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>> Mr. Tony Kojundic: You actually watch this happen.
In this set up here this is the example that they did
right before your eyes-- you watched them batch
the concrete and watched them truck it over to the pump.
The guys got to rake it out of the shoot by hand
and it dried up that quickly.
They actually made the concrete in front of your eyes
and showed you the phenomenon of it drying up.
They weren't lying.
[Kojundic laughter.]
>> male speaker: [unclear audio.]
>> Mr. Kojundic: No because they couldn't
make concrete out of it and they couldn't do anything with it.
It literally dried up.
Dried up to the point where i say it's like a brick mix,
you couldn't pump it you couldn't do anything.
It was drying up right before their eyes.
>> male speaker: [unclear audio.]
>> Mr. Kojundic: Normally the mixed accordance
to ACI had workability of an hour and a half.
>> male speaker: [unclear dialogue.]
>> Mr. Kojundic: To less then 30 minutes.
In the laboratory they were able to keep the properties for
an hour and a half slowly losing though.
As the concrete begins to set up but in this case
it was very quick.
>> male speaker: [unclear dialogue.]
The lab that did the mix design?
In Sacramento, so they used all the local materials.
That was all checked.
>> male speaker: [unclear dialogue.]
>> Mr. Kojundic: They're not able to place it.
Everything up to this point is fine.
Just a lot of ideas.
Remember it is volume at this point.
>> male speaker: [unclear dialogue.]
>> Mr. Kojundic: The right one will be in there.
I guarantee it.
The right one will be in there if you generate at least
10 to 15, you'll get the right one.
Where did the water go?
We know that cement water really doesn't react that quickly.
Cement water takes some time for that chemical reaction like
baking a cake, it takes a while.
It takes some hours for it to start reacting.
So we know it's really not hydrating that quickly.
Something else is happening to the water.
Something else is making it dry up.
We've got middle of California in September
where it never rains.
So water is critical to everything, but where did it go?
Surface dry, truck dry?
>> male speaker: [unclear audio.]
>> Mr. Kojundic: When they made it,
it looked wet.
By the time they trucked it over to that site, you can see they
had to drag it out of the chute, they couldn't even
get it out of the chute-- it was drying up that much.
To them, it looked like it was setting up.
To them, it looked like it was flash setting.
The guys on site, they don't know any better,
they're just making concrete.
It looked like concrete over there, a hundred yards later
it looks like it's setting up to me.
We know that cement water doesn't react that fast.
Not unless you have really some super accelerators to
kick it off that quickly.
I don't know.
Did some people throw some accelerator in there?
Somebody threw in a jar of salt or something in there to make it
set up quicker, I don't know.
>> Dr. Wafeek Wahby: [unclear dialogue.]
>>Mr. Kojundic: And silica fume and air.
That mix design that was.
Yeah, I'll put that back up there.
That was the, pretty straightforward.
Cement, silica fume, sand, gravel, air, water reducers,
had the slump, got our strength.
Everything was fine in the lab.
Never made it in the field.
Never made the concrete in the field.
This is the first, your first attempt.
That's why you're called in.
Anybody have 10 ideas yet?
There you go.
In your groups, pick out the three that you think
are the better ideas, as a group.
You should all have the roughly the same ones.
If you have more than 10, begin to try
and go through and figure out your best 3,
which ones you think may be most likely.
They could just be your favorite ones.
>> male speaker: [unclear audio.]
>> Mr. Kojundic: Yes, when you do lab mixes,
special project lab mixes, they normally bag up the materials
that are going to be used on the project
and give them to the laboratory and use exactly
the same materials.
>> male speaker: [unclear audio].
>> Mr. Kojundic: Potable water.
No, it wouldn't be water from the same place
but it would be drinkable water.
It's not supposed to be, but that could have been
one of the ones down there.
When they do those mixed designs in the lab,
they'll bring, they'll fly the aggregate in,
fly the sand in, cement, everything.
Even the air entraining and water reducers and chemicals.
They'll make a true lab mix, but that's the big step between what
we call lab crete and field crete.
In the lab it was great, now you're in the field.
Now you have to make a real high performance concrete that's
going to last for 100 years in the middle of nowhere
and now all of a sudden it's not working the same way.
What happened, what's going on?
That's what we're trying to come up with here.
You guys got your favorite three?
What is your least favorite three?
Mark those.
Got your least favorite three with your most favorite three?
We need a spokesman, now, from our groups.
Are you ready?
Let's just do this real democratically.
To pick a spokesman for each group, on the count of three,
each group point to the spokesman.
Point to the person in your group you want to be spokesman
on the count of three.
Ready, one, two, three.
Who's got the most fingers?
Alright, the guy who got the most fingers,
he gets to pick the spokesman.
How's that?
The guy that got the most fingers gets to
pick the spokesman.
Alright, you pick a spokesman then.
Who wants to go first?
In the back, what's your top three?
Hang on, we've got to write these down somewhere.
We've got to keep track of these.
What do you got?
>> male speaker: [unclear audio.]
>>Mr. Kojundic: Okay, humidity?
>> male speaker: [unclear audio.]
>>Mr. Kojundic: What was the last one?
>> male speaker: [unclear audio.]
>> Mr. Kojundic: Okay, next group.
>> male speaker: We had a lot of the same
but truck contamination.
The truck that was bringing the material in
[unclear dialogue].
>> Mr. Kojundic: Okay.
Human error maybe while they were mixing it.
>> Mr. Kojundic: Okay.