AASHTO re:source Q & A Podcast

December PSP Insights - Performance Graded Asphalt Binder, Viscosity Graded Asphalt Cement, and Slurry & Micro Systems

January 02, 2024 AASHTO resource Season 4 Episode 31
December PSP Insights - Performance Graded Asphalt Binder, Viscosity Graded Asphalt Cement, and Slurry & Micro Systems
AASHTO re:source Q & A Podcast
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AASHTO re:source Q & A Podcast
December PSP Insights - Performance Graded Asphalt Binder, Viscosity Graded Asphalt Cement, and Slurry & Micro Systems
Jan 02, 2024 Season 4 Episode 31
AASHTO resource

John, Ryan, and Joe join us once again, this time to discuss the recent Performance Graded Asphalt Binder, Viscosity Graded Asphalt Cement, and  Slurry and Micro Systems samples. 

Related information: 

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Show Notes Transcript

John, Ryan, and Joe join us once again, this time to discuss the recent Performance Graded Asphalt Binder, Viscosity Graded Asphalt Cement, and  Slurry and Micro Systems samples. 

Related information: 

Share your thoughts. Send us a message.

AASHTO re:source Q&A Podcast Transcript

Season 4, Episode 31: December PSP Insights - Performance Graded Asphalt Binder, Viscosity Graded Asphalt Cement, and Slurry & Micro Systems

Recorded:  December 8, 2023

Released:  January 2, 2024

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

Guests: John Malusky, Proficiency Sample Program Director; 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 PSP insights episode that means we are joined by some very special guests.

00:00:33 BRIAN: We're going to start this time with Ryan LaQuay laboratory and testing manager for the proficiency sample program.

00:00:38 RYAN: Good morning, Brian.

00:00:39 BRIAN: And we've got John Malusky, the director of the AASHTO Resource Proficiency Sample program. Welcome, John.

00:00:46 JOHN: Thanks, Brian. Glad to be.

00:00:47 BRIAN: Here and finally we have Joe Williams, senior quality analyst from the ash Toe accreditation program, who handles a lot of the proficiency sample policies and rules and monitoring activities.

00:00:57 JOE: Good morning, everybody.

00:00:59 BRIAN: So as Kim said, we are going to be talking about proficiency samples today. The samples in particular are the asphalt samples. So we've got the PGB performance grade binder samples. We've got the viscosity graded binder program and that is. What are we? What's the initials on that? What are we calling that?

00:01:20 JOHN: It's still BAC. We haven't transitioned away from bituminous.

00:01:21 BRIAN: It's still.  OK. So it's BAC if you are a participant, you'll still see that, but it is viscosity graded asphalt binder. The rebranding has not gone well for BAC apparently. And then we're also going to talk about a third sample.  Which is SMS and that is.

00:01:44 JOHN: Slurry and micro surfacing.

00:01:46 BRIAN: So those are the samples going to talk about today. If you are a asphalt producer, asphalt laboratory or you're involved in slurry and micro, this will be something you want to hear. If not, we'll see you on the next episode. Of the podcast. Just because this probably won't be relevant to you, Kim, how do you want to start this out?

00:02:06 KIM: Way back in November 2023, November 16th, the report came out for performance grade at Asphalt Binder. So let's start with that one.

00:02:17 BRIAN: All right, John, give us a rundown about that sample.

00:02:19 JOHN: That PGB round was pretty regular round. We didn't see anything too crazy, too out of the realm from what we've seen in the past as far as I could tell, we did not have anything that was really out of the norm, nothing or we required a suppression of some sort.  Of property for any kind of not normal distribution. We did do our typical suppression for one of the MSCR parameters just due to the nature of the material and the test, it was the percent difference in J&R. Typically we see a little bit of distribution issues due to the devices so.  Other than that, it was a pretty normal round, nothing out of the realm.

00:02:59 BRIAN: Ryan, anything you wanted to add to that?

00:03:00 RYAN: Not really, uh. Our asphalt binder sample rounds have been pretty steady, nothing too different, not changing too much. You know, if anything would change the grade every now and then. I want to say this year. Was a 76.2. Sound about right, John?

