EP #147: Concrete Cracks Don’t Lie - ASR, AAR, and What’s Really Happening Inside Your Concrete

Dr. Jon Belkowitz (03:22)
Concrete Coffee Talk with John

Seth (03:25)
you

Are you kidding me?

Dr. Jon Belkowitz (03:27)
Every time I watch, I'm such a child, every time I watch that I cannot.

Good morning ladies and gentlemen, welcome to the show. It's our intelligent concrete coffee talk, but we have one of our most awesome guests ever, the legendary Seth Edward Tandon. Seth, how you doing sir? Welcome to the show.

Seth (03:48)
Well, thanks for having me. This is a little different for me. I'm usually driving. You're driving today.

Dr. Jon Belkowitz (03:53)
I'm driving today, but I really, I want your feedback and I don't want it to be honest. You can lie to me if you want to. but I want some type of feedback is to, should I give a shit John? I'm sorry. Why should I care? So that's what we're going to be doing today. So audience participation is huge.

Seth (04:13)
They're going to be confused by your, I mean, your little banner down there.

Dr. Jon Belkowitz (04:18)
What do mean?

Seth (04:19)
we're talking about a s art dot

Dr. Jon Belkowitz (04:20)
Yeah!

Seth (04:21)
Why does it say AAR?

Dr. Jon Belkowitz (04:22)
See, look at ladies and gentlemen, this is why Seth tended Seth Edward, excuse me. Tanded is a fricking living legend. Anybody else would let that fly by like contrails in the sky. Sorry. Chemtrails in the sky. But Seth noticed that we are talking about ASR, but we're going to generalize it. So what a R is and I'll just.

add the stage here. AAR is the general term used to describe an alkali aggregate reaction.

Now, I want your job today is, know, so Daniel calls me a fatalist and he says, I have bad bets. I'm you too much of an alarmist, John. Well, you know, sometimes somebody needs to sound the freaking alarm. Right. That's how you know, you're the you're an adult. Like when everybody looks at you to decide, is it time to call the plumber? Right.

That's how you know you're finally adult. If you're picking up a phone to call a plumber, you've made it to adulthood. And sometimes you need to sound the alarm and be a fatalist. And I would like to start this conversation off with this picture right here. You know, I wanted you to be honest about why should I care about not only AAR or ASR, which is alkaline silica reaction, but the

the whole spectrum of alkali aggregate reactions. And this is real concrete.

Seth (05:46)
Yeah.

It looks bad.

Dr. Jon Belkowitz (05:48)
You know, you're like a sphinx. It does look bad, Seth. This is what we call like, and I think the technical term is exudation. You know what exudation means?

Seth (05:58)
I do not know to me, you know, I'm a just a regular guy. I'm not a, I'm not a scientist like you.

Dr. Jon Belkowitz (06:06)
What would you call this if you didn't know what exudation means?

Seth (06:09)
It looks rusty, man. That doesn't look good. You see that on your concrete. It's, it's, it's bad news.

Dr. Jon Belkowitz (06:15)
Right, but it's not just rusty and, hey, let me zoom in on that just a little bit more. There's something going on here. Look at that. It's like oozing.

Seth (06:25)
Yeah.

Yeah, ⁓ that's what I thought was the ASR, that's the gel, right?

Dr. Jon Belkowitz (06:31)
It is the gel. But what's accompanying it that makes it look like something from an alien movie is rust. So you called it out. What normally happens is ASR, AAR, any of those weren't the primary mechanisms for concrete failure back in the day. Right? We had control of them. I'm talking the 80s through the early 2000s.

But as we started getting into the later 2000s, prescriptive to performance, driving the amount of fly ashes, we started creating an environment that was more conducive to this reaction. And the unfortunate reality is if you let ASR go and really ignore it or any of the alkali reactions, this is what it can turn into.

And like I said, ASR wasn't the primary mechanism, it was a secondary mechanism that led to more steel corrosion than the steel popping out, tendons hanging out. Okay, now we have to do something. But now it's gotten to the point that the reaction happens faster and happens so much more intensely that it's almost like, and for lack of a better analogy, a blastoma in the brain. It's...

