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Description
Welcome to episode 13 of the Maker and the Mix podcast, where Jeff and Caleb take on a fascinating topic that will challenge your understanding of concrete: “Is concrete really concrete?” In this eye-opening discussion, they tackle the mis/disinformation surrounding concrete in our field and embark on a mission to debunk commonly held thoughts, ensuring accurate knowledge prevails.
Join Jeff and Caleb as they dissect the misconceptions surrounding concrete, exploring the depths of its true nature. One particular aspect they unravel is how certain misconceptions can poison the nucleation sites of our understanding. Through their extensive experience and expertise, they shed light on the truth, enabling listeners to see concrete in its authentic form.
This episode marks the beginning of an exciting series Jeff and Caleb have prepared, where they delve into different aspects of concrete, dispelling myths and setting the record straight. As they journey through this series, they aim to enlighten and empower listeners with accurate knowledge, ensuring they are equipped to work with concrete confidently and effectively.
Tune in to the Maker & the Mix podcast to join Jeff and Caleb on their quest for truth. Through engaging conversations and contextual insights, they guide you towards a deeper understanding of concrete, allowing you to refine your craft and challenge long-held beliefs. Don’t miss out on this transformative series that aims to clarify misconceptions and revolutionize your approach to working with concrete.
Get ready for episode 13: “Is concrete really concrete?” as Jeff and Caleb navigate the fascinating world of concrete, debunk myths, and ensure your understanding of this versatile material is accurate and informed.
Plus, mark your calendars for our upcoming courses:
The Ultimate Creative Concrete Course: August 7-11 or December 4-8, 2023
– Join us for an intensive training experience where you’ll gain foundational knowledge, from mix design to sealers, for creating high-quality concrete projects.
2-Day Professional GFRC: November 9-10, 2023
– Take your concrete skills to the next level with our Professional GFRC course. Learn the techniques and methods for creating stunning GFRC projects.
Don’t miss these incredible opportunities to enhance your concrete knowledge and skills. Be sure to listen to episode 13 of the Maker and the Mix podcast to kickstart your journey of understanding concrete in its true essence.
Let’s embark on this enlightening journey together.
Transcript
Caleb Lawson:
Well good morning everybody and welcome to the Maker and the Mix podcast. It’s a gloomy 60
Jeff Girard:
Well,
Caleb Lawson:
degree rainy
Jeff Girard:
rainy day, yeah, it’s rainy
Caleb Lawson:
morning.
Jeff Girard:
here in Raleigh too. Good
Caleb Lawson:
How
Jeff Girard:
morning,
Caleb Lawson:
you doing
Jeff Girard:
everybody.
Caleb Lawson:
Jeff?
Jeff Girard:
I’m Jeff Girard, this is Caleb Lawson.
Caleb Lawson:
How you doing?
Jeff Girard:
Welcome to the Maker and the Mix. We had
Caleb Lawson:
So
Jeff Girard:
a…
Caleb Lawson:
what’s going on in your world?
Jeff Girard:
I’ll just… getting the shop settled and uh, done some spring cleaning, getting things organized. You know, we talked about that in past podcasts and you know, it’s, it’s important to like make an assessment of what you got and that sort of thing. Make sure everything’s in good working order, clean the tools,
Caleb Lawson:
It reminds me of,
Jeff Girard:
you know.
Caleb Lawson:
did you ever see that skit, it was an old British show, but old Greg? That was 15
Jeff Girard:
No,
Caleb Lawson:
years
Jeff Girard:
I haven’t.
Caleb Lawson:
ago. It’s the guy that he judges on Great British Baking Championship now.
Jeff Girard:
Uh huh.
Caleb Lawson:
But one of his little one-liners, he’s this really strange pond creature. And it’s funny, you should go watch it. It would be very funny to find it. But anyway, his Megan assessment is one of his lines. And every time somebody says that, it kind of reminds me of old Greg. But…
Jeff Girard:
It’s, you know, it’s one of those things where you like things build over time. You got dirt on the floor. You got chunks of concrete on the floor, your tools, you’ve been busy and all that. And it gets to a point and everybody has a different threshold. And I’ve been in some shops where there, there is no threshold and it’s kind of shocking, but
Caleb Lawson:
I feel
Jeff Girard:
I
Caleb Lawson:
like
Jeff Girard:
like
Caleb Lawson:
my
Jeff Girard:
to,
Caleb Lawson:
old one was one of those.
Jeff Girard:
yeah, you inherited that. So it’s not your fault. Um, it’s, you know, I kind of have a threshold of. It’s different, like if you could see my desk, I’ve got piles, right? But they’re
Caleb Lawson:
Are you
Jeff Girard:
organized
Caleb Lawson:
an organized
Jeff Girard:
piles.
Caleb Lawson:
pile guy?
Jeff Girard:
Well, they’re not so much organized in the sense that it’s a working pile that I know what’s there. Like I got receipts and I got my research book. So like anybody who know, so this is like important stuff, like documents. I have many of these. This is just like the latest
Caleb Lawson:
I want
Jeff Girard:
one.
Caleb Lawson:
to like
Jeff Girard:
And it’s…
Caleb Lawson:
raid your house and read them at some point.
Jeff Girard:
Yeah, it’s like almost, I’m like more than halfway done. And that’s just from, well, it’ll be almost a year, right? It’s actually, it’s a little over a year.
Caleb Lawson:
So do
Jeff Girard:
So
Caleb Lawson:
you have
Jeff Girard:
this is,
Caleb Lawson:
one per year basically or do they go,
Jeff Girard:
I just, I just go
Caleb Lawson:
is it variable?
Jeff Girard:
until I fill them up. So if I do a lot of, a lot of stuff, I might go through
Caleb Lawson:
What
Jeff Girard:
more
Caleb Lawson:
kind
Jeff Girard:
than
Caleb Lawson:
of
Jeff Girard:
one
Caleb Lawson:
stuff
Jeff Girard:
of these
Caleb Lawson:
goes
Jeff Girard:
a year.
Caleb Lawson:
in there? Like what’s worthy of
Jeff Girard:
Oh, gosh.
Caleb Lawson:
the composition notebook?
Jeff Girard:
sample dimensions, mix designs, observations, data, just stuff. Like, I don’t have it right here, but I have it somewhere. I can’t remember where I put it.
Caleb Lawson:
data
Jeff Girard:
I have one
Caleb Lawson:
like
Jeff Girard:
of these from
Caleb Lawson:
from the next generation.
Jeff Girard:
the very first concrete mixes I ever made. And I think somewhere I still have that sample. It was a little cubie kind of shape thing that I made. So I like to keep track of what I do. So I have some reference, I can go back and look at it, go, well, I use this particular ingredient or something was going on or what about this? And it’s hard to remember when you have lots of things going on in your head.
Caleb Lawson:
Mm-hmm.
Jeff Girard:
And sometimes it’s the small details that start to matter.
Caleb Lawson:
Right.
Jeff Girard:
And that’s gonna be a kind of recurring thread that weaves its way through these podcasts is… It’s not always the big, bold, obvious things that are important. It’s the small
Caleb Lawson:
Right.
Jeff Girard:
details that also are important. Sometimes they are even more important. And so, you know, doing, you know, when I’m developing, like when I’m developing all the alpha, this is basically alpha products, um, the, the polymer, the fluidizer, the defoamer. Um, that’s all the data from here. Um, mostly flexural and
Caleb Lawson:
Speaking
Jeff Girard:
density.
Caleb Lawson:
of which, I have an observation that I want to
Jeff Girard:
Yeah.
Caleb Lawson:
share. I may have told you this separately, but I was making something the other day. These little, I don’t know what to call them. They’re little triangles. They’re, I don’t know, this big. And they have a little medallion. that lives in them for Camp Ridgecrest over in Black Mountain. It’s a place that’s very close to my heart. But anyway,
Jeff Girard:
Kind of like a trophy plaque or something
Caleb Lawson:
yeah,
Jeff Girard:
like that.
Caleb Lawson:
kind of, but it’s like a commemorative thing. So
Jeff Girard:
Alright.
Caleb Lawson:
the medallion is gold. Well, it’s concrete, but it’s gold. and it’s treated to be gold. And it’s got the Ridgecrest logo in it, and it sits in. So it’s like intended to sit up on your bookshelf, be a piece of decoration for somebody who, you know, finds Ridgecrest to be a special place. I also made some plaques for like things the Alumni Association had donated and things like that. But anyway, I was casting some, because they ordered like a hundred of them. to
Jeff Girard:
on.
Caleb Lawson:
sell in the store. And so I’m still in the process of getting through all of those because they’re just, you know, I’m making five, six at a time. And I was making some Thursday and I had already made two or three batches. I have like three molds and so I’ll make they’re in rapid set so I’ll make them, you know. I can make 12 or 15 a day, let’s say. I mixed some up and it was just different than the other batches. I’ve got a mix design for these three. It’s like 12.47
Jeff Girard:
course.
Caleb Lawson:
pounds for all three of them that I can make at a time or per cast. And It was just different. It was like way more foamy and way more segregated and I didn’t use any extra plastic. Like I’ve got fluidizer, alpha fluidizer in there, but I didn’t use any more and the
Jeff Girard:
Mm-hmm.
Caleb Lawson:
water cement ratio didn’t change. And I was going back, I was like, what in the heck? Because I poured it and it was like just, you know.
Jeff Girard:
Yeah.
Caleb Lawson:
And it looked, I mean, they looked fine, but there was an eighth of an inch of foam
Jeff Girard:
Yeah.
