EP #097: The Power of Hyrdogels in Concrete Restoration

Seth (00:00.69)
Welcome to another episode of Concrete Logic Podcast. And today I have Dan McCoy back. He is going to talk to us or with us about aging concrete and how we responsibly treat and maintain concrete. But before we get started real quick, just to remind you all how you can support the podcast, you can do one of three things or you could do all three things. One is share the podcast with a colleague or a coworker.

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homepage of concrete logic podcast .com. There's a donation button. and I I want to think, we've had, a handful of folks, sending donations. Those are greatly appreciated, but, that's what that donation button's for. So you go, go on there and you click on it, smash it, whatever you want to call it. push that button, give any amount and it helps me, make the podcast better. I don't know if you guys noticed, lately, but

so folks have donated and what I did is I went out and I hired somebody to do the intro and the, outro. So, you know, that's the things you'll see, the more you give to the show, I throw it right back in. I'm not using it to feed my kids. I put it right back into the show for you guys. So with that, Dan, let's talk about aging concrete. you know, we there's.

Seth (02:23.698)
We were talking before we hit record about how we should treat it or heal it versus maybe just ceiling over the top of it. And you were talking about you've doing, you're doing something that you think nobody else is doing in Indiana. let's, let's tell us, tell us a little bit about what you're doing.

Dan McCoy (02:43.874)
Well, thanks for having me on again. And I love the new intro. it's, fantastic. It sounds like we're on a national national radio show. I love it, but I love coming on here and getting my concrete geek and my, engineer on, because I try to talk at home with my wife and I'm telling you what guys, if you're listening to this, your wife does not want to hear about it. I, I'm, it's one of those things. I start talking. get that glazed.

you know, look, and I'm just like, this is fascinating. And she goes, whatever you say. So yes, thanks for having me back on because it allows me to get my geek on a little bit and talk about some of the things that we're doing or trying to change in infrastructure, the way we look at things. And I think if the dedicated listeners will remember one of our last shows, I think we talked about

you know the aging infrastructure problem we specifically talked about bridges but aging infrastructure in general and and how we went from you know the National Highway Transportation Act by Eisenhower to build all this wonderful infrastructure that we use for commerce every day you know it's a big driver of how we get and do things if you have anything odds are it was delivered to you on the final stage by a truck and it got there using our

international highway system or other local municipality routes. There's a few private tollways out there, but a lot of it, the majority, the vast majority is public transportation in the means of you provide the wheels, we provide the road. And as I noted before, you know, even with current infrastructure standards and current infrastructure bills, we're not replacing that infrastructure in a manner

that will be to replace that infrastructure as much as needed. So we're having an aging infrastructure right now. We're dealing with, if there was one of those elderly care facilities for infrastructure, that's what we'd be running right now. And instead of producing,

Dan McCoy (05:07.054)
We're replacing that infrastructure. We're piecemealing it and replacing what we can, and we're trying to extend the life of our existing infrastructure in the United States. I have faith. We'll get there. Necessity breeds dollars, and once it gets bad enough, it'll eventually happen. But you'd need several trillion dollars to invest in new infrastructure. And as that happens, or before that happens, you have to take care of what you've got.

You've got to maintain these assets so that you keep health and welfare up and alive and working for people. And one of the things we've done in Indiana is I have the pleasure as a contractor to be on kind of like, I call it our McCoy, you know, special operations. Special operations because there are contracts.

Seth (05:58.237)
I like that name. That's cool.

Dan McCoy (06:04.014)
In indot and I'm not sure if other states I'm sure they do to some extent but we get basically This blank contract and it's called an ID IQ contract and it's ID IQ stands for indefinite description indefinite quantity so you're given a base bid on items of Here's kind of what we're gonna do. Here's the items you might see or like the current one is it's based on labor hours equipment hours material

And then you bid a markup to those against the competitive bid process. And then they choose who the lowest bidder is. And for the last five years, it's been us because it's been one of those things that is really fun to experiment with new things on. Because you're dealing with smaller, more local issues that I think you could broadcast and turn into larger issues, just like what we're doing today.

So one of the things we deal with are those projects that meet a specific requirement. Like I said, the Federal Highway has a list and they use AASHTO to do it with the bridge inspection that goes through a rating system. And then what that structure is rated depends on what funds it gets for the type of construction it gets. If it's rated extremely poor, then it gets put to the top of the list for replacement.

or if it's rated somewhat high, it doesn't get as many maintenance dollars, even though there may be something else wrong that needs to be fixed. And that's the scenario that we're in, mainly with IDIQ. Because if it was worse, it would already be in contract or in design to be ready to go to contract. So what you have are these assets that are of a particular age or have particular problems that...

are detrimental to the future of the structure without requiring a five alarm bell emergency on it. And you say, well, how can we get this structure to last a little bit longer, a couple more years? And that's one of the things that most of these projects have been about. We notice these problems, we can't do anything about these problems through capital funding and real bidding to do them, but

Seth (08:05.33)
Mm -hmm.