00:03:15 JOHN: Yep, I think so.

00:03:16 RYAN: Says there's not much fluctuation there so.

00:03:18 KIM: And how many participants do we have in that round about? I'm not going to quote you. I mean, you are on the record, but. I'm not going to hold you to it around about how many?

00:03:29 RYAN: 369.

00:03:31 KIM: I see that the sample numbers for this round it were two 73274, so I'm assuming from this that this is one of the sample rounds that we send out twice a year.

00:03:42 JOHN: That's correct, Kim. So one other thing that that I I just thought about now we had a a little bit of a discussion with us through the accreditation program and. Our IT management has to do with the significant figures that we're seeing with some of the test properties. I think I actually don't remember if we've mentioned this on the podcast before, but the multiple stress creep and recovery test, the AASHTO T-350 has an interesting reporting criteria where it's based off the number of significant. And it requires 3 figures to be reported, which is is great for, you know, reporting criteria for for general laboratories. But when it comes to us and our data analysis, that really throws a wrinkle in the reporting and in the coding simply because if you've got a value less than one, it forces 3 decimal places. If you have a value. Greater than one, it's only two, and our system struggles with that. I just noticed here and I think if I remember correctly, Pete Holter brought this up. That right now the average and standard deviation are shown to 7 decimal place.

00:04:48 JOHN: Because it was the only way that we could make it work with the code to properly report what needed to happen, we're still going to truncate the Z score at 2 decimal places. That's what we what we typically do beyond that. It's not of much value, but just so everybody where when they see those numbers and they see the a lot of extra decimal places, that's the reason why it's. It's got a little bit of a coating issue from our end. The whole goal should be to revise the stand.  Rendered a little bit more and actually set a number for decimal places rather than significant figures. You know, maybe go to three and be done with it and that'll get you.  The data that. You'll need no matter what.

00:05:27 BRIAN: Yeah, I agree. I don't really love the use of significant figures in the standards because you know, these standards should be used so that people can compare results. You know, a lot of effort gets put into determining what the Precision and bias statements are and. Then you know logically you'd have to have some reporting requirements so that people can compare their results appropriately and really does require you determining how many digits are going to be there, but not necessarily whether they those are significant according to the rules of significant. ears, Joe, are there any interesting proficiency sample participation rules associated with the performance graded binder samples?

00:06:11 JOE: Really aren't this one's pretty straightforward with any of these binder ones? The difficult thing is when there's different tests within the different programs, like for instance Cleveland, flash and specific. Gravity also also show up in the uh, BAC or BGA program with whatever acronym we're using for that one. So those ones span sometimes. So if somebody gets. Some low ratings on that we have to kind of go over and look at their other ones or if they're not submitting data on those, we have to look and see if they're participating in another place. But other than that, sort of their shared tests between the programs, there's not a whole lot any of these binder rounds any of these binder programs. We don't do a ton of accreditation suspensions for those, especially since so many of these tests are automated. When we do see a suspension a lot of times it does result in sort of a recalibration of the machine or maybe even the purchase of a of a newer machine or something like that. Usually it's something going on with the actual device and not not a procedural thing.

00:07:09 KIM: Ryan said that there was.  Like 370.  Participants. How many of those are actually accredited?

00:07:15 JOHN: From what I remember, PG brief is pretty high over 200 I believe for a majority of the tests there might be a few that are that fall with around 100, but I think most of those you know most of those facilities who do that testing, you obviously binder suppliers, refineries, terminals, modifiers. So I think we have over. 200 regularly. That consistently submit data for all the test properties.

00:07:38 JOE: Yeah, if if I had to guess, I'd say PGB is probably has more participants than BAC, right? Definitely most of our binder labs that are accredited, which I'd have to look and see what that nine number is, are almost always going to be participating in PGB. That's kind of that's kind of the the floor for where that starts.

00:07:55 RYAN: Yeah, the PGB enrollment is almost double the BAC enrollment.

00:07:58 JOE: Yeah, I'm not surprised.

