AASHTO re:source Q&A Podcast Transcript

Season 4, Episode 3: May PSP Insights

Recorded: June 1 2023

Released: June 13, 2023 

Hosts: Brian Jonson, AASHTO Accreditation Program Manager; Kim Swanson, Communications Manager, AASHTO re:source 

Guests: John Malusky, Proficiency Sample Program Manager; Ryan LaQuay, Laboratory and Testing Manager; Joe Williams, Senior Quality Analyst, AASHTO re:source

Note: Please reference AASHTO re:source and AASHTO Accreditation Program policies and procedures online for official guidance on this, and other topics. 

Transcription is auto-generated. 

[Theme music fades in.] 

00:00:02 ANNOUNCER: Welcome to AASHTO resource Q & A. We're taking time to discuss construction materials testing and inspection with people in the know.  From exploring testing problems and solutions, to laboratory best practices and quality management, we're covering topics important to you. Now here’s our host, Brian Johnson.

00:00:22 BRIAN: Welcome to AASHTO Resource Q&A. I'm Brian Johnson.

00:00:25 KIM: And I'm Kim Swanson. And we have another one of those PSP insight episodes that I know I love so much.

00:00:32 BRIAN: We do, and our special guests today are John Malusky. He is the manager of the proficiency sample program.

00:00:41 BRIAN: John Malusky, welcome to the podcast.

00:00:44 JOHN: Thank you, Brian and Kim. Glad to be here for another exciting discussion about soil.

00:00:49 BRIAN: Next we have Ryan Lacroix. Ryan has a position that I can never remember the title of.

00:00:56 RYAN: I'm the laboratory and testing manager for the profession sample program.

00:01:00 BRIAN: And then we've got Joe Williams, senior quality analyst for the AASHTO Accreditation Program.

00:01:08 JOE: Happy to be here.

00:01:09 KIM: I am excited about this topic even though I don't know what we're actually going to talk about. I always love these PSP insight episodes. Because that I learned so much, because even though I've been a part of AASHTO for over 10 years, I still don't know really what's all happening on the technical end. So, I always learned stuff in these kind of episodes.

00:01:32 BRIAN: We'll see what we can do about that, John. Let's start with the soil classification and compaction sample. This is one of our larger samples that we send out. Can you talk about how we prepare this particular sample before we get into what happened with the results?

00:01:48 JOHN: So this year was, you know, pretty typical blend of material start out with. Say a crushed limestone this year, so it's not that. We've never used it before, but it seems to work well and give this a good homogeneous sample. And then we also we blended that material with a I believe it was a 20 mesh clay, if I'm if I'm correct, I'd have to go back and double check on it. You know, try to vary the size of the clay. Specifically, to adjust the values for hydrometer mean between the 30 mesh clay or 20 mesh or 200 mesh. It allows us to. To kind of change the sedimentation. Of that product but other. That pretty standard material for us.

00:02:28 BRIAN: I didn't realize that, so when you. Order the soil. You can actually order the particle size by particle size of the clay.

00:02:36 JOHN: I believe that the supply that we select has I think 7 or 8 different clays that we can choose from, and those clays vary in particle size based off of you know the milling process and that they use. But we can get it anywhere from like a #10 mesh all the way to a 200 mesh so. We could, you know, basically 100% of the clay could be passing the 200 and we could also get it. So, it's 100% passing the 10. Obviously, the gradation varies in between, but we can change it up and it's one of the techniques we use to help adjust the samples a little bit as it relates to gradation  and sedimentation.

00:03:15 BRIAN: And the answer to this one and one of the applications for that particular material.

00:03:20 JOHN: The materials that we specifically found that work well, especially when it comes to blending and homogeneous stability, are used in refract refractory products or refractory operations. So, bricks, any kind of molds or cast anything like that seems to work out very well for us when it comes to blending and processing the product.

00:03:42 BRIAN: OK, that's interesting, I said I learned something new. Kim, you're not the only one who learns things in these.

00:03:47 KIM: John, what goes into the thought process of if you're going to add more of this or less of that?

00:03:52 JOHN: So, when I go through the design process, I run some. Of the tests that. A laboratory would use for the, you know, or when they're participating. I'll take a look at things like hydrometer liquid limit, plastic limit, Proctor. There and just kind of play around and it it it's one thing to look at the numbers, but it's another thing to also look at consistency. If I'm running a liquid limit that unless I really put a high amount of clay in it, it seems to act more. Non plastic has a lot of a gritty texture to it. I might back off on the sand and. Add a little bit more. Play just to make sure that we have some plasticity in it. I also like to try to vary maximum density. You know, based off Proctor. So basically, look at the numbers and change it around. But one of the other things and I know this is going to sound so like elementary. But how mushy It is, like how squishy is it going to package well? And another thing is how dusty is the material when we blend it. I'm sure everyone who listens to this listen to this podcast, remembers the red stuff we sent out. think it was two years ago. Or a year ago.

