EP #096: Understanding the Maturity Method in Concrete Construction

Seth (00:01.616)
Welcome to another episode of the Concrete Logic podcast and today we got Dr. Jon Belkowitz. He's back and we're going to talk about the maturity method. We've maybe once or twice on the podcast we've talked about it. But I think Jon's got a different angle than the way we approached it last time. Before we get started, just to remind everybody, can do

Three things to support the podcast. One is, if you learned something today from Dr. Jon, which you always, I mean, I always learn something most sometimes, no, all the time, maybe something you don't even want to know. Anyways, if you do learn something, what, what, what I would ask you to do is to share the podcast episode with a,

Dr Jon (00:47.411)
Right, there it is.

Seth (00:57.882)
colleague, a friend, someone that's interested in the concrete industry. The second thing you can do is if you go to ConcreteLogicPodcast .com, the homepage, there are two ways to get a hold of me. One is there's a contact link. And then the second way, there's a little microphone on the bottom right -hand side. You can click either way, excuse me. And what that'll do is one, the contact link, you can just

It's just like sending me an email. me an email and what I'm looking for is a topic suggestion or a guest suggestion. Tell me what you want to hear on the podcast because this podcast is for you. And then that microphone, if you click on that, that's just like leaving a voicemail. Like you're calling me on my cell phone and you're leaving me a voicemail. And same thing, just give me a topic or a guest suggestion. And that is much appreciated.

And then, the last way is on the, concrete logic podcast .com homepage. There's a blue button in the right -hand side. and you can click on that and that allows you to donate to the show in a couple of ways. And that helps the podcast, greatly, obviously it costs money to run a podcast. So what you do is,

Send me some money, say, Hey, I'm getting value out of the podcast. And then what I'll do is I'll list you as a producer of the next episode that is released. So if you look at the show notes, there's a producers listed. Yeah. and if someone gives a, a, a large amount, which we've had in the past, we'll actually, say something for you on the show. So if you do do a donation, you want me to do a shout out for you.

There's a little note in there. can do that as well. All right. That is it. Let's get into it with Dr. Jon Belkowitz. We're going to talk about maturity method. So you want to explain what that is first, and then we'll go from

Dr Jon (03:10.318)
Sure. Can I put a plug in for the donations?

Seth (03:15.61)
sure you can do whatever you want. You've been on this show almost as much as I've been.

Dr Jon (03:23.494)
It's, it's, you know, the amount of education folks are getting. it's a combination of academic and practical intelligence. I haven't had the don't chance to donate to the show, but I tell you once, once my finger heels, it's, it's typing the stuff out. I'm, did we donate? shit. We just donated. shucks. So.

Seth (03:48.287)
You just, you just donate. just saw it on my phone. Thank you.

Dr Jon (03:52.366)
I can preach now, right? Every, everybody needs to donate. This gentleman is taking the time to create the relationships, creating the ideas sometimes, and even stuff that he don't want to talk about to get a consensus based education to a larger concrete construction industry to help you. And for a few freaking Kansas school.

Seth (03:54.874)
That's right. You got, you can have the floor.

Dr Jon (04:20.11)
that you have to give up. not, I'm just saying go to like Kodiak instead, or, or instead of buying Starbucks, go to Dutch Brothers and put in 50, a hundred, $500. Don't be bashful. on a credit card. You know, you'll never see the difference. I'm freaking gone a little bit anyway in a weekend. All right. So can I share this presentation? Yeah.

Seth (04:44.036)
Yeah. I appreciate it. Yes, sir. Let's do

Dr Jon (04:49.42)
So, you know, the, those are pictures of the baby. That's not going to, there we go. all right. So I, I put this presentation together, not for us to, how do I, how do I do this? Whitney, how do I do this? share. There we go. Tricky son of a. So, you know, the, the title of this, we're writing an article, we're putting into a, a, you know, whole gestalt together on this course.

Seth (05:06.181)
bottom.

There you go, you got

Dr Jon (05:19.384)
Concrete maturity, when will the industry grow the up? And I promised, I've been promised to you that this was not going to be me complaining. All right? This is gonna be educational, so I'm gonna try to stick away from it. How do you make this disappear? How do you make

Seth (05:40.954)
You want to do like a full screen if you go down to the there you go right

Dr Jon (05:43.399)
Ugh, yeah we go full screen.

