EP #173: Is Fly Ash Helping or Hurting Your Concrete?

Seth (01:10)
And welcome to another episode of the Concrete Logic Podcast. What happens when a concrete mix design to earn lead credit starts creating problems on the job site? A contractor recently told me the engineer was requiring a significant amount of fly ash to reduce cement content and meet sustainability goals. Now they're dealing with cracking and low concrete breaks. So who's responsible? The engineer, the concrete producer?

contractor, where's the problem? How we're specifying sustainable concrete in the first place. Dr. John Belkowitz is back to help us understand what flyash actually does, why its availability is changing, and how we can reduce concrete's environmental impact without sacrificing quality or the construction schedule. How does that sound?

Dr. Jon Belkowitz (02:04)
It sounds like you gotta like bulletize it 'cause I don't remember all of those.

Seth (02:10)
We're gonna talk about fly ash today. That's what we're gonna talk about. but before we get started,

Dr. Jon Belkowitz (02:14)
I just want to make sure.

Seth (02:16)
wait, wait, wait, wait. Before we get started, I'm gonna do Dr. John Belkowitz's favorite part of the show first. And that's how you can support the show. So there's there's several ways you can do it. The first way is if you enjoy the show, please, even if you don't enjoy the show actually.

Share, share it with a colleague or a coworker. Get the word out.

Dr. Jon Belkowitz (02:38)
Do you think the show is crap?

Seth (02:41)
even if you think it's terrible, say share it and and say this guy doesn't even know what he's talking about. please share it with a colleague or coworker. the next way is if you go to the concrete logic podcast dot com website, there's a couple ways to get a hold of me, and this is important for for this.

purpose,

which I'm about to tell you, is so at the top there's a navigation bar and it there's a selection up there it says ask Seth. If you click on that, an email form pops up and what I'm looking for is a guest or topic suggestion, or you can even just send me a question, maybe a problem you're having on a job or upcoming job, send that to me.

even if you don't want me to discuss it on the episode, I'll get it to somebody that can help you out. All right.

Dr. Jon Belkowitz (03:29)
I thought I'd

I'm gonna discuss it anyway.

Seth (03:31)
I I wouldn't do that. Yeah. and then there's also a way to leave me a voicemail and it's the bottom right hand corner of the home page as well. it's a little microphone icon, you click on that. you can leave me a voicemail if you prefer getting a hold of me that way. there's also a donate button on there. You click on the donate button, a PayPal page pops up and you click on that and give any amount and you're like, Why would I donate to this show? Well, if you

You tuned in here, there's no commercials, there's no branding, from corporations and things that you gotta listen to. And the only way it we keep doing that is if you donate to the show. Or I'm gonna have to have I'm gonna start asking Doctor John to donate every time he comes on the show, which if we're doing

Dr. Jon Belkowitz (04:15)
First.

Seth (04:15)
that, man. Yeah. Holy crap. I'd be

Dr. Jon Belkowitz (04:19)
That might

have sounded like a joke, but that's a dang good idea. You gotta talk about that after. That was pretty good, man. That was a really good idea.

Seth (04:25)
But it all right.

and then if you want to ex ex expand on your concrete education beyond just the podcast, also go to concrete school dot co join that. That's the concrete logic academy. all right, that's it. for the intro. What what

Dr. Jon Belkowitz (04:45)
Wait, wait, wait, wait, wait, wait. That's not it. There's a book you've got

on Concrete Logic Academy. Which book

Seth (04:52)
Uh-huh.

Dr. Jon Belkowitz (04:52)
is that one with? That's like everything somebody needs to know on a concrete job site type book.

Seth (04:57)
well, yeah, we got a couple things on there. So like

Dr. Jon Belkowitz (04:57)
What was that book? Uh-huh.

Seth (05:00)
if you have new folks to the concrete industry, we actually have a link and it's actually in podcast form. It's it's it's audio. so you click on that and it's like eight or nine or ten episodes. And basically just giving someone a a brief overview of what it's like to be on a c a concrete construction job site.

And who are all the players? some of the terms you'll hear on a job site, things like that. It's a it like an introduction. I think that's what you're talking about. Yeah.

Dr. Jon Belkowitz (05:26)
That is exactly what I'm talking about. That for

all your newbies out there or you civil engineers who've never been out to the the plant or the job site who wanna sound like you've been out there, do.

It it it makes makes no sense why you haven't already looked at it. go to Concrete Logic Academy.

Seth (05:42)
Yep.

Yeah. All right. appreciate that.

