What Is Concrete Cancer in a Swimming Pool? An Engineer Explains ASR

What Is Concrete Cancer in a Swimming Pool? An Engineer Explains ASR

The Pool Guides Podcast – by River Pools

Guest: C. Terry Brannon, P.E. | Host: Cristian Shirilla

Cold Open

Terry Brannon: as experienced as I am, I'm uh hey, 76 years old and I've been in this 50 years. I can't look at concrete mix and tell you whether or not it's gonna have ASR. Nobody can. I went back a year later and the pool cracked to pieces. So I mean it just had cracks everywhere. So I first saw a few I first saw maybe four or five major cracks across the pool that that looked dangerous. And they were random in all spider webs in all directions. And then I went back a year later and there were probably thirty cracks, forty cracks in the same pool. It's a progressive thing.

Introduction

Cristian Shirilla: Hello friends, Cristian here with River Pools. Welcome to the Pool Guides Podcast, a show that helps you gather all of the information you might need to make well-informed decisions throughout the process of shopping for and having an in-ground pool installed in your backyard. Now, getting into today's topic, I came across a phrase a few weeks ago that in my 20 years working with pools through construction, marketing, managing outdoor aquatic facilities, I've never heard the phrase concrete cancer. More technically, alkali silica reaction or ASR. You'll hear us use those terms frequently today. But there seems to be a lot of it occurring in Texas right now. So I thought it would be a worthy topic to discuss today. Now, full disclosure, River Pools exclusively manufactures fiberglass pools. We don't work in the vinyl liner in ground pool space. We don't work in the concrete in ground pool space. But regardless of the type of pool you choose, More than likely, at some point, the construction process is going to call for concrete, making today's topic a worthy one. Now, in just a moment, I'd like you to meet our guide for the day, Terry Brannon. He's an engineer with 50 years of experience, 40 of that, 40 of it, being dedicated to the aquatic area. He's well known in the pool construction industry because he's a curriculum author for a leading pool construction certification course. He's also an ASR expert for the industry. Terry doesn't work for river pools and he's not here to sell you something, but he does have a bit of information that might be useful for you if you're thinking about having a pool built in your backyard.

Meet the Engineer

Cristian Shirilla: Well, Terry, thank you for joining the show. We really appreciate having you on. Um, you've got a lot of expertise, clearly. Uh but particularly in the pool industry. Why don't we start there and tell us a little bit about how how did you how did you go from engineering into this specialized sp space in the pool industry?

Terry Brannon: Well, that's a it's a very sordid story. Actually, uh when I went to uh engineering school at uh University of Texas at Arlington and I was working for city governments for eight years and uh I decided to go in private practice nineteen seventy seven. That's a long time ago, I know. And uh my specialty actually in school was water treatment and water conveyance systems. So I was in the water industry, wastewater treatment, chemical injection, things like that. open channel flow, storm flow, uh storm water flows, things like that. That's what I got into. So I I like to tell my students um that it wasn't a far leap to go from sewage treatment plants into swimming pools, but most of them aren't aren't glad to hear that. But uh that's actually where I got my background. And then because truthfully there's no engineering school I know of in in the world that actually teaches swimming pool construction. So this is something you learn out on your own and you learn from But my best teachers were were pool builders. Pool builders and contractors. That's who I learned from. And I learned from some of the best and uh then applied the engineering sciences to it and and um came up with uh kind of a knowledge base that I like to teach now that I'm in retirement and I can share with the world, I guess. So that's how I got there.

Cristian Shirilla: I gotcha. So how how did you you well, you're a course instructor for Genesis, which is PHTA's uh professional development uh course, if you will. Um this this show is geared towards homeowners, so just giving them a general idea of of who you represent here in the industry. But but the Genesis course is that's that's top level. I mean, that's that's worthy of being on your resume for certain, um in our industry. How did you how did you end up, you know, as as the leading I I refer to you as the leading concrete construction, you know, instructor for the industry. Is that is that fair to say?

Terry Brannon: well I think I'm one of. There's a lot of experts in the field and and all, but I and I don't claim any any superior expertise, but I hope we have at least equal uh expertise. But um in the course of my uh professional career as a a consulting engineer, m a lot of our work was geared toward water parks. We did a lot of commercial water parks and uh institutional swimming pools, universities, high schools, um competitive venues, things like that. But we did very few residential until we got into uh the higher end. You had to really be spending a lot of money on the swimming pool before we could get very interested in because we had overhead and all that. I've been retired since uh been retired from the company that I founded since twenty one. And in that time I have taken on all sorts of residential responsibilities and teaching. And that's of course what I primarily teach with um With PHTA and Genesis is the residential side of it. There are some differences. Structurally, not so much. Mechanically, yeah, there's quite a few differences in the equipment. But the structural, the structural questions that come up in in a water park, for example, are not a whole lot different than those that come up in a residential pool. I'm on an ASR committee, for example, the PHTA ASR committee, one of the one of several members on that. So that's kind of how I got into it. But Yeah, I I guess now it's eighteen years. There's been Genesis for twenty six years, I think now. And so about eighteen of that I've been teaching and one f one aspect or another.

