The reduced CO2 emissions of Geopolymer cements make them a good alternative to Ordinary Portland Cement.
Produces a substance that is comparable to or better than traditional cements with respect to most properties.
Geopolymer concrete has excellent properties within both acid and salt environments
Low-calcium fly ash-based geopolymer concrete has excellent compressive strength and is suitable for Structural applications.
Unit 4_Part 1 CSE2001 Exception Handling and Function Template and Class Temp...
Geopolymer Concrete
1. Geopolymer Concrete for Green
Construction Materials(Without
Cement)
Engr.Arivusudar NagarajanEngr.Arivusudar Nagarajan
Special concrete productsSpecial concrete products
2. 2
What’s wrong with cement concrete?
• Many concrete structures deteriorate after 20 years.
• Cement production releases high amounts of CO2 to
the atmosphere(1tonne of cement production releases
1tonne of CO2) thus contributing to 7% of world CO2
emissions.
• Cement is one of the most energy intensive material.
3. How to reduce the use of cement
• Partially replace the use of cement in concrete.
example: high volume fly ash concrete
• Develop alternate materials.
example:Geopolymer concrete
4. Geopolymer Concrete
• Hardened cementitious paste made from
flyash and alkaline solution.
• Combines waste products into useful
product.
• Setting mechanism depends on
polymerization.
• Curing temp is between 60-90 degree
celcious.
5. CONSTITUENTS OF GEOPOLYMER
CONCRETE
• Source materials :
alumina-silicate
Alkaline liquids
combination of sodium hydroxide
(NaOH) or potassium hydroxide (KOH)
and sodium silicate or potassium
silicate.
6. Preparation of geopolymer concrete
Geopolymerisation
Storage
Aggregate
Fly ash
Alkaline activator
NaOH + Na Silicate
8. The aggregates are prepared in saturated-surface-dry (SSD)
condition, and are kept in plastic buckets with lid
Dry Materials of Geopolymer Concrete
9. The fly ash and the aggregates are first mixed together
dry in 80-litre capacity pan mixer
. Pan Mixer Used in the Manufacture of Geopolymer Concrete
10. The liquid component of the mixture is then added
to the dry materials and the mixing continued
usually for another four minutes
Addition of Liquid Component
11. The fresh concrete could be handled up to 120 minutes
without any sign of setting and without any degradation in
the compressive strength
Fresh Geopolymer Concrete Ready for Placing
12. The workability of the fresh concrete was measured by
means of the conventional slump test
Slump Measurement of Fresh Geopolymer Concrete
14. ADVANTAGES
Cutting the world’s carbon.
The price of fly ash is low.
Better compressive strength.
Fire proof.
Low permeability.
Eco-friendly.
Excellent properties within both acid and salt
environments.
15. • Different source materials
• Properties of soluble silicate
• Contaminants
• Industry regulations
• New material
16. Research Context and Prior Work
• During the year 2014-15, the per capita electricity generation in India was 1,010
kWh with total electricity consumption (utilities and non utilities) of 938.823
billion or 746 kWh per capita electricity consumption.
• The utilization of fly ash has increased from 6.64 million ton in 1996-97 to a level
of 102.54 million-ton in 2014-15.
• Cement Production (179.9 mn tonnes – 2011) , CO2 emissions 167.Mt
• Cement production contributes 7% of human CO2 emissions
• Cement production - energy intensive process (heat raw materials to 2550 F)
19. Conclusion
The reduced CO2 emissions of Geopolymer cements make
them a good alternative to Ordinary Portland Cement.
Produces a substance that is comparable to or better than
traditional cements with respect to most properties.
Geopolymer concrete has excellent properties within both
acid and salt environments
Low-calcium fly ash-based geopolymer concrete has
excellent compressive strength and is suitable for
Structural applications.
So if the properties are comparable to OPC why are they not widely used.
It is possible to use recycled source materials like fly ash and slag but metakaolin has produced better results. However, the metakaolin requires mining of the kaolinite and heat it to make metakaolin. This adds additional steps that are not found with the recycled materials.
With different sources of soluble silicate need for the geopolymer production, they also show varied properties. This presents the need to develop a specific process for each source of silicate, which adds time and cost to it cement production.
Also contaminants in the fly ash or slag can affect the polymerization reaction and the properties of the final cement product.
The cement and building industries currently regulate the amount of non-OPC binder that can be used in the production cement so these regulations will need to be adjusted before any alternative cement product can break in tot the industry.
Finally, geopolymers are a relatively new technology and it will take time and to build a reputation in the industry.
Remaining R&D
Technical risk
Remaining milestones
Future enhancements
Need for outside expertise or resources