00:07:59 BRIAN: By that. Well, let's move on to. To the next sample, which is BAC. If you are a participant. But for the listeners that is viscosity graded asphalt binder. Now viscosity graded asphalt binder. Why is that different than performance graded asphalt, binder Ryan.

00:08:18 RYAN: Test is the short answer. The PG greatest is uses. The PG grading system the viscosity gradient is the older version of grading, so this is gonna be your. Tests more like just penetration, flashpoint, gravity viscosities and RTF O not as much as you know with the Sr. and and. Tests like that.

00:08:36 KIM: So, Brian. I have a question on our website. It's listed as viscosity graded asphalt cement. You just referred to it as asphalt binder. Is that the same thing?

00:08:44 BRIAN: They they're the same thing. I mean, they really are binders and and when you're seeing the use of the term binders more than cement because cement is actually its own material type. So I think when they use the term cement, I mean you so binders do. I guess you could say cementitious or sticky attributes, but they're not a cement. So like if you look at some old standards, you'll see asphaltic concrete used, which is not correct either. So I think a lot of these like cement and concrete type terms being used in asphalt is being.  Changed, but those are older terms, so like the grades are like a C dash, something that's asphalt cement dash.  Whatever it is, but I don't. I don't know if those John, have you heard anything about those changing ever? I mean, they've existed for so long. I don't know if that particular terminology will get changed even even with the use of the term binder.

00:09:45 JOHN: As it relates to the grading, I don't think we're going to see any kind of change at this point. It's probably just like a dead nomenclature. They're still going to call it an AEC. Whatever. They're not going to change that it. It's just I think it's too ingrained in the industry to make some kind of nomenclature change.

00:10:00 BRIAN: Yeah, I think you're right. It's hard when you're talking about a material type because you've got purchasing requirements and governmental documents.  And all sorts of other stuff labeling, you know, systems labeling. Uh, using that terminology. But we've got, I guess one thing with the AC materials is correct me if I'm wrong, but it's the same like you can have the same material. Be a PG and an AC. It's just the like what Ryan says. The test that you. Form. So do we use the same material for both typically?

00:10:38 JOHN: So there were times where we have done that we will order you know, a bulk supply of material and it you know maybe 253055 gallon drums full of material. And in the past we have done that where the material has been the same for the PGB and BAC rounds. More recently we have not done that. We have transitioned to our.  Performance graded rounds are typically modified, and you usually don't see any modification at all as it relates to viscosity testing. So the.  Round will typically never be modified. You know, that's just do the nature of the material that a lot of the tests that we see, like the viscosity testing itself, there is an issue with consistency and flow. When you add polymer, you know whether it be SBS or or some other type of polymer or PPA to the material, it changes the properties.  Of the the material obviously, and it introduces variability. When you pass you know the material through the viscosity tube. So generally we don't see any modified product for our our viscosity round, it's always a modified product or a very large portion of the time in the performance graded round.

00:11:45 BRIAN: How is our participation looking these days? These are not as popular as they once were, at least in the United States and Canada. So since those are the bulk of our participants, are we seeing a decrease in participation in this sample versus PGB?

00:12:02 RYAN: So our most recent round had about 182 and going back couple years it's been pretty static. I'm back five or six rounds and haven't gone under 170 or over 182, so.

00:12:14 BRIAN: I think we are experiencing a change in enrollment in some other viscosity grade tests and other samples though, aren't we? Like for as far as Recon?  Three goes on and multiplied asphalts or. Well, I guess the multiplied asphalts is the main one or or after extraction there were some tests that we had that were also discussed. The graded tests like penetration and I believe those have experienced a decrease though, haven't they?

00:12:41 JOHN: Yeah, that's correct. So this that relates to our solvent extraction round and the tests on the recovered asphalt from the solvent extraction, we saw a pretty substantial drop off in the kinematic and absolute viscosities after the absent or rotovap methods. We actually got so low that we just had to remove them from the program. There's another conundrum thing that Joe was talking about before, where the accreditation overlaps with so many different scopes and kinematic and absolute viscosity are actually or or were actually part of the solvent extraction around. Even though, you know that's an actual hot mix. The scheme, but those those we just had to kind of drop off the books and and get them out because there was just not enough participation anymore.