Okay. So first thing that I wanted to do is I wanted to define maturity and, and the maturity ASTM C 1074 -19 is available if you're an ASTM member, is, what is it? A hundred bucks a year now, something like that. if you get the concrete standards, you get this as part of it. If not, you pay like what? 50 bucks, 35 bucks, something like that. It's worth

It's 11 pages. It was written by some of the best, best concrete authors out there. There's somebody I'd like to suggest, which I doubt you're going to get this guy. I would like to be a producer of that show and that's Nicholas J. Carino. If you can get him to come and be a speaker and just talk about the work that he's done for ASTM with the U S Army Corps.

Amazing dude. But anyway, 1074 is called standard practice for estimating concrete strength by the maturity method. And I want to highlight that. This is not magic, right? We're estimating. There's no prediction here. Estimating is when we imply a finding or estimation implies finding the optimal parameter using

historical, whereas prediction uses the data to compute the random value of the unseen data. So we're not using any unseen data here. We're using historical data that we've created as accurately as possible. Right? Like, have you ever heard people say, well, was a calculated risk, right? You ever hear somebody say it's a calculated

Dr Jon (07:43.202)
Right? Well, you know, my problem is, is you don't know what algorithm they're using in their head to make that calculation. Right? The algorithm could be a plus B equals C, which in some situations might work. But in other situations to get C, we might have to put a factor on A. We might have to put a factor on B or a factor on A or B, or we might have to include a fucking Z. Excuse my language,

We try to use the most accurate histogram possible. And that's what this. That's what I wanted to talk to you today about, like Baker construction, you in your job site have, I mean, put this picture on this slide for a reason. You know, this picture was all about getting the job site done on time and we were using.

every method we could, not only the concrete mix design, but estimation methods to tell us when we can start the next phase of construction. Have you ever been a participant in something like that, Seth?

Seth (08:54.98)
yeah.

Dr Jon (08:56.078)
Right, right, right. So when you do that and you use the concrete maturity method, am I doing that too early, Seth? Am I showing that too early? The ASTM?

Seth (09:10.296)
No, I think. No.

Dr Jon (09:13.774)
Okay. So when we talk about this ASTMC standard, ASTMC 1074, I sent this to Seth yesterday, you know, for homework to read. Thank you so much for reading it. On the left -hand side and, and for my ASTM attorneys out there, even if you screenshot this and zoom into it, you can't read anything. I make sure I blurred everything out.

You know, ASTM is very big on that, Seth. You're not supposed to share ASTMs. They will like come after you like a jackal.

Seth (09:50.788)
Yeah, they were there. They were the first ones on their, on their website that I saw that when the AI stuff started, getting really hot, that they were saying that you can't use their documents to build, AI like bots.

Dr Jon (10:09.568)
I didn't, I don't even know what that means, but that sounds about right.

Seth (10:12.186)
That means that people are taking AI and you can take documents and just put it into a folder. And then you teach the AI to go in there and read all the documents. And you can create your own documents based on what documents are in that folder, just using AI. So ASTM had on there said, absolutely cannot use

Dr Jon (10:34.028)
That's pretty dope. That's pretty dope. Okay.

Dr Jon (10:40.45)
How do you prove that? I mean, that's great. That's great. Hey, listen, I, I think the ASTM website as, as jacked up as it is at times. And for those of you who are currently having issues with the ASTM, what is it? Dot org Whitney, whatever it is, the ASTM website, use a private screen. Like if you have ballots that you can't get to use the private screen.

Seth (10:42.36)
I have no idea, but.

Dr Jon (11:06.72)
And you should have no problem with the ASTM functions. know a lot of folks have been having problems with their platform, but the ASTM website, you know, credit to Scott, Orthy and the gang, like they have put together such a powerful website and a powerful system of tools for anybody to use. And it's a hundred dollars. Like the, the, the, the, the fricking, the, the conferences are free.

Like why would you try and steal anything from that or of all the organizations out there? Shame on you for trying to steal something like they, they spent money on me to go to my first ASTM, which I can't stand going to ASTM because it's just too parliamentary for me, but they paid for me to go. They helped them hold my hand, but they took me through all the sessions. They taught me about it. It's a great organization and people like Nicholas J. Carino

helped create 1074 created the ASTM for the estimation method using maturity. And it's 11 pages of well -written stuff. And I have written notes, I printed it out, I use electronic stuff to do notes now. I mean, shoot, even ASTM will show you the original version versus what we have now, and it'll highlight the differences for you. And then you have this state practice here on the right.