Dr. Jon Belkowitz (05:45)
John Belquitts recommends them.

Seth (05:48)
doctor yeah, maybe we'll put a stamp on it. Yeah, there

you go. all right. So

Dr. Jon Belkowitz (05:52)
You see I sh been shaving

the beard a lot, by the way.

Seth (05:56)
Yeah. You're looking clean. All right. Let's

Dr. Jon Belkowitz (05:57)
Mm-hmm. Mm-hmm.

Seth (05:59)
get let's get at it. So I had someone reach out to me with this exact scenario. so they're they're they're on a job or we're on a job that required certain lead credits. I think the do you know what lead is? Everyone knows what lead is, been around for a long time now. so they have

recycle content requirement on the job. and they on top of that, they have the GWP global warming potential reduction requirements on the job. So they have these two challenges and what the structural engineer did was they decided they were going to do that with fly ash. So basically they're specifying a cement replacement in the concrete

with fly ash at a great percentage. And what I was told is it's at that percentage for again, those two two goals in it. But on what has happened is that they're dealing with low concrete breaks and some cracking. And they're automatically pointing at the fly ash and saying, Hey, that's that's the problem. So I thought it would be good to explore that today.

I think we've talked about flyash on the show before, but I think it's good to revisit it. Let's talk about what it actually is, why it's not as available as it used to be, maybe some other ways we can we can achieve those the lead credits and the r the global warming potential reduction. Some other ways we can do that. So do you wanna clue us in what fly ash is, doc Dr. John? We'll start off with

that.

Dr. Jon Belkowitz (07:36)
Yeah, and I I think it once we get into the shtick about what's going on and why the flyers could have led to the problems, can you hear me all right? 'Cause you're making a funny face.

Seth (07:48)
Y Yeah. No. You're good.

Dr. Jon Belkowitz (07:51)
Okay. Is that just yeah, okay. so it's just your face. Go ahead. We have to

Seth (07:54)
That's just my face. That's that's my resting face.

Dr. Jon Belkowitz (07:58)
assume that fly ash was the problem. And that's a that's a pretty big assumption because a lot of things could've caused their scaling or their early age cracking issue. But that's what we're going to assume, and of course, many people are going to attack that. But let's take a step backwards. Class F fly ash is a coal

Combustion residue. And that means you start with apparent material, meaning your mind and sorry, I'm fumbling for words here. The coal that we get from underground, you know, from Pennsylvania, we use it either to create, you know, heat for steam and then electricity, and we do the same thing for

Not only electrical production for cities and towns, but we also do it for what is it called? Bitcoin mining, right? Or cryptocurrency mining. paper mills use coal combustion for energy source. the byproduct of that coal consumption is some type of ash. Now those ashes, are we still doing good on connectivity?

Those ashes could be separated. You have bottom ash, right? I think if you heard of that term before, really can't be used for a lot of things. And then at a different point you have or through a a different coal source, you have class C ash, which has a much higher calcium oxide content. And then at different point you'll have class F fly ash or through a different coal source. Now all of these are collected from bag houses, or they used to be.

Seth (09:36)
Mm-hmm.

Dr. Jon Belkowitz (09:37)
And when we get them and use them in concrete, the person who sells it to us is not a class F fly ash manufacturer, or so they used to be, they're more of a distributor. That kind of changed a few years ago, maybe 10 years ago, 12 years ago changed. and I think we're gonna get into that, but what fly ash used to be

When I first got into the industry back in the mid-90s, I was taught that it was the poor man's water reducer. That we put it into concrete to make it less expensive, to make it less fluid, and then it was also used to increase later strength, but the durability mechanism of it didn't really come into play until I started going out to the Western US business unit where we had to deal with ASR.

And then all of a sudden, Class F fly ash became this huge thing, especially in the what the early 2000, where we had this P2P prescriptive to performance, where we were trying to go to much higher volume fly ash mixes. Rich and I were talking about this today. The first time I ever met him, he was giving a high volume fly ash presentation at a high performance concrete convention in Dallas, and he was calling

BS on some of these high volume fly ash mixes. It was one of the best presentations I've ever seen. you need to get him to give that presentation. But anyway, fly ash was really inexpensive when I got into the market. I mean, up until what, maybe like 2007, it was fairly inexpensive and easy to get. But what had happened was, you know, back in 1978.

And I'm not trying to go back in time a tangent here, but we can't undo what we started in the late 70s, and that was a a transfer from fossil fuels to renewable energy sources. And I'm not trying to start a conversation about well, is a solar powered, you know, solar powered plant really worth it, and wind turbines are they really giving us the energy that we need?