00:05:00 RYAN: It's last year because it's all on my shirt right now.

00:05:02 JOHN: There you go. Yeah.

00:05:03 RYAN: In fact, they're doing one-year samples, so.

00:05:05 JOHN: So, Ryan's got the one year stabilities going on right now and that red clay blend that. We used was. Very, very high when it came to respirable dust. So, we did our best to contain it, probably going to eliminate it, but that is also a factor how it blends, how it looks, how dusty it is. So, we try to worry about many different aspects, not just the material properties and how they're going to relate to PSP and what the data is going to look like, but. Like I said, there's just some weird things that we got to worry about.

00:05:35 KIM: So how many like small little test batches do you do before you determine like this is it? Let's do this in bulk for everybody.

00:05:42 JOHN: So, I usually. Vary the proportions of sand and clay. I might start out with something like just. Easy 50/50, 50% clay 50% sand run a couple of tests, then I'll adjust it, you know. 45/55 You know, 40/60 mess around with. It sometimes if I'm feeling. A little excited. I'll go and throw some bent night in it to try to, you know, increase the water content for plastic limit or excuse me, liquid limit. Is it so? It just all depends on what we do. But like I said, we usually try to keep it within like a 10 to 15% range. And then when we do the design actually go for it. The samples need to be reasonably. Close so usually the percentages are within 5 to 10% of 1 another. We won't go too far beyond that just to make sure that we're staying reasonably close to each other.

00:06:31 KIM: Thanks for the insight on that. I never knew and again I've worked with you for a long. Time and I don't think I've ever thought to ask that question. So, thank you.

00:06:39 RYAN: And sometimes it works out easier than other times. This one go off his data. You tried four different blends before you hit the one you liked.

00:06:46 BRIAN: Well, the trial and error, I know that that trial and error has been a hallmark of the proficiency sample program forever, because you always try to mix it up and your predecessor would also try to come up with some interesting blends that would be not the same thing every time, because once you get too boring. In what you're providing, it becomes very predictable. What the results should be in the samples, so that's good. I know some people, you know, skeptics or critics would say, you know, you're trying to trick them, but it's just trying to make sure that we're still evaluating fairly instead of just giving somebody an easy answer every time. Let me ask you another question about these soil samples. I don't know if you're going to want to talk about this, but I know that the international shipping can be difficult for soil because of the implications of agricultural concerns, even though these are not.

00:07:47 BRIAN: We're not sending agricultural soil. We're sending process refined materials that are meant for construction. But how has that been going these days as far as getting soil shipped all over the world? Are we having any success getting it through where it needs to go?

00:08:06 JOHN: It depends on the country. It's very, very specific. We were struggling a little bit with the. Guam, that was kind of a little bit of a hurdle for us and actually Hawaii was also a bit of a. Challenge ended up getting into contact with some of the people at the Department of Agriculture in those respective locations. And once we explained what it was for, it wasn't for any kind of commercial use. It was for testing purposes. And how it's been treated prior to leaving our facility, they've been OK with it. So it cleared there without a our biggest hurdle right now has been Saudi Arabia. We are struggling like crazy to get not only the soil samples, but basically any sample through customs, you know through Saturday it's just been a super challenging effort. We are working with FedEx almost on a weekly basis at this point. And try to get those samples to the participants. Just working on different clearance for codes and customs.

00:09:07 JOHN: If there's any kind of permitting, the tough part for us is we've done some heavy investigation into permitting it from our end to get it through customs and the sample fees would have to go up probably fourfold for us to even make it feasible to get the product there, so that would you know, a fourfold increase in the fees would not even generate US revenue. That would be a break-even for those participants and for us. So, it's almost getting to a point where we're having those discussions about suspending service to Saudi Arabia and some of those other countries that. Were we're running into major challenges. And the tough part is, you know, the Saudis make up about 40% of our international business across the board. So, it's challenging what you know we don't want. To see that. Happen they use our products. We know they like it. We get a lot of positive feedback from that part of the world, but unfortunately, it's getting so challenging for us. They're not, you know, getting the service that they're asking for.