Dan McCoy (08:26.178)
we have this extra money to go attack those and extend the life of that a little bit. And many of these have been superstructure, substructure issues, stuff that people don't necessarily see too often, but it definitely precipitates the need to reconstruct or replace that asset in the future. So a lot of these structures are, we'll say, penciled in for replacement.

in 2029, 2030, 2032. But we just got to get them there and we want to keep that asset alive and viable for that time to get it there. And one of the ways, you know, we did this and I got to give full props to Dr. Belkowitz here being the nanosilica expert that he is, you know, he came up with this product, Eddystone.

is the name of it. And it's a really brilliant idea that comes from, you know, why don't we take those already underlying chemicals that are causing problems and use them to our benefit in aging concrete. So things like carbonation, things like, you know, especially in bridges or culverts where you see a lot of these nasty phosphates and chlorides, calcium and all this other stuff that

inevitably attack. Parking garages are one that I love the most because you think that's an interior concrete, but then you bring the outside in. Right? So in the Midwest here, you know, if you're driving in on a winter day, you're going through these treated roadways that have all this salt and grime, you know, and it begins to stick to the underbelly of your car. And then you get to work and you go in a parking garage and it's all nice and dry in there and you go into work. And while you're sitting there and work,

all these ice clumps are just dropping off, just like in your garage. I'm sure every one of you that lives in the Midwest or the upper North know that you can tell where you park your car in your garage because you can begin to see that deterioration of concrete where all this stuff starts to drop down and starts to eat away at the concrete, all these nasties. And when you go to a parking garage, it's great.

Dan McCoy (10:47.342)
Now, I know everybody listening to this show looks at concrete a different way than normal people like we just discussed. But once you hear this from me, you're going to start going to these parking spots and you're going to start looking at your garage floor and go, wow, when my car's not there, I know exactly where I park. I can see an outline. I can see where the garage door comes down and traps those chlorides in there. Wait, just wait. You're going to look.

And it's like how do we deal with that and in the the old in the old days in infrastructure? One of the ways to do it was was to use Old days, they're still they're still using it So it's to use the sealer healers that are out there and what those are or more like an epoxy based type thing So you you but think about what you're doing when you when you're doing that now

you see cracks or voids and then you use like an epoxy injection or you use a very viscous or a very low viscosity epoxy to hopefully go in there and try to fill in these cracks and then it cures in its own way but it's not a cementitious material in the effect of what does it do to the concrete? It essentially covers the concrete and then hardens.

So what you're doing is you're placing a stopping point there and you're covering it up. But there's blunt cracking that takes place underneath that. And years later, eventually when you go back and you can ask any concrete guy, let's say you've been around for 20 years, on the first couple of years, you went and applied this and then five or six years later, you go back and you sound it. And you notice that it sounds pretty hollow in there. Even

after all this is going on, it's because that crack has continued propagating underneath the surface. You may not see it, but it eventually forms and starts to pop out. And the folks at E5 and Dr. who had forgotten more about nanosilica chemicals than I can even speak to, came up with this solution to say, well,

Dan McCoy (13:06.902)
what if we could turn all these nasties in concrete into something good for the concrete that actually heals the concrete. So, and that's what was initially found with self -healing. Concrete was over several wet dry cycles. It began to form hydrogels and those hydrogels promoted CSH growth, which is the glue for concrete. And that's why you see a lot of these, even with the internal cures and the liquid fly ash.

you see this increased hydration up to a year out. think in one of your last podcasts, I think they talked about, you know, lightweight aggregate and the benefits of internal curing using lightweight aggregate as the way that poor solution stores that water and then releases it over time. And you end up with high strength concrete a hundred years later. And what's happening is, you know, normally,

I say in the old days, but if you're still using standard concrete, what you're getting is you're finding that you're really only hydrating about 70 % of that cement, right? And the rest just ends up being really expensive, fine aggregate in there. And what the nano silica and the internal cure with the lightweight aggregate does, because it's real porous and it holds water real well, is it releases over time, it releases that water over time, and it hydrates more and more of that unhydrated cement that you...

had eventually or you had initially when you mixed your concrete in the fresh properties and I remember I had a professor in college and he was a captain meeks I'll never forget he went to the US Naval Academy and he was a concrete geek man that's what he lived for matter of fact he was from Virginia and that's where his professional license was from but I remember him with that southern accent saying damn

Concrete kills forever. It kills forever. And it's true, as long as you keep adding moisture to it, it just keeps curing and curing and curing. The old wives' tale, it's not even a wives' tale, but the old wives' tale about the Hoover Dam, it's continuing to cure. It's continuing to cure time and time again as more wet and dry cycles, more wet and dry cycles begin. You hydrate that unhydrated cement particle as you're going.