Cristian Shirilla: Mm-hmm. Well, um, you know, when I was talking to Jason Hughes, the instructor on the fiberglass side of things, um, I said, Jason, who who teaches if you if you teach the fiberglass side, who teaches the concrete side? And your name uh comes up often from Jason in in great light. No, he speaks very, very highly of you. And um, and so so anyway, uh he enjoys his time out there teaching with you or alongside you. And um anyway, so it's Nice to be able to meet you finally and again, glad to have you on the show. Would you walk up when you walk up to a residential pool, um, a concrete pool or any pool at all, you're gonna look at things a little bit differently, than anybody else, certainly differently than the homeowner. And what are some things that you would notice that the homeowner may not notice or think of? And and why is you know why is this information valuable to the homeowner? 'cause we're gonna we're gonna talk about this as if we're speaking to the homeowner today, not necessarily the the pool construction professional, right? And there's a distinction there. So what do what do you notice when you walk up?

Terry Brannon: Well, uh I can immediately tell based on on just the few seconds of vision uh visiting the swimming pool whether or not it was designed by somebody that's been to some of our classes, for example, whether it has those features that make it a super pool. Uh you know, there's a you can take the same swimming pool and put it in my backyard or put it in your backyard and it'll look entirely different, right? And and so the a proper p swimming pool was designed to fit the house. It fits the house and it fits the lifestyle of the people that live there. My house is uh that's a French country, very traditional. I have a square pool with Roman steps down into it, a very very traditional swimming pool. My pool would look terrible in my next door neighbor's yard because he has a ranch. He has a what we call an East Texas ranchette, okay? And it would look terrible in his yard. He has an oval uh a a lagoon shaped pool and it looks great. But so that's what I look for. Does it fit? Is is a is there a wow factor when you walk up, is there a wow factor? And and whether that pool's made out of vinyl vinyl or fiberglass or aluminum or concrete masonry or shotcrete or whatever, it uh it doesn't make any difference what the materials are. Some of the best swimming pools I've ever seen. were concrete masonry pools with plaster stuck on them. so it has to do with whether that fits the environment, does it fit the backyard, does it fit the architecture of the house? And finally, does it fit the lifestyle of the people that live there? And I've seen so many pools that are just off the shelf. Hey, we we sell four types of pools and this is all we sell these four and the reverses of those four. And that's all the pools we make and take it or leave it. And you can tell that immediately.

Cristian Shirilla: Mm-hmm. Yeah. When when when something is just sort of dropped in place and not really uh thoughtfully added to them or incorporated rather. Incorporation is probably a better phrase there.

Terry Brannon: Yeah.

Cristian Shirilla: Well very good. With fifty years of experience under his belt, Terry can walk up to a pool and in about three seconds he can tell you whether or not it was designed and built by somebody who is educated and has experience in pool construction. But what he can't tell you, and what nobody can, is what's going on inside the concrete itself. Because there could be a chemical reaction that begins the day your pool is constructed. No one is gonna know it's occurring until about three years after the fact.

What Alkali-Silica Reaction Actually Is

Cristian Shirilla: So let's let's get to the topic for today, really. And that is around something I saw in the headlines um you know, just just back a few weeks ago this summer. And the phrase, the common phrase that homeowners might come across and I came across is what caught my attention is concrete cancer, which I've come to learn is actually alkali silica reaction. And so tell us tell us what that is and tell us what's going on there.

Terry Brannon: Well, the the proper term of the uh of the cancer, as you call it, and and I I personally I don't use the term concrete cancer because it has a very broad meaning, as you know, it means a lot of things to different people. But um ASR, um alkali silica reaction is a subset, meaning a smaller part, of a larger problem called AAR, alkali aggregate reaction. Certain aggregates are out there that We use obviously we make concrete with cement and aggregates, right? And certain aggregates, sands and rock, uh react adversely in the presence of alkaline. Now, what is cement? Well, it's a cement's got a pH of 12 and a half up to 13. So that's high alkaline already. Remember the pH scale goes from zero to fourteen, right? And cement's thirteen. So it's highly, highly alkaline already. And then we're going to put this rock in there that Reacts with the alkali. And what it does is it's certain rocks found all over the country, actually, probably on every continent, these aggregates react, create a gel. And this gel is expansive and it and it expands inside the concrete and starts breaking. It will literally break the aggregate, not just the concrete around it, not the cement paste. It'll break that too, but it breaks the rock. it'll literally shatter hard rock aggregates. And um of course here in Texas where I live, we have it's a big problem. We we have um something in the order of four billion dollars in class action lawsuits going on in Austin right now. All the cases have been kind of combined into one and it's it's a real problem. So alkali silica reaction in short is a chemical reaction that happens between the normal components in concrete and if the conditions are just right. This gel forms and explodes the concrete. That's what we're seeing.

