Geopolymer concrete is an alternative to traditional cement concrete that has lower environmental impact. It is made from industrial byproducts like fly ash and an alkaline solution, which allows it to set through a polymerization process rather than hydration. Geopolymer concrete has advantages like lower CO2 emissions, higher strength, and better acid and salt resistance compared to ordinary Portland cement. While it is more difficult to produce and cure than traditional concrete, geopolymer concrete has applications in pavements, retaining walls, water tanks, and precast construction elements.

1. Cement Chemistry
SAIFULLAH MAHMUD 王方
2093191
2021
Geopolymer Cement

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

7. 5
2.Geopolymer Concrete :Process
• Alkaline solutions induce the Si and Al atoms in the source
materials, example fly ash , to dissolve.
• Gel formation is assisted by applying heat.
• Gel binds the aggregates ,and the unreacted source material to
form the Geopolymer concrete.

8. MANUFACTUREOF
GEOPOLYMER CEMENT

9. The aggregates are prepared in saturated surface-dry (SSD) condition, and are
kept in plastic buckets with lid

10. 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

11. 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

12. 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

13. The workability of the fresh concrete was measured by means of the
conventional slump test
Slump Measurement of Fresh Geopolymer Concrete

14. Boundary between Geopolymer
binder , aggregate and reinforcement

15. 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.

16. I. difficult to create
◦ -requires special handling
◦ -chemicals like sodium hydroxide are
II. harmful to humans
◦ -high cost of alkaline solution
III. Pre-mix only
◦ -sold only as pre-mix or pre-caste material
IV. Geopolymerisation process is sensitive
◦ -lacks uniformity
Disadvantages

17. APPLICATIONS
PAVEMENTS
-light pavements can be cast using GPC
-no bleed water rise to the surface
-aliphatic alcohol based spray used to
provide protection against drying
32

18. RETAINING WALL
-40MPa precast panels were used to build a
retaining wall
-panels were 6m long and 2.4m wide
-these panels were cured under ambient
condition

19. W
ATER TANKS
-two water tanks were constructed, one with
32MPa concrete with
blended cement and other with GPC
-autogenous healing occurred in OPC due to
calcium hydroxide deposition
-in GPC tank there is little calcium hydroxide
-nominal leaking in tank healed rapidly due
to gel swelling mechanism
34

20. BOAT RAMP
-approach slab on ground to ramp was made using geopolymer
reinforced with FFRP
-entire constituents remained dormant until activator chemicals were
added
20

21. PRECAST BEAM
-GPC beams formed three suspended floor levels
of GCI building
-beams had arched curved soffit
-water pipes were placed inside them for
temperature controlled hydronic heating of
building spaces above and below
21

22. • Different source materials
• Properties of soluble silicate
• Contaminants
• Industry regulations
• New material

23. 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.

24. THANKS!
Saifullah Mahmud 王方 2093191
saifullah_mahmud@tongji.edu.cn