AASHTO re:source Q&A Podcast Transcript

Season 4, Episode 32: Common Findings in Concrete Assessments - ASTM C138, C172, C173, C231, C617, C1231

Recorded:  October 25, 2023

Released:  January 9, 2024

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

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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.

00:00:25 KIM: And I'm Kim Swanson. This is another Common Findings in Concrete Assessments episode. In previous episodes, I tried to guess some of the common findings or nonconformities for popular concrete standards and Brian would tell me how wrong I was and then share that actual information with you. So far, we've covered ASTM C1077, C31, D38, D78 and we ended the previous installment with my favorite for absolutely no reason, C511. So, Brian, what do we have on the docket today?

00:00:59 BRIAN: Capping and use of pad caps, so I'm going to cover capping C617.  First, this one is I'm just going to jump into it because you're not going to guess. This stuff.

00:01:09 KIM: You have zero faith in my ability to guess and pull something out of thin air, but. Go ahead.

00:01:14 BRIAN: OK, alright, alright, let's see what you got. Try. Let's try me on capping.

00:01:19 KIM: What's the name of the test?

00:01:21 BRIAN: Again, it is my confidence is dropping.

00:01:24 KIM: That's going to help me figure it out.

00:01:26 BRIAN: Right now. So this is C617. This is capping cylinders for compressive strength testing.

00:01:34 KIM: Based on other things that you've said, I'm going to guess that one of the top not conformities about capping is that something's not lubricated.

00:01:49 BRIAN: That's a great guess, but it's not the case. But there is. There is a lot of of comments. [KIM: Dang it.] About that in concrete strength testing.

00:01:59 KIM: I'm just saying as we go on, I'm going to get. I'm going to pick up steam here and just, like, absorb all of this knowledge and get a guess correct. I promise.

00:02:07 BRIAN: OK. Well, just so you know, I don't think there's anything about lubrication in the rest of the in the rest of. The test we're going to talk about.

00:02:14 KIM: Well, you did say that previously though. Right. Something wasn't. And so I was just that.

00:02:17 BRIAN: Yeah, there were two. There were two of those. So that was not unfounded.

00:02:19 KIM: See, I didn't just talk. Alright, continue now with the actual non conformities.

00:02:23 BRIAN: OK, so you probably did not know this, but there are supposed to be daily checks of soundness, plainness and thickness on the capping. And that is not typically done. So again, I'm not permitting this by saying that, but those were common findings that those daily checks were not done, other things, the strength of the capping compound is supposed to be tested regularly is they mold cubes of it and they test them for strength.

00:02:48 KIM: OK.

00:02:49 BRIAN: End condition of the cylinders being capped was not checked. Some issue with exhausting fumes or capping outside something like that, so that so this it's sulfur capping compound, so it smells like rotten eggs, right? So you what you want is the that's supposed to be in a hood. It's supposed to be exhaust.  That this is another one of those facilities issues you might want to tell your landlord. Hey, I'm going to need to drill a. Hole in your.  Wall and have a hood put in. Is that OK with you? If it's not OK, this is I probably can't move into this facility.

00:03:20 KIM: Yeah, you know, this me guessing would go much better if I actually had a clue. Of what these tests were but continue.

00:03:27 BRIAN: It would, but you you know what you're doing pretty well.

00:03:30 KIM: Well, not in this episode, but what's next on her list today?

00:03:35 BRIAN: All right. So let's move on to another related 1C1231. This is the. Use of pad cap. So there are three things that people usually do with cylinders. They either cap them with the sulfur capping compound or gypsum. They use these pad caps, these pads. So what they have are these. They're these steel caps that they put a pad in that has a certain hardness, that's their.

00:03:56 KIM: All right. OK.

00:04:00 BRIAN: They cushion it and level out the load when they're being tested for compressive. And there's the third thing is that they grind the ends, which, by the way, you may have heard about this. We wrote a standard on grinding the ends of cylinders. This is typically done for ultra high performance concrete. It is almost a real live full standard in ash toe and once it becomes so, we hope to get C1077 to recognize it. And allow people to use that as 1/3 option so that people who don't want to do. C1231 or 617 anymore because they all they do is grind the ends are able to do that. So that's the long term plan anyway. Let me get back to 1231. So let's take a guess. So I explain what that is. What do you think?

00:04:41 KIM: OK.

00:04:42 BRIAN: The common issue is.