00:10:06 JOHN: So, it's just it's been tough lately, specifically with soil and Saudi and. You know the mixtures. I think, Ryan, what do we probably had 70. Percent of the. Mixture samples the asphalt mixture samples come back recently just because of the samples, not clearing customs and the other thing is too Saudi is very specific. They have a non-destroyed clause when it comes to shipment. Other countries will simply. Just throw the sample out and burn it. Get rid of it however possible, but Saudi Arabia has a no destroy clause in their protocol, so they will export it back to us at our expense. So that makes it challenging. We just shipped the sample paid for to get there and then we have to pay for it to get back and the lab still didn't get any. So just this is not really a a good system right now and it's not working out very well for us. So, we're having discussions internally about how to handle things internationally moving forward.

00:11:01 BRIAN: Well, that's really complicated. Hopefully the rest of the discussion goes a little bit easier. So, let's talk about the data, which should be more complicated, but well, let's maybe I should reserve. Judgement. John, what did we see this time? With the soil samples. So, we're talking about 187 and 180. Nine is the sample pair for the soil classification and compaction sample. What was interesting in the data, if anything, what kind of trends or what? What's the top-level analysis from that sample round?

00:11:32 JOHN: Pretty typical Brian, seeing a lot of similarities between previous. Pounds with the standard deviations. It was good to see that we had some consistency there. We're starting to get some more data coming out of the 7928, the Hydrometer that the newer version of the Hydrometer and able to make some comparisons and draw some similarities and differences between T. D8 and D422 so that's been good to see. We're getting, like I said, getting some more information there. You know, once again just another typical PSP had a little bit of variation in liquid and plastic limit, which was good. Same thing with the proctors. We had a little bit of variation compared to I shouldn't say variation as in material variation but variation as in average values. So, it was. You know, starting to also get more data here for soil resistivity and pH, the sulfate and chloride ion contents are a bit challenging. Those have come up a little bit different than we anticipated.

00:12:34 JOHN: They have a very high coefficient of variation, so the standard deviation is almost the same as the average. It's almost 100%, so at this point it's a little bit tricky. There's something going on there that we got to figure. Out we may have to go and try to do some work on the back end. Ryan and I might have to look at figuring out a way to make a sub sample for those and do some spiking to get the chloride and sulfate ion contents higher. But that's stuff that we have to have to play around with in the future, something obviously we can't go back and change now, but we have to look to make some improvements overall. But once again, you know, pretty typical round for. Us the one. S values are very consistent from year to year, so that's what we would like to see.

00:13:15 BRIAN: Ryan, what do you think about the chloride ion content results?

00:13:20 RYAN: Whenever you look at those two samples compared to everything else, there's. The a much larger standard deviation. Uh, you know, newer methods to us, something we haven't dealt with as long. So going back to our catch phrase of trial and error, we'll figure it out. Just might take us a few rounds.

00:13:35 BRIAN: Did you think that there are some potential improvements in the test method that could improve the overall performance?

00:13:46 RYAN: Great question, Brian. Off top my head, I'm not sure that we'll definitely look into it.

00:13:50 BRIAN: So, Joe handles the proficiency sample rules for accreditation. And he also handles a lot of the review of the sample rounds to see if there are any unusual results from an accreditation perspective. But I know we were talking the other day and noticed that there was a lack of participation in a few of the tests. How's that looking now?

00:14:15 JOE: Participation in those. PH and corrosion test is that definitely going up? Definitely a lot of labs are catching on that they do need to submit data for those that they're accredited for those or they're dropping those tests. If they don't want to maintain. That accreditation, I think. It's good to really quick summarize how we handle suspensions from PSP issues just to so. Everybody can keep in mind that it actually takes two years or. Or two sample rounds for a suspension to take place. It's two rounds of. The ratings of 0 or one on a single line item or data not being submitted for a tests or a combination for both. So, this sample round we had 144 suspensions that we need to process, that QA's need to process and. That's about 10% of the accredited labs that are enrolled in the soil.

00:15:09 JOE: The interesting part of that is that 124 of those 144 labs, the suspension is caused in some part due to data not being submitted. So I think as far as participation goes, that's something to really keep in mind that in most cases, if you participate and you submit data as you're supposed to. For your accredited tests. You'll probably be OK.

00:15:33 BRIAN: Especially with those standard deviations that John was just talking about.

00:15:36 JOE: Yeah, with those ion contents, I did take a look really quick, and we only had one suspension for 290 and that was because data was not being submitted. So, no labs were submitted for missing on their standard on those high standard deviations, so.