That's neither here I I don't care about that right now. What our federal agencies did starting in seventy eight out in Colorado, I think was NREL or it ch changed into Enrel in the nineteen seventies, eventually caught up to us. Wait, wait, wait, am I dying here?

Seth (12:03)
Interest

Nope, you're good.

Dr. Jon Belkowitz (12:06)
NREL changed the game back in the early two thousands and then we had the Tennessee Dike burst that you know unloaded a whole bunch of you know coal combustion residue into the subdivisions. We had the government accountability office eighty five dash ten R, which changed what fly ash was recognized as, and we started manipulating our fly ashes to make it cleaner.

or or to at least change them up. They're probably smarter people who could talk about what happened at those at that at the time. but basically what happened is our our fly has started changing a lot. The big change was when we went to you know natural gas, wind turbine, and solar. And when did we start doing that? The major shift. Was it 2007, 2008 time frame?

Seth (12:55)
Sure. We'll go with that. Sounds good to me.

Dr. Jon Belkowitz (12:56)
Right? Like especi

especially in Colorado, we started seeing out in the eastern parts of Colorado, right before you started hitting like that Wyoming, Idaho area, like the as you're going out seventy west, all these wind turbines started popping up all over the place and where we lived on this mountain top, in Elbert, if you looked east, at night you saw these ready red blinking lights.

Right? And by 2014, when we moved there, the horizon was just littered with these lights. We just started going away from coal consumption for energy production. So what happened was was this shift. And it was shifting from using the coal or the coal ash from the bag houses to reclaiming coal ashes from ponds.

And the stuff that we threw away in the dikes, eight hundred acre dikes from, Billing Montana's plant number three and four that were shut down in two thousand seventeen or eighteen time frame, it was a race to get over to those lakes. Eight hundred acre lakes just filled with coal combustion residue. what we're not doing is is a a a a recyclable product or I I guess it's not a it it doesn't have a low carbon footprint to it as people imagine.

you're dredging something up, you're you're dredging it, you're transporting it, you're cooking it, you're grading it, you're benefiting it, and you're transporting it. There's a lot of water and there's a lot

Seth (14:26)
Yeah.

Dr. Jon Belkowitz (14:27)
of heat involved, a lot of blending, a lot of energy involved. So we have to differentiate what we had when you and I first started in the industry, when we both had full head of hair back in the late 90s, to what we have now in the in-between. So

There is a requirement, and the best way to do this, if you're an ASTM member, excuse me, if you're an ASTM member, you can go and check out ASTMC 618 from 2002-2000 time frame. And at the same time, you can look at the 2026 version, and you can compare the two on one screen, and it will highlight red what was taken out and green what was added, something to that effect. And

What we have for the 618 for class C, Class S, and Class N is a gross misinterpretation of what it was intended to be. And now anything, anything is allowed in. And unfortunately, there might be some good combinations of coal combustion residue from a a lake bed, but I don't think it's the same. And that's what I'm trying to say. When I say class of flyish is dead.

The price that we used to get for fly ash and what we used to get from the distributors is nothing like we're getting today unless we order it from the eastern horn of South Africa, from a coal combustion plant that was built pre-apartheid, and they're using export grade coal. Now, if we get it from them, not here in the US, okay, we're talking some, but then that stuff.

Goes to the cement producers because they use fly ash. So anything the ready mix producer is gonna get is going to be a bastardization of anything you'll see in the Portland Cement Association manual, the the flyash book from, you know, what's his name? HM Ness, or I I can't remember his name. But I I think that's the thing that people they're using flyash, especially class F flyash.

In a very general term, and it's just not what we used to have. So that's the first place I want to start. And what that means

Seth (16:39)
Yeah.

Dr. Jon Belkowitz (16:39)
is more that picture I sent you, more s what's it called? Leftover carbon, more leftover soot, more water demand, more chemicals to benefit the fly ash. and that can be something that's just silica and alumina-based, or that could be some type of powdered high-range water reducer or accelerator. So

Again, it's just not what we used to get.

Seth (16:58)
So for so

if I was just want to sum up what you just you just went

Dr. Jon Belkowitz (17:03)
Please.

Seth (17:04)
through. so a couple things I w I I'm taking from that is like cement, not all fly ashes are the same. So I so when you're on a job and it says you you need to have fly ash for your mix and your producer says, Hey, we're g we we're using this

fly ash and maybe in the middle of the job they run out of that flash and they're getting it from somewhere else, you need to re-look at your flash, right? It's gonna be it could be two

Dr. Jon Belkowitz (17:34)
my gosh, always.