Cristian Shirilla: Yeah, well that that's what caught my attention. Uh not only the phrase, but the the amount of potential damage that is occurring right now. They're they're a this is relative to Texas, but they were talking about some thirty thousand pools. Am I getting that number right?

Terry Brannon: That's pretty close. Yeah. And it's not just Texas. I I'd urge you to be sure your the listeners know that that it's it's been documented in at least thirty eight states.

Cristian Shirilla: Okay.

Terry Brannon: Texas is the worst, but the second worst, believe it or not, is Virginia, Washington D C for some reason. There's a concentration around Virginia and Washington D C.

Cristian Shirilla: Okay, interesting. and I in my research I had also discovered that this has popped up before in the home construction industry up in New England.

Terry Brannon: yes.

Cristian Shirilla: Uh discovered in in you know, foundation pours, footers, things like that. Uh so this is not new, but how how far back does this go and and how how often does this pop up? Is this you know, is this an every year thing? Is this does this show up in in pockets, you know, in time? How how far back are we looking?

Terry Brannon: Well, it has its own history here. In the in in the forties, uh early nineteen forties, a an engineer with the Cal uh Caltrans, California Department of Transportation. his name was Stanton, I believe, and Stanton found uh this this phenomena and wrote a paper on it. And so it's been around for at least since the forties probably existed long before that. I mean, the concrete or cement the cement formula, concrete formula that we deal with now was developed by about nineteen six. So I'm not surpr I'm not saying that it didn't occur since 1906, but 1940s when it was really documented. And uh the the problem exacerbated in the s in the 70s because we started having a shortage of certain materials and we started we had aggregate issues, we had in especially in Texas, we had shortages of aggregate. Um, and then of course, just prior to COVID, we had uh extreme shortages of product called fly ash and things like that. When that happened, the quality of the concrete started getting questionable. And we started having these episodes occur. Most of the things that have occurred happened since 2016, 2015, 2016. And it unfortunately takes about three years to develop. Sometimes people say it may even as much as five years, even out to ten years. But it takes I've never seen it less than three years on any case that I've been involved with.

Cristian Shirilla: So that's an explanation of the reaction of ASR. But if this is a problem not exclusive to Texas, no, in fact, there are about 38 states where it is occurring. The second highest concentration is actually in Virginia. So the next obvious question is: who let this happen? As it turns out, it has nothing to do with the person who built the pool.

Where It Comes From

Terry Brannon: Problem with that is the builder built the pool three years ago.

Cristian Shirilla: Right.

Terry Brannon: He's he's he's finished. He's been paid. The homeowner's happy. They got grass established. They're living the life out there. And now the pool starts cracking up. And they start going back to the builder. The builder, he's three years down the road. And now he discovers he's got he's got a liability problem. And that's why these lawsuits are happening. And insurance companies are not helping either. The insurance companies are kind of taking Taking the approach that this is a non coverable event in some cases and they've been challenged in some of the state courts. Um but but that's that's how it ha how it all started happening and in mainly because of shortages in proper aggregates and in fly ash that occurred in the mid seventies, mid uh teens, I should say, to twenty fifteen, twenty sixteen.

Cristian Shirilla: Yeah. W well that so that was bringing me to my next question. This is not this doesn't necessarily stem from the pool builder. This is stemming from raw materials, you know, where the concrete is mixed, correct?

Terry Brannon: Yeah. Yeah. But poor pool builder is a the poor builder and you got the homeowner who's the ultimate consumer. And you got the pool builder who the pool builder is no less a consumer. He's buying the concrete from the plant for heaven's sakes. And he's having that ship to the site in the truck and he takes it out of there. And and as experienced as I am, I'm hey, seventy six years old and I've been in this fifty years. I can't look at concrete mix and tell you whether or not it's gonna have ASR. Nobody can. The only way to do that is to do extremely expensive testing of the aggregate, which takes a year. So there's no way for the pool builder and there's no way for the homeowner to look at the mix and say, that's that's good mix, that's bad mix, this is going to be a problem, it's not gonna be a problem. But it's the pool builders who are getting, well, I shouldn't say it's just the pool builders, the pool builders are getting sued, the the concrete suppliers, the cement suppliers, the aggregate suppliers. The finishers, the shotcrete installers, uh all of these people are being sued in the in these lawsuits. It's a shotgun thing and they're just involving everybody. And of course the insurance companies that go with all of those people.

Cristian Shirilla: Sure, yeah. Man, what a what a mess. Um Yeah, I mean I mean that's a that's a really big industry mess. So if if if the testing itself is is um incredibly time consuming and of course you you've got the you know the dollar, the resources tied to that, um this fly ash replacement, how do they know if that's what's needed or can that automatically be applied at the plant? Just tell us a little bit about about fly ash or tell us more about that, what it's used for. When it's introduced, why it's used.

Terry Brannon: Well if I if I could, let me let me give you um the three legs that that this ASR uh depends on.