00:04:44 KIM: One of the common issues with that is I'm guessing it is that the pad hardness thing isn't clean, isn't flat. Something's not flat.

00:04:58 BRIAN: You know, that's a really good guess. It's not the pad that's not flat, but it is the bearing surface of the.  The CAP that is not. Yeah. So you were right. You were right. Poor condition of the bearing surfaces is one of the.  Issues now related to the pads they're supposed to keep track of the number of times they're used, and then once they're overused, then they have to throw them out and replace them with another one. And that's what usually ends up going in. Those transport containers is they take the used one, they put them in the bottom. So even though they're out of service for use in C1231, they're perfectly fine. For transport according to C31, so that's that's a good thing.

00:05:33 KIM: That is.

00:05:34 BRIAN: Other things qualification of the pads was not performed. That's something that they can do if they want to use them longer than they're supposed to.  Or if they're testing something that's higher than what is supposed to be tested, the next one cylinder not checked for alignment and also the ends of the cylinder is not. Checked for depressions.  So those are other related issues.

00:05:54 KIM: You don't want a depressed, whatever you said.

00:05:57 BRIAN: No, no. The mental health of. Cylinders is very important.

00:06:04 KIM: Really important. Oh, goodness.

00:06:07 BRIAN: OK. So those are all the lab tests. So the next one are field tests.

00:06:09 KIM: All right. This is I'm going to where I'm going to excel, I think. This is really.

00:06:15 BRIAN: Yeah, I think so. I think this is your. This is going to be your wheelhouse. The field concrete field testing.

00:06:15 KIM: I'm just waiting for the field test. This is I'm feeling confident. OK, let's go.

00:06:22 BRIAN: All right, so C 138 unit weight.

00:06:25 KIM: I'm going to say something's wrong with the balance on that one.

00:06:29 BRIAN: That you know. What? That's you're right, that is an issue that comes up is that and I was just talking to somebody the other day about this, that they have issues with their band. Chances. Well, you know when you've got fuel equipment, it's handled more roughly than lab equipment, right? So sometimes if people aren't taking care to maintain it properly, they can have issues. Now, I actually Full disclosure, I did not add that one to the most common finding list, but it is relatively common. Other ones that came up, there's a strike off procedure. OK, for at the top of the measure, when you're running the test that a lot of times people don't follow it according to the standard requirements, so they get a note for that other procedural issues determining the mass of the measure before dampening it that came up.  That and measures had not been standardized annually, so there's a requirement to do that annually, so you know exactly what it is, because you're making these relative measurements all the time with it. You want to make sure that that's correct.

00:07:26 KIM: All right.

00:07:26 BRIAN: That's it for C138 unit weight next C143 slump.

00:07:31 KIM: What's the full name of this test? And I will give you my answer.

00:07:34 BRIAN: Let me pull it up. Hold on. Standard test method versus slump of hydraulic cement concrete.

00:07:39 KIM: I think one of the most common findings for this test is related to. Through the saturation of the sample.

00:07:49 BRIAN: That is incorrect.

00:07:51 KIM: Darn it. OK. I said it so confidently I thought you were. Gonna say yeah. That's it.

00:07:55 BRIAN: No. So so it's so slump is it's like a consistency test for the fresh concrete. The common issues were related to the testing issues with the slump being measured incorrectly.

00:08:00 KIM: MM. OK.

00:08:10 BRIAN: And they're supposed to rod.  That, and they don't do that correctly sometimes.

00:08:15 KIM: I thought you said rot. ROT.

00:08:17 BRIAN: Rod ROD rotting.

00:08:19 KIM: I was like, what the heck is rotting? OK, continue.

00:08:22 BRIAN: Running, sorry, the other issues slump cones not checked annually or not checked properly, so there are specific ways to check the slump cone that are in the standard and they have to follow those requirements and a lot of times they don't do it. This is an incredibly basic test though, so they put the concrete in. It's like Soupy, right? Like it's wet concrete, so imagine like.

00:08:46 KIM: OK.

00:08:47 BRIAN: Kind of sloppy fresh concrete going into this mold and when they remove it, they measure how far down it's slumped and it has to be like a certain slump to be molded and used. OK, there's not a ton of stuff that came up. It was typically the same things over and over again.

00:08:56 KIM: OK. Yeah. So what's the? Next standard on our list today.