Seth (17:35)
s different things. Yeah. So if you're one fly ash isn't the same as another flash. So that's that's the the I think

Dr. Jon Belkowitz (17:42)
That was always the case though.

Seth (17:43)
Yeah. Well I I'm just saying if someone's not familiar with it and say a contractor

an engineer or whatever, someone that's not dealing with concrete all the time and they're the ones they're writing the rules, right? We're playing by their rules. I think

Dr. Jon Belkowitz (17:57)
Amen.

Seth (17:58)
the big thing to understand is hey, flash from from one spot to another is not the same. so so we need to take a a a look at that.

Dr. Jon Belkowitz (18:07)
If somebody

promises you over a two year, one year, six month period, they can get you the exact same flyout for the exact same price, that will not happen.

Seth (18:17)
Right. and

Dr. Jon Belkowitz (18:19)
With no changes.

Seth (18:20)
then yeah, and on top of all on on top of all that, since yeah, here in the US we've been retiring the the plants that burn the coal, the it flash isn't readily as available as it was before. So like d doctor John mentioned, now what we're doing is we're dredging it up from bot these these

these ponds and they're pulling out of the bottom of these ponds and reworking and then putting them out on the market as a flash. so again

Dr. Jon Belkowitz (18:52)
Or

Seth (18:52)
it's

Dr. Jon Belkowitz (18:53)
you're getting people to ship in fifty thousand tons every twenty nine days and it's coming from t third world countries like the Eastern

Seth (19:00)
Yeah.

Dr. Jon Belkowitz (19:01)
Horn South Africa where they can still burn that type of coal that export gray coal at those temperatures to get us the ash that we want.

Seth (19:10)
Okay. So let's talk about now that we we talked about where the fly

Dr. Jon Belkowitz (19:13)
Yeah.

Seth (19:13)
ash is coming from and the and the and the challenges we're having today on getting them. What about what what happens chemically with fly ash versus cement? Can you talk about that?

Dr. Jon Belkowitz (19:28)
I can

Seth (19:28)
I can't.

Dr. Jon Belkowitz (19:29)
but I've got four kids. I've got employees. Do you

Seth (19:32)
Uh-huh.

Dr. Jon Belkowitz (19:33)
wanna freaking get me killed?

Seth (19:35)
no, I don't want to get you killed. Well I'm just okay, let's go back to the beginning. So we're talking we're

Dr. Jon Belkowitz (19:38)
So right.

Seth (19:40)
talking about l let's talk talk about the this particular contractor saying that they're having cracking and low breaks. Is is is the flash a possible issue or not?

Dr. Jon Belkowitz (19:53)
So I'm assuming so fly ash what it used to do is used to, you know, combine the silica and the fly ash used to combine with the calcium hydroxide in solution to pozzillonically create this denser version of our backbone of concrete strength, the calcium silicate hydrate. And as long as the poor water solution with the hydroxides were available, you know, you would have this, I hate to say self-healing, but this

longer term development of our concrete glue, right? Our CSH. The fly ash that I'm saying now isn't like that anymore. So now just we're discussing not what good things it still does, because it's it's it's negligible at worst and maybe a little at best of what's happening. I'm trying to say this is I'm trying to shorten it as much as possible. But

It's the bad things. the carbon content that is consuming admixtures or monopolizing water, and then from there it's having a negative impact on our fresh properties, and then we have to add more water and admixtures that contributes to what's it called? Our strength reduction. And when you're talking to finishers, one of the things that I relied on when I was working with my finishers is that the there was a change in the control of bleed water.

because you weren't you weren't hydrating, more of that bleed water rose to the surface on a controlled level. it wasn't either there or it's not. And especially where we were up in the mountains, where you have extremely high evaporation rate at five thousand to eight thousand feet, you needed more bleed water, and that's why we liked fly ash. And in by the way, if you don't know, because fly ash doesn't go through this class F.

Fly ash does not have the calcium oxide content, it only contributes to long-term hydration through posolonic activity. Some of that water is not going to be used once we get it down the chute in the hydration, and because of gravity, it's going to be squosed to the surface. And that we can either use to combat evaporation rate, which what we did in Colorado, or some of the finishers finish it back into the mix. I'm not saying you should do that.