00:15:51 BRIAN: Some good insights. So, you remember you got to play to win. Make sure you submit that data if you're credited for a test or you really are putting yourself at a disadvantage and risk potential suspension just for lack of participation. Let's talk about the hydrometer. We did get some questions about why we continue to offer the old Hydrometer test, which we T88 and D422 and the new Hydrometer, which is a combination of a lengthy procedure for the gradation coupled with a lengthy procedure for the hydrometer on the finer particles and I cannot off the top of my head remember the ASTM test designations for those. Kim, can you help me out there?

00:16:40 JOHN: 7928 Brian.

00:16:43 BRIAN: So, 7928, and what's the gradation part?

00:16:47 JOE: 6913.

00:16:49 BRIAN: 6913, thank you. Thank you, Kim.

00:16:51 JOHN: Kim's voice just changes all the time.

00:16:53 BRIAN: Kim is she's got a little bit of a frog in her throat today.

00:16:58 KIM: I do thank you for noticing. I apologize for that. There we go.

00:17:03 BRIAN: We are working it out.

00:17:04 JOE: 6913 is not included in the program though it's. Just hydrometer, it's just 7928.

00:17:10 BRIAN: Ohh, is that right? Oh, I thought we were including. So OK, alright, my mistake. OK, so let's talk about that. How did the two compare this time? Are we seeing tighter standard deviations on the new Hydrometer? Are we seeing different results between the two, like significantly different? Why I shouldn't say significantly because it opens up a whole statistical significance conversation that we don't need to have. But are we seeing any larger changes between the results than expected, John?

00:17:44 JOHN: Taking a look at some of the standard deviations for D7928, they appear to be pretty consistent. One, the 1S value has been right around .002 for the. I guess this is the particle diameter at 4 minutes of sedimentation. So, we're seeing a lot of consistency across the board. This is just one example that I've cited here. When I go and look at the bigger picture in comparison to some of the values. From the former 422 or T88 and seeing how that compares to D79. 28 There's actually quite a bit of overlap when I take the data, and I, you know, just do an overlay on the two different test methods. See quite a bit of consistency. One thing I specifically targeted when I did some evaluation this time was looking at the particle. Diameter for 422.

00:18:42 JOHN: At the .001 millimeter and compared that to the D7928 particle diameter that was closest to .001. And that came out to be .0012 the standard deviation of those were right around the same it was about 3%. There was over 60% of overlap in the data, so 60% of the time a laboratory could have submitted the same data and got satisfactory ratings, which is pretty interesting to see how similar those two tests are. As the data turns out, even though they're completely separate test methods.

00:19:18 KIM: Do you want to see the overlap?

00:19:20 JOHN: I'm not sure I I would say this way. [KIM: OK.] I would anticipate that the data would be similar because you're still using a hydrometer, right? You know all of that stuff with Stokes, law and sedimentation, it should be similar if the material is similar. It's just that the prep. The procedure for 7928 is drastically different than D 422.

00:19:41 BRIAN: I mean, I think you'd want to see from the standards perspective, you make all these improvements cause you want to see it tighter tolerance. You want to see more repeatable results. And I think the other concept that we had talked about in one of the other episodes when we actually dug into this topic is. Through better methodologies for Prep. You should come up with a more true result of what that gradation or particle size analysis should be, and I know that was a big sticking point for switching to the newer standard. So those are the kind of things we'd. Want to look for but. It's hard to tell. OK, which one is more correct? Especially when you're looking at our proficiency samples. But I don't know how you could really determine that because the test result is what determines the trueness, right? So, I guess it depends if you feel that it's a scientifically sound methodology or not. Ryan, any thoughts on that?

00:20:48 RYAN: So, I actually just made a note to myself. This is something we could dive into once we have time and energy. We have the data, you know we can look at it over the years, see how well it's improving, see how well compared to each other. So it's a rabbit hole to go down at some point.

00:21:00 JOHN: Just took a quick peek here to try to, you know, ballpark the 1S values for that .001 millimeter particle diameter size. And they're very consistent between the two test methods. They're right around 3%, give or take, based off the material that we sent. But they appear to be fairly consistent, which like I said that that's what you would expect. They're following a similar methodology. You know, when it comes to sedimentation in a cylinder.

00:21:27 KIM: And we dive into this transition from ASTM D422 to D6913 and D7928. Could you tell I was reading those? Yes, you could. In season one episode 24 of the podcast if you want to go. Get some background on that from a few years ago. I'll put a link in. The show notes as well.

