AASHTO re:source Q & A Podcast

Common Findings in Concrete Assessments - ASTM C31, C39, C78, C511

December 12, 2023 AASHTO resource Season 4 Episode 29
Common Findings in Concrete Assessments - ASTM C31, C39, C78, C511
AASHTO re:source Q & A Podcast
Show Notes Transcript

AASHTO re:source Q&A Podcast Transcript

Season 4, Episode 29: Common Findings in Concrete Assessments - ASTM C31, C39, C78, C511

Recorded:  October 25, 2023

Released:  December 12, 2023

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

Guests: name, title, organization

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.

00:00:24 KIM: And I'm Kim Swanson. Today we have another common findings or non conformities in concrete assessments episode. Last time we covered some of the more general requirements that labs had issues with and we went into the details about ASTM C1077. As a reminder this is a family feud type episode where I will be trying to guess what the most common non conformity for a standard without any technical knowledge of that standard. So, let's dive right into this one. Brian, what are we talking about today?

00:00:55 BRIAN: Next one we're going to cover is ASTM C31, which is the standard for molding cylinders and beams. OK, think about what the most common finding could be on this one for a test that you don't run.

00:01:07 KIM: No. So if you're molding, I'm just going by what, what going by, what the name of it is, if you're molding cylinders and beam, I'm thinking that the most common issue people have is something. Not being the right size or the right dimension like there is the the mold isn't correct or something's not. The right size.

00:01:32 BRIAN: That's a great guess, but it's not correct. So nice try. Thanks for playing. So one thing that was interesting about this and I guess I wouldn't say it's totally surprised me, but it is noteworthy.

00:01:34 KIM: Darn it.

00:01:45 BRIAN: That most of the issues were related to being molding.

00:01:48 KIM: I'm trying to envision what a beam is versus a cylinder.  I don't know.

00:01:52 BRIAN: So for C31 the the cylinder is is going to be a vertically tested cylinder, like a cylindrical specimen that you put in a compression machine and you you smash it, you you see how strong it is. A beam is tested in a three-point loading. Device that it's tested horizontally.

00:02:14 KIM: OK. But is it the?

00:02:15 BRIAN: Same but it's the same standard for molding both for some reason.

00:02:21 KIM: OK, so this one is just about molding them, not about actually testing them.

00:02:24 BRIAN: It's about molding them and there is an element of transportation in it too, so that will give you a hint on what might go wrong. So there are procedural issues with molding. And then you've also got.

00:02:30 KIM: OK.

00:02:37 BRIAN: An issue with containers that are used to transport the specimens from the field to the lab. So there's a requirement to prevent the specimens from jarring, so you know people a lot of times with the cylinders they'll use what basically looks like what you'd see in a grocery store where you're storing 2 liter bottles or transporting 2 liter bottles.

00:02:43 KIM: OK, OK.

00:02:57 BRIAN: Of soda.  So imagine that. With used rubber pads at the bottom of each one to prevent them from jarring. So that's a common one, and then quite a few on molding the beams and then the other one is that there are these single use cylinder molds that are plastic that people use and they're not supposed to.

00:03:03 KIM: OK. Got you.

00:03:20 BRIAN: We use them without verification according to the standard C47. Money. And that happens all the time. So they really should be following the requirements. People don't and then they get written up for it. Mistakes happen. People learn from them. They make adjustments. They should stop doing it right? Like so. I'm not saying like ohh yeah, people do it like it's OK. It's still not OK. You have to follow the requirements and. Yeah, I find. That that is actually an issue. Like sometimes when I'm talking to people like I have to make it clear like, no, I'm saying you can't do. That I'm not saying it's OK. I'm saying like, mistakes are OK to happen, but you can't, like, plan to make the mistake and continue to make the mistake, take corrective action.

00:04:02 KIM: It's. Yeah, it's. Yeah. It's kind of like you once you know better. You have to do better. So, like, if you didn't know it was a thing. You OK? Find the mistake that you didn't know. But now you know, what's the thing? And you know how to do it correctly? You.

00:04:08 BRIAN: That's right.

00:04:15 KIM: Need to continue to do it correctly.

00:04:17 BRIAN: Yes, and don't hide it and don't lie to the assessor when they come to your lab or lie to whatever Inspector on the project is. Just do it the right way, because if you do get caught lying, it's a much bigger problem. Like we have the thing called refusal of service. They're we'll just stop. Accrediting you? If you lie to our our people, we don't want that to happen like we would just want. We just want things to be OK. Really. And and and don't most people, right?

00:04:46 KIM: I would hope so. Most people do, yes.

00:04:49 BRIAN: OK, so let's move on to the next one. Now C39 that is testing cylinders.

00:04:51 KIM: OK.

