AASHTO re:source Q&A Podcast Transcript

 Season 3, Episode 34: Sieve Requirements and ASTM E11 

Recorded: December 15, 2022
 Released: January 3, 2023

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

Guest: Gary Pasquarell, Vice President of Quality and Training, FROEHLING & ROBERTSON 

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

 Transcribed by Kim Swanson and MS Teams.

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 [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. 

 [00:00:21] Brian: Welcome to AASHTO resource Q&A. I'm Brian Johnson.  

[00:00:24] Kim: And I'm Kim Swanson. And who do we have with us today, Brian?  

[00:00:27] Brian: Well, we have got Gary Pasquarell on the line from Froehling and Robertson. He has graciously agreed to show up to ask a question. He sent me an e-mail the other day and I thought, boy, this would be a really good one to put on the podcast because I'm sure other people have questions, and Gary, thank you so much for joining us today to talk about this in person.  

[00:00:49] Gary: Oh, thank you, Brian. It's my honor to be part of this. I think it's a great service for the industry and I wish I was on giving answers. You know, it would sound a lot smarter, but I'm OK with asking these questions because I imagine they're questions that a lot of people ask.

[00:01:05] Brian:  I wish that I sounded more intelligent when I answered the questions. So maybe one of these days we could just switch it up and I could ask the questions that other people have and you can just answer them.  

[00:01:18] Gary: Assuming I know the answer. 

 [00:01:19] Brian: Well, this is this is going to be an interesting one for me because I don't know if I'm going to be able to handle this one, the right way, so we'll do our best though. 

 [00:01:27] Kim: I'm going to say you both know more about this topic than I do, so I think you can ask better questions, Gary than I could ask because I don't know anything about this, so I'll just be here listening and learning with the rest of the listeners today. 

 [00:01:40] Brian: All right, that sounds good. We'll take this journey together along with our listeners. 

 [00:01:43] Gary: Yes, yes, supporting each other. So yeah, my question. You know I was going over my QSM and for our company and I was looking at sieve verification and you know we all know that there's this ASTM E 11 standard that specifically addresses the specification for sieves and it gives very stringent requirements for sieves, based upon what kind of sieve and it gives three types of sieves, and it's pretty complex, but I have never seen anything in the AASHTO resource literature or any of my interactions with you all. When you've come to our laboratories, I've never seen any reference to E11 or any time that we've been cited for not being in compliance with E11 and then you know the question arose well, then you know what is E11 and is that something that we're supposed to be aware of and in compliance with? Or what is your take in AASHTO resource on E11 as far as requirements on my laboratories doing sieve analyses? 

 [00:02:55] Brian: I'm going to do my best to answer that one. I think first of all, a lot of the standards assume or presume that a test will be in conformance with E11. So, I think it gets cited in quite a few standard test methods when there's reference made in the apparatus. However, if you look at AASHTO R 18, which is what a lot of, well, everybody who is AASHTO Accredited is concerned about there is not a reference like you said made to performing a check of the sieves against E11 requirements, where people do get confused though is that there is an example in the back of the current version of R18 that shows that E11 is used as the procedure to check the sieve. Now that's just an example, it's not a requirement and there is in the table that is what is important. It says to check the openings of the sieves for coarse aggregate sieves and then for fine sieves you just check the physical condition, but in neither case does it refer to E11 as a mandatory procedure that needs to be used. 

 [00:04:07] Gary: OK, that makes sense, and I think that's been our working assumption. Because you know, you start looking at the requirements in E11, and they're pretty difficult. You know. Depending on the type of sieve, you might be looking at taking. I'm just looking at the table at table one. You might be taking 200 measurements on a sieve using precise. It's not called a microscope, but I don't even know what those devices are called. I have one, but I don't use it except to look for. Sure, just give an overall look at a sieve of say, a #200 sieve when I want to see what the mesh looks like, but yeah, Oh well, actually, here's some sieves where you have to do 1000 per 100 square feet, which boils down to whatever for a specific sieve. So anyway, we're talking about. Whatever the numbers work out to, I've worked it out and it's an amazing number of measurements that you would have to take if you were complying with E11. And as you said, R18 just says hey, if you have a your 200 sieve or your one number 100 sieve you're looking at it from the standpoint of do you see any damage? Does it look uniform? Look at it through a light. Are you seeing any aberrations? Has it separated from the frame? Is it still tight? And sort of that kind of quality. And then you also have a very good reference document on your website that talks about this so. In your experience, what do people do with calibrating their sieves in actual practice and CMT laboratories, what how does that divide out? I think you alluded to it, but you just don't mind clarifying.  