Seth (07:28)
Yeah.

Dr. Jon Belkowitz (07:43)
increasing the concrete size in a confined space. And normally that means it has to push the concrete up, develops almost like a muffin top, and our concrete softens from within. That's the biggest problem with ASR. It looks like a surface issue, but by the time it's gotten to the surface, you're up the creek without a paddle. Now again, why the heck would you care about?

Seth (08:05)
Well, it's a sign that something else is going on. we kind of talked about this a little bit, ⁓ you know, the concrete logic podcast, episode one 45, which was released this week. If folks hadn't listened to it yet, but, ⁓ we were talking about, protecting the surface of the concrete, right. Making sure we're doing a good job protecting the surface so that the, ⁓

Dr. Jon Belkowitz (08:10)
And it's.

Seth (08:31)
It doesn't penetrate into the lower level or layers of the concrete. Yeah. Penetrate. Yeah.

Dr. Jon Belkowitz (08:37)
Penetrate.

I like the word diffuse better. One, it doesn't sound sexual and two, it's more direct. mean, normally the stuff that we're talking about is water with some type of contaminant like an alkali or an oxide, something nasty. Right. It fuses through the concrete. A paint or a sealer penetrates, hardens and then anchors itself.

We want diffusion through the cracks in the pores.

Seth (09:04)
Does that make sense? It's already, it's a sign of there's already moisture getting down to the rebar, right? And corrosion happening and all kinds of nasty things going on inside the concrete.

Dr. Jon Belkowitz (09:16)
You know what the crazy thing is? The steel in our concrete, especially the most, you know, extreme steel, and I think I have a picture of it here. Hold on a second. Here.

I love this picture. Look at this. This is a picture that Brian Green sent me for one of my books. This is Miami. This is a wharf. And this is the underside of that wharf that really gets all the salt spray. And maybe I should zoom into that a little bit more. Can I do? So, the concrete, when concrete...

bends, especially a concrete beam bends. So this is a concrete. See, this is why I didn't want to do the flipping what's it called?

Seth (09:57)
What's that?

Dr. Jon Belkowitz (09:58)
The blurry background.

Seth (10:00)
Can't see. ⁓ yeah, there you go.

Dr. Jon Belkowitz (10:02)
All

right. So when you have a concrete beam, so this thing right here, these long things, they're beams. They're beams glued onto a concrete deck. But what their job is, is to take the load that's above and their job is to bend. Right? Now what happens in these top squares here, it looks like I'm wearing a hat, in these top squares here is you're going to see them squeeze. Right? The bottom squares here, they're going to stretch.

See that? So the top is when it bends, when the concrete bends, the top is in compression and the bottom is in tension, right? Almost like one of our flexural beams that we put in the compression machine. So we put steel, the majority of our steel, we put it in the bottom of our concrete beam. And there's what? Two, three, four layers of steel. You can kind of see it right there, right? We've got a whole bunch of strands that are falling into the ocean. that.

Seth (10:27)
Yep.

Dr. Jon Belkowitz (10:53)
So cool. But all that steel here, look right there, this is perfect. All that steel right there is protected by 50 millimeters, two inches, if you're not French, of concrete.

millimeters or 50 millimeters, that much, that much. And the worst part about concrete is we know it's going to crack. Every crack tells a story, but that's why the good Lord started concrete with the letter C because concrete cracks. And especially where we have a wetting and drying environment where the concrete swells and then it contracts and then it gets chlorides in it and goes through calcium oxychloride formation, the concrete falls apart, right? And then

Seth (11:10)
Right.

Dr. Jon Belkowitz (11:32)
corrosion happens. So this goes back to, we didn't really give a shit about ASR until it started doing things like this, compromising the entire concrete structure. And when it does that, the steel, that's when we have the primary concrete failure mechanism. ASR was secondary. Does that make sense?

Seth (11:50)
Yep. I'm following you so far.