Cristian Shirilla: Okay. Please.

Terry Brannon: Sometimes it's volcanic, sometimes it's limestone. Some of the limestones that we have here in Texas are reactive and some are not. So it's from all over the country, reactive aggregates. It has to have the alkali and it has to have moisture. There has to be water present. Okay. That's the three things. Where the fly ash comes in is that years ago we engineers discovered that fly ash is cheaper than cement, than Portland cement. Or it was. It used to be. It was a waste product. Well, guess what it was a waste product from? Burning coal to generate electricity. Okay. What did we what did we stop doing in the mid 2000s? We quit building coal burning generating plants, right? We quit using. We converted. In Texas, we converted over to natural gas and most of the country did followed suit. So we're not burning as much coal. So where do they burn coal today? India? And China. Guess where all the fly ash comes from? All the fly ash that we are seeing now is coming from India and China with very few exceptions. There's some small localized uh Plant construction, plant uh plant building that's going on of one plant here in Central Texas is starting to produce fly ash. But what we found out is, engineer, is that if we would replace uh as much as twenty-five percent of the cement in a batch of concrete, if we would replace that with fly ash, equal amount, weight by pound by pound, okay, we'd A, we'd get a more workable mix. B, it would pump better, it would pump through the hoses better because it's like little little ball bearings. Fly ash is a particle smaller than cement, which is hard to believe, but it's smaller than the cement particle. So it's like ball bearings. So it's workable, it pumped better, and it did not affect the strength adversely, and it did not affect the uh setup time or anything like that adversely. So it was a w and was cheaper than cement. So that's why we went to fly ash. Then with the fly ash shortage that started occurring around 2015 or so, we quit putting it in the concrete mix. And guess what happened? All of a sudden we started having reactive things. When you add fly ash to the mix, twenty-five percent of the cement replaced with fly ash, you won't have an ASR problem. We've not seen that. It it it's been laboratory and it's been university tested. It's been run through the mill. And they're They just simply do not have ASR problems. And it's because it lowers the alkalinity of the mix. And so it takes away that it takes one of those three legs I talked about. It takes away the alkaline side of it, the pH. It lowers the pH down, lowered maybe to twelve, gets it down out of that 13 range, and now you don't get ASR. But we don't have, we don't have coal-fired plants anymore. So it's one of those uh unintended consequences, they call it. Right. We do away with coal fired plants, we no longer have fly ash and and locally available. And like I said, it used to be a waste product, it was cheap and all that. Now we're importing it for heaven's sakes. So not cheaper.

Cristian Shirilla: Three conditions have to line up in order for ASR to occur. Remove any one of the three, and you won't have a problem. Well, for decades, we were producing a byproduct that was quietly handling one of those three things until we stopped producing it. But there's a second variable that is at play here that has nothing to do with the mix of the concrete. It has more to do with how the concrete is applied during the construction process.

Wet Shot Versus Dry Shot

Cristian Shirilla: There a difference in the because concrete pools are built with with two two methods, right? There's there's let me get these terms right. Um dry shot placement, which is your gunite, I believe, and then ah shotcrete is the other, right, which is more wet. Am I using those terms correctly?

Terry Brannon: Well, sort of. You're using them the way the c the business understands them, but technically technically. As an engineer, I gotta it's technically. Yeah, that's why. ACI 506 specifies the product is called shotcrete. All that the all of the product is called shotcrete. That's pneumatically applied. That means d driven by air, right? That's what the word means. Pneumatically applied concrete through hose. It's not just pumped concrete like we would pump out to a slab out on the baseball field or something. This is this is pneumatically shot through a nozzle. Okay. Now that there's two versions of that. There's wet shot, which is basically transit mix out of the back of a truck through a chute and into a pump. Okay. Then there's dry shot, which is a dry mixture with no water in it, and the water's added at the nozzle. The difference is the water where the water's added. And in wet shot, the air is added at the nozzle to drive it home in dry shot, water is added at the nozzle, it's already under air pressure and it's driven out. And so it's two different processes. And for some reason, all of the ASR occurs in one and not not the other.

Cristian Shirilla: So w which one?

Terry Brannon: Wet shot, almost all of the cases, almost all, not all of them, but almost all of the cases of ASR have occurred with wet shot transit mix. The dry, the gunite, what we call uh gunite as you know is like Coca Cola or Kleenex, it's a trade name. But but what we call dry shot or or gunite, very few cases. Very few cases.

Cristian Shirilla: And does that have to do more with uh you know moisture being introduced more thoroughly or sooner uh in the mix than you know, right at the nozzle? It's gotta be it's gotta be the moisture content, right?