Which is two pages and I'm being F generous with two pages because I felt like I was being generous with 11 pages on the left, but two pages does not even for a second take into account what needs to be done to create this estimation method. And what they're doing is either they're throwing the factor of safety out the window of, or whatever money you were hoping to make by saving time on the schedule. It's a crap shoot. It's a crap shoot.

So when people are half right. So, I mean, that's that, that's the biggest problem that people have with maturity that they say either, well, the maturity curves are not matching up with what's happening in the field or my maturity curve, you know, the curve itself is not matching up, you know, lab versus field, or I even simulated in the lab what I should have seen in the field and they're not matching up or,

Seth (13:03.226)
Why do you say

Dr Jon (13:31.054)
My maturity curve tells me I'm supposed to have this strength, but I'm much more than the allowable 10%, which I think ASTM allows as well state DOTs allows you to be plus or minus 10 % of the actual maturity or strength value. So people are well outside of those envelopes and they're like, what the heck? know, maturity was supposed to be, and some engineers, I want to shake them. They call it a prediction method.

foreseen the unknown year. and that's because, you know, this is like Stephen Hawking's, what was it? What is it? A brief history of time? don't know if you know much about that, that book, but the joke is in the physics community that is that everybody owns the book, but nobody has actually read it. Right. And it's, it's the same thing as ASTMC 1074.

that everybody uses maturity, but nobody has read it. Like to the point where there's a state in this continental United States region that has paid an engineer to freaking spark notes, this very important ASTM down to seven or eight statements. Like shame on that engine. know I wasn't going to do that, but I did do it. I'm sorry.

Seth (14:52.08)
Yeah. I mean, I, I, I'll admit that yesterday and today are the first times I've read ASTM, C 10 74, and I've had maturity on my, on my jobs. So I, I thought, the, the, just going back to your comments about people being frustrated that things aren't matching up what's going on in the field with them setting it up. So to, to do this properly.

Dr Jon (15:13.038)
Great. Great.

Seth (15:20.644)
You have to plan ahead, right? So you got to do the maturity method process ahead of the job. And, and I can tell you more times than not, especially in the last three or four years, everybody's in a rush to get the job started because it just, the, the, the time to prepare for work for, for projects seems to been, just in the last few years has been condensed for some reason. have, there's so many reasons why it's been going on.

But I would say

Dr Jon (15:52.056)
Can I, wait a second, a second, wait let's not jump away from that. Let's put this towards another industry, right? I don't know why if it's the haircut, but you seem like you're an avid hiker,

Seth (16:07.595)
sure.

Dr Jon (16:09.102)
Sure. Would you ever go on either a difficult hike or a rock run or camping without planning for it and preparing for

Seth (16:24.117)
I, I, I know what you're getting at, but

Dr Jon (16:27.308)
Hmm. Okay, then let's go away from that. Would you ever, let's say, you know, you're working with a surgeon, you know, you're getting some cancer. Well, they got a lot of procedures to do. Okay, well, you know what, with your procedure, I'm sorry, let me just turn the light here. With your procedure.

Seth (16:45.434)
turn the lights

Dr Jon (16:47.104)
Yeah, I know. We're trying to save some energy, know, intelligent concrete, all about carbon footprint reduction. No, let's say for your procedure, like, you know what? We just did not do the preparation just because we just didn't have the time. So we save some time by not preparing. Is there a chance that the surgeons are going to sacrifice something or the hiker is going to sacrifice something?

by not putting that due diligence and that investment into the preparation. Is there a chance?

That was

Seth (17:26.366)
no, I get, I get what you're, you're, you're saying. but anyways, what, what I was getting at is if you read through the ASTM and the procedure of that, I could see how corners are being cut. So what you're getting out in the field, cause that was one of the things I wanted to highlight when you get in, I don't know how far into that procedure you're going to get, but something popped out in my head that I saw, that.

that had to do with, let me see, I pulled up real quick actually. Hopefully I didn't.