00:21:50 JOHN: This could go to Brian and Joe as well, but I was under the impression that one of the major reasons why we haven't moved away from D422 is simply due to specification. Is it still a major player in the industry?

00:22:04 BRIAN: Definitely. We still have a lot of laboratories accredited for D422, several 100 and the other issue is T88 is still a valid test method that is published by AASHTO, which is the equivalent of D 4/22. So, I think as long as those two are still. Being used? Then we'll. Still offer that in our program.

00:22:27 JOE: I was going to say the same thing. You know, that's with any ASTM standard, even if it's allowed to sort of sunset or they use the phrase come off the books. That just means it's not being maintained anymore. It's not being actively revised or kept up to date anymore, but the standard is still available on the ASTM Website agencies can still specify it, so just because it's not being actively maintained anymore, a lot of laboratories still want to be accredited for it or running it and being asked. To run it.

00:22:56 BRIAN: For those listening, I would like you to guess how many laboratories are currently either accredited or suspended for ASTM 422. Right now. The old hydrometer. Let's go around the horn. Ryan, you already looked it up, didn't you?

00:23:09 RYAN: That was that was what I had my hand raised for.

00:23:12 BRIAN: OK, we'll skip you, Kim.

00:23:15 KIM: Stay 500.

00:23:18 BRIAN: OK. All right, Joe.

00:23:20 JOE: Well, the only thing I looked at was the labs number of labs participating. In D422 and it was about a 1000 and change. So, I'm going to say.

00:23:34 BRIAN: Right. Ohh John.

00:23:36 JOHN: Kind of did the same thing Joe did. I looked at the number of labs who submitted data. And it was around 1000. I'm going to. I'm going to go a little more specific here. I'm going to just guess. And I'm going to say 849.

00:23:49 KIM: Alright, I would like the record to show that I just blindly picked a number. You guys actually did some research and I have no clue. So, I just want to throw that to the listeners that I just guessed. So just there we go.

00:24:02 RYAN: I'd like to bid $1.00, Brian.

00:24:04 BRIAN: Uh, no, but price is right. Rules do apply here, so our winner is Joe Williams because the number is actually 815. So close John was closer, but he overshot it. Yeah, I should have. I should have laid out the rules before we guessed, though. But I think in just in general around our office, the price is right rules to apply when we're guessing numbers. I don't know why that is, but we do.

00:24:32 RYAN: At least he wasn't pleasant.

00:24:32 BRIAN: That's not how we do. Our that's not how we do our proficiency sample. Getting this so I don't want people to get.

00:24:35 KIM: But I was just like, how often?

00:24:37 BRIAN: Confused by that view.

00:24:38 KIM: How often are we just guessing numbers as a staff like this is not. Terribly common, but maybe I'm just not in the right departments.

00:24:45 JOE: We did an app a good bit with these same kind of situations with these same kind of situations. How many labs are in this situation are accredited for this test? We'll let everybody take a guess, yeah.

00:24:57 BRIAN: Yeah, it is typically stuff like that. So, I don't want anybody to think that we're making accreditation decisions based on uh methodologies used by game shows. So we don't do that, but it's just if we're having some kind of trivial discussion. So hopefully people were interested in finding out that that many laboratories are still accredited for it because I think some people. I think that the use of that standard is really kind of falling out of fashion, and it really isn't.

00:25:21 KIM: Well, I had a question about that. Do you think that they are still being accredited for it and seeking accreditation for that? Standard just because. They've always had or do you think it is actually because they are, they're working on projects that are requiring that.

00:25:38 BRIAN: They're working on projects that are requiring it. I know I've heard, and I don't know if this has changed recently, but last I heard, the US Army Corps of Engineers is still. Uh, recognizing D422 and that is a massive specifier in the United States. So, there are a lot of laboratories that do that kind of work, and it's important for them to maintain accreditation for that test method. So, unless that changes, I don't see this number falling out anytime soon. And uh, I know that there were some people that thought that our charge was to facilitate the changeover to the new method and that is not what we do here. So, we kind of see what people are using and then we respond accordingly. But we're not trying to drive that change because we don't frankly know. If that is the change that needs to happen, only these specifying agencies would know that, Joe.

00:26:37 JOE: Yeah, just to kind of go back to a topic. We talked about a second ago on the same topic. John, is there any conversation or request to include 6913 in the PSP program? Which is the partner to 7928 the course particle gradation I have.

