EP #168: Are We Mishandling Concrete Admixtures?

Seth (00:01)And welcome to another episode of the Concrete Logic Podcast. And today I have back with me concrete Bob Higgins. And he was back on episode 160. And at the end of that show, we promised we would bring Bob back and talk about mishandling ad mixtures. So we put we put the adSeth (00:24)Mixtures in our concrete to make it better. better workability, better set time, better pumping, better finishing, hopefully better durability. But what happens when we start stacking chemicals into a concrete mix without really understanding how they interact with the cement? Are we are we fixing problems or are we creating new ones and then blaming the cement, the weather, the batch plant, or the contractor? So today,Seth (00:50)Bob's gonna help us with that. We're gonna talk about whether we are miss handling admixtures and what might be doing what we might be doing to the concrete we place every day. But before we get started, just like just to let everyone know how you can support the show, the the first and easiest thing you can do is if you enjoy the show or you learn something out of w one of our we're over, we're approaching a hundred and seventy episodes now.Seth (01:19)we want a a good way to help out the show is to share the the podcast with a colleague or a coworker. It's pretty easy. Tell them to look up concrete logic on any anywhere they listen to podcasts. the next thing you can do is if you go to the concrete logic podcast dot com website, there's a way that you can donate to the show.Seth (01:43)So in the upper right hand corner, there is a donate button. And you click on that and a PayPal page pops up and you can donate any amount. And we've had some donations come in lately. we're on a bit of a streak, and today I want to thank Joshua Huckabee. I hope I'm saying your last name right, Joshua. If I'm butchering it, I'm sorry, man. but I appreciate your help.Seth (02:09)and when you donate, also folks, when you donate, put a message in there and I'll read it on the show if you'd like to. So Joshua, thank you for your donation. I also skipped over a way that you can reach out to me and and give topic or guest suggestions. There's on that concrete logic podcast dot com home page, there's a couple ways to get a hold of me. There's an ask Seth navigation.Seth (02:35)button at the top, click on that, email form pops up, and you can fill that out and and and and suggest a topic or guest suggestion. and people have been doing that. I'm I'm falling behind. I gotta get get through that list. people have been doing that. And also on that same home page on the bottom right hand side there's a little microphone. You click on that and you can record a voicemail and and same thing. Looking for topic or guest suggestions.Seth (03:00)And then the last way, at least the currently the last way you can support the show is there's the concrete logic academy. so right now you could check out concrete school dot co and join the academy for free. And we have a bunch of courses on there. if you want to continue your education in the in the concrete industry, that's a good way to do that. And also th this week we released aSeth (03:26)a prototype of a game that we're trying out. Another maybe a little bit more fun way to learn things about the concrete industry. And the first one we put out was you're a project manager on a concrete on a concrete construction job. So it'll there's a series. It's kinda like but I don't know, Bob, they I don't if you read these books or not, but when I was a kid it was like choose your own adventure kind of thing.Seth (03:52)So the the game's kindBob Higgins (03:53)Yeah.Seth (03:54)of based based on that. So you pick, you know, there there's not a there's not a right or wrong answer, but it can impact your score. So check that out. check that's on the concrete logic academy. like I said, you can go to concrete school dot co or concrete logicacademy.com to find that. All right, Bob. with that, let's get back into it. So let's let's talk about it.Seth (04:16)Are we are we mishandling our ad mixtures?Bob Higgins (04:20)the more I've been doing research on the ad mixtures, the more concerning it is because there have beenSeth (04:26)Well that's the problem. You you'reSeth (04:27)you're you're looking. You shouldn't look. Just just just ignore it. Just yeah.Bob Higgins (04:32)Yeah, no. And I'll tellBob Higgins (04:35)you what, that is a rabbit hole that I've gone down and to be really, really blunt I'm horrified. And I it also makes me understand why there's so much conflict. The conflict is outside of the people arguing about how things are b being done. The concreteBob Higgins (04:54)Ready mixed producers, they produce concrete. They think they're doing a good job and they're doing what they're told to do and what they're supposed to do. The concrete finishers, for the most part, go out there, do what they're supposed to do, and everything else. But the big problem is you can do everything right and have an absolute disaster. And much of that is well beyond their control, and