Seth (18:07.674)
kick you off course

Dr Jon (18:09.598)
No, no, no. Hey, listen, I've got notes here, so I've kicked myself off course, but I've got a list of consequences of misuse. So when you give me, when I do have that chance, I could just go into the top three that we found out from the different contractors and ready mix providers that we

Seth (18:13.242)
Yeah.

Seth (18:26.498)
OK, well, if you could at some point, you can address it now. if this one item that I saw a couple of times in the ASTM, it says, the method does not take into account the effects of early age concrete temperature on the long term strength.

Dr Jon (18:33.154)
Let's do that,

Dr Jon (18:44.534)
Mmmmm

Seth (18:47.352)
And there's things you have to do to adjust for

Dr Jon (18:51.926)
Right, right. So early age temperatures impact on later strengths. I think that is a general statement. I don't know why they needed to include that. I think that might be you're adding something that is unnecessary. Somebody might've brought it up and it was a point of contention that they're not going to let go of the negative unless you put this in there. But you know, that's, that's when you don't, don't know what later age strengths.

are going to be based on early temperatures. A 90 day strength is not going to be dependent on a 24 hour, seven day temperature change. And as it turns out, once we get past the first 24 hours or even later, you know, the 96 hour point or 76 hours, what does it come? 24, 48, 76, okay. 72, then it's 96. I was terrible at math. But.

the heat of hydration that we're measuring and we're making predictions off of once we hit that 24 hour mark, we don't have the instruments that really can measure not out in the field anyway, the di calcium silicate hydration mechanism. And that's really what's happening over a long period of time. You you have the five stages of cement hydration. You have the mixing phase.

which is an enormous spike of heat that we rarely get to see with this piece of equipment. That's within the first few minutes. Then we have this dormancy period, which is where we transport concrete and we put it in the forms and we finish it. It's anywhere between two and four hours and sometimes more. Then we have this acceleration period, which is the peak, or takes us to the peak of cement hydration. Now, this acceleration period is when...

You know, the cement chemistry is really starting to take off and that's that tricalcium silicate or the a light. Now, once we hit that peak and we start dying off, it's not that we're losing the rate of reaction. It's just that there's a conversion of the tricalcium silicate to the dicalcium silicate. And of course the pozzolanic reaction, a whole bunch of shit is going on everywhere. Tyler Lay has an amazing cement hydration theater that

Dr Jon (21:18.254)
I, and I think I even put this in your fricking list of questions to ask him if we can redo the cement hydration theater with PLC cements. And I want it to be a later stage calcium silicate hydrate. That's all I'm asking. but if you don't know what the stage of hydration are, I recommend one of his cement hydration theaters. And I think there's two of them. but that later stages, the deceleration and then the plateau stages four and five.

We can't really see those and based off of those, mean, it's the temperature or the exothermic reactions are so low and the rate of temperature change we get from the ambient environment is so great at that point that we have no freaking clue how to use that to estimate it. There's just no way to estimate. It's not, have no clue. It's just too random to estimate it based off of those temperatures. Does that make sense?

The best thing that we can do is we use it for mass concrete where we do use temperature sensors, not really maturity, but temperature sensors to tell us when the temperature has gotten to a certain point where we can remove the insulation and not have to worry about cracking from mass concrete. The temperature differential between the center of mass and the external fibers. So that's long -term stuff, but for maturity, we're using it more short -term.

So I guess that was the point of it. Then answer your question.

Seth (22:49.786)
Mm -hmm.

Dr Jon (22:54.926)
Okay, you sure?

Seth (22:55.056)
Yeah, I just reading further because they referenced the note six in here. What I thought was interesting too, account for the reduction in long -term concrete strength due to higher early age curing temperatures. The test specifiers should or could require the specimens be moist cured at an elevated temperature close to the expected average and place temperature during the first 24 hours after placement. I was just thinking in my head, how many people do

Dr Jon (23:24.556)
A lot of people, what, put it in maturity boxes or moist carrot or heat carrot?

Seth (23:31.376)
So if I'm reading this correctly, if there's an elevated temperature for the in -place concrete, are you not supposed to try to match that with your specimens?

Seth (23:46.21)
Or am I reading that incorrectly?

Dr Jon (23:53.419)
Hold on, we were having a lag over here, so I kind of have heard your question. Can you ask it again?

Seth (24:01.296)
so let me read that.