Caleb Lawson:
on top. that I ground down. And then I realized after I kind of was like, oh my gosh, I forgot the polymer.
Jeff Girard:
Yeah,
Caleb Lawson:
And so it
Jeff Girard:
makes
Caleb Lawson:
was
Jeff Girard:
a difference.
Caleb Lawson:
wild because, you know, Rapid Set obviously doesn’t have a polymer in it from the get go. I know they put polymer in some of their DOT
Jeff Girard:
other
Caleb Lawson:
mixes,
Jeff Girard:
product.
Caleb Lawson:
but. but it doesn’t have a polymer in the bag, in cementall, and so I’m adding alpha polymer. The surface quality difference was, I mean, it was pinhole city and a bunch of film versus no pinholes and no film.
Jeff Girard:
Wow.
Caleb Lawson:
And it’s just anecdotal, but it’s totally, totally fascinating.
Jeff Girard:
Yeah, I’ve seen that too. I mean, that’s kind of the whole point of when I was developing the polymer was… Air in your concrete, right? For those of you who understand, we’re going to, you know, talk a little bit more about what we’re going to talk about, as is the case, right? Entrapped air, bubbles that you see, things that cause voids and pinholes and honeycomb, things like that. Unless you want them for a visual point of view, and like Buddy Rhode’s hand-pressed is an extreme version of that, right? Generally, you don’t want air in your concrete because air weakens your concrete. It doesn’t make the concrete weaker It just air takes up space and air has no strength So the more air in your concrete the less concrete there is so what is there has to do more work and Then you start to get to the limits of the material So the more air in your concrete the weaker your concrete is going to be that’s kind of like a General rule of thumb that you can count on and doesn’t
Caleb Lawson:
Well, and
Jeff Girard:
matter what
Caleb Lawson:
I was just
Jeff Girard:
kind
Caleb Lawson:
blown
Jeff Girard:
of concrete
Caleb Lawson:
away with, because I used Forton, and certainly I’ve used other dry polymers, because I’ve used Buddy Rhodes, and it’s got a dry polymer of some kind in it. And then years ago, before I knew what I was doing, when I bought the company, before I came to CCI, I was using a product called AcroBond, which is actually a bonding polymer, not a curing polymer.
Jeff Girard:
Not the right kind of polymer.
Caleb Lawson:
So there’s, that
Jeff Girard:
That
Caleb Lawson:
could
Jeff Girard:
would
Caleb Lawson:
have
Jeff Girard:
create
Caleb Lawson:
been the…
Jeff Girard:
huge foaming issues when you use the right,
Caleb Lawson:
Yeah.
Jeff Girard:
when you use a good product, but for the wrong reason.
Caleb Lawson:
Yeah, uh-huh,
Jeff Girard:
Like, this is a
Caleb Lawson:
uh-huh.
Jeff Girard:
great bonding agent. Like, that’s a fantastic
Caleb Lawson:
But
Jeff Girard:
bonding
Caleb Lawson:
I was
Jeff Girard:
agent.
Caleb Lawson:
using
Jeff Girard:
That’s
Caleb Lawson:
it
Jeff Girard:
what
Caleb Lawson:
in
Jeff Girard:
it’s for. Yeah.
Caleb Lawson:
replacement of, I mean, it was like Chuck, and I love him to death, but he was like, well, I can’t get a Forton easy or it’s too expensive or something, and Acrobon’s really cheap and it’s available locally, and this is what you use, and I was like, okay, whatever. You know, but.
Jeff Girard:
And we can definitely touch on that later on,
Caleb Lawson:
Yeah,
Jeff Girard:
you
Caleb Lawson:
yeah,
Jeff Girard:
know,
Caleb Lawson:
yeah.
Jeff Girard:
get into the nuts and bolts
Caleb Lawson:
But it
Jeff Girard:
of
Caleb Lawson:
was
Jeff Girard:
the
Caleb Lawson:
fascinating.
Jeff Girard:
lot.
Caleb Lawson:
I mean, totally fascinating to experience. Because I switched from using a different polymer to using this polymer. And the surface quality differences there were amazing. But then I wasn’t really thinking about having a difference in surface quality from not having it in there.
Jeff Girard:
Right.
Caleb Lawson:
And you know, I know I’ve done some, a lot of research on, I mean, this was a podcast topic a while ago, but I ended up doing research on polymer and cementall as well, in addition to the pozzolan thing. So if you want to learn more about pozzolans, which is a, you know, we have an episode about it.
Jeff Girard:
Yeah,
Caleb Lawson:
So go
Jeff Girard:
and
Caleb Lawson:
listen
Jeff Girard:
we’ll touch
Caleb Lawson:
to our
Jeff Girard:
on
Caleb Lawson:
other
Jeff Girard:
it
Caleb Lawson:
episodes.
Jeff Girard:
again and all that.
Caleb Lawson:
But. I think the term poisoned the nucleation sites was used. And that’s a fancy term for it retards or slows down the hydration.
Jeff Girard:
It’s a bit
Caleb Lawson:
Which,
Jeff Girard:
of a…
Caleb Lawson:
well, it’s, so it’s
Jeff Girard:
Yeah.
Caleb Lawson:
a fancy term for slowing it down and it slows it down for the first hour of hydration. So if you’re not concerned about losing like 30 minutes, it’s fine. But anyway.
Jeff Girard:
Yeah, I’ve seen that. I’ve seen that research too. You know, you’re making little things, right? And you’re de-molding them probably
Caleb Lawson:
Tomorrow.
Jeff Girard:
what, in a couple hours?
Caleb Lawson:
Yeah, I
Jeff Girard:
An
Caleb Lawson:
mean,
Jeff Girard:
hour?
Caleb Lawson:
those little things I’m developing, I mean, honestly, it’s, because they’re thick, they’re like three inches thick, and so it’s a lot of density, right? So they’re,
Jeff Girard:
They’re pretty compact and
Caleb Lawson:
yeah, they’re,
Jeff Girard:
we’ll see this that, yeah.
Caleb Lawson:
I mean, they get hot fast. I mean, those things are, I mean, I’m not putting any retarder in it, so I mean, within an hour, hour and a half, they’re out, they’re done.
Jeff Girard:
And that absolutely shows that although
Caleb Lawson:
even with
Jeff Girard:
we
Caleb Lawson:
my nucleation
Jeff Girard:
are using
Caleb Lawson:
site
Jeff Girard:
polymer
Caleb Lawson:
poisoning.
Jeff Girard:
in a CSA cement, and sure, it might have some effect on its curing rate, it’s not having a real effect on your ability to cast and demold a quality piece and
Caleb Lawson:
in
Jeff Girard:
not having
Caleb Lawson:
a very
Jeff Girard:
to break it.
Caleb Lawson:
short amount of time. If anybody’s like, if anybody’s over here like, oh, that 30 minutes is gonna kill me, you might wanna rethink your business
Jeff Girard:
Yeah,
Caleb Lawson:
model.
Jeff Girard:
right. You know, you got
Caleb Lawson:
And
Jeff Girard:
to look
Caleb Lawson:
by
Jeff Girard:
at
Caleb Lawson:
the
Jeff Girard:
it.
Caleb Lawson:
way, when I showed this in the transcript, asterisk holds up very tiny gap between fingers.
Jeff Girard:
Yeah, yeah, tiny, tiny amount.
Caleb Lawson:
So.
Jeff Girard:
I always look at things from a practical, pragmatic point of view first.
Caleb Lawson:
Yeah,
Jeff Girard:
You
Caleb Lawson:
I
Jeff Girard:
know,
Caleb Lawson:
mean…
Jeff Girard:
you can get lost in the technical rabbit hole of minutia and nuance, but when it comes down to your everyday, hey, I got to cast something, I got to do 12 of these and I only have three molds, so I got to turn around these molds quickly, what am I going to do and what’s going to give me the best results,
Caleb Lawson:
Yeah.
Jeff Girard:
right? And if the combination of choices that you make allow you to do what you want to do, get the results you want to get, and have it turn out to be acceptable to the customer, then what’s wrong with that?
Caleb Lawson:
Mm-hmm.
Jeff Girard:
Right? That’s all that… I don’t want to oversimplify here, but let’s not forget
Caleb Lawson:
Well, the customer
Jeff Girard:
that important
Caleb Lawson:
is
Jeff Girard:
perspective.
Caleb Lawson:
not testing your concrete for the difference between an hour of curing hydration. And they’re not going to… It’s like… If you’re claiming that you’re getting 24,828 PSI, and I’m claiming that I’m getting 14,312 PSI…
Jeff Girard:
Does it make a difference?
Caleb Lawson:
The functional difference in a kitchen countertop is nil. And that’s why I’m like, okay, well. Let’s say for the sake of argument that some factor of the process that I’m doing or somebody else is doing or whatever is weakening my concrete by 1%. Or maybe it’s gaining
Jeff Girard:
Yeah, even 10%.
Caleb Lawson:
this, you know, even 10%. Maybe it’s giving it 15% extra strength. But if I’m already using something that is well above, I mean, when you think about the fact that we build roadways out of 5000 PSA concrete. Like It’s okay for a countertop to be 12,000 PSI instead of 15.
Jeff Girard:
Yeah,
Caleb Lawson:
You
Jeff Girard:
yeah,
Caleb Lawson:
know?
Jeff Girard:
which
Caleb Lawson:
Like…
Jeff Girard:
is still overkill,
Caleb Lawson:
Like, let’s
Jeff Girard:
master.