[00:05:48] Brian:  It's pretty consistent that people will do a physical check for the fines. So, like you said, making sure there's no separation. Around the edges of the frame where you've got the sieve screen meeting the frame, you know there's typically like welding or some way that it's held in place, and you don't want to have a situation where you. You've got damage there where you could lose material in there. You also want to make sure that you don't have waviness in your screens to the point where it makes your screen openings inconsistently shaped. [Gary: Hmmm.] And you also want to make sure there's no damage, so you mentioned the 200 sieve. I think that the 200 sieve is the most commonly damaged screen that you're going to find because it's used in washes, right for aggregate and soil, and it's not uncommon for pieces to land on it in and abrade the surface, which could eventually puncture that fine screen. And I can tell you from my assessing days, when I would inspect these sieves, you would find damage 200 sieve that people didn't know about and the best thing to do is hold it up to the light, use an eyepiece to get a good look at those openings and really like those when you start to see ones that are damaged. Those damage points really do jump out at you OK. That is something you have to do for all the fines. So, it do a visual check. Make sure you document it properly. Now for the coarses, this is where you see more of a discrepancy from lab to lab, because unless you're using E11 you have some options as far as how many openings you're going to check, right?  

[00:07:27] Gary: Right?  

[00:07:27] Brian: So, you can check a lot of openings, you can check them all if you want. Or you can check a minimum amount. And yeah, you have to consider your risk tolerance and if you're doing gradations, you want to make sure that those sites are going to be remaining in conformance. I will say that coarse sieves, generally do because they are very sturdy. So, unless they get damaged, dropped run over by a truck, whatever could go wrong, they're generally going to be OK. Overtime from a condition perspective. But you want to make sure that just over time wear and tear. They you know they're getting jostled around. There's abrasion there, you know you got materials bouncing around on them all the time, and make sure that there slight separations in those screens over time that will drive it out of tolerance and you would see that as a wider opening on one side and then of coarse the one next to it will be a little smaller than it should be because that space has got to be made-up for somewhere, Kim.  

[00:08:12] Gary: Right.  

[00:08:25] Kim: And you also want to be on the lookout for dry rotting resin that's on older sieve as well. I know this because I'm reading an article as you're talking that we've posted on our website about sieve and E11, so since making the grade part one and two are available on our website and I'll post them in the show notes as well, but as you were talking I was like, oh, that's I'm just kind of skimming and listening at the same time, and one of the things that you want to make sure is to look for is that the sieve mesh is connected to the sides well and there's no dry rot or anything else around there too.

[00:09:00] Brian:  That's a good idea, yeah? Evidently, you also want to make sure that no cats have gotten to your screens. I see a picture in the one article with a cat that has done some damage to a screen door, so watch out for those lab cats. Oddly enough, just a side note, we have gotten a corrective action from somebody before on a low proficiency sample rating then indicated the cat had gotten into the fine aggregate. So definitely keep an eye on those cats when you got your proficiency samples around as well.  

[00:09:28] Gary: Ah yes, yes.  

[00:09:31] Kim: I love that so much. I'm not going to lie. 

[00:09:34] Gary: And that would change the whole particle distribution depending on exactly what happened in that artificial Kitty litter environment and also, you'd want to definitely oven dry your sample. After the cat had been in it, so all kinds of wow this you brought up all kinds of things I never would have thought of which is one reason I don't have cats, that's just because if you're working in this environment, you can't afford to have a cat.  

[00:10:04] Brian: No, you can't.  

[00:10:04] Gary: Yeah no.  

[00:10:05] Brian: Yeah, you got unwanted additions and subtractions from the sample there. 

[00:10:10] Gary: That’s right, I mean.  

[00:10:10] Kim: I’m going to say I don't have a problem with this with my cat because she's not in, we're not in a testing environment, so it it's fine. My cats are fine. I'm going to say I'm pro-cat. I don't want to get hate mail thinking that we're anti-cats and we're not.  

[00:10:24] Gary: We are not, but I but I am pro-dog so but never, yes, but I agree never sieve a cat either, that's not right. No, you're quite right about that. Now, I'm one other thing that I find, and I think we'll probably just commiserate on this together, but as you read E11, some of the discussion of sieve types is confusing. Three are cited the compliance test sieve, the inspection test sieve, and the calibration test sieve. And I don't know about you, but I find it difficult to take those categories and then match them up with categories that we use in our laboratory. For example, if I'm imagining that a calibration test sieve is sort of like a reference sieve, well, we don't really have a reference sieve that we compare our daily use sieve against, so that's a weird concept for me, yeah?  