00:26:56 JOHN: Not had any personal discussion with anybody who wants it. I'm not sure if any of the feedback that we have solicited through the sample rounds that our quality manager collects has indicated that that we should consider adding it. If I do remember though. Brian, I think you and I had some discussion with some industry folks. About this and what we ended up talking about was that we would have to actually add aggregate materials in with the sample, we would have to go beyond +4 to ensure that we were getting a reasonable gradation for 6913 and that would have been a struggle. It would have caused homogeneity issues with the material and product and. Also production time if I remember.

00:27:37 RYAN: Yeah, pretty much the best approach to it would been having it be its own sample. We wouldn't be able to lump it. In with soil.

00:27:44 JOHN: Speaking of its own soil, one thing. That we may. Have to consider, especially for those the corrosivity methods. And the pH and resistivity that may be one thing where we have to break out into its own specific scope at some point looking at the data from previous rounds, the past few where we've had it, how we were talking about the coefficient of variation being almost equivalent to the standard deviation. That doesn't add a. Lot of value so. That might be something where we. Need to split out. Those samples and do a little bit more on our end. Add some material to spike it to actually get reasonable values that people can measure and that will allow us to take a deeper look into the standards themselves and see if we could make any improvements.

00:28:30 BRIAN: Yeah, there been some other soil samples people have been interested in, particularly geotechnical testing samples before we get into R-value in CBR, I wanted to ask you about. Whether or not there's been any movement on that, I know some people were thinking about sending out either loose material that can be compacted, or maybe some Shelby tube specimens that have been prepared, but I think that would be challenging. But where are we on that one, John?

00:28:59 JOHN: We're doing our best to work on it. And we can. It's a struggle. You know, Ryan had mentioned it. When we get the time and the opportunity, we try to take it to learn a little. Bit more we spend some time. We're actually working with our other resource staff members. To help facilitate and run our geotechnical course that we have that's been virtual and that asked to resource on site, they've all essentially reconstituted samples or prepared samples in house from materials that we had laying around from PSP. So they've gotten a chance to kind of play around with it. A little bit more. We're looking into using some of that methodology along with some of the other industry recommendations such as the under-compaction effort or method, and just trying to figure out a way to do it. But the hard part is trying to figure out a way to do it on a mass scale. If I remember correctly, we have almost 500 laboratories accredited for the various. Your technical tests.

00:29:58 JOHN: So, if you look at basic methods like consol, Shear. You, you and see you have to prepare basically one specimen for each one of those tests, and you do that in duplicate and that is a lot of time standing next to some sort of retrofit compression device that you're applying a certain amount of soil to for so many seconds. There is a lot that we have to research and continue to evaluate before we do this. But it at. Some point we are going to launch a program. It's it just probably won't be for a few years yet.

00:30:35 JOE: I've got one more thing on the soil. This is actually a question I got from a QA earlier today. This is about test standard D 4972. That's pH testing of soils. I was asked if the lab had to submit data for either the pH value in water or the pH value in calcium chloride or both, or how we were doing that. This is the third sample round that we've had this test. The first one actually only had one entry for pH value, but we've since then split them out. It is required that the laboratory submit data for both 4972. In the scope mentions that the measurements in both liquids are necessary are necessary to fully define the soils pH, and then the reporting section of that standard also indicates that they need to report the pH values in both liquids. So just a point of clarification there that laboratories. Accredited for that test need to be submitting data for both.

00:31:39 BRIAN: Anything you want to say, John, about that change from previous rounds to this round?

00:31:44 JOHN: Just that it was a recommendation from the industry. We had some laboratories contact us and they basically said hey, why did you do that, we said well. We originally just had it in water to try to keep it as simple as possible, and then they pointed us to the standards that it's actually extremely important for you to get the pH in the slurry. So please add it. So we did we take things like that into consideration all the time, especially with the data sheet comments and feedback. Yeah, I want to point out one of the other changes that we made. This year for soil resistivity, we actually specified the moisture content that. Should be used. When you're preparing your specimen to put in. The box and. That actually appeared to have dropped the standard deviation by about half. So rather than laboratories determining on their own what a saturated specimen looks like, we just simply said OK, 20% when we were playing around the lab doing our design work. That 20%, which looks like it's pretty saturated, so let's go ahead and use that. And it looked like it made a difference.

00:32:46 JOHN: I'm not going to 100% commit to yet because we need to see what a few. More rounds look like. But that may be something that could be viable for a standard revision in the future. If we see that we greatly improve the precision of a of a standard by simply specifying moisture content. So, kudos to all of the labs who are submitting feedback and letting us know what's going. On and hopefully. We can make some changes that are meaningful.

00:33:09 BRIAN: Brian, why don't you give us some insight into why that is the case?