Dr. Jon Belkowitz (11:51)
Right. That's changed. That's changed. Right. Now what we see, and before I want to show you pictures of job sites, now I want to, I just want to give you a quick illustration of what ASR is. Is that cool?

How do you minimize this?

Seth (12:06)
I don't know, you're driving, ⁓

Dr. Jon Belkowitz (12:08)
All right,

enough of that. Be nice. All right. So, you know, the, in my opinion, the greatest mind when it came to alkali aggregate reaction was the brilliant Michael Thomas, you know, professor at University of New Brunswick in, where was it? British Columbia, New Brunswick, Canada, you know.

But Mike was the expert for the Federal Highway Association. I believe he was also the expert for AASHTO, ASR, or ACI on all things AAR, ASR. And this was, if you look at the AAR facts book published by the Federal Highway Association, and it was published, I think, back in 2016. They came out with a new edition. But there's amazing case study stories, research.

A lot of it led by Mike Thomas. This is one of the bridges that they took out or they reviewed as one of the case studies. And what you can see here is that part of the bridge infrastructure was covered by a soil embankment. And that soil covered the concrete and protected it from freezing and thawing, wetting and drying. Now I zoomed in on it and you can see there's this diagonal line.

that separates where the soil was on the bottom versus where the concrete wasn't protected above the diagonal line. You can see this map cracking pattern. Now that cracking pattern is indicative of alkali-silica reaction. Something I had said to you earlier that every concrete crack tells a story. Concrete cracks don't happen by accident. And when we see a crack like this, when the three legs are 120 degrees apart,

almost freaking perfectly. If you trace every crack, look at that, oops, 120 degrees, 120, 120, 120, 120, 120. That is something that we call the Isle of Man crack. It looks something like this. And that is very specific to alkali silica reaction or even alkali aggregate reaction, the more general term. But freestyle.

deicing salts, shrinkage, plastic or drying, we don't get this type of crack. Now, where this comes from is alkali-silica reaction specifically is a chemical physical reaction, mechanical reaction that goes after a very specific type of silica in our aggregate. That's why it's got to be a specific type of aggregate, it's not just any aggregate. And it's a tetrahedral form of silica

which in a high pH environment breaks down and then it reorganizes with those alkalis to form this expansive gel. So we've got this picture on the left where we have our orange rock, don't ask me why I chose orange, surrounded by our cement paste with sodium, potassium, hydroxides. And then when all of that is in the right environment, the right pH, the right temperature, the right amount of silica, and then of course some form of calcium

We start the growth of this gel at the interface of our rock and our cement paste. That gel grows until it overcomes the sheer tensile capacity of the cement paste and the rock, and we start cracking. This is what it looks like under the microscope. It's really pretty, really, really pretty. And then you zoom in on it, you can see this fiber-like morphology, and that's the root at what causes more and more and more expansion.

That fiber-like morphology likes to draw in more water, which causes more expansion. And if you've never seen a bike race, this is the Isle of Man flag on the left, where it has three legs that are 120 degrees apart. And then we have what ASR looks like on the right. And you can see they're nearly identical.

Seth (15:41)
Okay. Has ASR always been a problem or is this a relatively new thing? our aggregates have changed over time.

Dr. Jon Belkowitz (15:50)
I want to say we first discovered it, it was like in the somewhere between the 20s and the 40s. In the 50s and 60s is when we did most of the research. And we had a good handle on it up until I want to say the early 2000s. And a good handle on it means if we were doing, if we had ASR,

⁓ We just included SCMs, the amount of alkalis, or excuse me, included SCMs, limited the ROC, did some investigation, evaluation to determine that we'd have reaction, and included those SCMs in the mix. That's ASR, and that's really what we've talked about. If it's ACR, which is alkali carbonate reaction, that reaction is a little bit different.

different. There's no cure for that. The only thing you could do is limit the amount of dolomitic limestone in your concrete to less than 20%. And that was determined back in the 50s and 60s. most DOTs, most ready mix providers, most aggregate providers have forgotten there. And especially with the use of type 1L cements. Now, I don't know if anybody has checked for that. And that's not meant to point fingers, but I'm pointing fingers at the fact that we haven't checked into at least

I haven't heard of anybody checking into that. We're running tests right now to identify, there some type of alkali reaction going on with something in the cement? What we've done is we've taken out the aggregate portion of our accelerated mortar bar test and it's just a cement paste. And if there's nothing in there that's going to cause expansion, I mean, that bar shouldn't move a flippin inch or 0.0001 inches.