00:13:26 BRIAN: Yeah. So. If the proficiency sample program stops collecting data or stops, including, let's say, penetration or one of the viscosity tests. On the recovered asphalt after extraction, and let's say your testing laboratory is currently performing those tests on the recovered asphalt and you aren't even in viscosity graded sample. What what do you need to do?

00:13:52 JOE: Well, you've got two options. One would be to enroll in that viscosity graded sample or drop the accreditation for those test standards. Basically, the way it goes. That is.  If there is a proficiency sample program available that includes the tests that you're seeking or that you have accreditation for, then you need to enroll in that program. Like John said, kinematic viscosity and the so this would be in the solvent program. We just didn't have much participation in it, so those were dropped out of that program. So yeah, the labs. We need to enroll in the the VGA program for that, but I don't think it was too much of an issue because that participation was so low that would have to mean that labs were participating in the VGA program. Otherwise if that was the only program they were enrolled in the HMS program. That solvent program. We would have taken action on that a while ago if we saw that they were only enrolled in that they weren't submitting data, so there might be a couple cases, but I don't think any have come across my desk so I don't think it's.  Really a big issue.

00:14:52 BRIAN: Now, Ryan, did you notice anything with the materials or the tests performed on these samples this round?

00:14:58 RYAN: As far as my memory goes, uh, this was pretty straightforward as.

00:15:01 BRIAN: Well, let me ask you about the homogeneity testing that you perform, Ryan. So one thing that the proficiency sample program does, because they're accredited for ISO seventeen O 43 for proficiency. Programs they need to perform basically consistency testing on the materials to make sure that they're consistent before they go out the door, so they have to take samples every so many in the round randomly sampled and tested in the laboratory by Ryan to make sure that they are a consistent product. So what tests do you perform on the PG?  The and the the viscosity graded asphalt before they go out the door.

00:15:44 RYAN: So we run gravity.

00:15:45 BRIAN: Just specific gravity.

00:15:47 RYAN: Yep, because we're pulling from multiple drums and multiple cans. So we're looking for a.  Make sure that it's a repeatable value across the board on.

00:15:54 JOHN: These so right. So first, we don't have the capacity to test any viscosities cause we don't have kmac and absolute RTF would be a nightmare to try to test. 10 samples would probably take like 2 weeks for us to try to do it in the lab change in mass, which is not going to show that much variability. So we picked.

00:16:04 RYAN: And even then, it would just be change. In mass.

00:16:11 JOHN: The test method that we feel will show us evidence of sort some sort of segregation, right? Density is pretty much it, it's either high.  Low or right? On even a flashpoint, like the flashpoint, you may have a sample that flashes at 300 and then another one that flashes at 3:10. And there could be complete variation. You just have no clue. So we identified this as the most appropriate test method to select for homogeneity and stability, right?

00:16:34 RYAN: We run this sort of gravity. We usually have a variability within the samples tested of about .002.

00:16:43 JOHN: That variability, right, that's spread across the 10 samples and the the 10 samples that we pull and the 20 that Ryan tests, that is 25% of the single operator precision.

00:16:47 RYAN: Since it was tests, yeah.

00:16:55 JOHN: In the stand. So we are 1/4 of that potential error itself when we do the testing. So it's generally extremely good.

00:17:04 BRIAN: That sounds pretty tight. So what would be considered a failure for you when performing those tests?

00:17:11 RYAN: So whenever we run through the tests, we check the statistics of it using analysis of variants, also known as an ANOVA test. So we do that. We also do the I'm particularly fond of this one, the sniff. Test some. Some smell weird. Some look weird. Usually that's the first flag that comes up. Then we run through the statistical analysis and see if it holds out. Usually it does so in this case we ran it through the ANOVA and you know to be considered valid. We're supposed to be under the critical F value of 3.0204 which? Usually no problem. We're under every time.

00:17:45 BRIAN: And is that the standard deviation you just that number? Was that standard deviation or what was that yeah.

00:17:50 JOHN: That's the critical value for.  The F tests for the number of samples and replicates that we use, so that's just in a table, right? That's just in like the F distribution table and statistical.