But we use it to combat evaporation rate. Bleed rate is greater than evaporation rate, we're good. If bleed rate is lower than evaporation rate, you're up the creek without a pattern. The newer fly ashes, because, and I'd love you to share that picture, because they have more impurities in them, like I said before, they're going to monopolize additives, water, and anything else, and that water that was intended to rise to the surface or get squosed to the surface to overcome evaporation rate, it's just not there.

We just don't have it because it's being held back. Does that make sense before I move on?

Seth (22:38)
Yes, makes sense. Yeah, 'cause

Dr. Jon Belkowitz (22:40)
Okay.

Seth (22:41)
d isn't in isn't the two classes of fly fly ash the one it needs cement to partner up with it to to to work and then one of was a actually acted like cement.

Dr. Jon Belkowitz (22:57)
So class C has enough calcium oxide in it that it will start its own hydration process. And I believe it's something greater than 10% calcium oxide. Because that's what you need to kick off the hydration mechanism. So we take our cement particle, we drop it in a bucket of water. You have tri and di calcium silicate. They start dissolving into water and open space. And you're left with this very thin soup of calcium and silica.

Well, at certain levels, that calcium and silica becomes more concentrated as you get closer to the cement particle. As your calcium and silica ratio reaches like 2.7, 3.2, whatever those magic numbers are, you start having things precipitate out of solution. Or before that, when it gets thicker, you start having things precipitate out of solution. It's called calcium hydroxide. Neither bonds to itself nor anything else, but in the presence of silica, it will phase into

calcium silicate hydrate or develop into the phase calcium silicate hydrate. Once our calcium silica ratio gets to about 2.7 to 3.2 we start gelling our calcium silicate hydrate network and those are cementitiously developed calcium silicate hydrate. But we all have all this byproduct this calcium hydroxide hanging around doing nothing. Nothing. And

Calcium hydroxide can can catalyze ASR and it can contribute to calcium oxychloride formation from de-icing salt. So we want to do something with that. So we normally add a pozzillonic material like class F flyash. Now, class C, as in Charlie, if you add water to it, it will harden on its own over a few hours or even a couple of days. With the class F as in Frank, you can add as much water to it. It's just going to still stay in a jelly form.

It's never gonna harden. it doesn't have that calcium oxide. It's that calcium oxide plus silica which gives us our backbone of concrete strength.

Seth (25:00)
Perfect.

Dr. Jon Belkowitz (25:00)
Ten percent.

Seth (25:01)
Great explanation. Thank you.

Dr. Jon Belkowitz (25:03)
shake.

So

the question was why can they see cracking?

Seth (25:06)
Yeah, d yeah. Well, I guess what could be a call we're not blaming Flash, we're not saying Flash is the problem here, but what could have happened? What yeah.

Dr. Jon Belkowitz (25:14)
Okay, stop. Let's blame Fly Ash just for a second. You know, if if

if it if it definitely was shitty fly ash, just we cannot blame the fly ash later. I will take some of the fly ash distributors out for stake. It'll be stake and shake, but we're still going for stake. But

Seth (25:31)
Well,

just like any any anything else, there's people that are doing it right out there and ones that aren't so right.

Dr. Jon Belkowitz (25:36)
Right. Right. Well,

what we're doing is wrong. Let's be honest. We are starting at a conclusion. But this

Seth (25:44)
Yeah.

Dr. Jon Belkowitz (25:44)
is only for educational purposes. A good scientist, a good petrographer starts with theories and allows the conclusions to develop and then they check it off of the theory, right? Checks and balances. So we're already starting with a theory

Seth (25:58)
Okay. Sounds good.

Dr. Jon Belkowitz (26:00)
that fly ash was wrong. So if the fly ash was wrong.

If there was unspent or carbon that wasn't removed, it was that jet black one versus that beige one that we looked at in that image, you would have water monopolization. It would be hard to get air developed in the mix. Your water reducer wouldn't act like it normally acts. And that means when my truck finally got to the job site.

Either I was throwing chemistry into the back of the truck or adding some water until I got my slump. Now, do I need to go into what's happening when we add water or chemistry to the back of the truck, or can I get into what's happening at the fly ash in the mix level?

Seth (26:49)
Let's just focus on the flash for this one.

Dr. Jon Belkowitz (26:52)
Right, what's happening with the fly ash in the mix? Why is it doing that, right? So when I was a kid, you were a kid, when we got fly ash, it was like the honey that your grandma and grandpa used to get from the farmer's stand. Right? They were getting honey from the beehive. We were getting class F fly ash from the bag house. Right? Pretty darn pure. Does that make sense?