00:09:10 BRIAN: Next one is C172 sampling concrete and this you would not know the common ones without really knowing this test because I I wouldn't have guessed.

00:09:18 KIM: All right, I'm going to guess anyway, because I'm invested in losing this game that no one's Keeping track of.

00:09:20 BRIAN: Go forward.

00:09:24 KIM: For sampling it is that what this test is for?

00:09:27 BRIAN: sampling. Yep.

00:09:28 KIM: I'm going to say something's not done at the correct interval. Some maintenance is not done at the correct interval. For something.

00:09:35 BRIAN: So close.

00:09:36 KIM: Oh, OK, stop talking.

00:09:37 BRIAN: If you had stopped that something was not done at the right interval, you would have been correct and actually you would have been exactly right, because the most common issues were these two issues related to sampling, which is the sample was not taken at two or more intervals.

00:09:42 KIM: OK.

00:09:54 BRIAN: And then those two intervals, those two portions were not recombined to ensure uniformity of the samples. So those are the big things that happened. And in a room full of testing labs, they were all nodding. Their heads so. I was like, OK, that really resonated with them. Other issues that there's a time element to this. So the time taken between sampling and molding the cylinders.  Is supposed to be less than 15 minutes.

00:10:17 KIM: OK.

00:10:18 BRIAN: So that's an issue. And then the time taken between sampling and running the slump, temperature and air content is supposed to be less than 5 minutes. So those two things happen, so that that's it for sampling.

00:10:28 KIM: OK, what do we have next?

00:10:31 BRIAN: Next, we're going to talk about. About air in concrete, so there's two ways to measure air content in concrete. Actually, there's more than that, but the the two we're going to talk about that are required in C1077 are volumetric and pressure. So volume metric is C173. Let's take that one first.

00:10:52 KIM: All right, I'm going to say something is not the right size.

00:10:56 BRIAN: That is not correct. The biggest issues with this test is people don't run it very often. And so certain areas of the country, they run it and certain areas of the country they don't. But people want to maintain accreditation for it just in case they ever get a sample that needs to use this test. So the procedural findings are just that. People make every mistake you can possibly imagine running this test because they're not that.

00:11:19 KIM: OK.

00:11:21 BRIAN: Good at it. The specific details are not important because they most people are gonna be like I don't even know that test.

00:11:26 KIM: That's all of it.

00:11:28 BRIAN: So move on please.

00:11:29 KIM: Question though, can you, I mean laboratory technicians can read the standard while the persons there.

00:11:38 BRIAN: They can read it, but they're not. They're just not familiar with it. So like, if you're, if there are techniques involved with something and you just don't do it except every two years or once a year when you're running.

00:11:44 KIM: OK, OK.

00:11:50 BRIAN: Examples. You're just not going to be good at those techniques, so and you'll forget things, especially when people are watching you. That, that's that's one thing that I think we do understand that people get nervous, especially you've got a young technician possibly that is just used to kind of doing things on their own and all of a sudden they've got somebody with a clipboard or a computer staring at them while they're doing it.

00:11:53 KIM: OK.

00:12:11 BRIAN: It could be a little nerve wracking, so sometimes people just make mistakes.  Cause of that? But the other thing is that the standardizations are not performed annually or correctly. That's super common, especially if it's equipment that they don't typically use. They're not gonna remember to break this thing out and go through this. Procedure that they don't really care about cause they never use it right. That's gonna get noted.

00:12:36 KIM: OK.

00:12:37 BRIAN: Alright, next I I think you're I. I like your chances on this one. We're gonna talk about C230.  One pressure meter.

00:12:43 KIM: I'm gonna say calibration interval is missed.

00:12:48 BRIAN: Yes, you are correct. So this one is supposed to be standardized every three months. Three months of very tight interval. This is field equipment which is probably in somebody's truck and you're trusting that field technician to bring this back at that interval and and take care of business. They might not do that without a lot of reminders. So I think this one is very commonly missed. There's another thing that is I do feel very bad.

00:12:56 KIM: That is.