Caleb Lawson:
just… Let’s
Jeff Girard:
Yeah.
Caleb Lawson:
get that, you know? So, um…
Jeff Girard:
Perspective, and that’s kind of really, let’s kind of move on to the topic of today because we’re just kind of shooting the shit here, which is kind of a new format. Like my lighting, I got some fancy
Caleb Lawson:
I
Jeff Girard:
lighting.
Caleb Lawson:
do. Yeah,
Jeff Girard:
Yeah, it’s like,
Caleb Lawson:
is it changing? Oh, I
Jeff Girard:
yeah,
Caleb Lawson:
didn’t notice it changing. That’s
Jeff Girard:
it’s
Caleb Lawson:
fun.
Jeff Girard:
a little LED lamp that’s sitting on the floor behind me because that’s, you know, this is expensive
Caleb Lawson:
No, I
Jeff Girard:
studio
Caleb Lawson:
like that.
Jeff Girard:
on here, yeah.
Caleb Lawson:
Yeah, you’re…
Jeff Girard:
It normally lives in the living room, but.
Caleb Lawson:
Wait, have you ever seen those lights that go around TVs and mimic the…
Jeff Girard:
Yeah, I don’t like those.
Caleb Lawson:
Oh, I kinda wanna try one to see if I hate it, but I’m like on the fence, you know? I’m gonna
Jeff Girard:
So,
Caleb Lawson:
get one and put it behind the TV and see what
Jeff Girard:
yeah,
Caleb Lawson:
Lauren says the next
Jeff Girard:
Warren’s
Caleb Lawson:
time we
Jeff Girard:
going
Caleb Lawson:
watch
Jeff Girard:
to like
Caleb Lawson:
a movie.
Jeff Girard:
that. Have it
Caleb Lawson:
She’s
Jeff Girard:
pulsed
Caleb Lawson:
gonna be like,
Jeff Girard:
and flat.
Caleb Lawson:
oh.
Jeff Girard:
Where was I going with this?
Caleb Lawson:
Yeah,
Jeff Girard:
Oh,
Caleb Lawson:
so
Jeff Girard:
okay.
Caleb Lawson:
well,
Jeff Girard:
So,
Caleb Lawson:
we’ve been chatting a lot
Jeff Girard:
yeah.
Caleb Lawson:
off the podcast about misconceptions that we see online. I mean, Jeff, I know that you, one of your biggest forms of learning and entertainment is YouTube. You know, you don’t,
Jeff Girard:
Hehehehe
Caleb Lawson:
I know, it’s just really into YouTube, guys. And it is a fantastic platform, but you like to watch a lot of engineering videos and fabrication videos and things of that nature. And I think you’re
Jeff Girard:
And
Caleb Lawson:
watching some sort
Jeff Girard:
none
Caleb Lawson:
of cast
Jeff Girard:
of them
Caleb Lawson:
in place.
Jeff Girard:
are concrete, by the way. None of them are concrete.
Caleb Lawson:
No. He sent me all sorts of channels, and I’m like, you’re watching machining. You know?
Jeff Girard:
Yeah. One of my favorite podcast, uh, YouTubers is, uh, she’s a software developer or a software engineer in Canada and her hobby is making, is machining
Caleb Lawson:
Is this
Jeff Girard:
and
Caleb Lawson:
the
Jeff Girard:
she’s
Caleb Lawson:
one you sent
Jeff Girard:
making
Caleb Lawson:
me the
Jeff Girard:
steam
Caleb Lawson:
other day?
Jeff Girard:
boilers. Yeah.
Caleb Lawson:
Fascinating. So you don’t have cable, right? You watch
Jeff Girard:
No,
Caleb Lawson:
those channels
Jeff Girard:
no,
Caleb Lawson:
instead.
Jeff Girard:
I don’t need cable. I hate cable.
Caleb Lawson:
He’s got
Jeff Girard:
Yeah.
Caleb Lawson:
long-form YouTube over here. And so listen, I’m getting more into it. Because obviously, everybody tunes into YouTube if you’re trying to fix your car or whatever, or you’re trying to cast concrete in place. And I feel like I’ve had a number of people say, oh, YouTube University. And I’m like, yeah, there’s a lot of bad information on there. But there’s
Jeff Girard:
It’s
Caleb Lawson:
some really
Jeff Girard:
a lot
Caleb Lawson:
good
Jeff Girard:
of
Caleb Lawson:
information,
Jeff Girard:
good.
Caleb Lawson:
too.
Jeff Girard:
And the thing is it’s hard to separate the wheat from the chaff, right? Cause you’ll see, I don’t know, recently I bought a 3D printer and so there’s like a
Caleb Lawson:
Video’s
Jeff Girard:
gazillion
Caleb Lawson:
galore.
Jeff Girard:
YouTube videos on which one to pick and how to set it up and which filament to use and blah, and all this and you know, it’s a lot of it’s good and I will say this. The intent of the person or people creating the videos is generally very, very positive. They want to be helpful, right?
Caleb Lawson:
Yeah, if you can hear buzzing in the background, I’m getting an amber alert. Sorry about that.
Jeff Girard:
That’s all right. You can barely
Caleb Lawson:
And
Jeff Girard:
hear it.
Caleb Lawson:
my phone is up there, so I can’t
Jeff Girard:
Yeah.
Caleb Lawson:
really adjust it at the moment.
Jeff Girard:
So, what I want, what we want to talk about really has to do with the general, the scope of general knowledge about concrete. We’re going to start pretty broad and basic, kind of like a
Caleb Lawson:
Yeah.
Jeff Girard:
little bit what I touched on here.
Caleb Lawson:
Well, because you, we were talking earlier before we started recording about how, you know, I mean the foundation of like the modern world is concrete, right? And we’re used to it in massive monolithic, you know, steel reinforced
Jeff Girard:
It’s the number one building material
Caleb Lawson:
in the world.
Jeff Girard:
in the world.
Caleb Lawson:
In the world.
Jeff Girard:
In the world. It’s not the oldest, but it’s certainly the most, on a volume basis, the most common, the most
Caleb Lawson:
Yeah.
Jeff Girard:
prevalent. And I will, I’m gonna kind of go out on a limb here, and this is just me sticking my finger up in the winds of statistics and say, 99% of all the concrete everywhere, that’s used for anything. is largely aggregate-based steel-reinforced concrete.
Caleb Lawson:
Yeah.
Jeff Girard:
You know, stuff that has rocks and stuff that has rebar in it. And that is the paradigm that most people have of concrete. And it’s… well, it only makes sense. But we work, you know, in the concrete countertop industry, and of course we do a lot more than just countertops, but we’ll just use that term for now. In the last, I’m going to say maybe… 15 years has really shifted away from all that.
Caleb Lawson:
Yeah.
Jeff Girard:
And we now use what is kind of really considered exotic, esoteric,
Caleb Lawson:
It’s
Jeff Girard:
boutique.
Caleb Lawson:
almost like, I mean you said this earlier, we’re not really, I mean for the sake of argument we’re using the same material, but really,
Jeff Girard:
Yeah,
Caleb Lawson:
are we using the same material, you know?
Jeff Girard:
right, right.
Caleb Lawson:
It’s like,
Jeff Girard:
It’s, uh,
Caleb Lawson:
technically
Jeff Girard:
we don’t have rocks in
Caleb Lawson:
it’s
Jeff Girard:
it
Caleb Lawson:
concrete,
Jeff Girard:
and we don’t use
Caleb Lawson:
but…
Jeff Girard:
rebar. Um, we can, but we don’t use steel rebar. We use either fiberglass or basalt or there are a few people who use like carbon fiber rebar, but that’s super expensive. And so we won’t even bother going there. Um, but by and large, we do things. I mean, we follow the same rules of concrete and that’s kind of where we were, we’re, we’re getting to. But the kind of, the way we can use our material has really radically changed this industry. And that’s kind of the whole point of some of these discussions we’re gonna have is,
Caleb Lawson:
Yeah.
Jeff Girard:
if you’re interested in this industry, whether you’re gonna just, hey, I wanna make an outdoor kitchen for myself, or I wanna do an indoor kitchen or my bathroom for myself, or even better, hey, I’m thinking about doing this as a business because it’s… You know, it’s interesting. I’m drawn to the creative aspect of it. Um, and I want to learn more about it. The first thought people have is, okay, I’m going to do it out of concrete. And the first thing that comes into mind is, you know, the stuff you can buy at
Caleb Lawson:
Cast
Jeff Girard:
a home
Caleb Lawson:
in
Jeff Girard:
center,
Caleb Lawson:
place
Jeff Girard:
right?
Caleb Lawson:
from Home
Jeff Girard:
Or
Caleb Lawson:
Depot
Jeff Girard:
it comes out of a
Caleb Lawson:
or whatever.
Jeff Girard:
truck. That’s the material. And then how do you cast it? Well, cast in place, cause that’s how
Caleb Lawson:
Yeah,
Jeff Girard:
most
Caleb Lawson:
I mean,
Jeff Girard:
concrete
Caleb Lawson:
I’ve seen,
Jeff Girard:
is made.
Caleb Lawson:
I’ve seen, I started, I was looking at the Zcounterforms website for something and now every targeted ad in the world, in the world, is Zcounterforms. So they’re doing some very serious marketing, but, and all of that is cast in place. They’ve got that plastic mesh that goes in there and all. stuff. But you know, so we were talking about all of this and this is going to be a very, you know, Jeff and I are fairly technical and I recognize that, but I kind of wanted to shift a little bit into a more conversational sort of like, because that’s how my brain thinks anyway.