they don't even know what's going on. One, there's a cascading effect when you start mixing these ad mixtures.Bob Higgins (05:21)Because one of the constants in chemistry, and I don't know why they're not considering this, when you add one thing, when you change one thing, you've changed everything. There's a cascade effect. There's not just a direct effect that this has for the cellulite. You add something to increase the slump, it has an effect on everything that's going on in the concrete. And that's assuming everything goes right. And what was really interesting, there was aBob Higgins (05:48)Comment made about when microbial growth occurs in these water-based products and adhesives and admixtures, concrete admixtures that are water-based are particularly vulnerable to this. And and one of the manufacturers was stating that the microbial growth has no effect on the performance of the admixture. And I knew he was wrong.Bob Higgins (06:10)So I did a more little bit more research, and that's when I went down this deep, deep rabbit hole. the admixtures put in the concrete, let's just say that everything works well. If you put it in, everything works well. Every everybody's happy, there's rainbows and your unicorns everywhere. Let's say that everything's good. However, when you're storing and shipping the product, they have to put a biocide in it. The biocides that they put in these products.Bob Higgins (06:37)depending on the temperature, as it accelerates past eighty degrees, the biocides break down very rapidly. in a modest heat between say about eighty degrees to ninety five degrees, it takes about a week or so for the biocide to break down. Now where they're being stored, and I've seen this where they're storing their shipping and they put it out in the sun, they put them in these hot trucks, once it gets past 105 degrees Fahrenheit,Bob Higgins (07:04)The biocytes can break down within minutes. Minutes.Seth (07:07)And and andSeth (07:08)to interrupt you d just so for my education, a bio side is that something you put in for for to to you know, to keep the product in the right chemistry, right? It's kinda likeBob Higgins (07:22)It's to yes to keep it's actually to prevent microbial growth because the polymers and the other materials that they put in the admixtures, there's a lot of microbes that will eat it. They they find it very tasty. So theSeth (07:35)okay.Bob Higgins (07:35)bugs will go in there and eat it. So they try to keep the bugs out of it. Unfortunately, this breaks down and the bugs start eating it now, where it gets really bad, it's not only are they consuming the the materials that are supposed to be working.Bob Higgins (07:48)But the bugs poop. That's basically what they do. And it's acidic. So it changes the pH, it changes the rheology, it changes everything about the product. So by the time the product arrives at the job site, it nowhere near resembles what's been claimed. And it really irritates me that the that a manufacturer would come out and say, Well, it doesn't make any difference, it's not gonna hurt the performance. Yes, it does.Seth (08:17)Yeah.Bob Higgins (08:17)It absolutelyBob Higgins (08:18)does. I mean what's that?Seth (08:20)WhatSeth (08:20)it what does that look like? Like, you know, some of these come into like a tub, you know, a big container. Like the ones I yeah.Bob Higgins (08:25)Yeah, they can get there's there it can get wBob Higgins (08:28)yeah, it can get watery, it can change color, it can develop a smell to it, it's like a sour milk smell, and there's other different odors depending on type of biocide and w what what's being consumed in the byproduct. So they're so basically it's just off. And you'll see lumps and bumps where it looks like cotta almost like a really huge curds of cottage cheese. There's all kinds of things it can do.Seth (08:54)Well that's gross. I said that's gross. yeah. soBob Higgins (08:54)And when you add that into the concrete, huh? You've probably seen it. Yeah, you've probably seen it. And when you put that in,Seth (09:04)yeah.Bob Higgins (09:05)it it hinders the performance. It doesn't help.Bob Higgins (09:07)hinders performance. And it's totally preventable, but the thing is they have to really put they should be shipping these things in refrigerated trucks and keeping it in a in a mild environment. They don't do that. I checked with several manufacturers, not you know, just as a general inquiry, I didn't want to tell them who I was, but as a general inquiry, and the dismissive nature andBob Higgins (09:35)and cavalier attitude towards this was horrifying. And the thing is it's not just heat. Well a good example is there there's this manufacturer that shipped some adhesives not just admixtures but they shipped the admixers and adhesives the adhesives had had a scum on top of it a mold growth the manufacturer instructed them just to mix it back in and just go ahead and use it wellBob Higgins (10:02)So so I told the the the installers and the concrete people, I said, Okay, well go ahead they tell they tell you it's okay. Okay, so let's pretend you're holding