00:13:14 BRIAN: About this one and I wish that the standard was different and I don't know how to get there, but there's an aggregate correction factor that's required for use in this test.  Method and a field technician cannot really do that in the field. They need somebody in the lab. They need somebody who has the raw materials to do this. The producers are not always providing this information to them and they really would need to. So I think a lot of times when what happens during the assessment is there. The laboratory technician or field technician are asked about this and they don't know the answer, so they get a finding on it and people argue about it. But really the best way to fix it is for people to join. People really understand this should join ASTM and try to get this changed to something that makes more sense to them.  I'm not close enough to this to be able to come up with proper wording for it, but there are tons of people who who can and should be more involved in that, so that would be great to get something more reasonable and realistic in there and and then there's some procedural notes that are relatively common, but they're not super exciting that that could be talked about.

00:14:22 KIM: OK.

00:14:23 BRIAN: But people do run this one a lot. They generally perform better running C231 than they do C173.

00:14:30 KIM: So what's the next? Standard on our list today.

00:14:34 BRIAN: And I think the last one is the temperature. The you do have to take the temperature of.

00:14:38 KIM: OK.

00:14:41 BRIAN: Fresh concrete and I really like your chances on this. Feel free to guess all of them.

00:14:46 KIM: I'm going to say that the thermometer is out of range or something.

00:14:51 BRIAN: That is correct. Well, out of range.

00:14:53 KIM: No, out of out of I don't know out of the thermometer, I'm going to say everything has to do. With the thermometer.

00:14:59 BRIAN: OK, that is correct. They all have to do with the thermometer.

00:15:03 KIM: Somehow. OK, so my first one is that they're using the wrong type of thermometer for. It's that they're supposed to be. Seeing a like thermal couple and they're using a thermistor or something like this.

00:15:14 BRIAN: Believe it or not, it's not the issue. So this one they use probably one of the I I'm going to say one of the worst quality, they're not like like.

00:15:23 KIM: Are you sticking it in the concrete?

00:15:23 BRIAN: Not super precise. You stick it in fresh concrete. It's not like the most precise thermometer that you're going to run into.

00:15:30 KIM: So then they say.  One of them.  Is that they're dirty thermometers that they haven't cleaned them correctly.

00:15:35 BRIAN: No, but I bet that's an issue in the field. I bet that's an issue. I don't want to say that. That's not. That's not a crazy answer.

00:15:44 KIM: All right, so why don't we talk about why don't you talk about the actual ones as opposed to? Me trying to guess all of them.

00:15:49 BRIAN: OK. All right. I thought you would have nailed this one. The testing thermometer was not standardized every year that was, that was one of the top ones. The other one is. So there is a requirement for the reference thermometer as well. So the thermometer you use to standardize your working thermal.

00:15:55 KIM: OK. Yeah.

00:16:04 BRIAN: There's there's issues with those not being calibrated, or some issue with the record or the type of thermometer being used, but I I think it was mainly the not calibrated in records not being complete. The third one is during testing there's a requirement that once you take the temperature you have to close the void that was left. From removal of that thermometer, and that was not done. So I think that's the only real procedural issue with that one.

00:16:31 KIM: You're right, I should have gotten all of those.

00:16:34 BRIAN: Yeah. The third one, maybe not, but it makes sense when you hear it, right? Ohh yeah, of course it would be like that, right?

00:16:38 KIM: Yes, for sure.

00:16:42 BRIAN: But yeah, so so that's it. That's it for common findings on concrete tests. I hope that that was useful to people. If you have any comments or questions about those, feel free to e-mail me at bjohnson@AASHTOresource.org and we'd be happy to help you with some more information.

00:17:03 KIM: I think we're going to have a list of all of these out and in the companion document and just kind of very briefly list out what those common ones are. So you can keep that in mind. So I'll add a link to that and again we'll have links. To how to?  Appropriately resolve these non conformities and findings with your quality analyst and what documentation and kind of stuff that they'll be looking for for those different types of findings. Hopefully this was useful to people.

00:17:32 BRIAN: I hope so. I mean, people wanted to hear it. I the people that I've talked to about it, they seem very interested in. That they're good reminders for technicians to know about if you want to go over it with your staff. I don't think that would be a bad idea. It's always good to be reminded about things that could go wrong, right?

00:17:49 KIM: Yeah. And I think if we do this again with tests that I'm vaguely more familiar with, I'll do better than the I think I was Like 2 for.  Whatever we did, I think I only got 2. Right here on my guess is so.

00:18:04 BRIAN: I think you did fine for, not for not not working in a concrete lab. I think you did just.

00:18:10 KIM: Fine. Hopefully people at home did better at our game and again, thank you for listening and thank you, Brian, for going through all those with us. 

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