Seth (24:09.488)
account for the reduction in long -term concrete strength due to high early age carrying temperatures, the test specifier could require that specimens be moist cured at an elevated temperature close to the expected average and place temperature during the first 24 hours after placement. So are they saying? Yeah. So instead of that. Yeah. So instead

Dr Jon (24:29.628)
yeah.

They

Seth (24:37.936)
cheering at whatever, you know, 75 degrees in a bath at the lab. My understanding is they should increase the temperature of what it could possibly be at the in -place concrete. Is that right?

Dr Jon (24:55.7)
Yes. Yes, yes, yes. And I get into that here in a little bit. If I could just jump into some of the definitions we're skipping out on. Can you still see my, you know, screen?

Seth (25:01.016)
Okay. Yeah, go

Dr Jon (25:11.052)
Yeah, you can see it. Right? No, you can't. I stopped it. No, there it is. Okay. So this is maturity, right? I want you to ignore the shit on the left here. So when, when we concentrate on maturity, what we're saying is maturity is our concrete reaching a certain strength at a certain age. Right? It's like figuring out some of your kids.

Seth (25:14.149)
Yes.

Dr Jon (25:38.958)
Right? You want your kid to bench 135 pounds. Well, you have to wait till your kid gets to a certain equivalent age. Like they're not going to be able to do that at three years old. You might have to wait till the kid's 15 or even 18 years old to bench 135 pounds. It's the same thing here. What we determine in our standard maturity temperature or in our laboratory temperature, laboratory maturity curves is in the basic

or standardized environment with all things being perfect and equal, this is what it will take to get my concrete to a certain age where it can support a certain strength. Right? Now, once we get out to the field, shit changes. It's no longer the perfect

And normally that's temperature related. We hope it's not mixed design related because if it's mixed design related, then a maturity curve should go out the flipping window. But as long as it's temperature, and that means temperature of materials, ambient temperature, I don't care what its temperature, but something that changes the temperature of the concrete. And when it does that, either if the temperature gets really freaking cold,

In that case, it's going to take a lot longer for it to reach that equivalent age to reach that specified strength. If it's hotter out and the concrete heats up, well, just that heating up will kick off the thermokinetics of cement hydration. And I'm going to reach that equivalent age or that equivalent ability to bear that strength a lot sooner.

Does that make sense?

Seth (27:36.314)
Yes.

Dr Jon (27:37.966)
So we have what we create in the lab, which is our standard. And then we have what happens in the field, which is the cold and hot. Cool.

Okay. So, no, it's not moving forward. You asked the question, standard cured versus I call it a maturity box cure or match box cure. So what happens is when we have, let's say mass concrete and you take a bunch of cylinders and you put an either

You know, most people aren't putting them in a cooler or in a bath. They're pulling them underneath the fricking tarps, right? Or underneath the blankets, or they put them right out on the slab. Is that a fair assessment?

Dr Jon (28:32.494)
That is not going to be a consistent match to what is going on in the slab. And it's you're losing that thermal mass and what that thermal mass is going to do to the thermokinetics of cement hydration. So absolutely there are engineers who not only require an insulated box where the cylinders are held closely together, similar to cast in place concrete,

But even when you go to the ASTMC 1074, they tell you to use something that lets you know whether or not you're in the right direction. Most of the, one of those is cast in place concrete cylinders where you're actually cast into the concrete and you pull them out, not into an insulated box like this. And you even got companies now where the maturity sensor,

will not only send you the temperature and the maturity information, but it is also connected to a maturity box that changes the temperature based off of what the temperature of the concrete is feeling on the job

Seth (29:47.732)
that's cool.

Dr Jon (29:49.174)
Right? Isn't that awesome? Okay. So this is the maturity measuring procedure, right? First you have determine, do you mind if I go into this?

Seth (30:05.082)
Go for

Dr Jon (30:06.478)
because this is going to be what people get wronged. First, have determining the data temperature or the equivalent energy. Then you have developing the maturity curves in the laboratory. Then you have placing the maturity meter in a logger or logger in a concrete cylinder or field element. And if you're doing mass concrete,

The guides and standards tell you that you've got to do a one cubic meter block ahead of time. From there, you're recording the temperature and time, recording the maturity from the field concrete, and that even includes where you're putting it in the sensitive areas in your elements. Then you're comparing the maturity data.

to your strength method and that's that secondary method because remember this is not prediction based on unknowns. This is an estimation method. Again, the word prediction is not even in ASTM and you're using those to not really develop, it's more deploy. There it is, deploy the maturity curves.