a an outdoor party. A bird flies overhead and poops in the punch bowl. You skim it off, tell everybody, don't worry about it, you can still drink it. Any volunteers?Seth (10:24)Right. Yeah.Bob Higgins (10:26)n no, no. It changes everything. That this changed the chemistry, besides being disgusting, it's changed the chemistry and it'll continue to change as it sits. And on the other hand, when these materials are shipped during the winter, unbeknownst to virtually every manufacturer I've talked to, and this is a condemnation of the lack of sophistication and quality control of these materials.Bob Higgins (10:55)is they do not know that there's there's a there's this window of densification that water goes through. It's between thirty-eight degrees and forty-one degrees. If you're shipping during the winter, even if the product doesn't freeze, it can get damaged within this temperature range. So one of the ways to control it, funny thing enough, is and I've had people do this, is shipping a refrigerated truck because if the refrigerated truckBob Higgins (11:22)truck is in the in the 50s you're protecting the the material because they're not dropping into that critical area at 39 point between 39 degrees and 39.5 degrees is considered the densest form of water but between 38 and 41 degrees the water basically compresses it creates micro hydraulics it actually pushes the solids out of the way by pushing the solids out of the wayBob Higgins (11:51)the the product begins to break down, it disassociates. And no matter and the more times it does that or the longer it sits in this environment and if it goes through warming and cooling periods, I don't know how much damage there is. And they don't have a clue. They didn't even know that damage did. I said, how can you not know that the the densification of water is going to push the solids out out of the way for a water-based product.Bob Higgins (12:17)It probably does that with other liquids, but I've focused on water base. And that is where we're having the problems with these admixtures. They're adding these complexities to it by not having a quality control program. So I my biggest advice to any ready mix producer, demand this be put in writing and these things should be monitored. Because I was looking at this one company, they could actually monitor.Bob Higgins (12:44)what the what the shipping is doing and it could give warnings at temperature, humidity and everything else depending on what you would do with it. It can give a warning in the truck or where they're being stored by you know attaching it to the pallet. And if it hits these temperatures, there the customer should refuse it. That's a quality control. So I I think I told him I said you folks are missing the boat because you should be promoting this.Bob Higgins (13:12)To these types of companies, but they said when they approached the manufacturers, they didn't care, they didn't want to do it. Because they felt that they were accepting a responsibility that wasn't theirs. Well, now it's the shipping company's responsibility. We gave them a good product. I said, Well, how do you know? How did you store it? Did the biocides break down? And and it just kept one thing after another. The domino effect was crazy.Seth (13:36)Yeah. What but the I imagine on the all these admixtures there's a label on there and it says it it needs to be between certain temperatures, right? Most ofBob Higgins (13:48)Yeah, but this it says do normally says do do not freeze. If it it says don't apply it or use it between certain temperatures, but there I haven't seen a warning about the shaping temperatures. Have you?Seth (14:02)I haven't been around in a b in a in a little bit, so I can't say that's why I asked you. I I imagine they haveBob Higgins (14:09)Yeah.Seth (14:09)I know like on like you mentioned adhesives. you know, I go go buy a a you know, a cocking gun tube of adhesive for the house or something. I know I know on there it's gotSeth (14:24)Pretty sure it's got temperature things. So I would think admixtures got the same thing. And they did these guys buy it in b these big old bulk tubs. I've been in I've been inside one I was sharing with you before we got started. I've been in one of those sea containers where a a concrete producer had all of his ad mixtures, you know, where they store in the container but and where it's hooked up to the plant. And that sea container wasn'tSeth (14:51)conditioned at all.Bob Higgins (14:53)Exactly. AndSeth (14:54)So I imagineBob Higgins (14:55)the thing is, yeah, the and the temperature ranges they give you are for installation. It has nothing to do with the sh how how they're being shipped or anything else. I meanSeth (15:05)Mm. Yeah.Bob Higgins (15:06)the the chemically defensible range for an admixture is between forty one and eighty six degrees. Outside that as it's being shipped, storedBob Higgins (15:19)or or warehouse, if it goes up above or below those temperature ranges, you're in trouble. The ideal temperature is between 50 and 77 degrees. If as you keep as I kept digging, I kept realizing said that you