00:33:13 RYAN: Anytime you can control a variable you know it brings in that accuracy. You know we're making that that target just that little bit tighter. You know, while it might not be the situation they're dealing with for our situation, any part we can control, we're going to have better results from.

00:33:28 BRIAN: Yeah, I thought you were going to get. The electrons and.

00:33:33 RYAN: No, we're, uh, I don't think we have time for that.

00:33:35 BRIAN: We'll move on then. Let's talk about some rounds that we've had for a really long time and people have been hammering out these CBRS forever, right? And we've got not great results typically as. Far as the. Coefficient of variation historically has been how are the CBR results looking these days?

00:33:55 RYAN: More the same. Pretty much, you know, if these were, uh, these were samples that you were running, you know, in your own lab, on your own project. Your CBR at .2 inches is greater than your CBR at .1. It's just you're running this. But for us, we're just looking for the results. That's all.

00:34:10 BRIAN: How's our repeatability looking though? How did the labs perform? The spread look like.

00:34:14 RYAN: Uh, we got a 1S of about 9:00 with the results of 26 and 31. Not great.

00:34:22 BRIAN: Lot of room for satisfactory ratings in there, which is which is good. So Joe probably not a whole lot of suspensions related to CBR, I assume.

00:34:33 JOE: No, this round we only had 10 total suspensions for CBR and again six of those ten and some part were related to data not being submitted, so get your results in.

00:34:44 BRIAN: That's right. If there's one take away from this episode, I think it is that you have to get your sample results in. It is a requirement of the program to be accredited. You do have to participate in the assessment program, and you have to participate in the proficient sample program. It's used as a tool for improving the quality of your testing. Of course, but you can't do that unless you submit the data.

00:35:09 KIM: Are you trying to say even if you think you have quote UN quote bad results, still submit the data?

00:35:14 BRIAN: Yeah, that's what I was almost saying, but I stopped short of saying that.

00:35:16 KIM: OK, you stop it.

00:35:19 RYAN: Right, well, so.

00:35:19 BRIAN: But thank you for correcting it.

00:35:21 RYAN: If it seems like something you're concerned about is your machine malfunctioning or something like way off base the big one we get is. We never see this type of material out here. These aren't numbers I see normally, but we've had people call like, hey, we had to call in external calibration service providers to come in and redo our machines because we thought we were wrong. It was just they went the results they were expecting.

00:35:45 BRIAN: Yeah, that's interesting. I guess that would be a good tip to have people check before they go through that process.

00:35:53 RYAN: Right. If it's something extreme, it's better to at least ask first, or at minimum submit it. Note it to yourself. Hey, we had concerns about this and there's your corrective action.

00:36:04 BRIAN: OK, sounds good. Let's move on to R-value. Are we seeing a decrease in the participation levels? For R-value.

00:36:12 RYAN: Let's say we have 135 this year. How's that? Trending, John, look right now.

00:36:16 JOHN: But if I had to guess, knowing what I know, it's been pretty consistent, plus or minus two or three labs each year. So it's been fairly stagnant for a very, very long time.

00:36:29 RYAN: 127 hundred 31132. Cool. Yeah, 120, so 100 and 30s.

00:36:34 KIM: For some perspective for our listeners, the soil classification sample had just about 2000 participants in it, where you're talking about the R value is has 130 ish and how many does the CBR have? Since I don't think. We talked about that.

00:36:50 JOHN: CBR's around 5:50 to 600, so there are quite a few more labs in CBR who still do it, but the one thing that really limits us with CBR is the potential for us to have material that actually. That's one of the things that's super tricky for us to try to manage. I kind of mentioned earlier that we may do something like blend some bent night in the material to try to get. It to swell. It doesn't seem to work very well. We checked homogeneity, still get reasonable numbers, but it's just something that it's almost like it's just when it's natural base. Underneath the ground that you're pulling the product from, it works out and you can see some swell or, you know, some expansive material. But it's really tricky for us to get it to blend in properly and it just it doesn't seem as well. As you would. See something like that in real world experience.

00:37:39 BRIAN: So, with R-value. We're looking for what properties?

00:37:44 RYAN: For R-value, all that we collect is the moisture content as we see it's in the R value AT300PSI exudation pressure.

00:37:52 JOHN: That's it. 2 parameters.

00:37:54 BRIAN: OK. I don't have much on R-value.

00:37:57 JOE: There were no or value suspensions.

00:37:59 KIM: We have fewer. Participants in the R value than the other soil samples we've talked about today is that because it's just not popular with specifiers. Or is it that the data can be found other places? So I'm just curious of why we would have less participate?

