Concrete in the 22 Century

siennatearfulUrban and Civil

Nov 25, 2013 (3 years and 8 months ago)

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Concrete in the 22
nd

Century

Ken Day

Innovative Concrete Technologist

Hon. Member, and founding
committee member, of CIA

Is it Useful to Attempt
Prediction?


A
n a
ccurate 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
M
P
a

has been produced



Concrete of over 150MPa is now being
used in precast bridges in USA
(and we thought their technology lags!)


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 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?

A
vailable 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


Significance for Education in
Concrete Technology



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

C
ontinued
P
rofessional
D
evelopment

certainly
req
uired



A qualification in structural
design is
an
inadequate

basis


for specification and control



Significance for Education in
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 being
allowed to specify or control concrete


Significance for Education in
Concrete Technology

Unfortunately neither CIA
nor ACI ordinary
membership provides this

Significance for Education in
Concrete Technology


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

How will Concrete be
Produced and Controlled?



There will be w
ell
-
proven, tightly
controlled mixes with last minute
adjustment for all available factors
(slump, temperature

and

QC data

on materials and concrete
)
(JIT!)


How will Concrete be
Produced and Controlled?


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

Critical knowledge is of:



what is possible in the way of
testing accuracy


Conclusions

Critical knowledge is of:



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
AN
Y
INDIVIDUAL TO KNOW
EVEN 10% OF THE TOTAL
AVAILABLE KNOWLEDGE
ABOUT CONCRETE


Conclusions


BUT IT IS POSSIBLE TO LEAR
N
HOW TO FUNCTION AS A
FORWARD
-
LOOKING,
RECEPTIVE, DISCRIMINATING,
AND CONTRIBUTING MEMBER OF
THE CONCRETE FRATERNITY