know the temperature range they gave us, don't apply it if it's lower than this temperature, above this temperature, or use it. You know, you gotta cool the concrete and or whatever else they're doing.Bob Higgins (15:45)Even there, they're not giving any regard to the product as it's being handled, stored, and delivered. So what are what are the concrete ready mix producers getting? They don't know.Bob Higgins (15:57)So there is there's another cascade effect. So they use a product that's supposed to do a certain thing. Things go south, they get more bubbles in it because there's aerates because of the the acidic nature or it does all kinds of things. And then then the other thing I I read, so I saw this this micrograph and also some a slice of this petrographic analysis on the concrete, and there were all these bubbles in there.Bob Higgins (16:25)I said, well what's the air I said look look at the air errant trainment. Said, well, the ones that are not spherical are not considered errand trainment, so they don't count that. What?Seth (16:35)You yeah.Bob Higgins (16:35)What? That's that'sBob Higgins (16:37)it's a hole. It's got air in it. It's air entrainment, whether it's intentional or not, but ASTM doesn't count that. They exclude that from the count. What?Seth (16:48)just thinking of it more simply. you're I mean I that's why I bring you on the show to to go into the deep details of chemistry and I try to I try to keep up with you. But what just logically I'm thinking about if you're sending a admixture product and I I've been I was in the shipping business for a short amount of time. I've been inside back of trailers back and sea containers before.Seth (17:12)And they're not conditioned and it gets super hot or super cold depending on what the weather's doing or what time time of year it is. But I would think if it's leaving the manufacturer's facility and and it's being shipped across the country in the back of a you know, FedEx or UPS truck or whatever transportation company they're using, it's it's gonna, you know,Seth (17:38)more than likely be lower or higher than the that t ideal temperature range. So once it gets to that that concrete producer that that admixture is no longer the same quality as it was when it left, right? So it's I don't you know, it's it still may do what it's supposed to do, but not to the full extent that it would haveSeth (18:02)Done at, you know, if they took it right from the facility, like it was fresh, you know, fresh off the floor, the manufacturing floor. It's brand newBob Higgins (18:10)Yeah.Seth (18:10)ad mixture, it'll work. So I'm just wondering if concrete producers are having to use more of the admixture for it to do what it's supposed to do because it's already been damaged. Do you think that'sBob Higgins (18:21)But if yeah, but if they use more of it, what happens? Everything goes out of balance. And then whatSeth (18:26)Yeah.Bob Higgins (18:27)you do is you're adding it and and if it's being damaged like that, especially if it s shifts the pH, it creates more damage to the concrete. So there isn't an adjustable range to get it to slump again, for example. If you got one that you want it to slump with a with a like a plasticizer or superplasticizer, one, it won't function and two, it's chemicallyBob Higgins (18:49)aggressive to the concrete. It it'll do things in the concrete it's not supposed to do.Seth (18:55)Right.Bob Higgins (18:56)I becauseSeth (18:56)Yeah.Bob Higgins (18:56)I don't want to go into the the full detail of 'cause it's pretty complex. And I'm gonna give a a real simple example of just how much temperature and even humidity can change things. I was doing a a I was I was doing some modification, some surface modification on the concrete. And in San Diego when I used to play around with this products called sodium methyl siliconate. It's just a kind of a cheap littleBob Higgins (19:27)water repellent and it works very well in dry environments and in laboratories it comes out great. However, when I did it indoors in Florida and outdoors, the outdoor, no matter how much you put on it, would not develop any water repellency. And why was that? Because the humidity was too high for this material to carbonate. It depended on carbonation to develop its repellency.Bob Higgins (19:54)It wouldn't carbonate in Florida. So I so they got zero, we got zero reaction with that no matter how much we put on. Zero. There was no repellency. There's no change between that concrete and the entry of concrete, whereas indoors in a controlled environment was excellent. Now, a lot of these admixtures are evaluated the same way. They are not evaluated in extreme temperatures when they're being placed in the in the field.Bob Higgins (20:20)There there's so much wrong with the quality of shit.Seth (20:21)Why not? Why why why isSeth (20:23)that?Bob Higgins (20:23)Ask them 'cause I I'm pissed off. I'mSeth (20:25)there would be some kind of ASTMSeth (20:28)thing that you would cite or something that said, Hey, you need to you need to test your admixture at these extreme, you know, real job site kind of