Dan McCoy (15:32.3)
this in aging, it's like, can we do that to an aging concrete? Right? Cause we've got all these, these older concretes that we know still have, you know, as Warren Buffett says, you know, when he's, when he's, when he's looking for, maybe not a good stock, but a good for right now stock, you know, he calls it the cigar theory, you know, and I love cigars, but he says, maybe, maybe you look around and on the ground, you find a cigar, that's, that somebody's left and it's got one good puff in it. You know,

And you want to take advantage of that one good free puff. Well, that's kind of what we're doing with age concrete and, and, and how we're treating it with these nano silicas is we're taking this and it's got this unhydrated cement particle, but then it's always got these nasties in it. How do we use these together? and that's where the solution comes, comes into is just the delivery method happens to be nano silica. So you place this in.

in a surface saturated dry condition and what it does is it's like if you view a crack as a cut on your skin, it's an antibiotic, right? What it does is it goes into the crack or it goes into the open pores. Keep in mind that nanosilicose are incredibly small. They're a thousand times smaller than a cement particle on a micro scale or on a nano scale, a thousand times smaller. So these voids seem really big to a nanoparticle.

And it goes in there, but there's other nasties that are in those pores too. The chlorides, the sodiums, iron oxides. It's got all these nasty things. And what it does is it breaks down that nanosilica and instead of pushing away from each other with electromagneticism, it causes them to come together and stack. And then what that does then is it purges the bad stuff and collects the water.

And then it saves that water for hydration for the unhydrated sherman using a hydrogel process.

Seth (17:32.85)
And what is a hydrogel? You've said it a couple of times.

Dan McCoy (17:36.206)
So a hydrogel, and now don't get me wrong, you need to talk to the chemical expert on this, which we all know was Dr. John. And I'm so tired of throwing things his way, but he's done it for 20 years. So this is like old hat to him. But when we say hydrogels, we specifically mean the gels that form in concrete.

Seth (17:45.661)
Yeah

Seth (17:53.224)
Yeah.

Dan McCoy (18:01.578)
One of these, there are bad hydrogels too. Any space ball fan out there will tell you there's two sides to every Schwartz. He's got the upside, I got the downside.

Seth (18:09.864)
That's two podcasts, episodes that you've referenced space balls.

Dan McCoy (18:13.39)
So ironically, working in the concrete industry is a lot like being in space balls. the bad shawards in this case is the cancer of concrete, right? We've got...

Seth (18:20.484)
boy.

Seth (18:34.651)
ASR.

Dan McCoy (18:35.634)
So we've got the alkali -silic reaction, which is a bad hydrogel, right? It begins to expand in there. It creates these pressures that we don't want because it accepts the bad chemicals and begins to expand causing crack, blunting, and all this other stuff. But the good stuff with the nanosilicas forms not the same hydrogel, but I like hydrogel. And it's just like it sounds, hydrogel. And what that gel does is it becomes harder and harder over time.

not harder than the concrete, eventually promotes that CSH growth while purging the bad stuff out. So things like carbonation that we have with age concrete, takes advantage of that differential in pH. As the pH comes down, it's, you know, alkalized susceptible. And then it takes those, it takes those nasties and begins to purge them out, but it also breaks down itself to collect water.

and then the water is saved in the hydrogel and it begins to promote that calcium silicate hydroxide reaction. So that's the glue of concrete, the CSH concrete.

Seth (19:42.686)
So if you're looking at a crack, just a V of a crack, it's bridging the two sides of the crack, right?

Dan McCoy (19:52.642)
Better yet, it's coating all the way down and into the crack. And then it finds that crack blunting and relieves that pressure that would be propagating a crack. And it pulls the nasties out of it, creates that hydrogel. And then at the bottom of the crack, it begins to form CSH, essentially re -healing the concrete by turning.

Seth (19:57.265)
-huh.

Seth (20:02.822)
Okay.

Seth (20:10.908)
versus sorry to interrupt you versus the tip traditional way is if you were to treat a crack is routing or chipping away the bad concrete and then shoving epoxy down there.

Dan McCoy (20:15.213)
No.

Dan McCoy (20:28.514)
Right, right, because what you're trying to do is you're trying to, in that essence, you're trying to stop crack propagation by filling it with something that is going to fill a void. That's essentially what you're doing is filling the void so that it stops that. you're, it's, it's those epoxies and don't get me wrong. I still think on surface treatment, if you've got some early age cracking, one of the best things to do now, there, are other nanosilic is out there that you can place.

on that early age cracking that will promote this as well. Notice I said silica not silicates. There's a difference because those form gels too. They just over time they need to be reapplied. They begin to break down like a silicone gel would. Right, right. They need to be reapplied. But the other one, you you're playing with the chemistry of the cement matrix. They actually foster and grow new concrete or

Seth (21:13.8)
Like a sealer. Yeah. Yep.