00:17:58 BRIAN: Analysis OK, I don't know.  That means so. So you've got this number. What are you comparing to see if it's below that number?

00:18:06 RYAN: It's basically a comparison of the variance between our data results. So we take all these tests, run them through or run them, allocate the results, you determine the average within the replicate samples, the overall average of the whole thing about another 10 or so equations to get down to the F value. So it depends on how deep into stats you wanna.

00:18:28 BRIAN: Get today. I wanna get so so deep in the stats that Kim hangs up. On the call, that's.

00:18:34 KIM: We are not far from there.

00:18:38 JOHN: Wait, I I think Ryan already said it all it is is comparing the variation between the two duplicate tests that we run the replica test and the variation between the entire round, the entire poll, and if the variation in those values is less than 3.2 effectively then it's considered an acceptable test.

00:18:57 BRIAN: So you don't know the answer until you get the round results back.

00:19:00 JOHN: No, no, no. We know before because we do the test ourselves.

00:19:03 RYAN: This is using data from ourselves and statistical analysis. It's not involving the results. From those customers, the participants at all.

00:19:10 JOHN: The participant resolved.

00:19:12 BRIAN: OK, so you have performed, let's say 10 tests, 10 specific gravity tests on this asphalt binder. Yeah. And let's say your average results are 1.03. Uh, for this specific gravity, which is a common number, and let's say you end up with a result. That's like let's say.  .05.  Would that be within the reasonable limits for a typical round for you?

00:19:39 RYAN: So the last time we had something trigger, all the results were 1.031.029 except for the one sample, which was a whopping 1.034, and that's enough for it to.

00:19:52 BRIAN: Be an outlier. 1.034 was enough. OK. I mean, that doesn't really surprise me. 1.05 would be, I think. Kind of an outrageous number for. Yeah, not 1.034 result, which was.

00:19:59 RYAN: It's something's wrong with that one. Something's very wrong there. Enough.

00:20:05 BRIAN: Out would you say? OK, that that is likely a material issue or a testing issue or a sampling issue or some handling or prep issue that seems like it's outside, like pretty far outside, you're expected results on a sample that's otherwise consistent.

00:20:23 RYAN: Yeah, our.  Yeah. Our best guess is something in the material in either how it was procured or transported or settled in the the drums. So what we did in this case, we reran the sample itself. Again, I ran it. John ran it again and then we pulled samples from around it. So it was just. Something. Something weird we, you know, we did our root cause investigation, tried to track down any leads that we could and try to, you know, eliminate those issues. But yeah, we can't say firmly what it was.

00:20:54 JOHN: Yep, not sure it's. I mean, the material was a 63 or 6422. Excuse me, G grade, but if I remember correctly, I think in the spring. So this is what's interesting, right? So in the spring we had to suppress viscosities because of this issue.  With this round, with 271 and 272 viscosity grated PBC round we we suppressed a bunch of, we actually suppressed all of viscosities from that round because of the issue, but it was interesting as like I said, it was isolated to a very small number of cans. This material that we used was used for.

00:21:14 RYAN: Yes, that's where the issue is.

00:21:30 JOHN: Like I said, we order in bulk. It was. Used for all. Of the asphalt mixture rounds, so Marshall Beam gyratory solvent ignition. We only saw the issue as it related to this. This viscosity around, so we suppressed the line items that were affected from viscosity rounds 271 and 272.  And now we're in round 273 and 274, the same material in the same shipment, but somehow it's consistent. So This is why we feel like there was just some inconsistency that occurred within those specific that that probably single drum that was poured as part of 271 and 272 where this issue occurred. The good part is the proficiency sample crew keeps a log of where they pull the samples, what sample rounds they go into, the dates that they were pulled.  And then we were able to backtrack and find the specific situation where it occurred and where it took place.

00:22:22 BRIAN: Wow, that's that's impressive. I didn't. Realize you did that.

00:22:24 KIM: If you do notice issues with something like that, you try to handle it before the. Sample goes out.