reality situations, you know. You know, h right like right now we're recording in August. It's stinking hot out, you know. It's like yeah.Bob Higgins (20:48)Yeah, yeah.Bob Higgins (20:50)Yeah, it and where I live here in Ormond Beach, it's it's ninety-three degrees outside with a heat index of about 110. That will destroy a biocide within a day easily. So now it's starting to develop microbial growth. How much microbial growth does it take to disturb the fundamental chemistry of these admixtures?Bob Higgins (21:17)There's no data on that. It says it'll do it. If somebody does an AI, say what does microbial growth do to concrete admixtures? It's horrifying.Seth (21:28)Well let's do that. What does microbial growthBob Higgins (21:32)Yeah, go yeah, do that while we're talking. It's horrifying. So what does microbial growth do to concrete admixtures? And thenSeth (21:39)It's thinking.Bob Higgins (21:40)you're not hearing it just from me, huh? It's thinking, yeah.Seth (21:43)It's thinking.Bob Higgins (21:44)Yeah. It's probably going, crap. I wish you could ask.Seth (21:46)It says microbialSeth (21:49)growth can spoil or degrade some liquid admixtures while they're sitting in storage, especially products that contain organic compounds that microorganisms can use as a food source. That's why admixture formulations may include preservatives or biocides, which we've been talking about, to control bacteria yeast and mold.Seth (22:12)blah blah blah. depending on the chemistry, you can see things like loss of active ingredient, viscosity changes, odors, gas formation, sediment, slime, plugging of dispensing equipment, and inconsistent admixture performance.Bob Higgins (22:29)Now, add what happens if the spio when the biocide breaks down?Bob Higgins (22:33)When it gets a so what happens to these admixtures when the biocide is exhausted?Bob Higgins (22:37)But wait, it gets worse.Seth (22:40)But wait, there's more.Bob Higgins (22:41)Yeah.Bob Higgins (22:42)It's crazy. So I'm glad you're you know, 'cause I want people to fact check what I say.Seth (22:47)When the biocide is exhausted, the admixture loses its microbial protection. At that point, any bacteria, yeast, or fungi present can start reproducing in the admixture instead of being suppressed. Construction admixture suppliers use biocides specifically to protect these water-based products during storage because microbial growth can keep the finished admixture from functioning as intended. Once growth takes off, the microbialSeth (23:14)Microbes can begin consuming or altering organic components in the admixture. They can lead to changes and we said this but viscosity, odors, gas generation.Bob Higgins (23:26)Yeah.Seth (23:27)In other words, the product theBob Higgins (23:27)And I mean that is soSeth (23:29)product in the tank may no longer behave like the product that was originally formulated in testing. That sounds that sounds like what you just said.Bob Higgins (23:36)Yep. And it's it's pretty interesting 'cause as I kept diving deeper and then if you go to the other extreme where you say what happens to water based products between thirty eight and forty one degrees, it's just as horrifying.Bob Higgins (23:50)So yeah, I'm glad I want to be fact-checked on your podcast so people will know what to ask and how to do their own research and demand a quality control from these manufacturers. If they're not willing to give it,Seth (24:03)So what whatBob Higgins (24:04)don't buy their product.Seth (24:06)Yeah.Seth (24:06)So ba I mean a big help h I I think would just be shipping it in a like you said, a refrigeratedSeth (24:15)Truck. Yeah.Bob Higgins (24:15)Truck, yeah. At a con withBob Higgins (24:16)a controlled yeah. But even when that left the manufacturing facility, I see them where they have these warehouses and it's hotter than hell in those places and they don't do anything to control the temperature. And they throw a bio side in it, they get they go, don't worry, we've got a bio side in it. Well biocides are effective as long as you don't burn off. Heat really, really burns them off quickly.Bob Higgins (24:40)You looking at the temperature, what that does.Seth (24:40)yeah,Seth (24:42)I did between thirty eight to forty one degrees. atBob Higgins (24:47)Yeah.Seth (24:47)thirty eight degree thirty-eight to forty one degrees Fahrenheit, most water based concrete act mixtures are not freezing, but you can start getting into a temperature range where some formulations become less physically stable. The exact behavior depends heavily on the product chemistry, soSeth (25:05)It's saying don't treat that range as a failure point. it says many liquid admixtures actually freeze closer to the upper twenties, and manufacturers generally specify their own storage limits. What can happen though as they get colder is increased viscosity, slower mixing within the storage tank, and potentially separation or crystals crystallization ofSeth (25:29)certain dissolved components. If an admixture has already started separating or forming solids, the concentration at the pump pickup may no longer represent the concentration of the original form formula of the original product. That creates a dosing consistency problem, even though the dispenser says it delivered the correct amount. So it's clogging clogging the dispenser up.Bob Higgins (25:53)Yeah. And and even whenSeth (25:54)So you're not Yeah.Bob Higgins (25:56)you remix even when you remix it, you've got phase separation in some of these products. Cause if you go deeper, say what within this range there's micro hydraulics going on. What does that do to the solids?Bob Higgins (26:10)'Cause yeah, 'cause with these AIs are kinda dumb. 