Terry Brannon: Yeah, you're gonna shoot dry shot drier because you you you order the concrete from then from the plant. W you know, they have to they calculate how much absorption you're gonna get in the aggregate. They also account for the distance of travel and then when it shows up at the at the site, uh you've seen it and I've seen it, where the guy, the foreman on the side says, Add twelve gallons. You know, he just adds water at the site based on some some empirical visualization he has of the concrete mix. this is too dry, we need it wetter. And he adds water. It just tends to be wetter. Okay. With dry shot, you're adding the water to nozzle. That guy at the nozzle has total control. And he's spraying that mix onto the wall and he can make it stay up. If he gets it too wet, it'll slough off and he's wasted his time and material. But he knows if he gets it just right with the right amount of water, it's gonna stick. You can even shoot the underside of bridges. And overpasses and and stick it to that. They line tunnels with the stuff. So a good gunite guy, good dry shot guy, can make it stick and he's adding just enough water to react with just the right amount of cement. And so we don't have this surplus water, which is the second leg of the problem. PH and then second leg is water. If we get too wet of a mix, we get we get this moisture moving around. We have these voids inside the concrete. And and it's full of c of uh calcium hydroxide and that's the fundamental building block of the of the ASR.

Cristian Shirilla: Got it. Got it. So it does it um, just going back, does it never happen with dry shot or just it rarely happens?

Terry Brannon: It could still happen. I only know of two cases in Texas right now. And I'm I mean I'm sorta plugged into the entire industry in Texas, but I I only know of two cases w uh where ASR was a problem. I'm I'm sure there's more, but it's not anything like thirty thousand cases. uh

Cristian Shirilla: And and do these does ASR show up in I I guess anywhere concrete is applied, right? I mean, do we see it in concrete patios around pools, sidewalks, other things like that? I mean this is this is outside of how a a a concrete pool is constructed because or constructed, uh a vinyl pool, a fiberglass pool, y so many people just go with a concrete deck, right? But the same problem can occur there.

Terry Brannon: Yeah, it's poured it's is it's not a function of the pneumatically placed concrete shotcrete. It can be it's just the concrete. If it's poured concrete, if it's retaining walls, if it's traffic barriers, if it's freeway bridges, if it's concrete, it's subject to this. Uh it's occurred in patios, it's occurred in houses, house foundations and slabs, driveway slabs. I saw a steakhouse up in North Dallas one time. The I was going to a steakhouse with my kids and the sidewalk had obviously been attacked. It was broken up into pieces and everything. Clearly it was a an ASR attack. It was a sidewalk for heaven's sakes. So yeah, anything concrete. Not just the shotcrete, not just concrete shells, it's also the decks.

Cristian Shirilla: Yeah, okay. In almost every case of ASR that Terry has seen, they all have one thing in common: the placement method used for constructing the concrete pool. But the thing is, the problem is not exclusive to pools. Patios, decks, footings. If it's made of concrete, it's fair game. So if you already have concrete in your backyard, how would you know you have a problem?

What It Looks Like

Cristian Shirilla: So um you you talked about usually showing up in about three years time. How how does it how does it manifest? When does it begin to become visually obvious that something's going on? What are the signs and symptoms when it when it occurs?

Terry Brannon: Okay. Um, well, first of all, we're all familiar with the fact that one of the rules of concrete is concrete gets gray, it gets hard, and it cracks, right? I mean, that's the three rules of concrete. And yeah, it will crack. And and a concrete shell will crack. I have yet to ever see in fifty years. I've never seen a pool shell that did not have at least one crack in it front in in concrete. Okay. That doesn't mean it's ASR. I get lawyers all the time wanting me to go look look at a pool. And they say, well, I say first question is, when was a pool shot? Well, it was shot two months ago. Well, it's not ASR. It it's just not. So the way it manifests, though, is it you'll get a random crack. It's a crack that's not associated with where you would usually expect to see stresses, such as at a vanishing edge wall where the weight is. So you've got this big tall wall, or you got the raised beams, or you've got a spa resting on the or or maybe you got a house column resting on a corner of the pool. Those would be s something you could say, hey, that's probably stress related. But if you've got a a shell that's in the open and then you start seeing these random cracks in places that you're not used to seeing them and they're not straight, straight cracks usually imply a flexure uh or some sort of engineering force applied to it. Okay. But when the cracks are random and they start off um in a random direction, And they the cracks from ASR will typic underwater will typically be fairly clean. In other words, there's not that calcium carbonate. We've all seen that white crystal develop in a swimming pool or through a retaining wall. That's calcium carbonate. And it's a hard, it's a hard crystalline product. This stuff is a gel. And so if it's below water, that it kind of you could rub it off. It'll it'll rub right off. And it's typically gray to green. So above grade, above let's say a um a raised bond beam, for example, or a raised spa, if if it's oozing a a gray to green material that doesn't appear to be hard, it's likely ASR. If it's white and crystalline, it's probably just calcium carbonate that we typically see in a in a swimming pool.