Dan McCoy (21:27.262)
hardened paste. Let's put it that way. You're not growing new concrete. You're more of a hardened paste using the hydrogels. So that is one of the... and I realized... so the other thing that's really nice about nanosilicons is they love water, right? And so what I've discovered is, you know, when you go in for structural patching, usually

Let's say we're high strength structural patching. So when I mean high strength, I'm not talking like at UHPC like Bill Coolidge makes, but more so of I've got a pretty small patch to do on a pretty significant number, like a beam, that maybe sees a lot of shear stress. But over time in our joining system, it's taken a lot of waters and a lot of salts and it begins to break down the end bearing of that concrete.

And so you want to strengthen that up. Maybe the rest of the beam is good. As a matter of fact, it probably is, but maybe you have some indie bonding in the strands. And one of the things you carefully want to do is support that member and then take away all the bad stuff, chip it out just like you would a structural patch and put that back in. Well, what I would do and what I do is place the nanosilicate in there and it takes all that bad stuff and begins to create these hydrogels immediately.

And then I take a high strength patch over it, you know, like a CECA patch or any name brand patch that you want to put out there. And if you want to throw in some fiber reinforcement or carbon fiber reinforcement in there for high strength fiber patching, that, you know, that's, that's all part of the process. But what I like is you apply the neosporin, the antibiotic to it, and then you place the patch back over it. And what you see is increased bond strength between the newer patch and the old.

Seth (23:15.602)
Yeah, patch probably performs better.

Dan McCoy (23:17.994)
Yeah, well it lasts longer, right? That's what you're going for. You're going for the longevity. So you're restoring the strength as best you can. Because nothing's better than a perfect member anyway. I mean, you're just trying to hold it in place and keep it alive for another couple years and keep that asset viable. So when you use this, the Eddystone product on aged concrete, it takes advantage of the fact that

You've got a lowering pH due to carbonation or due to some of these phosphates or these chlorides coming in. And it takes advantage of that. And the more you give it and the more wet dry cycles it goes through, the harder and better it gets. And the more propagation of CSH that you see. And then you end up with, just like we do with the nanosilicate concrete treated today in the mix, you're going to end up with...

not necessarily all around, but in that area you're going to end up with taking advantage of not 70%, you know, you've got 30 % of those unhydrated cement particles left. You begin to hydrate more and more of those unhydrated cement particles. And, you know, you end up with, if you core it in several years, at that location what you're going to find is a greater population of hydrated cement in that area, which is everything positive that you wanted to do in the first place.

Seth (24:43.388)
Right. Huh.

Dan McCoy (24:46.254)
It's all fun stuff, right?

Seth (24:48.604)
Yeah, well, it makes, it makes, it makes a lot of sense. I guess if you just look at it, utilizing the chemicals that are in there that you don't want in there and use them for good is basically what's happening. Right.

Dan McCoy (25:04.258)
Yes, yeah, yeah. that's essentially what you're doing. You're using the reaction between that nanosilica and its chemical makeup and how it's made. Now there's a million and one different ways to make a nanosilica. I think we've covered that before. There's good ways and bad ways to make nanosilica. They're not all created equal. That's my note for the day. And the other ones that we talk about are patented processes and...

and they're very specific in how you can manufacture and that it is a manufactured product. Once it goes through the facility and it comes out being exactly what the user wants, depending on what they're going to do with it. And obviously they're used everywhere from ink pens to wastewater treatment plants, the stuff that you use every day. But as far as being used in concrete, it's just fairly recent. And these things.

Seth (26:00.028)
Yeah. How long have you been doing this process where you've been applying the nano silica before you're doing your repair?

Dan McCoy (26:10.048)
two years. Two years.

Seth (26:12.668)
And how do you go back and determine that you're getting the results that you want?

Dan McCoy (26:17.966)
So this is an interesting case study that we did. There was an asset within INDOT that we had actually built. We are on McCoy. We had actually built in 2000, I think, 99, 2000, somewhere around there. They were expanding the highway system on I -69 netting, replacing pavement. And there was an old abandoned railroad.

that the new highway or the replaced highway was going to go over. But since it was an abandoned railroad, why should we replace that bridge when it's a bridge over nothing, essentially? So what they wanted to do, Inda, what they wanted to do was just basically tear out the bridge, which we did, and then fill it back in and, you know, a standard earth bank, you know, because it wasn't crossing a waterway, was crossing

An asset to the railroad that was no longer in use track had been removed. You know, it was just railroad right away that they were done with and Ironically enough there was one property owner that owned property on both sides of the highway and He said whoa, I have I Like that access. I like being able to go from one property to the other

with all of my equipment, all of my valued assets. And it was an auction company. And if anybody's ever heard of Auburn, Indiana, it's one of the Auburn Court Duesenberg Festival and the Auburn auction. But that's how they would move these Duesenbergs in high dollar, I mean, we're talking million dollar cars, from the museum on one side to the auction floor on the other. It's a huge property. And so he said, wait a minute, wait a minute.