But when it comes to alkali carbonate reaction, it's aggressive. It can happen within months, within a year, within two years, as opposed to alkali silica reaction. You need many, many years, or at least you used to. But the reason why we're going through this is because we've seen a lot more ASR, could be ACR, in concrete that's less than three years old, sometimes seven days old. And again, every concrete tells a story.

Concrete doesn't crack by accident. There's always an effing reason.

And when this happens, you've lost your concrete structure. Like ASR, you can seal it. You can grind off a little bit at a time. That was something that Mike was known for. He represented a bridge in, was it the British Columbia, BC that grew seven to eight inches every couple of years. And it grew into

and had caused issues with the hydroelectric equipment with the dam. So every few years, contractors had to come in and cut the concrete around the hydroelectric equipment. So if you're building, let's just say you're building, I don't know, an elevator shaft for a parking garage or a multi-story structure. You cast it.

You cure it, you rip forms off, everything looks kosher. Seven days you come back and it looks like this picture on the bottom.

especially with an elevator shaft, because that's all restrained. Now, can you use the elevator shaft if it looks like this throughout the entire thing?

Seth (18:54)
Yeah.

Dr. Jon Belkowitz (18:59)
I mean, this is ridiculous. You've never seen this before, have you?

Seth (19:02)
Nope, not me personally.

Dr. Jon Belkowitz (19:04)
That's crazy. And you place a lot of freaking concrete, don't you?

Seth (19:09)
I don't personally, but Baker does, yes.

Dr. Jon Belkowitz (19:11)
I wasn't, I'm sorry. I say you, I mean, royal does. And the unfortunate reality is Baker's going to run into this. We're working with DOTs all over the nation that are asking the hell is this John? Yeah. And why do we need to know about ASR or AAR or ACR?

Seth (19:16)
Yeah, Baker does.

Dr. Jon Belkowitz (19:31)
And that unfortunate reality is we are in a new era of concrete.

Seth (19:34)
Yeah.

Dr. Jon Belkowitz (19:35)
If you ever, you're to start looking for ghosts now. That's what it's called. Where you start looking for concrete cracks and these concrete cracks, this is...

When you have these types of cracks, it's just a matter of time until you have to... When I say time, let's say your yearly maintenance is 20 years. Like, okay, that's when we place it, we come back 20 years, and that's when we have to maintain it. For you, elevator shafts, you don't ever have to maintain it. I mean, this would be a year or a couple of years into building. Worst case scenario, it'd be seven days. How would you approach this?

Seth (20:05)
Yeah. Well, what I was going to ask you, what are some tests that you can do prior to a project?

Dr. Jon Belkowitz (20:11)
And

there's so many arguments in the industry over this. What we're running right now is something called the... Ow, son of a biscuit. We are running something... We don't cuss on this show, by the way, Seth. Seth Edward Tandit. We run a number of tests, my favorite, which for some reason everybody, vast majority of the academic side of the industry cannot stand this test.

Seth (20:25)
sure you don't.

Dr. Jon Belkowitz (20:36)
and it's ASTMC 1260 or 1567. They are the accelerated mortar bar tests. You're making a three prisms that are one inch by one inch by 10 inches, 10 inches, 11 inches. Anyway, you measure them or you cast them and then you put them in a sodium hydroxide solution at 175 degrees Fahrenheit for 14 to 28 days.

Expansion cannot exceed 0.1 % at 14 days for the DOTs or 0.08 % at 28 days for the FAA folks.

And what you do is 1, 3, 7, 14, 21, 28. You measure the length of it on a length comparator.

that make sense?

Seth (21:22)
Yeah. What about your aggregate?

