Concrete in the 22nd Century(II)

7/28/2019 Concrete in the 22nd Century(II)

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Concrete in the 22nd Century

Ken Day

Innovative Concrete TechnologistHon. Member, and founding

committee member, of CIA


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Is it Useful to Attempt

Prediction?

An accurate prediction of the

situation 100yrs from now may

seem unlikely

But some of my concepts from

the early 1950s are only now

beginning to spread widely


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Can We Influence the Future?

Can we afford such delay?

Why does it happen?

Some things introduced 100 years

from now may already be available,

but struggling for acceptance


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The Climate of Change

There are huge changes due toadmixtures, resource shortages,

pollution considerations, and thecomputer revolution

Concrete can be made without

cement and reinforced without steel

It can be a self-compacting fluid


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What will concrete be like?

Reactive Powder concrete

essentially mortar, often with fibres,

with strength of several hundred MPa

has been produced

Concrete of over 150MPa is now being

used in precast bridges in USA(and we thought their technology lags!)


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What will concrete be like?

There is a rapidly increasing trend to

Self- Compacting Concrete (SCC)

This matches the reduced availability of

skilled site personnel and the reduced

tolerance for visual defects and forexcessive noise and industrial injuries


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Can We Cope with this?

These new concretes rely heavilyon chemical admixtures, pozzolans

and other finely divided materials

Concrete has become a high techmaterial and is becoming more so

What is the significance of this?


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Is Concrete Important?

The production of concrete is used by

some economists as a measure of a

countrys economic strengtheven its degree of civilization

Population is increasing worldwide but insome countries there is already a tax on

carbon dioxide generation


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How Much Concrete Can We Afford?

Concrete is not just another material

it is surpassed only by water as the

most used material on earth

So it has an enormous impact on the

environment, on capital expenditure, onresource consumption, and on pollution


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How Durable should Concrete be?

Do we want our concrete to last

2000 years or 20 years?

The most expensive, most

resource-consuming concrete is

that which has to be replaced


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What Resources will be

available?

Is there a limit to the resources

available for the production of

concrete?

and will it all be Portland

Cement concrete?


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Is Concrete Eco-Friendly?

Portland Cement production is

already second only to the

automobile as the major

generator of carbon dioxide -

greenhouse gas!

What will the answer be?


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Available Resources

We cannot continue to throw

away mountains of fly ash andslag

But will there always be suchmountains?


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How Will We Use Them?

If so, will we use them alkali-

activated in geopolymer concrete,with no Portland Cement at all?

Or will we use High Strength, HighDurability concrete to make thinner,

lighter structural members?


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An Interesting Long-Shot

Has basalt fibre reinforcement afuture?

(similar to glass fibre but muchhigher melting point)


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Significance for Education in

Concrete Technology

Need for flexibility cannot teach ability

to invent but must not stand in way

New developments as likely to come

from chemists, geologists, IT analystsetc, as from concrete technologists


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Concrete Technology

Practitioners as well as students

must learn how to keep up to dateContinued Professional Development certainly required

A qualification in structuraldesign is an inadequate basisfor specification and control


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Concrete Technology

ill-informed specifiers have held back

progress for decades, especially in USA

There will be a legal requirement for an

appropriate qualification before beingallowed to specify or control concrete


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Concrete Technology

Unfortunately neither CIAnor ACI ordinary

membership provides this


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Concrete Technology

Will there be an appropriate

grade in future?

A qualification such as that

provided by the UK Institute ofConcrete Technology is

required


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How will Concrete be

Produced and Controlled?

Still likely to be centrally mixed anddelivered by truck

High-tech heavily computerisedplants providing the ultimate in QC


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There will be well-proven, tightly

controlled mixes with last minute

adjustment for all available factors

(slump, temperature and QC data

on materials and concrete) (JIT!)


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Trucks will have built-in

devices to provide fine-tuned

workability control

(already available but rarely installed)


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Howwill Concrete bePurchased?

Via Internet (except large projects)

Purchaser will nominate brief

requirements

Computer will offer nearest standardmix and state properties and price


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Howwill Concrete bePurchased?

If stated properties not acceptable,purchaser will tighten specificationand Computer will offer revised mix

(and revised price!)

Regular and large customers will havecode number to give agreed discount


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Conclusions

The fundamental things to

learn are principles on whichconcrete technology is based


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Conclusions

Look for factors affecting actual

durability, impermeability,dimensional stability, strength,environmental friendliness etc


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Conclusions

Rather than preconceived (and

probably outdated) ideas of

maximum or minimum contents

of particular materials and of

grading requirements.


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Conclusions

Critical knowledge is of:

what is involved in the realistic

evaluation of mix proposals


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Conclusions


what is possible in the way of

testing accuracy


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Conclusions


how to detect change in the

quality of a continued supply of

material and problems in theoperation of a production facility


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Conclusions

WE MUST AVOID ERRORS OF THE

PAST IN WHICH STUDENTS WERE

TAUGHT ALREADY OUTDATED

FACTUAL INFORMATION AND, SO

EQUIPPED, WENT FORTH TO

INHIBIT FUTURE DEVELOPMENT

BEYOND THE NARROW CONFINESOF THE LITTLE THEY KNEW.


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Conclusions

IT IS NOT POSSIBLE FOR

ANY INDIVIDUAL TO KNOW

EVEN 10% OF THE TOTAL

AVAILABLE KNOWLEDGE

ABOUT CONCRETE


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Conclusions

BUT IT IS POSSIBLE TO LEARN

HOW TO FUNCTION AS A

FORWARD-LOOKING,

RECEPTIVE, DISCRIMINATING,

AND CONTRIBUTING MEMBER OFTHE CONCRETE FRATERNITY

Concrete in the 22nd Century(II)

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