Jeff Girard:
Yeah.
Caleb Lawson:
And we were just talking about the misconceptions of the material or the general understanding of the material. And so we kind of thought, yes, well, let me preface this by saying, if you want like a university lecture style, uber technical informative, I mean, phenomenally informative talk, Jeff, I believe you have a webinar or a seminar that you did on how concrete works and it’s on the website and I will link it.
Jeff Girard:
And definitely to interject, if you really want to get into some of the technical stuff,
Caleb Lawson:
Yeah.
Jeff Girard:
you know, get this book, right? Portland Cement Association, out there, I’m trying to point backwards.
Caleb Lawson:
Mm-hmm
Jeff Girard:
Design and Control of Concrete Mixtures. Now, this is the 15th edition. I think there’s a more current edition, but when I was in school, pushing 40 years ago, I learned with the 11th edition. So. This one has actually colored pictures in it, so
Caleb Lawson:
Mm-hmm.
Jeff Girard:
it’s more advanced. Mine didn’t. It was black and white. But the information is still relevant. They just
Caleb Lawson:
Yeah.
Jeff Girard:
add to it.
Caleb Lawson:
And so all of that to say, if you want to really dive in and sit through like a university style webinar, I actually pulled it up here. I don’t know how to… ConcreteCountertypeInstitute.com slash free dash training slash
Jeff Girard:
Share
Caleb Lawson:
how
Jeff Girard:
the screen.
Caleb Lawson:
dash concrete dash works. dashvideos forward slash esl show screen. But I wanted that for a… Look, I can share a tab. That’s fun, look at that.
Jeff Girard:
We’re learning this new platform.
Caleb Lawson:
I know, this is exciting. So
Jeff Girard:
There we are.
Caleb Lawson:
there it is. You can see the link up here.
Jeff Girard:
Yep, it’s free.
Caleb Lawson:
It’s free and it goes through, you know, we’ve got mixed designs on the website that, you know, can be purchased, etc. So if you want to really dive into that, we are going to be doing kind of a series, if you will, on this topic, but much less, you know, much, that’s a very, very high level like. overview of the bones and we’re going to get into that but in a much more conversational format. So
Jeff Girard:
Yeah. Just
Caleb Lawson:
all of that
Jeff Girard:
as
Caleb Lawson:
to say.
Jeff Girard:
an aside, if any of you have ever been to my, I’m retired now from it, but my world of concrete presentation, I used to speak, I don’t know, for 14 or 15 years at world of concrete, and I talked about concrete countertops and things like that. And that’s kind of taken from that lecture.
Caleb Lawson:
Yeah.
Jeff Girard:
So it’s, it’s along
Caleb Lawson:
So this
Jeff Girard:
the same
Caleb Lawson:
is
Jeff Girard:
lines
Caleb Lawson:
the,
Jeff Girard:
as
Caleb Lawson:
this is the concrete, the concrete talk coffee edition complete
Jeff Girard:
Right.
Caleb Lawson:
with leopard print mug that I stole from my wife. And I keep bringing it because
Jeff Girard:
I got
Caleb Lawson:
it like,
Jeff Girard:
flowers on mine.
Caleb Lawson:
yeah, it has way more capacity than my other mug and it keeps things hotter longer. So swig, you know,
Jeff Girard:
Nice,
Caleb Lawson:
if you wanna support
Jeff Girard:
nice.
Caleb Lawson:
the podcast, I’m drinking out of your mug.
Jeff Girard:
Um, yeah, so. Just regular concrete, you know, the getting back to the concept that people have. And this is where I see, and this kind of the point of all this, many homeowners, DIYers, general contractors who want to make something out of concrete, like what we make and what we teach people how to make, their first thought, which is a very logical thought, is to go and use ordinary concrete. And that’s like the first. I don’t want to say it’s a mistake, because you absolutely can make things using a bag of ready blended concrete from a home center. But it’s far from ideal, and you are severely limited as to what you can do, and you also have to be very careful about how to properly treat it.
Caleb Lawson:
Mm-hmm.
Jeff Girard:
Mainly because the things that product… or type of product, because there’s lots of different products, right? The things that type of product is made for, think about it. Sidewalks, patio steps, setting a fence post, setting your mailbox,
Caleb Lawson:
It’s
Jeff Girard:
that
Caleb Lawson:
made
Jeff Girard:
kind
Caleb Lawson:
to
Jeff Girard:
of
Caleb Lawson:
be
Jeff Girard:
thing.
Caleb Lawson:
big, thick and reinforced with seal.
Jeff Girard:
Big, thick, aesthetically not very demanding.
Caleb Lawson:
And we’re gonna,
Jeff Girard:
It’s like, you’re
Caleb Lawson:
I feel
Jeff Girard:
going to
Caleb Lawson:
like
Jeff Girard:
build
Caleb Lawson:
there’s
Jeff Girard:
something
Caleb Lawson:
a lot
Jeff Girard:
out of
Caleb Lawson:
of.
Jeff Girard:
a two by four. So you go to a home center and you buy the two by four. Okay. They’re not exactly a hundred percent straight. They’re not exactly a hundred percent perfect.
Caleb Lawson:
They’re also not exactly 100% two by four.
Jeff Girard:
Right.
Caleb Lawson:
So there’s that.
Jeff Girard:
There’s that, right? And, um, but they do the job they’re meant for. And if all you’re doing is framing a wall or doing something like that or building a shed, good enough. And that’s kind of what this kind of, that kind of concrete is for.
Caleb Lawson:
But if you’re making a cutting board, maybe not,
Jeff Girard:
Right,
Caleb Lawson:
you
Jeff Girard:
or
Caleb Lawson:
know?
Jeff Girard:
you’re trying to build a grandfather clock or an armoire or
Caleb Lawson:
or a violin.
Jeff Girard:
a violin.
Caleb Lawson:
You wouldn’t use plywood for a violin, would you?
Jeff Girard:
Heck no, would you? Yeah,
Caleb Lawson:
Go listen to episode one if you’re curious what that’s about.
Jeff Girard:
exactly. I like what you did there.
Caleb Lawson:
I’m going to go to bed.
Jeff Girard:
So that’s kind of the… That’s really the gist of all this is if you don’t really understand the limitations and the benefits of the material you’re working with and you don’t understand the limits and the requirements of the thing you’re trying to make and you’re trying to fit them together It ain’t gonna work, right?
Caleb Lawson:
Yeah, so if you will for a second, define for us kind of industry standard sidewalk concrete and then maybe also define for us the type of exotic
Jeff Girard:
All right,
Caleb Lawson:
concrete
Jeff Girard:
so
Caleb Lawson:
we’re using.
Jeff Girard:
let’s say that you’re going to.
Caleb Lawson:
I’m gonna do
Jeff Girard:
You
Caleb Lawson:
a
Jeff Girard:
know,
Caleb Lawson:
fence
Jeff Girard:
you’re
Caleb Lawson:
post,
Jeff Girard:
a poor
Caleb Lawson:
I don’t
Jeff Girard:
sidewalk
Caleb Lawson:
know.
Jeff Girard:
or poor patio or whatever, right? Now there are thousands and thousands of different concrete mix designs, different proportions of rocks and sand and cement and things like that. And I’m not going to get into that because that’s kind of esoteric. It’s like, what’s your grandmother’s recipe for spaghetti sauce? Like
Caleb Lawson:
Right.
Jeff Girard:
everybody’s spaghetti sauce recipe is different. But if you lined up a hundred plates of spaghetti that had different hundred different kinds of spaghetti sauce. you would look at it, walk in and say, oh, those are all plates of spaghetti. That’s
Caleb Lawson:
Right.
Jeff Girard:
kind of the level we’re at right here. So if you’re pouring a sidewalk or maybe more relevant, something a little bit more structurally demanding, and definitely structurally different, is you’re gonna have rocks, gravel, crushed or natural aggregate, large aggregate, sand and Portland cement. So that’s your basic, those are the basic three ingredients. And then of course, water. So there’s four ingredients in regular concrete and pretty much that’s it. So you’ve got your coarse aggregate, that’s a bulk filler and it’s an important
Caleb Lawson:
Oh,
Jeff Girard:
to keep in mind.
Caleb Lawson:
hey Terry. Terry’s
Jeff Girard:
Um,
Caleb Lawson:
logged on.
Jeff Girard:
Hey Terry,
Caleb Lawson:
Welcome.
Jeff Girard:
let me, let me click on this. Let’s see the
Caleb Lawson:
Some
Jeff Girard:
people.
Caleb Lawson:
little chat.
Jeff Girard:
There he is. Um. you’ve got your fine aggregate, your sand, and that fills in the interstitial spaces in between the big rocks. And then the cement and the water, that’s your binder. We’ve already talked about cement in a prior podcast. So you’ve got your filler and your glue. Now that’s grossly oversimplifying things, right? And when they’re blended in a roughly the right proportion, you’ve got a mixture that is easy to work with, easy to mix. You can cast into a shape, whether it’s a sidewalk shape or a wall shape or whatever you’re making. And then it will start its chemical reaction, get hard, and be a structural element. Now… the, what we’re talking about right now is just the concrete side of things. And it’s important to realize that with concrete, concrete is a material that is rarely used all by itself in making things that have to do work. So with a sidewalk or a driveway or a patio, you might dig a hole flat in the bottom, maybe put some plastic sheet down, build your forms, and maybe lay some wire mesh in there, which is not structural reinforcing, by the way.