[00:11:21] Brian: But let me let me also add to that these are not what you would think when you look in E11 terminology, Section 3, they define what those are right? So, you have test sieve, compliance test sieve, like you said, inspection test sieve, and calibration test sieve. Your mind can conjure up all sorts of meetings for that, right? But then when you actually look at the definition, it's more about the statistical chance of having an opening that's out for each level. Then how you use those. Which is kind of interesting.  

[00:11:52] Gary: Well, you're right, it's yeah, it's more like a grande... What are the three?  

[00:11:57] Kim: Vente, tall, grande. Are you talking about the Starbucks sizes that don't match that don't actually match up with?  

[00:12:00] Gary: The star Starbucks sizes so. 

 [00:12:04] Kim: Small, medium large.  

[00:12:05] Gary: Right, so these are more quality of sieve categories rather than use categories.  

[00:12:12] Brian: This is an area where I am not able to provide a good answer and I think we probably should throw something out here for any sieve manufacturers and maybe we need to have a follow-up with one of them about how they use that terminology, because this is certainly not for the end user to be thinking about cause and just to give you an idea, we're talking about the compliance tests sieve says that a test of manufactured using sieve cloth which has been inspected prior to being mounted in the sieve frame, and it meets the requirements of table one in part based on the standard deviation of the required number of sample openings per 100 square feet of sieve cloth not exceeding the maximum allowable for a confidence level of 66%. So, is that something an end user would be expected to determine, or would have 100 square feet of sieve cloth to check?  

[00:13:10] Gary: Right exactly it's obviously a manufacturer's standard at that point. 

 [00:13:15] Brian: Right, and that's always been my view of E11 that it's really geared toward the manufacturer. It doesn't say that in the standard though, so that is just a presumption that I have based on the text that's in the standard. So that was the compliance test. Then you go to inspection test, and it raises that confidence level to 99%. And then for calibration test set, we're at 99.73%. So, each level brings a higher confidence level, which also means more checks and lower measurement uncertainty for those checks, right? Like? So, you've got more confidence that your measurements are going to be accurate using those sieves.  

[00:13:55] Gary: Wow, OK. Yeah, there's, and there's no real guidance for us as to which category of sieve we need for our testing purposes, so it's very difficult to apply this particular standard to what we do in CMT laboratories.  

[00:14:13] Brian: I would agree, because you're also not going to see that it, you know, when it says test sieve in a in a standard test method or in a practice, it's probably not going to say compliance test sieve that has been constructed in accordance with section 3.1, point 10.1, where it gets into all of that detail.  

[00:14:32] Gary: You know, have you ever encountered construction materials testing laboratory that does attempt to comply with E11? 

[00:14:42] Brian: I don't know that I've ever seen anybody go to the lengths that it says in here, so there is an annex that includes a procedure for inspecting sieve cloth and test sieves, which that would be the part that somebody would be following right, and it doesn't seem too unreasonable when you look at what you have to do for a coarse. So, you know. So, it says you know if it has 15 openings or less, measure all full openings. So, for sieves having more than 15 openings, so this would be all of your fine sieves, right?  

[00:15:14] Gary: Right, right?  

[00:15:15] Brian: And even some of the coarses.  

[00:15:17] Gary: Even some of the coarse, yeah.  

[00:15:19] Brian: Yeah, so it says you have to do these three things so it gives you 3 procedures. One is visually inspect the condition against the uniformly illuminated background, which we kind of talked about already, and then it says the second was inspect for oversize openings per the tolerance in the table, and it says to you know, methodically check them. Now, this is where it gets a little hairy. It says openings and fine mesh sieves are best viewed when magnified optically in the optical method that the minimum number of apertures examined shall be in accordance with table one. Magnifications listed in table one may be used, so you've got some non-mandatory language peppered in there, but the third one really, I think, takes you beyond what would be the realm of reason for most laboratories. So, to determine the average opening size for apertures less than 1 millimeter in micrometers, the standard deviation and average wire diameter measured opening shall be spaced over the full diameter of the test sieve figures A 1.2 and A 1.3 indicate options to measure the individual openings of an 8-inch sieve. The minimum number of openings to be measured it's given in table one for test sieve size, other than the 8-inch diameter values are shown, that table should be modified at proportion of testing area. Determine the average opening along the center line of the sieve cloth separately in two directions parallel to the warp and shoot wires, respectively. Which of course we all know what those are being non-sieve manufacturers. If the required numbers of opening are more than the available in either of these two path patterns, additional parallel paths shall be used. So, it gets very technical and then it gets into determining the average opening of the sieve cloth. And show some diagrams for ways you can do that, but and then there's some statistical analysis for to guide people on figuring out what the standard deviation on average aperture size is. So, I would say that that is all kind of beyond what is, you know, the alternative is if we look at R 18 requirements check physical condition of the sieves. So, compare that to what I just went over.  

