geopolymerconcrete.ppt

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.

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Howto 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

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.

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.

Preparation of geopolymer concrete Fly ash

Alkaline activator NaOH + Na Silicate

Aggregate

Storage

Geopolymerisation

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 formthe Geopolymer concrete.

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MANUFACTURE OF GEOPOLYMER CONCRETE

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

Dry Materials of Geopolymer Concrete

The fly ash and the aggregates are first mixed together dry in 80-litre capacity pan mixer

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Pan Mixer Used in the Manufacture of Geopolymer Concrete

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

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

The workability of the fresh concrete was measured by means of the conventional slump test

Slump Measurement of Fresh Geopolymer Concrete

Boundary between Geopolymer binder , aggregate and reinforcement

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.

4.Applications of GPC • Pre-cast concrete products like railway sleepers,electric power poles etc. • Marine structures • Waste containments etc..

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

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.

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