Caleb Lawson:
said
Jeff Girard:
That’s
Caleb Lawson:
it so.
Jeff Girard:
secondary reinforcing for crack control, but so we can largely ignore that. And you just pour the concrete in the hole, fill it up, strike it off, finish it, and you’re done. And with that kind of application, the structure is actually the ground that the concrete’s sitting on. So you just cast the slab on grade. And
Caleb Lawson:
which
Jeff Girard:
with a slab
Caleb Lawson:
is,
Jeff Girard:
on grade,
Caleb Lawson:
they’ve
Jeff Girard:
it’s
Caleb Lawson:
super compacted it and
Jeff Girard:
yeah,
Caleb Lawson:
yeah.
Jeff Girard:
the ground is actually the engineered structure and the concrete is a cap that spreads the load. So if you drive on it, it spreads the wheel loader out. So you’re not punching
Caleb Lawson:
sink
Jeff Girard:
a hole
Caleb Lawson:
into
Jeff Girard:
into
Caleb Lawson:
the ground.
Jeff Girard:
the ground. Okay. I don’t want to take away
Caleb Lawson:
That’s
Jeff Girard:
that from
Caleb Lawson:
actually
Jeff Girard:
the import.
Caleb Lawson:
a really good definition. The concrete is not the structure in that particular
Jeff Girard:
Right.
Caleb Lawson:
instance. And so when we’re making things, the concrete is the structure.
Jeff Girard:
Yeah, and I have a lecture on this. I’m just getting a prop here. So when we’re making a countertop or a wall panel or something, all right, we cast it on our casting table and as soon
Caleb Lawson:
for
Jeff Girard:
as
Caleb Lawson:
the
Jeff Girard:
we
Caleb Lawson:
transcript,
Jeff Girard:
pick it up.
Caleb Lawson:
Jeff holds ruler up.
Jeff Girard:
Jeff holds ruler up, because I happen to have a ruler, right? So we are making a beam, whether you realize it or not, or whether you intend to, as soon as it comes off your casting table and you pick it up, it is now self-supporting and it’s a beam. And if you pick up a slab that’s brand new and you support it incorrectly, it’s going to do this. I’m flexing it, okay? When you flex something, you create tension on one side. Tension is what causes cracks. So good practice is when you’re demolding it you rotate it up on edge So it’s a lot stiffer Geometrically stiffer and now it can’t flex and if it can’t flex it can’t crack because it’s not creating tension in it So now we can pick it up and move it around Okay, so a countertop that spans an open cabinet is a beam a table a bench. It’s all a beam, right?
Caleb Lawson:
Well, and to illustrate too how little they’re, you know, good information’s out there. I have a client right now, super high-end builder. I mean, their work is incredible. And they asked me, you know, we’re doing some countertops for them. And they were like, well, we’ve got a 40-inch span between two cabinets. Are you sure that’s okay? I’m like,
Jeff Girard:
Right.
Caleb Lawson:
yeah. They were
Jeff Girard:
Yeah.
Caleb Lawson:
like, but you’re sure. I’m like, yeah, it’s fine. Don’t worry
Jeff Girard:
Right.
Caleb Lawson:
about it. I got it.
Jeff Girard:
So
Caleb Lawson:
You know, it’s like they don’t really, it’s
Jeff Girard:
yeah.
Caleb Lawson:
just not known
Jeff Girard:
Right.
Caleb Lawson:
because we’re essentially, we’ve engineered a new stone.
Jeff Girard:
So if you’re, again, we’re working with, we’ll call it sidewalk concrete, not to be derogatory, but just as a general classification
Caleb Lawson:
Sure.
Jeff Girard:
of something that doesn’t need a very high compressive strength, 3000 PSI, 20 MPa is good enough. If you’re really, you know, wanna blow the budget, maybe you do like four or 5000 PSI. So that’d be what, like 25, 30 MPa, 35 MPa, something like that.
Caleb Lawson:
These are numbers I don’t know.
Jeff Girard:
you know, high strength, high strength, you know.
Caleb Lawson:
Yeah, I mean, 5,000 PSI concrete at the home center is, you know, that’s
Jeff Girard:
Yeah, that’s considered
Caleb Lawson:
high strength to come.
Jeff Girard:
high strength, which is actually good for what it is. And…
Caleb Lawson:
And that’s, you know, I’ve heard somebody ask, you know, like does it work? And then the answer was, well, how do you define work? And I think what, for the purposes of this, we’re defining work as it does what it says it’s gonna do. So that mix says that it’s good for those applications.
Jeff Girard:
Right.
Caleb Lawson:
It works.
Jeff Girard:
And it reaches that strength in 28 days.
Caleb Lawson:
Yeah,
Jeff Girard:
Well,
Caleb Lawson:
does
Jeff Girard:
guess
Caleb Lawson:
it
Jeff Girard:
what?
Caleb Lawson:
work for what we need it for? No, not so much,
Jeff Girard:
No,
Caleb Lawson:
or
Jeff Girard:
not really.
Caleb Lawson:
not adequately anyway.
Jeff Girard:
And this is where I’m getting to, is it’s important to realize that kind of concrete, just like 99%, 99% of all concrete used in the world for everything from bridge abutments to foundations under skyscrapers to sidewalks to, well, maybe not sidewalks. uses steel reinforcing because steel or reinforcing in general provides a tensile capacity to resist that bending. Concrete on its own, unreinforced concrete, is weak in tension and what’s worse is it’s not just weak in tension it’s very brittle and if you’ve got a crack or a weak spot or a fissure that essentially a crack has zero tensile strength and If you make a piece of concrete, a countertop, you cast a big slab and you cast it thin because your customer says, I want, I want a, I don’t want any seams and I want an inch and a half thick because that’s kind of the normal or inch and a quarter, which is more of a standard nowadays. And I don’t want any seams. So I’m going to cast a big long 12 foot section and you cast it out of home center concrete. The likelihood that you’re going to be able to demold this, do what you want to do, and install it is It’s a risk. It’s a low probability that you will be successful. And what do I mean by success? You can move it and it doesn’t crack. It doesn’t split in half. Because without any reinforcing in here, it can’t resist the tensile forces that are generated from just moving it. So
Caleb Lawson:
Yeah, I
Jeff Girard:
it’s
Caleb Lawson:
mean,
Jeff Girard:
basically
Caleb Lawson:
I have
Jeff Girard:
going to break itself.
Caleb Lawson:
tons of experience in that because before I came to CCI’s ultimate course, which as a plug, we’re having August 7th through 11th, and December 4th through 8th, I think.
Jeff Girard:
Something like that.
Caleb Lawson:
I’ll link that later in the podcast. And then we’re also doing a GFRC two day in November 9th and 10th. So if you want to learn more, come to those things.
Jeff Girard:
Absolutely.
Caleb Lawson:
And I will screen share the link at the end of the episode. But I have a lot of experience with that, because I was doing a sand mix without reinforcing wetcast before I, I mean, because that’s what Chuck did. I didn’t know any better. You know, thank God I know better now. But I was, I mean, they basically, you look at them and they break. They break themselves. By contrast, I just cast and it’s back in the shop. a 15 foot, which 15 foot’s not, I mean, I know plenty of y’all have casts
Jeff Girard:
It’s
Caleb Lawson:
bigger
Jeff Girard:
unwieldy,
Caleb Lawson:
than 15
Jeff Girard:
but
Caleb Lawson:
feet.
Jeff Girard:
it’s not huge by
Caleb Lawson:
Yeah, I mean,
Jeff Girard:
today’s definitions.
Caleb Lawson:
yeah, I mean the table I’m sitting at 16 feet, but anyway, and it’s three inches thick, it’s not really, it’s three inch edges and some whatever. But I mean, moved it around no problem, you know, we flipped it with a forklift and then adjusting it on the car, you know, it’s got a little flex to it, but because
Jeff Girard:
Mm-hmm.
Caleb Lawson:
it’s properly reinforced. it’s fine. And getting into, you know, how we would define what we do, you know, it’s glass fiber reinforced concrete. And when, you know, I think there’s a, we can get into this later in a different episode in this series, but the reinforcing of this being glass fibers, there’s a misconception, I think, out there that PVA fibers have the same properties as glass fibers from a reinforcement perspective, and that is just not the case.
Jeff Girard:
Yeah, they don’t. Not from a real world perspective.
Caleb Lawson:
No, I mean, I mean, and I know you’ve done some testing and it was because both Jeff and I had that perception that they were more or less the same, you’re not going to really sacrifice that much if you change from one to the other or whatever. Not true.
Jeff Girard:
We can get into that, into the deeper aspects of that in another podcast. But.
Caleb Lawson:
Well, Terry mentioned in the chat, not to mention sink and cooktop cutouts in countertops are getting bigger, increasing the risk. And he’s totally right. I had a sink in a countertop earlier in the year, February or March, and the hole for the sink… Now, this was an inch and a quarter thick countertop, and the hole for the sink was like 49 inches wide.
Jeff Girard:
That’s huge, yeah.
Caleb Lawson:
It was some massive triple bowl sink with like a drain board integrated into it and all this cutting board stuff and all these accessories and it was in a commercial space that I had to fly up over a glass railing with a
Jeff Girard:
Mm-hmm.
Caleb Lawson:
boom, I mean it was ridiculous. So yeah, Terry,
Jeff Girard:
And
Caleb Lawson:
thank you for that.