Most people cut items one and two, which are the most important items. Either they cut them out totally, they just develop the maturity curves in the field, or they don't even do item number one and they just assume the datum temperature is

Dr Jon (31:50.208)
or the equivalent energy is zero. Now, before I go further, do you have any questions to include what is the datum temperature or what is the equivalent energy?

Seth (32:07.312)
yeah, what is

Dr Jon (32:10.328)
It's expensive.

Seth (32:11.93)
First number

Dr Jon (32:13.91)
Yeah, the first thing it's really expensive. That's what it is. And that's why most people don't do it. It should cost. If you're using a maturity curve, and this is where people should get off. If you're using a conch, especially the people who sell the maturity meters, that's not true. You don't have to do it. You don't have to do anything. I mean, you, you don't have to take a driver's test and jump in a car and you can drive, but if you want to use maturity correctly, you need the date of temperature.

or the equivalent energy and it should cost you about 15 or $20 ,000 to create. Okay? So that's the first thing. Right? It's expensive and you need it. Now, when we do our maturity testing or our maturity curve, there's this little, you see this T datum? You see this little guy right here? This T D A T.

Okay. And we don't even have to use it. You see it again there. is the T D A T there's another one. see this little queue up there, right? You know, Q like, you don't have to P to have a PhD. Those things that's the datum temperature and that's the activation energy. And nobody ever fricking does those things. And what those things tell you is, first of all, you can get it from the ASTM. The ASTM will tell you that if you're using a type one cement,

At a 0 .47 water cement ratio, your datum temperature is equal to zero. No admixtures. Does anybody ever use that type of mix there, Seth?

Dr Jon (33:59.214)
The datum temperature, I love knowing these definitions. The datum temperature is the minimum temperature you need to kick off the thermokinetics of cement hydration. This little Q over here, which is the equivalent age method. So you can either use the time temperature method or the equivalent age. This based on the equipment that you use.

the equivalent age method that Q, which is the alternate of the datum temperature, it's the activation energy. And what that means is not to sound fancy schmancy, but it's the minimum amount of energy you need to kick off the thermokinetics of cement hydration. So it's similar to a diesel engine. If you don't have glow plugs and if you don't heat those cylinders

You're not going to kick off that engine. If you don't have a certain temperature for the concrete, if you don't have a certain amount of energy already in the concrete, the concrete hydration, the setting is going to fall asleep. Right. Now to determine that Seth, to determine that is a lot of fricking work. Here it is. All right. The initial steps. All right. How do I, you still see on my screen, you ready for

The whole idea behind using maturity is something like this, where we have elevator shafts, right? We want to place our concrete and as soon as that concrete hits temperature, we want to turn and burn our forms, right? Rip them open, put them on top. that means concrete's got to be strong enough so that it doesn't fall out. Concrete's got to be strong enough so that we can start doing some structural work to

And if it's not two things can happen. One, can lose money. Concrete can break and we have to redo it to concrete falls out on top of people and people can die. Let's hope that's not going to happen, but those are the major issues that we have when concrete goes wrong or when maturity goes wrong. You ready for this to get the date of temperature. You remember what I said? It costs 15 to $20 ,000. You ready?

Dr Jon (36:25.966)
I don't know why I did that. can't see the screen. There you go. You got to do three grout mixes, right? Three grout mixes. I didn't say concrete mix. You start out with three grout mixes that occurred at three different temperatures. Now these three grout mixes have to be representative of your concrete mix. Now you have to break those grout mixes over 32 days. Then normally you're starting at 12 hours.

But you have to start at the timeframe that it takes to reach or half the timeframe it takes to reach 2400 PSI for your grab. And for my ASTM junkies out there, I apologize if I'm getting these numbers wrong. I'm trying to remember a lot of things. So please always go back to the ASTM to get the numbers right. Don't use my words as gospel. But so you break these over 32 days and remember.