Dr. Jon Belkowitz (21:23)
Right, so we're doing it right now without aggregate, but the primary purpose of this test is the potential for ASR with the aggregate. So what most people do is they just, you know, either throw their rock or their sand. And what I mean by that is it's a very specific gradation that you have to use. So C1260 gives you a gradation where you take your rock, you grind it up, then you sieve it.

and then you recreate a gradation using that ground up rock to make a mortar. Now it could be rock or sand, but the idea is you want as much surface area of that aggregate, because remember, this is an accelerated test. Now there's another test that's not 14 or 28 days, it's 12 months to 18 months. And that's ASTMC 1293. You're doing concrete prisms, so the actual concrete mix, but you're putting sodium into the mix,

and then you're keeping it at room temp 71 to 77 degrees Fahrenheit, and you're measuring over long term. Now it has the same type of requirement. I can't remember what the expansion limit is, but if it doesn't work well 12 months with your cement, you got to use an SCM and then go to 18 months.

The other way of doing it is using, there's a new AASHTO test called the MicroPrism, and then, there's a test that I absolutely love. It's a British test. It's called an ASR gel pad test. And you're not measuring expansion, you're measuring ASR gel growth, and it's only a 72-hour test. Flipping amazing.

Seth (22:51)
Huh.

Dr. Jon Belkowitz (22:51)
So there's a lot of different ways. Most of them are reactive and therefore mixed design. I'm sorry, proactive and therefore mixed design.

Seth (23:02)
And this is what do ready mix suppliers do this test on their own or do you got to get third party involved?

Dr. Jon Belkowitz (23:09)
Normally, the aggregate provider will do the test as part of their quality control because it's for aggregate potential. But yeah, the ready-mix provider, based on their cementitious composition, because they might not use the same cementitious as the aggregate provider, and they're definitely not using the same secondary cementitious material. So yeah, they'll want to run it on their own, and it's not expensive.

You only got to do it once in a while to see, do we have a new change in our aggregate or we have a change in our cement? Is there a reason to be concerned?

Seth (23:37)
So what is the cadence that you should be doing this test for if you're ready to make supplier?

Dr. Jon Belkowitz (23:43)
I see that's a dangerous question. Every time you do a submittal.

Seth (23:47)
Yeah.

Dr. Jon Belkowitz (23:48)
I mean, but what does that mean to the ReadyMix provider when they get the chance? I mean, they don't have their own research budget. So what they'll have to do is put that cost onto their end user. replacing this, I mean, you can see this is not a small structure and the structure above it too, if I could zoom out, this is a water reclamation structure and it grows now. If it was just a sidewalk, even the sidewalk, I have a picture of a sidewalk somewhere.

and the sidewalk balloons up because the sidewalk can't grow down. It's restricted. So what it does is instead of having a flat top, the sidewalks have starts having a balloon top. And normally what the township or the county does is they either grind it themselves or they make you grind it as a homeowner and they charge you fines until you do that. Now you expand that same concept to a pavement. Right. Same thing is going to happen in a pavement.

even let's say at an airport. And that's why certain airports have been tearing out pavements to the point that they have Mount Everests of concrete that are now buried on the airport installation. But the same thing happens where you had a flat or a little bit of a crown pavement. And now because you've grooved it and you're using a crap load of deicing salt, it's ballooning up a few inches every year. And now it's either

tear out the concrete, place it, or mill it and grind it to a CSP of three.

Seth (25:06)
What's CSP?

Dr. Jon Belkowitz (25:08)
Concrete surface profile. So polished surface has a CSP of zero. The more you scarify the surface, the more friction, frictional resistance you have or BPN value, that force of friction.

Seth (25:09)
Okay.

Gotcha. Huh.

Dr. Jon Belkowitz (25:22)
I'm trying to sound more smarter than I am. You know what I'm trying to say, right?

Seth (25:24)
Well, if I don't, I'll ask.

Dr. Jon Belkowitz (25:26)
Right. I'm trying to say a CSP of three is less slick than a CSP of zero. A CSP of zero is almost polished surface. A CSP of three is like a ground up surface.