Jeff Girard:
that’s an
Caleb Lawson:
That’s
Jeff Girard:
excellent
Caleb Lawson:
true.
Jeff Girard:
example of where. understanding the role of like, we work at GFRC, right? So generally the glass fibers that are mixed into the concrete function as a reinforcement. And we’ll get into the nuts and bolts of that in another podcast a little, we’re gonna
Caleb Lawson:
Because
Jeff Girard:
dig. Yeah, yeah.
Caleb Lawson:
we’re going to be talking about this topic for the next, what, three, four weeks
Jeff Girard:
Three,
Caleb Lawson:
probably.
Jeff Girard:
four, yeah. So we’re kind of going very shallow, high level, and then we’re gonna dig deeper as we go. But. Those kind of situations are perfect examples of where you can now start incorporating the appropriate kinds of external reinforce or internal reinforcement like fiberglass or basalt rebar where you need that extra tensile reinforcement to work to keep that slab. I mean, when I’m, our countertop here is, has that. The table you’re sitting at has it in it. When you need extra strength. especially because you have a hole. When you cut a hole in a countertop, you’re making a giant weak spot. So you can almost guarantee where it’s gonna crack.
Caleb Lawson:
Mm-hmm.
Jeff Girard:
And, you know, we’ll get into more of how reinforcing works and all that, but getting back to the, you know, just the plain concrete, home center concrete or sidewalk concrete, you have to have reinforcement in that. And because of its nature of having a large volume of coarse aggregate and fine aggregate, You know, the bulk of its ingredients are sand and rocks. You can’t put enough fibers of the right kind of fibers in that mix to
Caleb Lawson:
All
Jeff Girard:
gain
Caleb Lawson:
right.
Jeff Girard:
the kind of internal reinforcement without drastically affecting its workability. You know, you couldn’t do it. It’s a wrong mix of sign. And we’ll get into that. It’s like, why is that? Why can’t you just take any mix and turn it into something else? And… This is kind of the first. that I see a lot of people trip up on is they pick the wrong concrete for the wrong reason.
Caleb Lawson:
Right.
Jeff Girard:
And I’ll get, I’ll get like, messages on Facebook, I’ll get emails from, from folks like, well yeah, I want to cast this outdoor bar top and I want to do casts in place and I’m going to do this and that. And I’m using, you know, a regular concrete mix or something to that effect, you know, whether it comes from a truck or from a home center,
Caleb Lawson:
Mm-hmm.
Jeff Girard:
which they’re not exactly the same. Don’t, don’t equate the two. but they’re similar in the sense that they still have rocks.
Caleb Lawson:
Right.
Jeff Girard:
And… The notion is, well, I’ve got this material, and it says it has this strength, therefore I’m OK. And that’s really not the case, because addressing the strengths aspect of it, it’s 5,000 PSI mix, or if you’re in a different country, it’s whatever. However it’s classified. That’s compressive strength, which is squeezing. So if you have two blocks of wood, and you put a car jack on it to lift up your car, Those blocks are in compression. So it’s very strong in compression. Um, a rope has no compressive strength. A chain has no compressive strength, but
Caleb Lawson:
It’s
Jeff Girard:
it
Caleb Lawson:
like
Jeff Girard:
has
Caleb Lawson:
it’s nice to know,
Jeff Girard:
tensile
Caleb Lawson:
but it’s
Jeff Girard:
strength,
Caleb Lawson:
not,
Jeff Girard:
right?
Caleb Lawson:
you know.
Jeff Girard:
Compressive strength is a nice rule of thumb. And in reinforced concrete design, when, when a structural engineer like myself is designing a structure, you have the concrete’s compressive strength, which is addressed. So that kind of governs the overall shape and size of the piece you’re casting. And there’s other factors that go into that, but let’s just simplify it here. And then the steel reinforcing takes all the tension. So you have concrete, which has a compressive aspect of it, and that’s its quality. And then the steel reinforcing, pretend this is steel reinforcing, it’s going to be here, you know, down low. And its job is just to do tension. And when they’re bonded… properly and they’re located properly inside the structural member, they work together. Concrete’s doing the compressive side, the steel’s doing the tension side, steel does other things too, but those two, they’re kind of independent, they’re equal and opposite.
Caleb Lawson:
Right.
Jeff Girard:
So you can’t take the steel away and expect the concrete to do the job that the steel needs to do, and you can’t put the steel in the wrong place because then it doesn’t do its job. And with conventional kind of concrete, you have to have both of those together. And getting that right is not easy. And I’m not, again, what I’m not saying that you can’t do a lot of cool things with that, but because you’re now working with a composite concrete and steel working together, the closer they are together, the less effective they are. Like the stresses go up and then you start overloading one or both. So in order to be effective and to make, give yourself a margin of error to be able to make this without having to like look at everything to within a fractions of a millimeter of being precise, you separate the two. That means the thickness of the concrete you’re casting in becomes greater.
Caleb Lawson:
bright.
Jeff Girard:
Three inches, four inches, that sort of thing. And when you do that, sure, you can cast some great stuff, but now if you’ve got a three inch thick slab, that’s heavy, right? That’s what. roughly 35, 36, 37 pounds a square foot.
Caleb Lawson:
No, I think it’s more than that because if I remember correctly, I think two-inch thick solid concrete is 40 pounds a square foot.
Jeff Girard:
Okay, there you go. Heavy, that’s all
Caleb Lawson:
Lots.
Jeff Girard:
we need to know, it’s heavy. And now if the minimum thickness you can do is two inches or 50 millimeters, minimum, okay?
Caleb Lawson:
Ready?
Jeff Girard:
That means you’re not casting very big pieces because how are you gonna move that? How are you gonna put that on? Like if you’re gonna do a wall panel, like 22 years ago I did a job in Seattle where the architect said, I want shower wall panels and I want them to be two inches thick. That’s crazy. Why?
Caleb Lawson:
Why? Ugh, I mean…
Jeff Girard:
Because that’s what they thought concrete could do. That’s what they thought thin was. Well,
Caleb Lawson:
Yeah,
Jeff Girard:
nowadays
Caleb Lawson:
I actually
Jeff Girard:
you could do a half inch panel.
Caleb Lawson:
had somebody, somebody was talking to me about something. It was somebody who had taken ultimate and they were asking me a question. And we were talking about, oh yeah, it was a previous student and they were asking me about hearth. And you know, we were talking about thickness and you know, it was like well the general contractor wants it monolithic, you know, poor. inches thick or something. It’s like once at full thickness, you know, I was like, well, okay. You need to understand that part of your job is educating them because that’s not required in the material that you are providing
Jeff Girard:
Right.
Caleb Lawson:
for them. So it’s like, yeah, the drawings may call for steel reinforced aggregate based 14 inch thick concrete, but that’s not necessary for the strength. that they’re asking for. You can do it as a three quarter inch shell, and you should because that would be horrible.
Jeff Girard:
And to qualify that, most things like a hearth for a fireplace are, they’re decorative in the sense that, okay, we
Caleb Lawson:
Well,
Jeff Girard:
have this
Caleb Lawson:
the
Jeff Girard:
shape.
Caleb Lawson:
maximum that you need to be able to do is sit on it.
Jeff Girard:
Right, right. So it’s not holding up a house. It doesn’t have a 500 or a thousand pound per linear foot vertical load applied to it. It’s not like you’re casting a footing in the ground that has to support the whole building. You’re casting a decorative shelf,
Caleb Lawson:
Yeah, well,
Jeff Girard:
more or
Caleb Lawson:
and
Jeff Girard:
less.
Caleb Lawson:
Terry just mentioned, you know, a huge mistake people make. I appreciate having people in here. This is fun.
Jeff Girard:
Yeah, that’s great.
Caleb Lawson:
Huge mistake people make is the assumption that concrete will work just because there’s steel in there. No consideration of what reinforcement is actually required or placement of said reinforcement.
Jeff Girard:
Right.
Caleb Lawson:
So, yeah, because, you know, like Jeff was mentioning earlier, you know, in a sidewalk, you put the reinforcement in the middle. So, obviously, you should put it in the middle in every other application. Not.
Jeff Girard:
Yeah, wrong, wrong. And
Caleb Lawson:
Um,
Jeff Girard:
I’ve got a webinar on that too.
Caleb Lawson:
yeah.
Jeff Girard:
So just go to the CCI website and we’ve got a webinar about how reinforcing works. And it was probably one of the very first YouTube videos ever made. It’s very dry, it’s very boring, but it’s very educational because if you don’t
Caleb Lawson:
Man, that’s
Jeff Girard:
understand.
Caleb Lawson:
really great
Jeff Girard:
So,
Caleb Lawson:
advice. Go listen to this very dry, very boring video.
Jeff Girard:
Yeah,
Caleb Lawson:
Hehehehehehe
Jeff Girard:
absolutely, yeah. You know? If you
Caleb Lawson:
And so,
Jeff Girard:
don’t,
Caleb Lawson:
yeah, so we’re…
Jeff Girard:
if you want to be successful, it’s very helpful to understand how the nuances of things work. And concrete is one of these mysterious materials that it’s, you know, it’s not like wood, it’s not like steel, where, you know, you have a chunk of steel and… Okay, let’s… So this ruler has a shiny side and a cork side, right? So it’s a… The two sides are different, right? So let’s pretend… that the cork side is the concrete side and the steel side is where the reinforcing is. Okay? If I cast this and I put the steel where it’s supposed to be when I’m moving it, or it’s being used, which is on the tension side, which is on the bottom, because it’s gonna want to bend this way, right?