When we hit that Tennessee dike burst, and we had that government accountability office 85-10R, which changed how we viewed class flyash, we had account for every iota of it. It's called subtitle C, Subtitle D, Cradle to Grave. On accounting for Flash, we had to clean it, we had to do a lot of different things to it. Fly Ash started changing a little bit. What we didn't hear or see in the background.

Was all the transfer from coal combustion energy to renewable resources? Are we still tracking?

Seth (27:55)
Yeah, but focus on what the Flash is doing.

Dr. Jon Belkowitz (27:59)
When the chemistry that we added to the fly ash to make it seem and act like the fly that you and I got when we were kids, that chemistry, the benefiting agents in the what we now get is having some type of interaction between unintended interaction with our admixtures and with our cements.

So because we're not getting, and I'm just trying to make it a full circle now, the pure source, we didn't have to worry about that that as much back in the ear late 90s, early 2000s. When that changed as we hit the 2010 time frame, fly ashes started doing bad things to our mixes because we put something in the fly ash. We turned that up to eleven when we started losing coal combustion sources for our fly ash, and we had to go to the lake beds.

For fly ash. Now we're ramping up the benefit agents, the chemistry, the weirdness, the it's changing and we don't get to see it. Cause that's the funny thing. We were we were sitting in an ASTM meeting. It was that meeting, and the person in charge, you've had them on your show, everybody in the meeting, and I'm trying to shorten it up that they're putting limestone fines in fly ash.

And everybody was like, what? And I would love for you to have Colin Lobo, because he's the one who asked the question. He asked the question: So we're putting an unknown amount of limestones in our cement, we're putting an unknown amount of limestones in our fly ash. How are we supposed to calculate water cementitious ratio? And the guy in charge of that ASTMC said, Well, why does that matter? To Colin Lobo, he said that.

Seth (29:51)
So what we're saying is the cracking could occur not because of putting the fly ash in the mix. What we're saying is what's going on within the fly ash itself could be impacting yeah. Gotcha.

Dr. Jon Belkowitz (30:05)
Yeah. Right. Yeah, if we had a pure

source of fly ash, I would love it to go in the fifteen, twenty, twenty five percent. If you're New Mexico,

Seth (30:14)
Yeah.

Dr. Jon Belkowitz (30:15)
thirty five percent.

Seth (30:16)
Okay.

All right. So

Dr. Jon Belkowitz (30:18)
So what should they do to get the global warming potential?

Seth (30:22)
Yeah, I think that's where we're at now. So what are what were some other ways we can do the it's let's let's say we we're having problems with we're not even having problems with flash, but what are s what are some other options we could do?

Dr. Jon Belkowitz (30:39)
Join ACI 323 and get the global warming potential code changed. It's a ridiculous code. Start with

Seth (30:47)
Yeah.

Dr. Jon Belkowitz (30:48)
that. Well, they're looking for people. What that's them saying it, not me. Yeah. Well they came to Rich and I. They came to Rich and I and they

Seth (30:52)
Really? They w want the the big lift? Yeah.

Dr. Jon Belkowitz (30:56)
said, hey, we know it's ridiculous. If you've never read it, you should read it. You shouldn't be able to say anything about it until you read it.

Seth (31:03)
we had

a we had a whole episode about it.

Dr. Jon Belkowitz (31:06)
Well, I'm talking to the public here, your your your people.

Seth (31:08)
I got ya.

Dr. Jon Belkowitz (31:09)
Yeah, it's ninety nine dollars. It's worth every penny because it's what you have to abide by, especially if you're doing federal projects or these bigger, data centers. but you're

Seth (31:19)
Yeah.

Dr. Jon Belkowitz (31:19)
just making inferior concrete. It says it. It says that even even in the overdesign section that's required on three eighteen and two fourteen, you know, y you know, reduce your overdesign and

disregard certain other codes. And they say that compressive strength is not a good indicator, but that's all we have, so we're gonna use it. It it's just that's my first place. I would change that. Besides that,

Seth (31:45)
Well it's it Yeah. That's

Dr. Jon Belkowitz (31:50)
your I'm sorry, I'll shut up after this. Your other option is there's s fifteen different ways that it's

use or fifteen times it's used three different ways, you can get the engineer of record who is the the qualified responsible gosh I can't remember the term authority of jurisdiction so they have the

Seth (32:14)
There it is, said

Dr. Jon Belkowitz (32:15)
there they have the authority of jurisdiction of saying we don't have to use this this is ridiculous right

The way Rich does it, it is he shows them the price. So he show because fighting it, you're not gonna fight it. And trying to meet global warming potential without using some type of crappy SEM or even okay SEM, because even our slags aren't what they used to be. And you can't use enough silica fume. So get some recycled aggregate. And even that's hard because they're processed like a champ. So either get the authority or jurisdiction to say nope, no, thank you.