00:22:31 RYAN: Well, on most of our samples I test them before they even leave the facility. Some we have issues with space we can't get that in time. Just gotta go outdoor. But yeah, we're always trying to. If there's an issue to, you know, be aware of it and take any steps we can to fix it before it gets out to the.  Participants. Yeah, the hard part.

00:22:49 JOHN: Is when you know some of our samples.  Of 4008 thousand packages.  Is and it's a little bit tricky to kind of pull them all back if something happens in that instance. You know we rely on the data analysis process and we have the fail safe is is what we saw with rounds 271 and 272 for the viscosity we suppress. If it's not caught in homogeneous stability, and it's apparent when the round is analyzed, then we'll go ahead and suppress the ratings at that point.  So none of the participants have any negative effect on their accreditation.

00:23:20 KIM: Just like the performance graded asphalt samples, the viscosity graded asphalt are also sent twice a year. You've mentioned like the spring sample.  And things like that. Why is that?

00:23:32 JOHN: That was actually an industry recommendation. We were can't how long these rounds have existed. This is probably maybe Brian has an idea probably 30-40 years I would think at least viscosity is probably even longer than that you know, so you know it's basically an industry recommendation that we. Do these samples at six month intervals just to ensure that that you know the testing and performance was acceptable?

00:23:58 BRIAN: I would say this industry welcomes frequent testing because it's so important for quality control testing for these producers. I know like some of the user producer groups, at least one that I had spent a lot of time with over the years. They run 9 internally, they're they're performance graded binder proficiency, sample testing that they run and and they seem to have no problem and no interest in reducing that that last I checked unless something has changed over the last few years that I had been.  But that doesn't seem to be a a hassle for them they seem.

00:24:35 JOHN: To like it, I think most suppliers test daily to ensure that their product is meeting specifications. So you know another gravity test is no big deal when they're already testing every single day so.

00:24:47 BRIAN: Let's move on to the third sample and it that we're going to talk about today and that's a slurry.  In Microsystems sample, this one is quite different in its list of test methods and the material, the material type and actually the way it's, you know, produced and. I mean there's a lot of things that are different about.  Slurry and micro, then the other samples that we have. John, do you want to give us a rundown of of what this sample is and how you guys?

00:25:17 JOHN: Prepare it. Yeah. This one's definitely, you know, one of our smaller sample rounds, but it's probably our most challenging to design just due to the nature of the materials. So the participants receive a bag of moist, fine.  Or get some emulsified asphalt cement and water and we basically prepare. Send them the instructions that include the the recipe or the batching procedure. As to how to prepare the material, they mix it by hand and then they either you know, screen it into a mold, poured into a mold, do some sort of casting, and then they'll remove the mold after the material starts to cure. A little bit. And then they'll run specific tests on it, such as like vertical and lateral deformation, sweep testing, sand adhesion. Cohesion test. So there's, you know, there's a completely different array of test methods that are used for this surface treatment. And just to you know, everyone's clear that that's listening. This is the preservation technique, right. So we're talking about applying something over the top of the existing Rd. That's in reasonable in a reasonable state of its life to extend the life of the pavement. So it's it's a very thin layer, may only be like 1/4 inch thick. You know 4 or 5mm thick. It can go all the way up to A to 1/2 inch or 12.5mm thick, but usually does not get any thicker than that, just meant as a technique to extend the life of pavement.

00:26:37 KIM: Did you say that we send water in the box with them?

00:26:42 JOHN: Yep, that's correct, Tim.

00:26:43 KIM: And why is that?

00:26:45 JOHN: So the slurry and micro mix formulation, when you're doing the these, the. Test and the testing that's associated with it. The chemistry of the water is extremely important. The whole process of a microsystem or slurry system breaking and setting is chemically driven. So if you have water that is either acidic basic.  Hard. Soft.  It makes a substantial difference when you're doing your mix formulation and your mix time and consistency, temperature of your laboratory is extremely important. Relative humidity, all of it has a huge impact on the performance of the mix and the potential lay down and capability of it. So we try to send.  All the same cement and the same distilled water from the same lot. So everyone is trying to to test from the same level. We don't want a laboratory and. You know that's using their water in Maine to be different water in Arizona. It's going to have a huge impact on the mix, time and formulation.