Cristian Shirilla: Okay. So

Terry Brannon: I followed this on a a Central Texas pool that I was involved with here about three years ago down in uh down toward Waco, Texas. I went down and looked at the pool and it had a few cracks and we we said, that's suspicious. I went back a year later and the pool cracked to pieces. So I mean it just had cracks everywhere. So I first saw a few I first saw maybe four or five major cracks across the pool that that looked dangerous. And they were random in all spider webs in all directions. And then I went back a year later and there were probably thirty cracks, forty cracks in the same pool. It's a progressive thing. Now that pool was, when I first looked at it, was four years old. It was already four years old. And um in in the fifth year it was cracked a high hood. Now in in

Cristian Shirilla: When you say when you say cracked, I mean this thing is beginning to leak water or we're just talking surface crack.

Terry Brannon: It it popped um on a uh it had this pool particular pool had a tanning ledge. It popped the edge plaster all along the top corner of the tanning ledge, the where the where the drop off is. That whole the horizontal line all the way across there, all that plaster popped off. And then there were tile on the steps, it was popping the tile off of the steps, the delineator tiles, and it was popping the tile off the spa. And and the waterline tile. It was popping the waterline tile and it was running all the way to the main drain. And yeah, it was leaking. It was um as I recall that that pool was leaking somewhere like six inches a day for thousand square foot pool, backyard pool, residential pool. Six inches a day and it was leaking really badly. And one of the cracks went one of the cracks went through the skimmer um concrete through that thickest part of the pool where the skimmer is. And uh it went right through that too. So yeah, it does take time. It's gonna show up um for some reason it shows up in tanning ledges and steps first. Almost always if a pool has such a thing, it shows up in tanning ledges and steps first and then progresses eventually and gets into the bottom of the pool. I think that has to do with rebound incorporation, some other reasons, concrete structural issues, but it for some reason it does show up in those locations.

Cristian Shirilla: Wow. Random cracks and a residue you can rub off with your thumb? Terry has seen a pool go from five cracks to over 40 in just one year. At that point, a homeowner would certainly want a definitive answer. And there is a test that can be performed. But what is the cost and is it worth it? That's a tougher conversation.

Testing, and Why Replacement Is the Repair

Cristian Shirilla: So if if if somebody thinks that they might have um ASR occurring, might have some concrete cancer going on, what what are the costs uh what are the costs to confirm or deny? You know, what can somebody expect in the testing phase of this to to identify the issue?

Terry Brannon: Yeah, this is part of the problem. The um the test that I've been quoted for some for somebody to come out core and and then send the sample off for mass spectrophotometer readings and all this kind of stuff is like ten thousand dollars. So the y obviously if you got a pool that costs seventy thousand dollars or ninety thousand dollars, uh ten thousand dollars is a pretty significant investment.

Cristian Shirilla: Right.

Terry Brannon: The contractor, I primarily work with contractors these days and not so much homeowners, but I work with a lot of contractors. The contractors I work with say, well, I can spend the ten thousand dollars doing a postmortem to decide whether this is ASR, or I can look at it and see that it's gotta be fixed. The pool, if it's in this bad shape, has likely got to come out. So do I spend money doing a post mortem or do I just say, okay, I'm replacing the pool? And most of the contractors I work with have just decided to bite the bullet and replace the pool.

Cristian Shirilla: Yeah. Not not go to that testing.

Terry Brannon: But if you want to have the testing done, it's about ten grand to verify. Oh, and then what do you know? At the end of that test you get a report back that says, Yeah, that's how you're so now you

Cristian Shirilla: The expense of testing verified what you visually were very confident in. And you're no better off than you were, right?

Terry Brannon: You're you're now you're ten thousand you're ten thousand dollars poorer and and but you know it's ASR.

Cristian Shirilla: And how long does that test take? How long does it take to do that?

Terry Brannon: particular test isn't and they can do that within uh period of a few days or weeks. The the um the test I mentioned that took an hour, I mean took a year. That's an aggregate problem that a concrete plant would do when they buy new sources, when they locate new sources of aggregate. They'll run out, take those samples and test them for a year and make sure they're not gonna be ASR um a problem. There is another test that's available for testing aggregates. that the concrete plant could run and I think it's affectionately known as a sixteen day test. I don't remember the ASTM numbers on it. But um the the only problem is it has about a fifty fifty um false positive rate. So you could Yeah, fli yeah, flip a coin. I mean gee whiz it's it's just about as accurate. So it takes about a year for the the concrete aggregate supplier to verify that his stuff is okay.

Cristian Shirilla: You know my gosh.

Terry Brannon: But no, for for postmortem no. For post mortem they can determine it through a microscopic examination, they can determine really quick whether it's a whether it's ASR. It's just a matter of getting the sampling done and uh and meanwhile you've lost the use of your pool and you've got a hole in your pool wall where they took a core and all that kind of thing. So

Cristian Shirilla: I mean the big thing is this is not repairable. Uh, 'cause you just said a second ago, you you've identified the problem. Now what? Now you know you have to replace it or you you knew that before. This is not a repair or replace. This is replace is the repair, correct?