What if I, he says, what if I throw in some money and you guys build us a tunnel? And we said, well, that's interesting. Let's see what Indot thinks. Indot saw that and says, well, if you pay for it and then you manage it afterwards, then we're more than fine with that being an asset under our asset, which was the highway. And we built that in 2000.

Dan McCoy (28:46.414)
and then covered it up. it's essentially a tunnel that's 16 feet by 14 feet by, man, 300 foot long. yeah, it's on a skew. you know, it's a pretty good skew. And what we use segmental cast in place concrete pieces as we went. So like a moving form system, just like with a tunnel. And we built that and then tore down the bridge and then backfilled around it. So essentially it's a large,

Seth (28:55.145)
wow, yeah.

Dan McCoy (29:16.194)
dry cast in place culvert, right? But it signifies one of the problems that we have. This is why it was unique. It signifies one of the problems that we have with our aging infrastructure is not all of the elements or the structures that cross highways or go underneath highways or bridges, right? We still have to be able to move water. And you have a lot of these smaller structures.

whether it's a reinforced concrete pipe or whether it's a true culvert or precast culvert, the way you put it in is you can't do it all at one time. They're so big. You end up with cold joints in there. And then you try to protect those joints as well as you can. But where you see the beginnings of that asset falling apart, or at least the trouble is at the cold joints, right? If you can eliminate a cold joint in something that's meant to be continuous, you're eliminating a big headache.

for the future, right? So you try to eliminate those as much as possible, but in this tunnel, we did these in 40 foot segments. So we've got like seven, we've got like seven coal joints in there. And it's covered up by about 12 feet of earth packed material and clay, you know, back filled with like a B barrow and then B barrow is like a really, really fine, well, of course, to find sand.

Seth (30:13.438)
Mm

Dan McCoy (30:41.166)
But that's what you normally see on the drawings, you know, in the commercial world I'm sure you see in some of your sections that you don't really care about so much where you see earth on the other side. It says engineered fill, right? So that engineered fill when we talk about it as engineers in the geotechnical sense, all that means is it's soil that I know what it is. We know it's moisture content. We know its angle of repose. We know that it's a drainable material, so it's not going to build hydrostatic pressure.

Seth (31:01.18)
Yeah, okay.

Dan McCoy (31:10.252)
That's what we backfill it with. But again, I said the key word, drainable material, right? What does that mean? It means that all the waters and chlorides and salts that come in from up top eventually come through and then go around the structure to drain out in a way. But what you have over this large flat structure is you eventually have pooling that takes place up there around these cold joints. And eventually that moisture builds up and starts to work its way through.

And then you have, keep in mind, a culvert's open to air on the top, even if you've got water running through it. It's open to air on the top. And it's gonna go through freeze -thaw cycles just like anything else underneath. So you have moisture coming down through this crack. A freeze -thaw pops, freeze -thaw pop. And you begin to see this joint breaking out, and begins to look pretty ugly. And that was one of the problems with this asset.

And luckily enough, we got word that something had gone wrong in the process of whoever was responsible to take care of it. The property owner said 20 years ago that he would take care of it. It was supposed to sign a legal document saying that he would. Evidently, nobody followed through on NDOT. It was lost in limbo. NDOT still maintains this structure to this day. They never wanted to. They never wanted it. And finally,

The asset manager in the area and the program director was just like, well, this is just a liability for us. We've got active traffic going overhead. We don't need it to be a problem. We're just going to fill it in. And I said, whoa, whoa, wait a minute. I got an idea. And the idea was, is everything in Indiana, just like most of rest of the country is going to, we're installing trail networks like nobody's business for walking trails and biking trails.

You know give you that park atmosphere that sense of community and I said, whoa one of the biggest benefits in a trail system is separating Is separating vehicular traffic from pedestrian traffic and bike traffic, especially in an interstate system. So you have very few crossings of That type along an interstate highway and I said, I don't think we want to lose this I think as a matter of fact these old abam and railroad

Dan McCoy (33:38.658)
railways are perfect places to put these trails. That's what they've been doing for most of the time. They take these old abandoned right away because nothing's ever been put on it because the railroad is everything forever. And they put a walking trail on it then. So it's fairly clear of utilities. It's fairly clear of buildings over a couple hundred years. So it's an easy access, just wide enough to put in a nice walking trail. And that's when the existing property owner

and a couple other trail organizations got together and says, yes, we would like to save this asset and we would like to take care of it. And I said, that it's something that I could turn into an experiment, which is exactly what I did with the hydrogels. So we went in there and we basically said, well, if you're going to fill it up anyway, or if it's no use to you, me core it, make some Swiss cheese and get some.

samples out of it see what we're doing. So that's exactly what we did. And we went in there and to get to your, this is a long way to get to your answer if your question is where have you used it before and how do you see it working? And we said, okay, we're going to, we're going to split it right down the middle. We're going to treat this half of the tunnel and we're not going to treat this half of the tunnel. And the joints look fairly uniform as in to the point where they look horrible, like really bad.