You're doing this over three temperature ranges. You're doing it at your standard temperature range, whichever you're going to place it at. So if it's the dog days of summer and you're using it strictly in the dog days of summer, your standard temperature range is going to be higher than 23 degrees Celsius. And then you got to do a certain amount under that. I would say 10 degrees, nine degrees and certain amount above that. And you got to do the same thing. You got to break it over a 32 day cycle. Then what you do is you plot the inverse.

of time versus strength. Right? So now that you get all these numbers, now you start doing the math. Now, once you do that math, you're going to plot. So once you get all the strengths, those 32 different strengths for those three different temperatures, now that you have these plots, what you then is you plot the intercepts on a time. Is that a time versus, it's a temperature.

versus the inverse of our time scale. Let me get back to it. And then from there, when you plot these three, it's going to give you a Y intercept, right? And what that means is if you take this line and you trace this line all the way down to our Y axis, it's going to give you an equivalent age or excuse me, a temperature at which you reach this equivalent

Dr Jon (38:52.846)
And here in this case, we have a datum temperature of a negative 7 .2 degrees Celsius. Or I'm sorry, it's not going to be a Y intercept, it's going to be an X intercept in this case. Because our temperature scale is on our X axis. So if you look at the line, it's going to hit the X axis after the

Seth (39:15.706)
Mm -hmm.

Dr Jon (39:19.054)
So that means, so if you remember this number, negative 7 .2 degrees Celsius, if we go all the way back to our, our, what's it called? Our equations. Here we go. See that T datum. That's where we put this. And if you have a zero there instead of a negative 7 .2, or what's the difference between a negative 7 .2 and a zero, a negative 7 .2 means that it can be.

negative seven degrees Celsius out, which I don't know the conversion, but it's F and colder than zero at negative seven degrees Celsius. My concrete can still set up a type one at a 0 .47 with no admixtures will have a problem setting up at negative seven degrees Celsius. Is that a fair assumption?

Dr Jon (40:15.694)
Right? So if you don't put that correction factor in there, if you don't prepare yourself to go camping, you might go camping in the Adirondacks in the middle of, or better yet in the fricking Rockies in the middle of May, where you can get 20 inches of fricking snow and you're not prepared. Same thing with your maturity curves. Was that too much of an analogy?

Seth (40:37.796)
Huh? No, no, no, that makes sense.

Dr Jon (40:41.518)
Okay. Okay. So, when you do that, from there, that's when you get your time temperature curve, you throw your data, your activation energy, whichever equation you're going to use, that establishes your curve right there that tells you how your concrete temperature changes over time, and then you start looking at connecting...

whatever strength it is, you don't have to do compressive strength. You can do flexural strength, can do shrinkage, can do cracking, you can do setting time. You could do anything you want, you're just connecting it to that maturity

Seth (41:24.965)
Mm -hmm.

Dr Jon (41:27.392)
And yeah, when you're doing this, this is something else that bothers me. And I'll shut up for more questions after this. Whenever you're doing, there are maturity companies out there who are selling this technology, amazing technologies, and they're telling people to throw out cylinders.

That's not what you're supposed to do. It's an estimation method. It's not the way it can't replace cylinder. can't replace everything. When you look at the 10 74, it tells you, have three other methods to use. One of them is cast in place cylinders. Right. It tells you to make cylinders as just part of it, but it says, Hey, don't trust the maturity alone. This is just an estimate. got a second guess, man, or you got to use a second test.

to make sure that it's fricking lining up. So they give you three methods to choose

Dr Jon (42:27.534)
What do you

Seth (42:27.93)
Huh. No, that's surprising as well. The second method to validate the maturity method.

Dr Jon (42:39.158)
It says it like on the first page, man. And this is Nick Carino. Again, if you haven't met Nick Carino, I haven't met Nick, Nicholas Carino, and I want to. He's quoted the maturity method provides a relatively simple approach for making reliable estimates of in -place strength during construction. That easiness, that customer experience is based off doing the preparation work. And yet it costs.

Seth (42:42.586)
Does

Dr Jon (43:08.642)
money. There's a lot of work involved, but either that, or you're going to pull forms too quickly, or maybe you're waiting too long to pull. Maybe you could have pulled forms eight hours

Seth (43:24.016)
So when a ready mix supplier says, I have these mix designs that are set up for maturity method, that's probably what they mean. They've gone through that datum

Dr Jon (43:36.302)
I'd know, because if you look at this state method here, you this is a state method. They tell you to take out sections 8 .4 in the appendix. This one right here.