Change the 323 and the guy who was in charge of it got some award. So please, somebody step in from the practical side of the industry, because there was like 15 people on this committee, only three of them had concrete experience, and the rest of them were academics. It was just written fast and it wasn't really tried and true. But the way Rich does it, he doesn't argue. Okay, you want that global war, okay, but it's gonna cost you X amount more.

And when they see what the standard mix price is, which is a really good mix, it just doesn't meet this fictitious value that somebody came up with

They normally go with the lower price mix.

I don't know any other good way. And it's not, Johnny, it's just you have to sacrifice too much. We still need to make concrete. It's still supposed to be gray concrete that comes down the chute and into the formwork. I love the idea of lower con lower carbon concrete, but this carbon negative. we're we're we're developing these concepts that if you don't stand behind.

You're the devil. And it's requiring us to sacrifice long term concrete. And look at 323. 323, which is the code we're talking about, it only goes through A2 to A6. A6 represents the gate of the concrete producer. It doesn't count what happens, even if the truck expires. Even if the truck is not only rejected but has to be returned to the plant.

Still a good truck 'cause across the threshold.

Seth (34:25)
Yeah. This this is what I would do. what you're definitely can do it your avenue and that would change concrete this the game we're playing right now would change it the long term of it. And the short term I would suggest getting your concrete contractor and your producer on board early. And like you mentioned this briefly earlier is

instead of having a prescriptive specification, you go to a performance specification and say, hey, these are this is what we want to achieve. We wanna r have this much recycled content in our concrete. We wanna have reduce our global warming potential. No, no, no. No it's

Dr. Jon Belkowitz (35:07)
Well that's that's prescriptive. That's prescriptive.

Seth (35:11)
not. Prescript prescriptive is when you tell them what to put in the soup, as Dr. Saichi says. Not not

So in this specification that I'm talking about, they said, Hey, you're using flyash as a S CM. So that's a prescriptive specification. What I'm saying is these are the goals, overall goals of the project. This is this is what we want to do. We wanna reduce our carbon footprint by this much. We wanna have recycled content in there as well. Okay.

Dr. Jon Belkowitz (35:42)
When you prescribe a number that your global warming potential can't go over, indirectly

Seth (35:51)
Uh-huh.

Dr. Jon Belkowitz (35:52)
you're prescribing a limitation on cement.

Because if I say you

Seth (35:56)
Yeah, I can see that.

Dr. Jon Belkowitz (35:57)
can only have 283 points for a 5,000 PSI mix, I can only

Seth (36:02)
Uh-huh.

Dr. Jon Belkowitz (36:03)
use about 480 pounds of cement. And to get

Seth (36:07)
Okay.

Dr. Jon Belkowitz (36:07)
that 5,000 PSI, I might have to go to a 0.38 water cement ratio and chemistry the crap.

By the I have to get on on the

Seth (36:14)
Yeah. Well,

Dr. Jon Belkowitz (36:15)
call.

Seth (36:16)
I think it's a it's it's a step in the right direction from hey, this is your this is the SEM you gotta use, this is the percentage you you're allowed to use up to, this is your water cement ratio that you're allowed to use, et cetera, et cetera, et cetera. So if we can get an incre

Dr. Jon Belkowitz (36:33)
I I I don't

Seth (36:35)
incremental step towards, hey

This is this is the goal of the job. Let's bring our co concrete experts in into the fold and and get them involved instead of getting to a point where it's already, specifications are done, drawings are done, you know, everything's done. Bid bid the

Dr. Jon Belkowitz (36:53)
Problem is

Seth (36:54)
job as is. Because that's what's happening on these jobs. Is I just talked to a producer yesterday. He's like, I I'm I'm giving you what the spec says. I was like,

Dr. Jon Belkowitz (37:04)
Yeah,

that well that that's the conversation

Seth (37:05)
Okay.

Dr. Jon Belkowitz (37:06)
I wanted to have. You I gave

Seth (37:08)
Yeah.

Dr. Jon Belkowitz (37:08)
you what the spec says and you're still complaining about it? This is what you wanted.