I mean, you've got oxidations, stalactites, I mean, bad stuff, right? You can see that water just leaking and pools on the floor of where that water's draining through like a percolator in a coffee cup, right? It's just coming through. And we said, you know, and I sent those pictures to Dr. John and I said, so is this the stuff that you were talking about? You want to try this? And he starts frothing at the mouth and he's like, these are great. This is fantastic. And I'm like, I've never heard anybody look at a

crack this bad and say this is fantastic. So we took some water samples and this was for a later product that actually has to deal with soil stabilization using nanoparticles. But you know when you take that water and you send it in you can do it the easy way right. There's a free kit you can go get at Home Depot to tell you whether your drinking water is good or not right. So you can go get this and you can collect this water and then you send it off to them.

Dan McCoy (36:01.784)
And then they'll call you back and they'll recommend products or a water softening system, you know, to clean your drinking water. And I got a panicked phone call from the third party agency that tests the water. And, you know, I put all my information on there and, you know, and I'd sent the water sample off and I get this call back. It's Franek and it goes, Mr. McCoy. And I said, yeah, yeah, I've been waiting on a call from you guys, the water testing agency. She goes, you're not drinking this water, are you?

And I go, no, no, no, I'm not drinking it. I'm, you know, just seeing what's there. They're like, boy, that's good. I would recommend looking somewhere else because there is a lot of nasty stuff in this, in this water. I said, that's interesting. Could you send me the report? They sent the report. Of course it's everything. It's take a glass of water and collect the runoff from your local highway in the middle of winter. That's what you had. Right. You've got.

Seth (36:44.016)
huh.

Dan McCoy (36:58.464)
You've got a lot of nasty chlorides and phosphates on there. Everything that you put there to prevent ice, everything that's running off the vehicles. It's definitely something you don't want to drink, but it's also all the bad stuff in concrete that we don't like to add to it. And that's where it was coming from. It was running right through there. So it had these nasty chemicals. And the best part is, is we have an unlimited supply of these nasty chemicals that are just coming down every year through that filtration system.

And the best way to tackle it was to say, okay, well, we're going to go up and we're going to sound it. So we did, we went up and sounded at the side, we were going to treat it and we knocked out all the loose stuff that was going to be a hazard. And it would just fall out in chunks. And then we would clean it using a high pressure pressure washer, water nozzle. You know, something generates around 3 ,000, 3 ,500 PSI to clean the surface off.

get everything out, get it surface saturated dry because it's key to have that water. And then we placed the nanosilica up there in a very fine mist. There's no health hazards associated, which a lot of other stuff you see health hazards associated with. But this one, you you just place this on here. And then I thought, well, this will be a long term experiment. Let's see what happens. We came back the next morning to do more of the other sides and you could actually see the hydrogels already forming.

in the crack. And that's what was amazing to me. It was just absolutely fantastic. You know, I was thinking about this the other day and sight or picture say a thousand words. If you say that a nano silica does something or any product does something but someone can't see it, even if you've got all the empirical data to prove that it's happening, they still think, nah, I don't know what's going on here. But way back in the day, if you showed someone a camera,

and said, this takes pictures of you. And nobody believed it. And you took a picture of them and then you showed them the picture. Then they go, this is taking pictures of you. I get it now. You've sold me. Seeing is believing. It's one of those things. But you just can't do that on the nanoscale and the microscale of the stuff that we want to happen. But in this essence, that's what you could see is those hydrogels forming. And the more water that was coming down, it had taken that water on the one side of the tunnel.

Seth (39:04.338)
huh.

Dan McCoy (39:26.158)
from the night before, the other side was still leaking and percolating and this side was just accepting all that moisture and all those nasties and forming those hydrogels, which then was gonna propagate and make, you know, via CSH was gonna rebuild and heal our concrete. So now obviously we wanted to do a lot more than that. We were just stopping there to see what would happen. So in a good world, what you would do.

Seth (39:43.792)
huh.

Dan McCoy (39:53.238)
is you would take something like that and you would incorporate it into your patching material. And then you would also do something to repair that joint of where you do have copious amounts of water coming in. You still don't need, you know, when I say you need water, you don't need that much water as far as healing over time. But it does everything to help and it's all the positive things. So that was my first real aha moment of, wow, this is really working. This is fantastic.