Caleb Lawson:
This
Jeff Girard:
If
Caleb Lawson:
way being
Jeff Girard:
all of
Caleb Lawson:
down.
Jeff Girard:
a sudden… What?
Caleb Lawson:
This way being down for those of you reading
Jeff Girard:
down,
Caleb Lawson:
the transcript.
Jeff Girard:
down when it’s installed, right?
Caleb Lawson:
Yeah, being carried as well.
Jeff Girard:
Up when you cast it, because we cast upside down. So
Caleb Lawson:
Right?
Jeff Girard:
if I pick the slab up or it’s a table, right? Let’s think of it as a table, right? Reinforcing at the bottom. I can put a weight on here and the reinforcing is gonna do its job, hold it all together and everything works. If I put the reinforcing in the wrong place, in the middle, let’s say, or
Caleb Lawson:
Yeah.
Jeff Girard:
up near the top. And I load it now. What’s taking all the tension? The concrete side, the cork side is the concrete side. So the concrete side is taking all that tension and regular concrete has a very, very low tensile strength. In fact, it’s so low that structural engineers never take that strength into account. We ignore it, we treat it as zero.
Caleb Lawson:
Hmm.
Jeff Girard:
We assume the concrete has already cracked and a crack has no tensile strength. So… If you put your, you can, you can load up a piece of concrete with tons of rebar, but if it’s in the wrong place, it’s doing less than nothing.
Caleb Lawson:
Mm-hmm.
Jeff Girard:
So we can get more into that in another podcast, but you know,
Caleb Lawson:
Well, I
Jeff Girard:
picking
Caleb Lawson:
think
Jeff Girard:
the
Caleb Lawson:
the
Jeff Girard:
wrong
Caleb Lawson:
bones
Jeff Girard:
concrete.
Caleb Lawson:
and the point of what we’re
Jeff Girard:
Yeah.
Caleb Lawson:
talking about is, you know, if you’re using the wrong concrete for the job, you know, it’s like all concrete isn’t concrete, right? I mean, that’d be a funny title for the episode because, like, I think about I’m a whiskey collector or I’m specifically a bourbon collector. So all bourbon is whiskey but all whiskey isn’t bourbon kind of thing. You know, or like all Bugattis are cars but not all cars are Bugattis, right? So we were talking earlier about, you know, a 14-year-old could theoretically get into a Bugatti because they claim it’s the best car in the world. That doesn’t mean they can drive it. Yeah. So. I don’t know. Oh, wait. Can we talk about too much Rio, please, Jeff? It’s also a problem. Reinforcement, Terry, is that what you’re referring to?
Jeff Girard:
Yeah, I mean there, there is such a thing as too much reinforcing. You can over-reinforce something, but that’s… That’s in the structural design and you have to look at what code says for the allowable cross-sectional area of your reinforcing relative to the cross-sectional area of your compressive zone. And those have to be proportioned correctly. And that’s the job of a structural engineer. So if you, if you put too
Caleb Lawson:
Well,
Jeff Girard:
much
Caleb Lawson:
but I think,
Jeff Girard:
reinforcing
Caleb Lawson:
yeah,
Jeff Girard:
in
Caleb Lawson:
we’re
Jeff Girard:
a
Caleb Lawson:
talking about in the context of what we’re doing, Terry. I can’t see if you’re typing or not, but in the context of what we’re doing, what would too much reinforcement do? Because let’s assume for the sake
Jeff Girard:
Right.
Caleb Lawson:
of argument that we’re not dealing with an engineer
Jeff Girard:
In practical
Caleb Lawson:
in this particular.
Jeff Girard:
terms, right, in practical terms. we can’t, it’s extremely rare for us to use too much reinforcing. I mean, you’re just basically throwing money away at
Caleb Lawson:
Now
Jeff Girard:
that point.
Caleb Lawson:
you could ghost the concrete if you pushed it down too hard or used
Jeff Girard:
Yeah,
Caleb Lawson:
too much or
Jeff Girard:
but
Caleb Lawson:
you know.
Jeff Girard:
I could ghost a piece of concrete by using one single piece of rebar. It’s not the quantity so much. It’s,
Caleb Lawson:
It’s how you’re treating it.
Jeff Girard:
it’s how you’re treating it. And if you have a lot of, but the thing is, if you have a lot of reinforcing in an area, the chances of ghosting, because you have to put in lots of pieces of rebar,
Caleb Lawson:
Go
Jeff Girard:
go
Caleb Lawson:
up.
Jeff Girard:
up every time you insert a new piece. So it’s, it’s not, you know, lots doesn’t mean. you’re gonna get it, it just means a lot, it means you have a greater chance of doing it because you’re
Caleb Lawson:
Right.
Jeff Girard:
doing it more often.
Caleb Lawson:
And that is, per the check, that is what Terry was referring to as
Jeff Girard:
Yeah,
Caleb Lawson:
ghosting.
Jeff Girard:
yeah. So ghosting, if you haven’t seen, I’m trying to see if I have a picture of that, and I…
Caleb Lawson:
do somewhere.
Jeff Girard:
used to. I got a collection of all these different things, so photos I’ve gotten over the years and, well, this kind of is one. All right, let me share my screen for a second here.
Caleb Lawson:
But where I was
Jeff Girard:
Thank
Caleb Lawson:
going with
Jeff Girard:
you.
Caleb Lawson:
the car analogy is it’s like while you’re looking for that picture.
Jeff Girard:
There
Caleb Lawson:
Oh, there it is. Here we go.
Jeff Girard:
we go. So this is a kind of ghosting
Caleb Lawson:
Ah.
Jeff Girard:
where you got these lines. Obviously it’s grid. Um, sometimes they’re darker instead of lighter. And there’s a kind of a misconception that folks think that because you’re reinforcing is big, it’ll ghost. Or if it’s close to the surface, it’ll
Caleb Lawson:
It’s
Jeff Girard:
ghost.
Caleb Lawson:
all about manipulating the surface.
Jeff Girard:
Right. Um. ghosting happens and this is
Caleb Lawson:
This isn’t a side,
Jeff Girard:
a little
Caleb Lawson:
but
Jeff Girard:
esoteric
Caleb Lawson:
still.
Jeff Girard:
noodling digging down into the rabbit hole of the micro mechanics of a heterogeneous granular and cohesive based system. You got big rocks, you got little rocks, you got cement paste, which is kind of like thick fluid. And if I’ve got all these particles, and I take a piece of rebar which is rigid and I push it into that material. Or if it’s inside that material and I move it, it sinks or moves
Caleb Lawson:
or
Jeff Girard:
around.
Caleb Lawson:
it creates a vacuum
Jeff Girard:
It
Caleb Lawson:
by
Jeff Girard:
moves
Caleb Lawson:
pulling it
Jeff Girard:
those
Caleb Lawson:
out.
Jeff Girard:
particles around, especially your steel. And as those particles shift around, they kind of create suction in between and the paste moves. Well, even cement paste is not like a uniform material. It’s tiny particles of cement and pigment and other things. And that in itself can shift and move and create suction and vacuum in it, and you’re really dealing with the movement of water in that system. And when water moves into an area, the water cement ratio in that zone where the waters move into goes up. And when concrete has a higher water cement ratio, it cures slightly lighter than areas that don’t have as high a water cement ratio. And in contrast, If you have an area of concrete that has lost moisture and its water cement ratio drops, it’s gonna cure darker. So sometimes ghosting, if you have a really dense mix and you push rebar in, which you should never do, never push rebar in, you can create an area where water’s pushed away and you get a dark line. And in other cases, where the mix is a little loose, you could create just the opposite where water’s being drawn in and it’s lighter like we just saw. So how do you prevent that? You suspend the rebar, it’s already in place, hung where you want it, and you pour the concrete around it so it doesn’t move. That’s how you prevent ghosting. And I’ve put rebar a quarter inch from a visible surface and you can’t see it because it didn’t move relative to the concrete. So that’s, I got, a side note of what ghosting is, how does it cause, and how do you prevent it? Just like we’ve done this intentionally in class, Caleb, remember how
Caleb Lawson:
Mm-hmm.
Jeff Girard:
we were casting a lounge chair. And so with GFRC, you don’t have to do this, but a common practice is you spray a mist coat. So it’s a mixture of concrete that has no fibers in it. And
Caleb Lawson:
And we put a hand print in it, if
Jeff Girard:
yeah,
Caleb Lawson:
I remember
Jeff Girard:
we
Caleb Lawson:
correctly.
Jeff Girard:
literally spray it. So you spray a couple millimeter thin layer of mist coat, and then we literally took a glove tan and pushed it into the concrete. Now we didn’t push our hand all the way through into the form. We just put
Caleb Lawson:
Just
Jeff Girard:
pressure
Caleb Lawson:
kind of.
Jeff Girard:
on it, but that pressure
Caleb Lawson:
created
Jeff Girard:
created
Caleb Lawson:
the ghosting of a handprint.
Jeff Girard:
a ghosting effect intentionally. Um, so that’s knowing what causes it and then using that to your advantage to create like this cool design, this cool effect.