Terry Brannon: Yeah. Yeah. Right now there are a lot of people who have come up with these ideas well, hey, let's go in and fiberglass the inside of the shell. that's been done in a limited extent. And some people were selling vinyl liners, and you can buy vinyl liners to fit your shell and you could align it with that. But simply coming in there and routing those cracks and filling them with epoxy and then plastering the pool over again, that's just a band aid. Then it's gonna occur again and again and again. and it's a I I didn't mention this earlier, but it's uh like cancer, uh it's a self uh fulfilling prophecy. It's a self-exacerbating problem. You get a crack, it lets in water. When you let in water, it creates the concrete cancer, the ASR, and then it cracks some more, then it lets in more water. So it's a it it's continually doing that. And so just fixing the cracks, I I guess I would say it this way. If a homeowner is gonna have to Foot this bill themselves. If they've since we were directing this uh program toward homeowners here, if the homeowner has to fit this bill to himself, they have nothing to fall back on, they have no legal challenges or liabilities that they can fall back on or insurance, then yeah, you go in there and you try to make this thing last as long as possible. You get in there and route the pool and fill it with epoxy and fix the concrete and put the plaster back down, knowing that two years you're going to do it again. And you just have to weigh that against, well, the cost of replacement of the pool is going to be eighty thousand dollars plus the cost of demolition. So you've got to fi factor in that extra demolition. And and it's more costly to build an uh a replacement pool than it is to build a new pool. And uh with the exception of the equipment that you don't have to replace, but y the shell itself, it's gonna be more costly to rip one out and put one in. uh and so

Cristian Shirilla: That's not a very good soap.

Terry Brannon: Yep, it it is fatal. It is uh once it's detected, if it's truly ASR you can forget it and just uh like a you could you could delay the inevitable, but eventually the pool's gonna have to be replaced.

Cristian Shirilla: Yeah. And even in even in the you know, uh if you were to epoxy and and recoat it, I understand putting one coating over top of a failing sub um, you know, base, the the crack is gonna transfer. If you were to put a vinyl liner in there, uh it's not attached, so the crack may not transfer as easily, but s but still the like what's the point of failure if you go with a vinyl?

Terry Brannon: Vinyl will reflect the crack in the shell. I mean, you're gonna see that ripple effect. Okay. You're gonna s you you're gonna see a crack. Uh you'd be able to feel it through your with through your toes. Literally, you'd be able to feel the crack in there. Um so the and and you're gonna have a a location where water can get underneath the liner and and anybody that works with liners knows that just a very slight differential head pressure from groundwater. And water in the pool, just a very slight difference will cause a blistering of that liner. It swells up inside the pool and you gotta get the water back out of there. You put a vacuum down in there and pull the water out of there, but then the water comes back and it's and you're gonna replace that liner, what, every seven years or so, six, seven years, ten years at best from if you really take care of your liner. So that's a that's a problem too.

Cristian Shirilla: Yeah, goodness gracious. Coat it, patch it, line it, repair it. It doesn't matter, the cracks are going to return. Once the issue has been identified as ASR, the only real solution is replacement. So protection happens for the homeowner long before construction actually begins. Terry says there's one document you should ask for. Very few people know about it.

What to Ask Before You Build

Cristian Shirilla: Okay, so uh so homeowners decide all the time between vinyl, fiberglass, concrete, um and regardless of the pool type, you're gonna get some concrete patio concrete's gonna be used in construction, you know, most likely. There's a ninety nine percent yeah, somewhere it's gonna be used. So h as the homeowner, what what do I ask? How do I what questions do I ask? How do I know up front that my concrete the concrete being used for my project Um, is ASR free or is you know, not gonna have these issues down the road?

Terry Brannon: Well, it's it's interesting. A lot of the concrete plants now are starting to issue certificates of uh ASR free materials. a lot of pool contractors are getting those certificates from their from their vendors. I know in the Dallas Fort Worth area that that some of the vendors will provide that certificate for an additional amount of money. I I'm I don't even want to quote the amount, but there's a fee, and if you pay that fee, they will certify their stuff to be ASR free. Okay. That's what a pool builder should do. And that's probably what a homeowner ought to also do is ask for certificates on that to say, you know, just just so I'll know that if it fails, I've got something to fall back on. I have a guarantee here that says this is ASR free. Because the one year warranty, the traditional one year warranty that we issue in contracting is not gonna cut it. It it you're not gonna see a problem in the first year. It's not a it's a it's it's not a warrantable claim. It's it's it's a latent defect, what we call a latent defect that shows up years later that was not possible of knowing the first year. And so homeowners ought to ask for that certificate, make sure it's a from a good source. Concrete guys ought to buy from from good sources. I think this ought to scare any pool contractors out of mixing their own. Okay. I would think so. Yeah. Going out there with a little one, two, two, three cubic foot mixer, you know, and all that. No, I think I would stay away from that. I think I would buy from reputable deliverers. If i even if I'm doing dry mix, I'm gonna buy my mix from a plant that's got uh got the technology and the testing and all that and the certifications, and we'll buy that dry mix and brought it bring it to the job in a in a volumetric truck and and mix the water onside. wet mix gonna buy from a reputable dealer and all that. I'm not gonna mix my own. And I'm not gonna go out and source my own aggregates or any of that kind of stuff. So it ought to scare the living daylights out of any contractor and scare them away from doing any of their own work. Uh maybe they use that mixture for doing post hole concrete or something, but don't use it for decks and pool shells for sure.