I can see using this in a lot of places. then you have an easier time understanding how it works with maybe surfaces that are that old or older. This concrete was only 20 years old, but a lot of times we're dealing with concrete that was built in 1930s and 1940s. And maybe you don't have really bad cracking because it's been pretty sealed from the environment as far as hardcore exposure.

But you still have carbonation taking place and you have those tiny little holes, everything that you can take advantage of, of that pH beginning to lower. Once you can take advantage of that and start replacing all those nasties with some good hydrogels, you're gonna reactivate the unhydrated cement particles that are in there, begin to grow some really self -healing concrete. cost was the other issue. It was absolutely fantastic. I don't know.

If any of you are out there listening in the Midwest, if you can find someone that can do vertical or overhead concrete structural patching for less than $100 a square foot, you're an absolute genius, right? I mean, if you can do it less than that, it's unbelievable because then you think, God, that can't be that expensive. Well, it is. And I've tried more than one way to skin a cat and it just takes that long.

Seth (41:30.397)
Yeah.

Dan McCoy (41:46.542)
It takes the right kind of mixture with the cement paste and the patch to get it right to stay there. And then if it's a deep patch, you have to add it in layers. And you're an absolute genius, but I was able to apply this stuff, labor and everything, and purchase the product. I was able to do it for like 10 to 12 bucks a square foot. So when you think about being able to prevent, maybe you don't want it to get that far.

when you want to be able to prevent something from like this happening, where you have these big, long, horrible looking concrete structures, which are sometimes fun to look at because you think, man, this asset really did its job. It's really done its job over the years. But if you can do things like that and apply it, then I used it on on an IDIQ project where we had to repair some beams.

that were the same way. And then we had patches falling on pier walls that would come off. They were old patches that were done 15 years ago. And you end up inevitably going back and placing the same patch. Well, it's because you can do as much as you want with surface prep, but you're still going to have that cold joint around that patch. It's still going to permeate and leave that moisture to come in, even with those nasties. And you're going to have that propagation that occurs on a micro level, builds up these intense pressures.

Seth (43:02.685)
Mm

Dan McCoy (43:15.23)
And if you can treat that prior or treat it as you see it with something that's going to be an antibiotic cream to put on the concrete, then now you're talking about a true sealer -healer, right? In the essence of you're using the bad stuff to create more of the good stuff, purge out the bad, create these hydrogels to make the good. And that's the stuff that we've been playing with. It's fairly exciting. I know I've done so much talking. I'm so sorry. You should probably.

Seth (43:43.506)
That's what you're supposed to do when you come on there. I keep telling people that like that they say, I feel like I'm talking too much. was like, that's why you're here. You're here to talk.

Dan McCoy (43:45.226)
I

Dan McCoy (43:52.718)
Right. But, you know, we'll come back to one of my other loves. And of course, if you guys know, you know, if you're listening now, you know that I'm a nuclear geek too. And one of the, one of the reasons that I'm fascinated about nuclear engineering and nuclear science is it's amazing how much we know about that process. This didn't come along until Enrico Fermi started this thing in the thirties, you know, and people said,

Okay, I can equals MC squared. can turn matter into energy with the right chemicals. And then they studied it and studied it and studied it. And now in a reactor, you can have nuclear engineers that know that if I run a reactor for this long at this concentration with the rods this close together, I'm producing this many atoms of cesium and this much plutonium. And I know exactly what isotope it is and how long the decay time is, right? We know that for

I get excited about this because we know so much about it and it was created, basically invented in the 1930s and 40s. We've had concrete for thousands of years and we still don't know what's going on on a molecular level as it starts to happen and what we're producing. It just blows my mind. And here we use it everywhere and all the time. And we know literally less about what's going on in that nucleation than we do than what's going on in a nuclear reactor right now.

Seth (45:18.726)
Mm -hmm. Yeah, I don't understand why people don't. Yeah. See that you just sold a concrete career right there.

Dan McCoy (45:19.598)
It just blows my mind.

Dan McCoy (45:27.342)
Well, right. mean, it's such a valuable material. know, I've heard Dr. Lay explain it a thousand times to a thousand different people. It's the most used manmade material on the planet. It's what we do. It's what we make. It's very cost effective for what you get out of it. And why not take care of it? Why not create new ways to reuse it? And that's where the magic of sustainability happens.

You know, how can we get these assets to last longer? Well, we can design them better right now We can use better materials right now that are meant for longevity and sustainability To get that asset that was a normally Meant to last 75 years to get another 25 years out of it minimum get a hundred years out of it 120 years out of it depending on the climate and other things like that But if you if you can do that and plan that well ahead

That's where you're making your environmental impact. If you can prevent doing all this and spending all this extra time and money in the future, then that's what you're doing. People tell me all the time, well, you're a contractor and you're an engineer. Aren't you kind of like a self -fulfilling prophecy? You're kind of killing your job in the future if you do it too well. And I'm like, no, that saves more money for the new infrastructure that we need. And I'll build that too.