00:27:53 KIM: All right, so it's. Just one way to reduce the variability that is. Inherent to that sample. That's what I was assuming, but then you were saying other things like they have to use their own mold or their own whatever and mix by hand and that's. Seemed like that was another variable, but we're not going to send a mold, so I kind of get that water.  Is easier to send.

00:28:13 JOHN: Yeah, that's what has the most substantial impact on on the variation in the testing. So this is like I said, it's one of our most challenging samples just because of the stability issues. The emulsion is a quick set emulsion, usually reasonably stable, but there are times where we do run into some issues.  With it the. Aggregate is also challenging. You know, we've gone through some growing pains with this sample. There's a huge difference in the chemistry of the mix. If the aggregate is freshly crushed and packaged versus material that's been crushed and has sat in the stockpile for a month or month and a half, there's a huge issue with the material being in. Moist sits in a moist situation, then being dried back and then having moisture added to it that changes the mixture formulation and mixed properties. So there are just an array of variables that have an impact. When this. When this sample round is is prepared in process. Well, very challenging. We, we actually rely heavily on our material suppliers to provide us with really, really good information prior to US packaging and processing this round.

00:29:17 KIM: And is this one of the samples that does not have extra proficiency samples available? I know in the last episode. We talked about that because we had paint and something else. So is this another one that we don't offer extra proficiency samples for?

00:29:32 BRIAN: That's correct. I know that becomes a problem with accreditation when people have no opportunity to get a an extra proficiency sample.  How are we doing on accreditation for the laboratories that are accredited for these tests? Do they generally run into accreditation issues for low rate, you know, repeat low ratings?

00:29:51 JOE: Not that I've seen this is another one of those ones where we don't see a whole lot. I'm kind.  Of looking at the report.  And I mean some of these tests, the one the 1S values, they're not super high, but you know they're not super tight either. So I think everybody has a pretty OK time hitting their numbers. I've looked at a couple of reports. It's all fours and fives. I don't think personally I've done an accreditation suspension for these, we actually just. So this is a newer sample type for us and I think rounds one through 8. We're just so I guess it was first four years. We're just sort of seeing how things went and it wasn't until rounds 9:00 and 10:00 when we started actually looking at them. So 2022.  So last year's sample would have been the first year we would have done any accreditation suspensions and I don't think we we did many if any at all. I do have a question for John and Ryan. I was looking at the rules for participation and kind of looking at the things it looks like when we first started doing this for the set and cure development.  Uh, we used to have a few more torque value parameters, so we used to go 30609120 up to 180. It looks like on the most recent round we took out 120 and 180. Yep. Is that something that we're gonna do from now on? Why? Why is that? And is that a permanent change or?

00:31:20 JOHN: So the the 120 and 180 are going to be taken out at this point forward.  This is. Kind of a a situation where we were looking at the data and seeing how things were trending and and effectively once you get beyond 90.  This your variation in the method is simply due to the surface of the mix, so it's like we're not really seeing any value in in reporting the data at that point. So we decided to remove it and that was a discussion and that had occurred between AASHTO Resource and the international Salary Servicing Association. Had a discussion back and forth, not really worth any value, so you probably need to change the app rules or maybe even we don't. I don't know because the rules really effectively didn't change. It's just going to be based off of the parameters for 3060 and 90 minutes instead.

00:32:07 JOE: Yeah, I just need to take a. Those two values, but I mean nothing really changes. I did have another question, is this one of those? I'm not super familiar with this material type because we don't do a lot of accreditation things with it. There aren't a ton of labs accredited. Would you say this is 1?  Of those.  Like trickle down samples where if they. Don't get their mix. Time, right? That's going to trickle down through the rest of the tests. Or are the tests kind of?