Seth (37:12)
Right. Right. Well then they're having then you what I'm saying the end result is then you got problems in the field and everybody's like, Why? So that's what we're tr trying

Dr. Jon Belkowitz (37:22)
What?

Seth (37:23)
to avoid. you could also reduce the amount of concrete on the job, right?

Dr. Jon Belkowitz (37:27)
Well that that's the thing. Mr. McCombs once said the fastest way to reduce the carbon footprint on a concrete job site is having your salesman call up to see if form work is ready before they release trucks. Like that right there will save a few hundred thousand, you know, cubic yards a year. But we don't look at the

Seth (37:46)
Yeah. Or you can reduce reduce

the size of your foundations, reduce the thickness of your slab, columns, e et cetera.

Dr. Jon Belkowitz (37:53)
Right. Right.

Seth (37:55)
You can you can do all that work. those are things that you can do. Yeah.

Dr. Jon Belkowitz (37:58)
But we didn't do that. We immediately

went to let's not work with the industry, let's tell the industry what to do. And again, I'm arguing that the three twenty three is a prescriptive method, because you're prescribing points

Seth (38:13)
Uhhuh.

Dr. Jon Belkowitz (38:13)
that you can't go above. and shoot, I challenge anybody to make a quality and I I don't mind defin defining what quality is. I know Rich hampers me on that, but

One thing that Rich said that I love a lot of what we've been doing lately, not only with performance-based concrete specifications, but also this global warming potential is duct tape specifications. We're not really stepping back and asking what do we want from this? We're just kind of throwing things together and taping layers on top of layers. And my problem with

Seth (38:47)
Yeah.

Dr. Jon Belkowitz (38:47)
this, hey, let's just make sure we're taking an incremental step forward.

We don't do incremental steps. We do a step, we make a gigantic change in the industry, and then we don't readdress it until five years later. Whether it's water cementitious, whether it's cement is the enemy, fly ash is gonna save all, or high ranges are the worst, or high ranges are the best, or you have to use SCCs, you don't have to use SCCs, or don't use cement because it causes shrinkage, or or do use cement because it causes I don't know.

Seth (39:20)
Yeah. Well w that's what I'm saying. We don't we w

Dr. Jon Belkowitz (39:21)
We never do things halfway in our industry.

Seth (39:23)
we don't yeah, we pulled the pendulum all the to one side and then we let go and it's gonna swing all the way to the other side. We don't wanna do that. That's why we do the show. Did I lose ya? What the heck

Dr. Jon Belkowitz (39:35)
No.

Seth (39:36)
is that?

Dr. Jon Belkowitz (39:37)
That's a book called Pendulum. You've gotta read this book. I keep meaning to tell you you have to. Yes, it's a great book.

Seth (39:40)
pendulum. You said that last time we talked.

Yeah. All right. yeah, I think we we beat the fly ash horse today. is there I mean we could

Dr. Jon Belkowitz (39:53)
I don't know. It's

Seth (39:55)
keep we could keep talking about but we're already forty plus minutes in.

Dr. Jon Belkowitz (39:59)
Well, and I've got another call to jump on. It's just my feeling with flyash, unless you're getting it from overseas, just admit that you're throwing garbage into concrete. And I am so much

Seth (40:09)
Yeah.

Dr. Jon Belkowitz (40:10)
happier throwing garbage into concrete than a landfill, but don't try to make it sound like flyash is doing something for good concrete anymore. Folks in Colorado will stand in line to tell you that.

Or I'm sorry, folks out in

Seth (40:21)
Yeah, well what

Dr. Jon Belkowitz (40:22)
the Western US business unit.

Seth (40:23)
Yeah. Well

Think if you were to sum up today, pay attention to what you're putting in your concrete. There you go. Thank you, Dr.

Dr. Jon Belkowitz (40:32)
Amen. Can we do

Seth (40:34)
John Belkowicz. What?

Dr. Jon Belkowitz (40:36)
Can we do concrete mixed design

with flyash next time?

Seth (40:38)
Maybe. We'll we'll see. Yeah. We'll we'll see what we can do. Yeah.

Dr. Jon Belkowitz (40:43)
Cool. Thank you.

Seth (40:45)
All right. All right. All right, Dr. John Belkowitz, thank you for coming on the show today. We'll have his link in there. Reach out to him if you got concrete problems. Telligent concrete. Right? Telligent dash concrete dot com. Check it out.

Dr. Jon Belkowitz (40:59)
There

it is, we paid extra for that dash.

Seth (41:03)
there you go. And folks, until next time, let's keep it concrete.