High Performance Concrete (Spring 2006) - Part 1


Uploaded by techEIU on 10.05.2011

Transcript:
[no dialogue]
Good morning everyone my name is Tony Kojundic.
You all can grab my business card there K-O-J-U-N-D-I-C.
Just call me Tony please--with the Silica Fume Association.
Our association actually sponsored here today by the
Federal Highway Administration, as you can see in the booklet
that you guys picked up there.
The silica fume user manual was published
by both the SFA and the FHWA, Federal Highway Administration,
and part of that effort is what they call technology transfer,
sharing what's been done in concrete technology over the
last 30 years or so trying to expedite the learning curve
of the next generation, you guys coming up through the ranks.
Before we get started I want to play a little tape here
to give you a little background here.
You know which button to push, thank you.
[♪ music playing ♪♪]
>> male voice over: "World News Tonight" with
Peter Jennings continues.
Now--"Solutions".
>> Peter Jennings: There are several ways
to dramatize tonight's solution--we could tell you
that a horizontal asphalt infrastructure anomally
is a curse for millions of American drivers at this time
of year that would be pot holes to most of us.
We could tell you that $52.5 billion a year goes to highway
construction and maintenance not to mention all the other money
to repair the bridges and other pieces of
the nation's infrastructure.
It is safe to say that we think if the Ancient Romans were
watching tonight they would be asking what took you so long?
Here's ABC's Jack Smith.
>> Jack Smith: Roads and pavements,
bridges and support columns.
All of what's called America's infrastructure is
slowly crumbling because of what it's made of does not last.
This is ordinary concrete and this is what happens
to it after years of punishment--it falls apart.
Most of the concrete in the nations highways and bridges has
a life of just 30 years.
What's the solution?
I'm standing on it--brand new stuff called
high-performance concrete.
This is a sample, engineers say this will last not
20 or 30 years but 100 years, maybe longer.
This is what America's roads and bridges could be made of
in the future.
Engineers at the New York State Department of Transportation
discovered how to make it two and a half years ago.
>> Don Streeter: We were surprised when
we actually did all the calculations and got
the test results back and said my goodness
this really is going to work.
>> Jack Smith: Researchers stumbled upon
the formula after the Clean Air Act forced power plants
to reduce pollution.
Huge quantities of industrial waste called fly ash began
piling up and collected from smoke stacks.
First used as filler in cement turned out to be the key
ingredient for strengthening it.
So this is one-quarter industrial waste?
But it makes the cement many times tougher?
>> male speaker: That's right.
>> Jack Smith: High performance concrete is
74% cement and 20% fly ash and 6% micro-silica
another type of ash all mixed with water.
When it dries ordinary cement is actually porous not solid
and that's how salt and water get in.
But the fly ash in micro-silica are 10 to 100 times finer than
talcum powder.
Professor Ken Holger of Cornell has found they literally
fill in the microscopic holes in cement and demonstrates it
with colored tennis balls.
>> Professor Ken Holger: The next thing I would
want to do if I want to densify this box
is get some midsized particles.
And take those midsized ones and try and get them into the box.
>> Don Streeter: They fill in the smaller voids
between the cement particles and we just have a very,
very dense material.
>> Jack Smith: More waterproof?
>> Don Streeter: Correct.
>> Jack Smith: Stronger.
>> Don Streeter: Yes.
>> Jack Smith: Last longer?
>> Don Streeter: Yes.
>> Jack Smith: The new concrete is 3 times
more water resistant, 20 times less likely to form cracks,
and in pressure tests has proven almost 20% stronger
then regular concrete.
However, modern scientists were not the first to make
high performance concrete, the ancient Romans were.
Mixing volcanic ash with their cement to make it far tougher.
It's one of the reasons the Colosseum
and other Roman buildings have lasted so long.
>> Paul St John: We really literally reinvented
what our ancestors 2,300 years ago had already done.
>> Jack Smith: At least 11 states are
following New York's lead.
High performance concrete is more expensive
than ordinary concrete but because it's easier to lay down
it costs about the same to use.
Engineers say not only can it be an answer to much of
America's infrastructure problems but it could
revolutionize all construction.
Jack Smith, ABC news Albany, New York.
>> Tony: They use the term
micro-silica in that video and that's just another term for
silica fume, which is the group we are here talking about.
As you know from news cast, most news cast are written
to an eleventh grade level.
So that was the introduction to high performance concrete as ABC
News conveyed it back in February 11, 1997,
nine years ago.
So that map they showed of the nine states or eight states
that have used high performance concrete right now
that map is complete.
Every state has used high performance concrete
on their bridges.
We will talk a lot about what Illinois does on their bridges
here and what they have done down here on Interstate 70
and up along 294, and in Chicago
as part of the presentation, but that's kind of the background.
The idea is that even though this was invented
two and a half years before they shot this video
so that would've been 1995, reality is that Ohio put down
their first bridge in 1984 with silica fume concrete.
New York did their first bridge in 1986.
The State DOT's have a way of studying things for a long time
before they flip a switch and go with it for full specifications.
So they look at this material in place for a number of years
before they went ahead and switched over and started
building all their bridges with high performance concrete.
New York and Ohio are two examples that since 1997,
every one of their structures having to do with a bridge
has been built with high performance concrete.
The mix design that they showed you there, those compositions.
Illinois, every state is a little bit different in
their learning curve.
Some states, to give you an example, I'm from Pennsylvania
and sorry to say I think we only have four bridges
that I would consider high performance concrete by design.
Where you go to Ohio and New York and they probably have
thousands already in place and that's what this
whole idea of technology transfer is--we don't want
people to have to reinvent the wheel.
We already know how to do this, the technology is already in
place we need to get it out there in our industry and
construction industry and begin using it.
The problem is that most of the technology that we use in the
construction industry is 30 to 50 years old.
We still place concrete the way they did--
our fathers and forefathers before us placed concrete.
As you saw on that one video there, the one fellow mentioned
about the Romans and the idea that we are going back to that
technology and that's where we will try and start.
When people think of high performance concrete
a lot of times they think of strength.
If a little bit is good then a lot must be better
and in a lot of cases that would be good.
If you are doing a high-rise building, this is 311.
This building here next to the Sears Tower
in Chicago is 311 South Wacker--they used high-strength
concrete as the columns in this building.
This is some 12,000, 14,000 PSI concrete.
Six million modulus of elasticity runs from the
foundation all the way to the top of the building here.
The idea of using high strength concrete, if you
were to design the building with 4,000 PSI columns,
the columns would be very large to support all that weight.
If you could make the concrete stronger and stiffer then you
could use a lot less columns to support that same dead load.
If you're Trump and you're leasing it at what a couple
thousand a square foot, that extra square foot that you save
by reducing that column size on every floor more then pays for
any cost differential for high performance concrete,
in this case high strength concrete.