Cristian Shirilla: Yeah, absolutely. Well, this has been um this has been an enlightening conversation. Uh Terry, we really thank you for for coming out. Are there any final thoughts? Like I I feel like the the concrete pool industry is is alive and well and will be for decades to come. Um this shouldn't scare people away from from deciding what type of pool is best for them and their yard. They should be considering all pool types. Are are there any closing thoughts for somebody who is in the early stages of planning a pool for their backyard? Um Just any other words of wisdom you can share.

Terry Brannon: Well, I first of all I would uh there are about a hundred thousand well, at last count I think there were about eighty five thousand pool builders in the United States. Um unfortunately we're not training in our programs and anybody and then we're not the only trainers, but uh of all the trainers out there, I don't imagine we're training more than ten thousand a year. And so ninety percent or so of these guys are out there building pools because that's the way their daddy built it or the way their granddaddy built it. And they haven't had any educational training or science. They don't know the science behind the concrete. They don't know the science behind the hydraulics and all this kind of thing. And I would urge them to get into that. look for builders that have certifications. There are certifications by PHTA, there's certifications by others, but find people that have obviously tried to improve their practice and are knowledgeable. And the the best thing I could advise a homeowner is do their homework. Find somebody that holds those certification the certifications and and ask them, have you been to class lately? Have you uh you know, do you have resources? Of course, we're always a resource to people that attend our classes forever and ever. That would be the best advice I could give 'em. One other thing I that we never got to, and is that third leg was that moisture. You know, I talked about pH. I talked about pH and I talked about the uh aggregate. The third thing is a moisture. What pool builders have not been doing is waterproofing their shells very well. And in concrete. Okay. Obviously. Vinyl vinyl fiberglass or waterproof shells. We're good there. But on concrete pools, uh concrete is very porous. Right. And and the denser we can make the concrete by shotcrete or otherwise, um, then the less porous it is. It's those pores that are killing us with ASR. So if we can make the concrete denser. Then we won't have the pore problem. One of the things we can do is apply chemicals like colloidal silicates that seal the concrete and fill up those voids, and then we don't get ASR and those things. So that's another thing. There's the if all we have to do is knock out one of those things, lower the pH by using fly ash, choose uh aggregates that have been tested and proven that they're not at reactive, and thirdly, keep the moisture out by. the addition of or spraying on of colloidal silicates or using liners, for example, uh or or s or go with fiberglass. And if they're in an area where if heck if they're their area where concrete is suspect, fiberglass is certainly a great option because it doesn't have any of those problems with ASR for certain.

Cristian Shirilla: Right, right. Well Terry, this has been uh as I mentioned, uh very enlightening for me. Um this is a very interesting topic and up until just earlier this summer I had no idea that this was this was um you know an issue going on in in the concrete world. So we appreciate your time very much.

Terry Brannon: Uh yeah, absolutely. Absolutely.

Cristian Shirilla: I I would say my dream show would be to have you and Jason side by side on an episode. To talk to to talk about concrete, to talk about fiberglass at the same time, 'cause I don't know that that's been done in the industry.

Terry Brannon: Yeah.

Cristian Shirilla: So I'd love to have that happen at some point. So I appreciate the offer for you to come back.

Terry Brannon: Yeah, well I would love to do it sometime. let give me a call, we'll talk some more.

Closing

Cristian Shirilla: So for ASR to occur, three conditions must be in place. One, there must be a reactive aggregate in place. Two, moisture. And number three, the right pH conditions. Break any one of the three, and the problem doesn't exist. Which means it's actually a solvable issue if homeowners know what to ask for. If you're planting a concrete pool for your backyard, or having an extensive amount of concrete poured as a part of your project, ask if the Concrete plant would certify the aggregate. Also ask how the builder plans to seal the concrete if you're having a concrete pool constructed. Any builder who's willing to discuss these topics and answer these questions is telling you something. But so is the builder who is not willing to have these conversations. And if you're still very early in your pool planning process, still trying to find answers to lots of questions, you can head over to RiverpoolsandSpas.com Find any number of blog articles covering a variety of topics. Heck, there's even a pricing calculator and even a tool that might help you decide which type of pool is best for you, your family, and the project you have in mind. I want to thank Terry for his time today, sharing his expertise and enlightening us on a topic that seems to have come out of nowhere, yet is affecting a lot of pool owners right now. I'm Cristian with River Pools. You've been listening or watching the Pool Guides Podcast. We'll see you on a future episode.