'Cause they only WellSeth (26:14)They're really dumb.Bob Higgins (26:16)yeah, well they can't they're they don't have very creative thinking, let me put it that way. Yeah, 'cause because there's 'cause there'sSeth (26:20)Right. Yeah. But they're it's you're the o you're it's basedSeth (26:25)on the operator. You gotta be good at asking it questions.Bob Higgins (26:29)Yeah, 'causeBob Higgins (26:31)'cause that range p introduces microhydraulics to the formulation and that will squeeze the solids out.Bob Higgins (26:38)What's really interesting is when I've asked some of these AIs, 'cause I've I crossed the board I'll ask several different ones, see what kind of answers I get. Some of actually appeared reluctant to answer the question. And I have to keep boring in on and getting specific on other areas of the question.Seth (26:56)Yeah, fun trick is to ask the Chinese ones aboutSeth (27:02)about being a c a communist. Yeah, that's a good that's a fun exercise. let'sBob Higgins (27:08)I'll bet.Seth (27:09)see. In that thirty-eight d degree to forty-one degree range, the main concern is that some dissolved solids can become less soluble as the liquid cools. I if a formulation is near its solubility limit, certain salts or other active ingredients can start to crystallizeSeth (27:27)precipitate out of solution rather than staying uniformly dissolved.Bob Higgins (27:32)And it didn't respond to the microhydraulics.Seth (27:34)No, I think we're too sm you're too smart for the AI, Bob.Bob Higgins (27:38)Okay.Seth (27:39)What I cannot verify is that thirty eight to forty one degrees is a universal c crystallization threshold for concrete admixtures. Yeah, I mean it would vary, I guess, dependent on the admixture,Bob Higgins (27:52)yeah.Seth (27:53)right? Dependent on Yeah. Yeah.Bob Higgins (27:55)Yeah, it would. And how muchBob Higgins (27:57)damage it causes, because some of them it's probably not a big deal, but others it could be a disaster. But we don't know what it is. Nobody'sSeth (28:04)Mm. Yeah.Bob Higgins (28:05)told us. So that's why that's why I'm emphasizing get that get this in writing. If anybody's using admixters, get it in writing. This doesn't damage it, this doesn't damage it, this doesn't damage it. So we gotta make sure that it isn't subject to hydraulic.Bob Higgins (28:23)separation in temperature ranges at 30 to 41. Because the freezing's a different story. We we know that damages water-based products. What they're not aware of is that the hydraulics in that range are is extreme and can push solids out of the way. Or the exhausting of the biocides when exposed to upper temperature ranges. And for God's sakes don't use an admixture if it stinks.Bob Higgins (28:51)If it looks wrong, it doesn't flow correctly and it stinks, don't use it. Even if theSeth (28:56)Right.Bob Higgins (28:56)manufacturer tells you it's okay. No, I want you to replace this. I bought I gave you good money for a good product. This is not a good product. Just put it that way. You don't have to go in theSeth (29:06)Yeah. And a lot of these guys setSeth (29:09)s set up the dispensers too, don't they? Yeah.Bob Higgins (29:13)Yes. Yeah.Bob Higgins (29:15)And if it stinks, don't use it. If it's wrong color, don't use it. If you see if you see scum on the surface, don't use it. I mean common sense folks, but they're not told this. And then like that one manufacturer said, well mix it in and keep and continue to use it. Ugh, I was horrified. I said, what's gonna happen if you use an adhesive like that and it starts creating indoor air quality problems?Bob Higgins (29:40)Now there's no traceability to where the genesis of this problem began.Seth (29:45)Yeah. Well, I think we gave some folks probably saved some folks today. so yeah, go check out yourBob Higgins (29:52)Yeah.Seth (29:52)ad mixtures. Go check out your dispensers, go smell your ad mixtures, see if there's anything floatingBob Higgins (29:59)Take a look atSeth (30:00)in that shouldn't be floating in All right, Bob, I appreciate you coming back on the show today, as always. We'll get you we'llBob Higgins (30:07)Well thanks,Seth (30:07)get you back on the next one. I think we're we're talking aboutBob Higgins (30:10)Okay.Seth (30:11)if if ifSeth (30:12)If y'all are interested, we're gonna get Bob on on a live QA with maybe Dr. Belkowitz. So keep a keep an eye out for that. All right, Bob. Thanks again.Bob Higgins (30:24)Thank you, Seth. Thanks for having me on again.Seth (30:27)Yep. And folks, until next time, let's keep it concrete.