00:38:19 JOHN: And I'm not very familiar with how it's specified who specifies it. It's one of those one of those tests that I'm not super duper familiar with.

00:38:28 RYAN: We have no labs of credit for it east of the Mississippi.

00:38:32 BRIAN: Right now there are 122 laboratories accredited or suspended for R-value. They are in Arizona, one in Arkansas. Most of them are in California. There's some Colorados, Hawaii, Idaho, Minnesota. Montana, Nevada and New Mexico. So not a whole lot of states still doing the R value. Some of them are DOT's and I wonder why they're doing them if they. Are if there are no, you know some of those, like Arkansas, there are no private labs in Arkansas that are credited for performing that test, though. So I wonder if that is. Just a remnant. Of an old. Specification that is hanging around there, so I'd be curious to see if that changes over time and it sounds like it's hanging in there for now until maybe a more high-tech test.

00:39:25 BRIAN: Takes its place, maybe with a smaller footprint that R-value test can be quite large. The equipment can be quite large if you talk about the R value device that is used, and then there's of course the rack of the different swell. The molds with the apparatus on it. I don't know what the technical term is for that.

00:39:51 KIM: I'm going to take your word for it, Brian, because I have no idea what you're talking about, so I'll just take your word that that's a lot of equipment.

00:39:57 BRIAN: It's a lot and when you see something that's got that big of a footprint, you wonder how long that that's going to be viable, when there are other new technologies. Coming out, that might be a better way to get data, but I don't know. Somebody must be happy with it cause they're still doing it. So who am I To judge?

00:40:14 RYAN: also fun is that the uh T190 was technically revised last year, so they're still working on it.

00:40:23 BRIAN: That is an interesting item. I was not aware of that. So I think we've covered these soil samples pretty well. Any last thoughts on the proficiency samples, John?

00:40:36 JOHN: I'm pretty much done.

00:40:39 BRIAN: John, we've exhausted John. John has slumped over in his chair right now.

00:40:41 JOHN: Done. I'm out. Yeah, it's it's a struggle here.

00:40:45 BRIAN: Ryan, you doing alright?

00:40:46 RYAN: Yeah, I've got, uh, one more Proctor left before I can say goodbye to that red soil.

00:40:52 BRIAN: And then we'll get you a new shirt.

00:40:53 JOHN: Ohh, that's actually. That's actually a good point, Ryan. You bring that up that the red material will no longer be shipped ever, because we ever because I'm saying ever man, because we've deemed it to be too unsafe for us to process.

00:41:02 BRIAN: Ever. You never say never.

00:41:10 RYAN: As long as we are in control of it, we will not be ordering. It or shipping it correct.

00:41:14 BRIAN: Is that right too unsafe?

00:41:16 JOHN: Yeah, because of the respirable dust, it's it's super high. And we just, we cannot prepare it in a safe manner for our staff. So I'm going to fix it.

00:41:28 JOE: How long have we been using? That sample that type.

00:41:31 JOHN: So we've been rotating it in about every four to five years.

00:41:36 JOE: OK.

00:41:36 JOHN: So we don't, we don't do it often, but it's.

00:41:39 RYAN: We do pair it with dust collectors and respirators on, but it's uh, it's more hassle than it's worth. Yeah, we're not being unsafe here.

00:41:47 BRIAN: I was going to say safety is such an important part of the professional sample program. That would have surprised me, but I know that that of. Course if there was a safety concern like it sounds like there could be, we would take action to eliminate it where possible, right? Isn't that on the hierarchy as?

00:42:06 KIM: I was just going to say isn't this an administrative control here?

00:42:08 JOHN: As the safety manager, I'm so proud of all of you right now because yes, elimination or substitution is really what we want to do. Look, it's you. Guys do pay attention, all those safety meetings that. I run, we do.

00:42:21 BRIAN: I mean, it's going to get in eventually.

00:42:23 KIM: It could be that we've been here so long that it's just absorbed into our brains. But I want to thank you all for your time today. I learned a bunch of new stuff. Hopefully our listeners did too.

00:42:34 BRIAN: Yeah. Thanks everybody.

[Theme music fades in.]   

00:42:36 ANNOUNCER: Thanks for listening to AASHTO re: source Q & A. If you'd like to be a guest or just submit a question, send us an email at podcast@aashtoresource.org or call Brian at 240-436-4820. For other news and related content, check out AASHTO re:source's social media accounts or go to aashtoresource.org.