[00:17:33] Gary: Yes, and so to your point. I think you have to be careful not to put that in in the headers or your tables of your QSM claiming somehow that you use E11, and we can loosely do that. Sometimes we site standards that we really. We don't really intend to follow. We don't do that to be deceptive, it's just we think it's being thorough. But we have to be really careful not to do that, because this is a case in point where E11 is something we clearly will not be able to perform in most laboratories, and so we shouldn't hold it up in any way is a standard or claim that we do.  

[00:18:12] Brian: I think that should be left to the manufacturer and in part of it is. And this is something we addressed in a recent episode about the R18 change. Was that I proposed that one of the issues is we've got this example in the back of R 18. That makes it seem like that's what you should do is site E11, and that that needs to be removed. And I think that would help people just give them some better guidance.  

[00:18:35] Gary: Yes, I agree.  

[00:18:36] Kim: So, I'm seeing that there's some other standards that reference sieves that may be useful or not useful. I don't, I don't know, but ASTM E 2427 standard test method for acceptance by performance testing for sieve. I don't know if that's applicable here as opposed to E11 and then there is also E 1638. Standard terminology relating to sieve, sitting methods and screening media.  

[00:19:08] Gary: Yeah, lift that. E 2427 is what I think it is. I'm not confident enough to talk definitively about it, but I have exposure to that standard enough to say I'm pretty sure that standard provides a kind of a actual sieve analysis approach to verifying your sieve. So, you actually put material through the side and then you compare it, but that's a very rough. I probably shouldn't speak too much about it because I I'm not, but I know, I know. Looking at it, I thought, well, here's another standard that really, realistically, we're not going to follow because to do that with every single sieve in your lab would be a bit much. The closest thing we get to that. Of course, is to do the sieve shaker time calibration. But that's more about the sieve shaker and it assumes the sieves themselves are doing a good job.  

[00:20:08] Kim: So, I was mentioning the sieves making the grade articles part one and two that we have on our website. Those were written in 2012 and state that go-no-go gauges are not acceptable. However, we did publish policy and guidance document on go-no-go gauges in 2021 that does explain that they are acceptable. Do you want to shed any more light on that, Brian?  

[00:20:36] Brian: Yes, those are acceptable now, as you indicated, which means that you may not have to be fumbling around with calipers. Anymore when you're checking those sieve openings, and I will say that is, that's one of the toughest thing about checking those openings is when you have a sieve that has a lip on the bottom. That comes up quite a bit and you try to get those calipers to be totally horizontal and parallel to that sieve screen so that you get an accurate measurement. That can be really challenging, but these go-no-go gauges allow you to have an easier time checking those, and there are some requirements. It doesn't just say you can just use them. There are requirements for how you to check to ensure that those gauges are going to provide you with an accurate measurement of both the minimum and maximum openings for those screens. So, check that out, Kim will put a link to that underneath this episode on our website and you can check it out if you are so inclined. There are a lot of different designs. Of those, some work really well, some do not, but that procedure and policy will help you quite a bit. All right, well Gary, thank you so much for your time today. I appreciate being able to have you on and talk to us about this and clearly, we all have a lot more to learn about ASTM E11 and these sieve requirements. I could see us getting a little bit more detail in this in the future, and if you're interested in getting to meet Gary, Gary will be on tour with the Technical Exchange in March. Those dates Kim? 

[00:22:16] Kim: The technical exchange in 2023 will be March 27th through the 30th in Fort Worth, TX. And if you're interested in learning more about it, you can go to ashtonresource.org/events and click on the link there to go to the event website. Thank you very much for your time though Gary.  

[00:22:34] Gary: It's my honor, Kim and Brian. It really is. I really enjoy it.  

[00:22:38] Brian: It it's always great having you on Gary looking forward to the technical exchange.  

[00:22:40] Gary: Thank you. Me too.  

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