00:32:33 JOHN: Independent of each other? No, I think it's definitely going to have some sort of an effect. So if your mix time is off pretty substantially, you're going to have issues you know actually forming and casting the material. So you may see an issue with your cohesion tests and your, you know, wheel track tests and your wet track. Operation. If you're not getting the right mix and you're getting an incorrect mix time, you may see some. Issues, especially if your if your mix times are high, you know higher than normally you're probably seeing a softer, more wet mix which is going to reduce your cohesion at 30 minutes and 60 minutes. So I think you'll definitely see some sort of an issue if the mix is too dry, you know, you'll obviously see, you know, issues in the in the exact opposite direction at 30 and 60 minutes. You may not see torque.  Values where they need to be, so just it's it's just all going to be dependent. But this like I said, this stuff is very very tricky, very challenging to handle you know. But it's it's interesting too, it's it's also missing. So I think we've had the program for seven years now.

00:33:30 JOHN: And we've seen pretty substantial growth and you know, I know we're we're still talking in the in the 30s.  And 40s. But this program started with 17 labs. So we have almost tripled our enrollment at this point, which is excellent. You know it's something that that was pushed towards us by the industry. You know the. The ISA Slurry Service Association came to us and said we want you guys to start this program. We want quality, we want credibility and we believe that AASHTO resource is the way to get this done. So that was awesome. You know, they they definitely hold their, you know, their program and their materials into a high standard. And this is one of those things where where we're moving in that direction. You know, they have a bunch of meetings during the course of the year in, in January, they're having a workshop this year. Here that I'm going to be presenting on AASHTO accreditation, sharing some information and then also participating in a workshop to specifically talk about hand mixing and how there's variability in getting or giving participants an idea of what a consistent mix looks like, what a mix looks like when it's actually.  Broken. How workable is it? And we're going to send some of the proficiency sample material to to show that. Yeah. So it'd be a really good opportunity for people in the industry and agencies to go to go get out there and actually get their hands in this kind.

00:34:50 BRIAN: Of stuff and see what's going on. So that is the international salary Servicing Association Workshop in Las Vegas. And when it when is that just in case people.  Are curious about it.

00:35:00 JOHN: I believe it's the third week in January.

00:35:03 RYAN: January 15th to 19th.

00:35:05 JOE: There you go.

00:35:05 BRIAN: OK. And then what is that isa.org.org slurry.org, if you're interested in attending that? So this is an example is very unusual for us.  Because, you know, typically people are used to seeing AASHTO and ASTM standards on these samples. We've got TB-100TB-109 standards. These are ISA standards that we are using instead of AASHTO because they are the prevailing standards and they are the industry. Standards that are used in these tests. I just want to make. Sure, people know what those are.

00:35:40 JOHN: One thing that has been, you know, interesting with this is that you know, we're starting to see some consistency as it as it rates specifically to to mix. Time. That's one of the tests. That's super subjective. In essence, you're just standing there with a cup full of this mix and slowly mixing it by hand and looking at it. And it's very, very subjective as to when you think the mix has broken and it's in good shape and it's it's done. You can't really work with it anymore. So we're at a point now, especially over the last.  Five years where we've gotten some good, reasonable data and we're almost at a point where we can start to publish precision.  Comments and run statistical analysis so labs have a good way to compare themselves between other other facilities, especially as it relates to, you know, doing mixed formulation. So you know supplier a you know test material that gets sent to an agency for verification that verification can be done and there's an actual number now or just about to have a number where people can compare the information.

00:36:40 JOHN: To each other, which is huge for the industry. So good to see, I mean glad that that the industry has been so supportive of this process even after those first few years of of hiccups, you know, just growing pains trying to figure out how things work, how.  How to ship? You know, it's it's one thing if you're shipping a a bucket of sand between facilities. It's another thing if you're shipping 30 to 40 samples across the the country. And I think we even have some participants in China. So to to get materials to, to go that far and and be consistent is is huge. So it's definitely seeing some growth.  In the program.  And and it's definitely getting a lot.

00:37:17 BRIAN: Better thank you all for your time today. I appreciate you going over these samples and all the different issues associated with them that again our guests were John Malesky, Joe Williams and Ryan Luque.

00:37:29 KIM: Well, before we go, I just want to put a plug in for our 2024 AASHTO Resource Technical Exchange, March 18th through 21st in Boston, MA, go to AASHTOresource.org/events for more details.

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