00:04:55 BRIAN: So there's quite a few procedural issues related to this and equipment related to testing cylinders. So I want you to think about.

00:04:55 KIM: All right.  OK.

00:05:01 BRIAN: That before you answer me.

00:05:02 KIM: OK. And this is for testing cylinders.

00:05:04 BRIAN: Besting cylinder is correct.

00:05:06 KIM: I think the most common non conformity for testing cylinders would be. That the equipment wasn't calibrated appropriately or to the interval.

00:05:19 BRIAN: Well, that is one of the top ones. So yes, you, you win, you win this round.

00:05:22 KIM: But with nothing, I win nothing. But I'm excited about that.

00:05:27 BRIAN: You win satisfaction of being right, which is worth something for sure.

00:05:30 KIM: Oh, that's worth a lot to me.

00:05:33 BRIAN: All right, let me run it down. So that to cover what you said. So compression machine calibration records some issue, either not calibrated according to the proper interval. Certain you know test points not covered that are required to be covered, something like that.

00:05:48 KIM: Is it just that records were wrong or that they didn't actually do the thing?

00:05:52 BRIAN: I have combined those two things in this it could be either one of those because some.

00:05:53 KIM: OK.

00:05:56 BRIAN: Times like if.  You get it calibrated, but you didn't do it right. It's the same as not doing it. If you didn't cover the relevant points, then it's like it didn't happen anyway.

00:06:05 KIM: But then if you did it correctly and you just didn't document it, that's not the same thing though.

00:06:11 BRIAN: So usually with compression machines, most laboratories hire an outside agency to do it. An outside agency usually knows what they're supposed to do. When you see this note, it's going to be they missed an interval.  Or maybe there's something if there's something minor wrong with the record, then yeah, it's not really a big deal. Like, that's one of those, like, minor changes that you can make moving forward. It doesn't really have an impact on your test results.

00:06:23 KIM: OK. What do you think this? Is so difficult or such a common finding for laboratories?

00:06:40 BRIAN: So there was a recent change to R18 this year related to this. So there's a a standard E4 that's used for standardization of compression machine.  In the standard E4 it says that the interval should be 12 months, but you can have up to 18 months to carry out that standardization of the compression machine.

00:07:00 KIM: But do you have to document why? It's longer or no.

00:07:03 BRIAN: No, you know. it doesn't really say that, but I think it just gives you like a grace period. I'm assuming it's related to and this is a guess that it's related to just complications with getting a compression machine calibrated at the proper interval or standardized at the proper interval, like getting a calibration company to show up and do it. I don't really know why six months seems extreme.

00:07:21 KIM: OK.

00:07:24 BRIAN: For leeway like, I think with people can handle getting it done within a month.  Of the due.  Date. That seems reasonable to me, but yeah, so that's in E4, so now it's in R18 and in a footnote in a table that says that that doesn't mean they can make it 18 and then try to get 19 out of it.

00:07:31 KIM: It also seems reasonable. Hard rule is by 18, but preferably not that long.

00:07:46 BRIAN: The plan has to be 12.  But if you if.  You goof up, you have up to 18. I mean, that's my interpretation of that requirement.

00:07:55 KIM: What are some other common ones?

00:07:57 BRIAN: Other issues, no records of cleaning and lubricating the ball and socket. That is the at the top of the loading frame of the compression machine and then some procedural ones. Cylinder not check for alignment with a small load before going through the compressive testing bearing surfaces, not plain diameters, not taking on the cylinders of the mid height.

00:08:04 KIM: OK, OK.

00:08:17 BRIAN: Their equipment numbers on to do so, they have to have calipers with like a little. End cap things so that they can actually check the diameter of the cylinder at the height. So what people have done like historically is they use this stuff called pie tape. So you wrap the tape around the cylinder and you take the measurement. Just imagine like if you're if you're making something right.

00:08:39 KIM: Ohh yeah, gotcha. Yeah, like a fabric tape. Got it.

00:08:42 BRIAN: That's what I was looking for. Fabric tape, so they can't do that. They can't use pie tape for this. They have to use calipers. So sometimes they don't have that and they have to get it. That that's pretty common. Uh, another thing is ends of the cylinder is not checked for perfect.  Regularity. So that's it for C39 lot there. It's an important test for concrete labs.

00:09:03 KIM: OK, what do we have next?

00:09:05 BRIAN: We talked about molding the beam, so there's a test method C 78 for testing the beams. You're never going to know. The most common one, and it was almost you won't even know that this is.

00:09:12 KIM: And not bad.

00:09:14 BRIAN: Part of the test.

00:09:15 KIM: Well, like, give me a shot. Don't just take Away the opportunity..

00:09:17 BRIAN: All right, I'll give you a shot. If you get it, you will get I'll figure some. Amazing award for you if you get this one.