Seth (43:50.916)
Yep.

Dr Jon (43:52.622)
That section on the right, they're telling you not to use the 1074 and shame on them for doing that. The thing on the right is the state saying, ignore everything on the left and do this. And they're telling you not to do. The fastest way to tell if a ready mix provider has or has not done it the right way, these are the ones to ask, is ask them for the datum temperature or the activation energy.

And if they have no clue what that is, that's like when you ask, that's how you could tell. know how much you like NASCAR when you can tell a race car travel driver isn't worth their salt when they don't know anything about gasoline. Like, why do you have those higher numbers in gasoline? Like as a race car driver, that's really basic stuff. You should know that. I know how much you like

Seth (44:46.926)
You keep saying that. mean, I've been to a couple, I've been to a couple races. mean, they have the Richmond race. I've been to a couple of those.

Dr Jon (44:48.852)
You don't, you don't. Are you

Dr Jon (44:56.686)
It's anything that deals with preparation. Like my favorite preparation story, do you mind if I'm going to stop sharing? My favorite preparation story is, there's a documentary on the Voyager 1, Voyager 2 spacecrafts that did the first outer planet tour for NASA and gave us our first pictures of Jupiter and Saturn. I've recommended this to you before. The documentary is called The Farthest Voyager in Space.

You know, they talk about how Voyager spacecraft two in one. Once you send a satellite in space, you can't fish it back. You can't bring it back. You have to ask all the questions. You have to do an amazing amount of preparation. And if you think about a satellite is aluminum and silicone, it's nothing more difficult than that. And Nicholas J. Carino and, despite the fact that it's not difficult, the amount of science and mechanics.

That went through that preparation and building method, Astrophys, all this stuff is, it's absolutely amazing. We're still getting information from the Voyager one spacecraft and it's in interstellar space, meaning it's in the cold bleakness of space where there's no starlight. Right. It is a simple mechanism that sends back a radio signal. Maturity as Nicholas J. Carino says,

is a simple estimation method. The simpler it is, the more work we have to put into it to prepare for the unknown.

Seth (46:46.456)
All right. Well, say I learned two, at least two or three things today. So you did, you did

Dr Jon (46:52.974)
If, if people read the maturity method and they are confused, they are not alone. I, I read that thing 15 or 20 times and folks I sent Seth my highlighted version. Like there are things in there that I still have questions on because the maturity method wasn't created by one person. It was created by a

people over many years. So there's a lot of commas in there. There's a lot of language in there that I still don't get and there's nothing wrong with that. There's a fricking annex. This is the last time you ever used a fricking annex. I know what the hell an annex was. I had to look up the word.

Seth (47:44.302)
Yeah, then you could dive even deeper and read all the references.

Dr Jon (47:49.068)
don't do that. There's some great references. Nick's work that he did with the U S army corps is if you want some good late night reading, that'll put you to sleep. Forget Ambien and or Lune Astra melatonin does nothing. No, he's an amazing writer, amazing fricking writer. does a great job with explaining maturity. And I believe most of his work was through the United States army corps of engineers.

And it's available. That means it's available for

So yeah, there are great, great references. And I think I, in that last slide, I refer to one of his papers. So it's in

Seth (48:36.868)
Well, cool. All right.

Seth (48:42.32)
So make sure I think the biggest

Seth (48:50.51)
Next time, you're getting into a job that's going to use, or plans to use the maturity method.

Ask about the date I'm

Dr Jon (49:00.11)
Or if, well, it's not just that, man. It's like, if people are frustrated from using it cause it's gone wrong. Like there's reasons why it went wrong. Like I remember I had a buddy who drove, or who bought a brand new Kawasaki Ninja 900 RR. Right? And every time he tried to start it, it would stall out on him. And it would stall out.

And it would stall out. Well, you got too much muscle and you don't know how to handle that bike. You're afraid of the bike. So you're not even willing to let that fricking clutch let go easily. the sound scares you. There's always a reason for things going wrong when you're not preparing correctly. And that's the biggest culprit here. Engineers, architects, and ready mix providers, even test operators who use maturity. Just read the directions.

Seth (50:00.218)
All right. Thank you again, Dr. Jon. Bringing things to light. Until next time, folks, let's keep it concrete.

Dr Jon (50:10.392)
T -shirts?