Seth (25:39)
Yeah. Yeah. I'm trying to, I'm blanking on another term.

Dr. Jon Belkowitz (25:43)
I know I'm blanking on it too and I'm trying to stay smarter and that's my freaking problem.

Seth (25:48)
Yeah.

Dr. Jon Belkowitz (25:48)
So, you the next question is, you said, how do we approach this? If you start seeing these cracks or some version of these cracks, how I cannot like go up a slide and they don't have to be big. They can be pretty gosh darn small. They could be the size of a, you know, a softball or baseball or half dollar. But again, it's these very specific cracks. It's trying to start annotating the ghosts.

When you see five different ghosts on five different job sites, and they don't happen in onesie twosies. You know, it's like, keep, I use herpes as an analogy too. If you go to a nightclub in New York, right? And you meet one person and they have herpes, it's guaranteed that, you know, 80 % of the people in there have herpes, right? So if you see herpes on or these, these Isle of Man cracks on one job site, especially if you use deicing salts, you're going to see it in another job site.

Once you see five job sites, because three is, you know, even three is a coincidence, right? But if you see five different job sites, it's time to call in a specialist. Have them core it out. You don't even need to core it out. James Instruments Humboldt Gilson sells a field ASR kit. You don't even need you can buy it yourself. It's like 1500 bucks, 1400 bucks. Buy it yourself, do the test.

Bob's your uncle. it changes color the way it's not supposed to, then you call one of your local specialists. Have them core it out and they can do another test. Then it's literally a spray of dye on and put it under a special light. It's like boom, boom,

Seth (27:15)
You take, you take a core and then do photography or.

Dr. Jon Belkowitz (27:19)
It's called petrography, but let's not make war what it is. You're literally spraying a Dion. That's the first place to start. You can start cutting and epoxying and looking at under a microscope, but oftentimes with ASR, what it does is it cracks through the rock. And again, that doesn't happen with steel corrosion or freestyle. It doesn't crack through the rock. ASR attacks the aggregate and it cracks its way through the rock.

Optically, you can see it. And then there are these UV dyes that you can use or UV radiant dyes that you can use that will show you, hey, here's some ASR gel, buddy, or here's an AAR gel. Now you've got to do more research to identify what are the root causes. And that's where a specialist comes in, whether that's a consultant like us or even a university. And I tell you, I love doing this research, but a university...

community college or local university, you know, in the in-between, if they have a concrete division, they know how to look for this. And it's great for the kids to get involved. So I wouldn't mind losing a contract to a university to identify this. You and you're looking at through the university, maybe $2,500 or less to do that research.

And if you just do the spray method, it be like 500 bucks. But if you could put it under a microscope that, you know, these high powered microscopes, have something called a scanning electron microscope, which instead of using a flashlight or a light bulb to light up the sample, they use, they bombard the sample with electrons. The electrons hit the sample and they knock out a secondary electron. They push into a valence electron space and they knock out a secondary electron.

Seth (28:32)
Yeah.

Dr. Jon Belkowitz (28:56)
When that secondary electron gets knocked out into space, it gets caught on a screen and that screen creates an image. That's how we create this image right over here. This image was created in the scanning electron microscope. So yeah, this was created not with a flashlight or a light bulb, this was created with an electron beam.

in this, like once a student sees, you know, it's not even this one, it's this one. Like once they see this, it's like, yeah, there it is, buddy. And how pretty is that? You don't get that with anything else. This is called an ASR gel rosette. Now, if you want to read a good paper, and I mean a good paper, there's a paper written by the great Kim Curtis from Georgia Tech, Professor Kim Curtis from Georgia Tech.

Seth (29:22)
Yeah.

Dr. Jon Belkowitz (29:40)
and it was on her PhD from 1996 on soft x-ray gel morphology for an alkaline silica reaction.

It's not a paper, it's a work of effing art. And what she teaches you about the fiber-like morphology is something that I teach to the university class on fiber-like morphology and steel. The morphology is so important, especially with ASR and the destruction of concrete. If we can control these wispy-like fibers, we control the ASR.

