the standards continue to persist. This is mainly due to the fact that many of these standards development bodies have different participants with different perspectives (as I mentioned in Part I of this series). However, there is an effort underway intended to unify the language used in these standards called “harmonization.”

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

When I was Quality Analyst at AASHTO re:source, I encounter countless CCRL report findings regarding curing facilities. Since there seems to be a lot of confusion and misunderstanding regarding curing facilities and their requirements, I decided to write an article about them. The intention of this article is to clarify the specifications listed in ASTM C511, Standard Specification for Mixing Rooms, Moist Cabinets, Moist Rooms, and Water Storage Tanks Used in the Testing of Hydraulic Cements and Concretes, and provide tips on achieving conformance to the requirements of the standard. This article is not an exhaustive account for all mix designs, regional specifications, or capabilities of each laboratory.

Hi, I’m Brian Johnson. You may know me from such failed ballot attempts as D140, C1077, D3740, and the new standard that will probably never be published on sampling from a truck bed. You may also know me from a successful ballot attempt on D5404, D2172, D3549, D2041, D3203, D3666, and the AASHTO Accreditation Program Procedures Manual. Why did some of these ballots pass through while others have failed in such a glorious way?

Why did I receive low ratings on the samples even though my results meet the precision estimate of the test method? That is bogus! Okay, I made up the “bogus” part, but you get the general idea. Why on Earth does AASHTO re:source disregard the precision estimate information when determining each laboratory’s proficiency sample ratings? It seems crazy, doesn’t it? Allow me a chance to explain the method to our madness.

The comprehensive training program starts with the hiring and selection process. We pour through hundreds of resumes each year to select the candidates that we will interview for the position. We look for individuals with a technical background, excellent communication and interpersonal skills, and a desire to travel extensively. Because our assessment staff are the only face-to-face interaction that our customers have with AASHTO re:source, we take the communication and interpersonal skills of a potential candidate just as seriously as we do the technical skills.

Many of you may not know the name Hveem because you have never turned the handle on a stabilometer or watched the steel pellets fall into the bucket of a cohesiometer. If you are not familiar, let’s get one thing out the way so you can read this correctly – the name is Hveem, and it’s pronounced like “veem” and not like “huh-veem”, “H-Veem”, or the guttural-sounding “chuh-veem.”

Why can’t AASHTO re:source conduct on-site assessments only during the winter instead of during the busy construction season? We are swamped in the summer! On a related note, can you also please stop sending proficiency samples during the summer?!

In 2010, I wrote “A Day in the Life of an Assessor” about what it was like to be an AASHTO re:source Assessor on the road. Almost 4 years later, as a Quality Analyst (QA), I spend most of my time in the office working with laboratories in the AASHTO Accreditation Program (AAP).

Ah the dreaded customer feedback request. Don’t you hate being bombarded with those everywhere you go? Restaurants, stores, hotels, on-line retailers, customer service reps, AASHTO re:source, etc. – the list never ends! I mean, do they even do anything with that information? Yes! Or at least they should.

You should be proud that your laboratory has been through an on-site assessment and has completed the requirements of the AASHTO Accreditation Program. Once accreditation is granted, your laboratory’s accreditation status is available on-line from the Directory of AASHTO Accredited Labs. Your customers can view this accreditation listing and will likely use it as a method of determining whether or not you are competent to perform a given task. So, it makes sense that your laboratory also has a policy for ensuring the competency of the subcontractors and vendors that you use.

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

Although it’s not rocket science when it comes to shaking rocks, there is some “rock-it” science involved. Hence, there are some basic requirements you should understand when using a mechanical shaker to test aggregates according to the following standards: AASHTO T 27, Standard Method of Test for Sieve Analysis of Fine and Coarse Aggregates ASTM C136, Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates AASHTO T 30, Standard Method of Test for Mechanical Analysis of Extracted Aggregate ASTM D5444, Standard Test Method for Mechanical Size Analysis of Extracted Aggregate