00:09:24 KIM: So is. For testing beams, that's just and. Those are tested horizontally. I just want correct.

00:09:31 BRIAN: That's right. And as as previously mentioned, yes.

00:09:34 KIM: All right, so the most common non conformity with that is that. Point in something isn't sharp enough.

00:09:45 BRIAN: That is, no, there is no. There's nothing related. Having a sharp point of anything in this test, but that's a it's a fair guess.

00:09:51 KIM: Alright, I don't know, I figured. That there was some.  Some pointy thing that needs to be pointed.

00:09:56 BRIAN: But but so. I have another one that you would you would not have known.  As part of.

00:09:59 KIM: OK.

00:10:00 BRIAN: The test shims so there are shims that are used could could be used in this test, so they were basically like if if I search the word. That is, like almost every note, it was related to shims. Some issue either not available wrong dimensions. They have to check to see that they need to use the shims before they actually use the shims, but some people just always. Use the shims so they get.  Notes for that other issue, some issue with curing. So for for beams you have to use tanks. You can't use a curing room if you have tanks you put it, you can put them in the curing room, but these beams have to be submerged in curing and some issue with temperature control.

00:10:40 KIM: OK, I have a gas nice at curing tank is stirring the curing tank part of this or no?

00:10:45 BRIAN: I don't know that that was a common issue. Anything about that like it has to, it has to have the right saturation. Didn't that? Didn't that even. Yeah. Even lime saturation didn't really make it to the list. But the other thing was the support blocks weren't lubricated every six months. That's another thing. And then incorrect loading rate on the machine. That was pretty common.

00:10:48 KIM: OK.  They didn't come up, OK.

00:11:06 BRIAN: Go back. to So those were all the C 78 issues.

00:11:09 KIM: All right, I was way wrong but. Continue. What's the task that we have?

00:11:12 BRIAN: All right, so next we're going to get actually, you know what I'm going to jump to curing since we're on this topic. So C 511, the standard for curing the common ones for that. And you wanna take a shot at that.

00:11:17 KIM: OK.  For curing tanks. I think the most common one is that.  Something's wrong with the pump in the carrying tank, so it's not.

00:11:32 BRIAN: Correct. That could be an issue. Yeah. So that specifically was not on the list, but it could be related to. So you get partial credit for that one. Yes, unlike the pointy thing.

00:11:40 KIM: OK. Marshall, credit.

00:11:47 BRIAN: Suggestion. So the temperature recorder standardization was a big one. Based on the one you said temperature range.

00:11:56 KIM: Hmm, OK.

00:11:57 BRIAN: Was an issue, so there's a temperature range for curing rooms, curing tanks that has to be maintained and that falls out and people it's OK if it falls out for a short period of time. They have to note that like they're even in the standard, there is allowance for that to happen because like if you maintain a curing room and you're loading and unloading cylinders from it, generally you're going to have a drop in temperature.

00:11:58 KIM: OK.

00:12:19 BRIAN: Or an increase in temperature depending on where you are relative to the curing room temperature. So that is permitted. But on the weekly evaluation you have to point it out you like. You would circle it and say, Oh yeah, we were loading cylinders. Basically it just shows control and that you're paying attention and you're doing your best to keep this up. This stuff is really important to people for anytime there's an issue where like a legal, like a serious legal issue with testing, I feel like it's always related to concrete.  Strength hearing and and monitoring that stuff has to be taken very seriously. So when people don't, I'm always kind of surprised. I don't wanna scare them.  But they should be aware that this is typically what gets handled very seriously, so they should be keeping track of this and making sure their temperatures are in range. Make sure specimens are in moist condition. That was another issue. Specimens weren't in moist condition. I don't know how many times I've seen photos of tanks with cylinders and beams sticking out.

00:13:21 BRIAN: Of the water. It's like this is that is not hard. That should not be happening. Other issues temperature, core standardization not carried out properly either not performed not performed in time not performed in place.  Issue with reference thermometer not meeting requirements. That's another problem and that weekly evaluation of data that I talked about people just not doing that. I think that's very common.

00:13:46 KIM: All right. And we do have some resources on curing facilities and things like that, and I'll link those in the show notes.

00:13:47 BRIAN: OK.

00:13:55 KIM: I think this is a good place to stop for this. 3rd and like the resources I just mentioned for C511, if you want more details on how to resolve these types of findings and nonconformities what type of documentation you need to submit and maybe some possible root causes for the issue, we've covered a lot of these aspects in different episodes and in articles on our website.  And I will of course post links to those in the show notes for this episode as well, and be on the lookout for a future episode of common findings and concrete assessments where I will once again make a fool of myself trying to guess some of the common findings and some of the other common concrete standards.

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00:14:30 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.