Seth (46:27.752)
Yeah.

Dan McCoy (46:53.164)
You know, so if we can do that, it's gonna be for the better. It's gonna be for the better.

Seth (46:59.25)
Yeah. Nope, I agree. Yeah, it's a...

what we need to be doing. mean, I keep, we keep beating, I guess, beating the drum saying that concrete's the most sustainable material on earth, but just not winning them all, Dan. Well, well.

Dan McCoy (47:19.896)
Yeah, well, if they all believe this, wouldn't be very, it wouldn't be very much fun. It forces us to do things like this and really do the testing that's required of why this is working and what's happening. It's a good thing. To be questioned on this stuff, I love it because the results speak for themselves, especially in the future.

Seth (47:24.882)
That's true too. That's true.

Dan McCoy (47:49.344)
It just, you know, if, you know, I remember Dr. John asked me one time, what's your ideal concrete mix? And, you know, and maybe I'm going to, I'm going to, you know what, for fun, let's, let's flip it on him folks. Seth, what is your ideal concrete mix?

Seth (48:06.283)
my gosh. The one that makes money. Yeah.

Dan McCoy (48:08.917)
OHH HA HA HA!

Dan McCoy (48:12.852)
I that. I do. like that. I like that because we've looked at so much, right? Look at all the stuff we can do. You know, had a steel like Bill Coolidge on before who I love and he talks about, you know, ultra high performance concrete, which in his world, you know, he cringes a little bit when you say concrete because it's a composite, right? It's his life. It's a goody bag of materials that is unlike any other, even different other UHPCs.

Seth (48:32.338)
Right.

Dan McCoy (48:39.628)
That's one form of concrete. And then we've got the lightweight that you discussed in your last episode, which we've used in bridge decks before, which we do in hospital floors, mainly for weight reduction and for the fire rating code. And it's difficult to pump sometimes, but treated right, you can do it all the time. And there's other benefits to using the lightweight aggregate, like the internal cure mechanism that basically Dr. Jason Weiss came up with.

15 years ago, 20 years ago, about, this is how internal cure is working with a lightweight porous aggregate. There's so much that we can do and so much more to learn. That's what's exciting. By the time it becomes more prevalent in the future, things like carbon nanotubes will become more prevalent and the price will come down on those and you can begin to make.

some higher modulus concrete with lower compressive strengths. And you can begin using less of the really high dollar coarse aggregate around. mean, there's just so much cool stuff that you can do with concrete. It's not you just call a ready mix company and say, I want concrete. All concrete's created equal. The dirty little secret is that even if you ordered the same concrete 20 yards and you get two 10 yard loads, they're not the same.

Seth (50:05.064)
Yeah. Yeah.

Dan McCoy (50:05.262)
That's the dirty little secret. Because they can't be. They can't be the same. They can be within a standard deviation, but they're not going to be the same.

Seth (50:14.898)
Yeah, yeah, we could talk about that for another for another hour, but I think I think we should wrap it up on your on your healing. I like like you said, they do address this the right way. So we're not keep on spending money on on frivolous repairs is is to actually address the the cause of the of the crack. Right. And then and then and

Dan McCoy (50:18.826)
Yeah

Dan McCoy (50:40.842)
Right. And I'm not saying take away the methacrylates of the epoxies. I think that's an acceptable method for covering up and concealing cracks. I'm saying we should do something to the crack beforehand.

Seth (50:57.692)
Yeah, then all that stuff, all the epoxies and sealers and all that will just perform that much better. yeah, all right. All right.

Dan McCoy (51:03.732)
Exactly. Exactly. Exactly. There's a of stuff to do that. But hey, I am I am so happy to be here. Thanks for having me back. I was supposed to give you some grief. think Dr. Belkowitz and maybe even was it Bill Coolidge? I think there were a bunch of them that were saying that if you've been on the show, you get a free t -shirt. Was that was that? You got to be. my God. I like that.

Seth (51:13.32)
Yeah.

Seth (51:24.894)
free t -shirt. Yeah, I to be on the show 15 times, I think to get a free t -shirt. Yeah, there you go. I keep, I keep moving. I keep moving the goalpost every time somebody asks about it. So

Dan McCoy (51:32.822)
I like that. What you put on.

Dan McCoy (51:39.032)
that's absolutely fine. Maybe you just need a couple of us to get together and just make you a t -shirt and just randomly send it to you and when you open it up you'll say that is the coolest t -shirt I've ever seen.

Seth (51:48.2)
It's cool. Yeah, we'll figure it out. But, all right, Dan, well, I appreciate you coming on the show as always. I always have fun with our conversations and we'll get you back on for sure. And folks, until next time, let's keep it concrete.