concrete in the 22nd century1

Concrete in the 22nd Century

Ken DayInnovative Concrete Technologist

Hon. Member, and founding committee member, of CIA

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

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

The Climate of Change

There are huge changes due to admixtures, resource shortages, pollution considerations, and the

computer revolution

Concrete can be made without cement and reinforced without steel

It can be a self-compacting fluid

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!)

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 for excessive noise and industrial injuries

Can We Cope with this?

These new concretes rely heavily on chemical admixtures, pozzolans and other finely divided materials

Concrete has become a high tech material and is becoming more so

What is the significance of this?

Is Concrete Important?

The production of concrete is used by some economists as a measure of a

country’s economic strength

– even it’s degree of civilization

Population is increasing worldwide but in some countries there is already a tax on

carbon dioxide generation

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, on resource consumption, and on pollution

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

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?

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?

Available Resources

We cannot continue to throw away mountains of fly ash and

slag

But will there always be such mountains?

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, High Durability concrete to make thinner,

lighter structural members?

An Interesting Long-Shot

Has basalt fibre reinforcement a future?

(similar to glass fibre but much higher melting point)

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 analysts etc, as from concrete technologists


Practitioners as well as students must learn how to keep up to date

Continued Professional Development certainly required

A qualification in structural design is an inadequate basis for

specification and control


ill-informed specifiers have held back progress for decades,

especially in USA

There will be a legal requirement for an appropriate qualification

before being allowed to specify or control concrete


Unfortunately neither CIA nor ACI ordinary

membership provides this


Will there be an appropriate grade in future?

A qualification such as that provided by the UK Institute of

Concrete Technology is required

How will Concrete be Produced and Controlled?

Still likely to be centrally mixed and delivered by truck

High-tech heavily computerised plants providing the ultimate in QC


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!)


Trucks will have built-in devices to provide fine-tuned

workability control

(already available but rarely installed)

How will Concrete be Purchased?

Via Internet (except large projects)

Purchaser will nominate brief requirements

Computer will offer nearest standard mix and state properties

and price

How will Concrete be Purchased?

If stated properties not acceptable, purchaser will tighten specification and Computer will offer revised mix (and revised

price!)

Regular and large customers will have code number to give agreed discount

Conclusions

The fundamental things to learn are principles on

which concrete technology is based

Conclusions

Look for factors affecting actual durability,

impermeability, dimensional stability, strength,

environmental friendliness etc

Conclusions

Rather than preconceived (and probably outdated)

ideas of maximum or minimum contents of

particular materials and of grading requirements.

Conclusions

Critical knowledge is of:

•what is involved in the realistic evaluation of mix proposals

Conclusions


•what is possible in the way of testing accuracy

Conclusions


•how to detect change in the quality of a continued supply of material and problems in the operation of a production facility

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 CONFINES OF THE LITTLE THEY KNEW.

Conclusions

IT IS NOT POSSIBLE FOR ANY INDIVIDUAL TO KNOW EVEN 10% OF THE TOTAL AVAILABLE KNOWLEDGE

ABOUT CONCRETE

Conclusions

BUT IT IS POSSIBLE TO LEARN HOW TO FUNCTION AS A

FORWARD-LOOKING, RECEPTIVE, DISCRIMINATING, AND

CONTRIBUTING MEMBER OF THE CONCRETE FRATERNITY

concrete in the 22nd century1

Business