You control the spice. You control the universe.

Seth (30:13)
And that's on the surface of the aggregate. Is that what we're looking at?

Dr. Jon Belkowitz (30:17)
It's between the aggregate interfacial zone or surface and the paste. There's something called the interfacial zone where there's this open space between rock and paste. And that's where it's just, we don't have a lot of paste that anchors the rock in. So this open space gets filled with pore water solution, which has a very high pH to it. That pH attacks the silica in the rock at the surface.

Seth (30:22)
huh.

Dr. Jon Belkowitz (30:44)
that silica breaks down, creates this gel that expands in between that space. And that's what starts causing that crack. Or that crack ink, sorry.

Seth (30:52)
Yeah.

Amazing.

Dr. Jon Belkowitz (30:53)
You know, it's amazing until it starts getting scary. Right? It's just like a fun thing to talk about until, you know, here, here's a beautiful pavement. Right? This is at an airport.

Seth (31:06)
Looks like alligator skin.

Dr. Jon Belkowitz (31:07)
Looks like a city map. Yeah, it's not crazing. cause crazy happens a little bit faster. It goes, you know, from surface, you know, to subsurface this, can almost see the concrete pushing up. You can always see the stress lines, these circular patterns where it's easier for the concrete to expand on the edges than it is in the center of the slab.

Right? So that's where, you know, it seems like the cracking is happening more on the edges. Well, yeah, it is. I mean, that's where a lot more of the salts are collected. But the reason why it's not cracking as much here is because the expansion takes longer because there's not as many free edges. There's more restraint on the circular pattern here than there is on the edges. And that strain is holding it back.

Seth (31:52)
Gotcha. He'll get there eventually.

Dr. Jon Belkowitz (31:54)
my gosh, yeah. And then, especially airports, you have something called FOD. You know what FOD is?

Seth (31:59)
No.

Dr. Jon Belkowitz (32:00)
whatever. Especially if you were in the military, you know what this is. It stands for foreign object debris or foreign object damage, where as it turns out with most of our fighter jets or our jet aircraft, you just need a handful of rocks or a handful of washers, throw them in the engines. Not that I'm asking anybody to do that. And you can destroy the entire aircraft or

making incapable of taking off. Well, the same thing is with concrete that starts spalling and flaking. When you get enough of these pop-outs and flakes, you know, now our runway, our taxiways become more of a liability than a wearable surface. Because this stuff right here, you can see where the cracks are starting to interweave and we start not losing only the top surface, but the subsurface.

and the rest of the body of the conch.

Seth (32:53)
All right. Well, we went way over time,

Dr. Jon Belkowitz (32:55)
We have some good coffee, we had good conversation, we had good people. So.

Seth (32:59)
And the intro was the best.

Dr. Jon Belkowitz (33:02)
wait for the outro. You're gonna love the outro. So next time on your podcast, what I'd like to talk about is why is this happening in my neck of the woods?

Seth (33:05)
boy.

Dr. Jon Belkowitz (33:13)
Okay. That itself, like, why are we seeing it from coast to coast where we haven't worried about it for the last 60, 70 years?

Seth (33:20)
All right. Sounds interesting.

Dr. Jon Belkowitz (33:22)
That's all we do here, buddy.

Seth (33:23)
Well, thanks for letting me come on here.

Dr. Jon Belkowitz (33:25)
My pleasure. Thanks for joining us, everybody. Don't forget to check out our website, our YouTube channel, and please go to the Concrete Logic Academy. You know, throw your donation of a cup of coffee. Make it at home instead of spending 10 bucks at Starbucks or five bucks at Starbucks, because the amount of information that you're investing in will pay dividends. And you can say that's a 10X. So for $5 you invest.

you should get back $50 worth of information. And I guarantee it because I've been doing that for a long, flippin' time. So Seth, thank you for having us on the show. Go concrete!

Seth (34:03)
Beat Ass Fault.

Dr. Jon Belkowitz (34:04)
How do you shut this off? No, really, like the off button. All right, here we go. You ready?