Concrete in the 22nd century1

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  • 1. Concrete in the 22 nd Century Ken Day Innovative Concrete Technologist Hon. Member, and founding committee member, of CIA
  • 2. 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
  • 3. 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
  • 4. 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
  • 5. 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!)
  • 6.
    • 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
  • 7. 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?
  • 8. 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
  • 9. 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
  • 10. 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
  • 11. 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?
  • 12. 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?
  • 13. A vailable Resources
    • We cannot continue to throw away mountains of fly ash and slag
    • But will there always be such mountains?
  • 14. 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 ?
  • 15. An Interesting Long-Shot
    • Has basalt fibre reinforcement a future?
    • (similar to glass fibre but much higher melting point)
  • 16. 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
  • 17. 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
  • 18. 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
  • 19. Significance for Education in Concrete Technology
    • Unfortunately neither CIA nor ACI ordinary membership provides this
  • 20. 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
  • 21. 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
  • 22. 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!)
  • 23. How will Concrete be Produced and Controlled?
    • Trucks will have built-in devices to provide fine-tuned workability control
    • (already available but rarely installed)
  • 24. 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
  • 25. 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
  • 26. Conclusions
    • The fundamental things to learn are principles on which concrete technology is based
  • 27. Conclusions
    • Look for factors affecting actual durability, impermeability, dimensional stability, strength, environmental friendliness etc
  • 28. Conclusions
    • Rather than preconceived (and probably outdated) ideas of maximum or minimum contents of particular materials and of grading requirements .
  • 29. Conclusions
    • Critical knowledge is of:
    • what is involved in the realistic evaluation of mix proposals
  • 30. Conclusions
    • Critical knowledge is of:
    • what is possible in the way of testing accuracy
  • 31. 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
  • 32. 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.
  • 33. Conclusions
    • IT IS NOT POSSIBLE FOR AN Y INDIVIDUAL TO KNOW EVEN 10% OF THE TOTAL AVAILABLE KNOWLEDGE ABOUT CONCRETE
  • 34. Conclusions
    • BUT IT IS POSSIBLE TO LEAR N HOW TO FUNCTION AS A FORWARD-LOOKING, RECEPTIVE, DISCRIMINATING, AND CONTRIBUTING MEMBER OF THE CONCRETE FRATERNITY