Caleb Lawson:
Yeah, so, you know, we’ve kind of been going on about this for a little while, so I probably want to, you know, kind of wrap us up, but I think this has been really, really helpful. Because what our goal is, is to kind of give y’all who are listening a definition of a What kind of concrete is the right kind of concrete for this? You know, what’s the right car to drive when you’re off road, right? What’s the right car to drive on a race car or a racetrack? You know, what should you be using for the instance, for the context? And then defining the word works. You know, we want you to understand. what it should be doing, how it should be performing for you and for your clients. And so, we’re giving you, kind of shooting a shotgun of information, but our hope is that it’s the right information for you. So, yeah, any final thoughts, Jeff,
Jeff Girard:
Yeah,
Caleb Lawson:
on the
Jeff Girard:
what I wanted
Caleb Lawson:
definitions
Jeff Girard:
to
Caleb Lawson:
of the two types
Jeff Girard:
kind
Caleb Lawson:
of
Jeff Girard:
of
Caleb Lawson:
concrete
Jeff Girard:
finish
Caleb Lawson:
that we’re
Jeff Girard:
things
Caleb Lawson:
talking about?
Jeff Girard:
up, and we’ve been talking a lot about home center concrete and that sort of thing and why it’s, how it’s really meant to be used and some of its limitations. And don’t get me wrong, you can still cast something two or three inches thick, properly reinforced and use that kind of concrete and be successful. I’ve done… very large projects. I did a big cast-in-place bar that used 18,000 pounds of concrete. We cast it four inches thick and it had half inch rebar in it.
Caleb Lawson:
Well, and that kind of ghosting is per Terry very common in the process of casting in the field when it’s vibrated too much in the steel.
Jeff Girard:
Yeah, yeah, or it’s moved
Caleb Lawson:
Or
Jeff Girard:
or
Caleb Lawson:
where the vibrating
Jeff Girard:
lifted.
Caleb Lawson:
prod hits the steel or whatever.
Jeff Girard:
Yeah, yeah, you can create lots of issues. Um, so I’m not saying that you can’t use it. It’s just the reason why we don’t use it. The reason why the concrete countertop industry as a whole has moved away from aggregate based concrete, even like one of my, what used to be my production mix, my 332 mix, it’s a… It’s a gravel-based mix. I think it’s seven days strength is… I had it tested many, many years ago. It’s like 6700 PSI at seven days, which is what? Like 40 something MPa. Like really strong at seven days. You still have to use steel reinforcing in it. And the reason why we don’t generally use that kind of mix anymore is because the stuff we make… is longer and thinner and we need more flexibility and it just is far too difficult or sometimes impossible to use steel reinforcing in something that’s that thin. Like you can’t put steel reinforcing in half inch thick concrete because the reinforcing’s, well some of it’s
Caleb Lawson:
Half
Jeff Girard:
half
Caleb Lawson:
an inch
Jeff Girard:
an inch
Caleb Lawson:
thick.
Jeff Girard:
thick, even if it’s quarter inch thick, even if it’s like I use ladder wire which is a little over an eighth of an inch thick, that’s still way too big
Caleb Lawson:
Which that’s
Jeff Girard:
for
Caleb Lawson:
also not, like, I don’t, we don’t, the ladder wire is for walls, right?
Jeff Girard:
Yeah,
Caleb Lawson:
Like
Jeff Girard:
I mean,
Caleb Lawson:
for between
Jeff Girard:
you can
Caleb Lawson:
blocks.
Jeff Girard:
use it as structural reinforcing, but not in something that is as
Caleb Lawson:
That’s
Jeff Girard:
thin
Caleb Lawson:
it.
Jeff Girard:
as, say, one inch or three quarters of an inch or half an inch. So that’s why we have to completely change the mix design. We have to completely change the whole nature of the mix to be able to do what we’re doing. And that’s why GFRC has really radically transformed this industry because now we’re not treating this as a discrete, separate… call it a binary composite. Reinforced steel, concrete and steel separate. The glass is mixed in and
Caleb Lawson:
It’s part of the
Jeff Girard:
because
Caleb Lawson:
matrix.
Jeff Girard:
we’re doing that we’re using special kind of glass fiber, we’re using a lot of fibers. We have to radically change the mix to make everything work together. And the things we do now that we can do now could never ever be done the way we’re doing them now with conventional concrete. So the things you get excited about seeing, the big projects, all that, that’s possible because we’re using materials that are far outside the realm of conventional construction grade concrete, which is good for what it’s for, but it’s not good for what we’re doing. So we have to really move away from that and kind of abandon a lot of the practices of… conventional concrete casting and conventional concrete application. But we can’t forget the basic fundamentals of concrete, which was what we’re going to touch on in the next series of blog posts.
Caleb Lawson:
So this was basically a very long sort of intro to the series which… Do we have a name for it? Are we calling it something?
Jeff Girard:
I don’t know yet.
Caleb Lawson:
I don’t know yet. But we
Jeff Girard:
What not
Caleb Lawson:
will…
Jeff Girard:
to do? No.
Caleb Lawson:
yeah, right? Oh, I actually had a… email it to you. I think what I emailed to you had a title, Jeff, I don’t remember. But regardless, we’ll think of something. long intro to a series and this is kind of why we’re doing it right there’s a lot of bad information out there that um and that’s you know in an earlier episode Jeff I think that’s you know we talked a lot about why you started the you know started CCI and a lot of that was because you know it’s like you figured out you did the research you engineered your mix and you were able to say things about your mix to your clients that really were not being able to the time and you know in order to save the industry as it were
Jeff Girard:
Mm-hmm.
Caleb Lawson:
you know and that’s a very large and lofty goal but I think it’s you know by and large you’ve accomplished it to this point is you know bringing good information to the people who need it
Jeff Girard:
Mm-hmm.
Caleb Lawson:
and that’s what we’re trying to do with the podcast that’s what we’re trying to do with obviously our classes so again and I’m going to share that part of the screen. We are… Join
Jeff Girard:
while you do
Caleb Lawson:
us!
Jeff Girard:
that. So like at that meeting… We were talking about all the problems that were in the industry at the time, very, very tiny little baby industry at the time.
Caleb Lawson:
Mm-hmm.
Jeff Girard:
And this is just an aside. No, they didn’t have this issue version or edition. They had an older edition. Several of the people at that meeting had this book. They had the same book I had. They had the same thing that I used. in class. So having the knowledge, sorry I banged my microphone here,
Caleb Lawson:
Huh?
Jeff Girard:
having the knowledge in hand and seeing the words is only part of the path to solving your problems because they still had problems and the thing is every single one of the problems that they were challenged with are answered in this book but because they don’t they didn’t have the technical background to understand and put those pieces together. They couldn’t use this information. And that’s why I started CCI is, how can I take complex technical stuff? A lot of it, there’s a big universe of knowledge about the concrete world. There’s been research over the last century or so. How can I distill that and make it useful? So… You don’t have to know everything, but what you need to know is actually going to make you successful.
Caleb Lawson:
Right.
Jeff Girard:
So it’s nice to know esoteric things about stuff, but if that doesn’t really help you, or you don’t really understand what’s going on, it’s not useful. It’s cluttering and confusing. And I don’t want to… I’m never going to dumb anything down. We’re never going to think you don’t know anything, or you’re stupid, or anything like that. But we do understand that there’s, there’s a limit to what you’re able to absorb and understand and use, especially when you’re learning and
Caleb Lawson:
Right.
Jeff Girard:
you can always learn more and find, you know, be more interested in some esoteric aspect of it. And then like you’ve been doing recently, Caleb on some very, very high level stuff. Is that necessary for your day-to-day job? No, but it makes you a better. fabricator, it makes it helps you talk to your customers more because you have greater breadth of knowledge, but more importantly it helps you make better decisions about what you what are good what’s good for your customers and for your business. So maybe you just avoid that fancy snake oil bottle of something that promises the world but doesn’t back it up with anything because it’s just a bunch of fancy words
Caleb Lawson:
Right,
Jeff Girard:
like
Caleb Lawson:
so with that I’m going to one last time plug the course so
Jeff Girard:
Mm-hmm.
Caleb Lawson:
I’ll show the screen again.
Jeff Girard:
And that’s the kind of stuff we talk about
Caleb Lawson:
Yeah,
Jeff Girard:
in the class.
Caleb Lawson:
so
Jeff Girard:
Yeah.
Caleb Lawson:
you know, this is the link, concretecountertopinstitute.com slash ultimate dash creative dash concrete dash countertop dash training dash two forward slash. I’m doing that for the transcript. and I’ll link it in the description of the video on Spotify as well as on YouTube. But yeah, this was the class that really transformed my career and the reason that I actually got really good at it. I hesitate to say that because I don’t want to sound pompous, but I’ve spent a lot of time developing the way that I make my concrete. So we’d love to see you. Register now, you know,
Jeff Girard:
Check it
Caleb Lawson:
August,
Jeff Girard:
out.
Caleb Lawson:
check it out, August 7th through 11th or December 4th through 8th, so give yourself an early Christmas present or a late summer present before your kids go back to school. It’s at my shop in Canton, North Carolina, just west of Asheville. Both times
Jeff Girard:
beautiful
Caleb Lawson:
of year
Jeff Girard:
part
Caleb Lawson:
the
Jeff Girard:
of the
Caleb Lawson:
mountains
Jeff Girard:
country.
Caleb Lawson:
are stunning. I mean, it’s… It’s a great place to live. It’s a great place to visit. So join us and learn all sorts of amazing stuff. Take a journey with us. So yeah, with that, we will leave you to be super excited over the next episode. And yeah, so thank you all for listening and hope you have a great week.
Jeff Girard:
Thanks for joining us. See you next week.