What are the main binders for GPC as per this code?

Low-calcium (Class F) Fly Ash and/or Ground Granulated Blast-furnace Slag (GGBS) are the primary binders. (Clause 4)

What is the recommended ratio of sodium silicate to sodium hydroxide solution?

A ratio between 1.5 to 2.5 by mass is generally recommended for achieving desirable workability and strength. (Clause 6.2.2)

Is heat curing mandatory for geopolymer concrete?

No, but heat curing at 60-90°C is highly recommended to achieve higher early age strength. Ambient curing is also permitted but results in slower strength development. (Clause 9)

What molarity of NaOH is suggested for M30 grade GPC?

A molarity of 10 M to 12 M is suggested for M30 grade concrete, but it should be finalized based on trial mixes. (Table 3)

IS 17208

: 2019

Guidelines for use of Geopolymers in Concrete

CurrentSpecializedGuidelinesBIMMaterials Science · Green Building and Sustainability

Download PDF BIS Portal Google

This standard provides guidelines for producing and using geopolymer concrete (GPC), an alternative to traditional cement concrete that uses industrial by-products like fly ash and GGBS as binders. It covers material specifications, mix proportioning principles, handling, placing, and specific curing requirements like heat curing.

Provides guidelines for the use of geopolymer binders in concrete, offering an alternative to ordinary Portland cement with lower carbon footprint.

Quick Reference Values

Ratio of sodium silicate to sodium hydroxide solution1.5 to 2.5 by mass

Ratio of alkaline liquid to binder material0.4 to 0.55

Typical heat curing temperature60°C to 90°C

Typical heat curing duration6 to 48 hours

Rest period before heat curingMinimum 60 minutes

Maximum free water to binder ratio0.25

Fly Ash fineness (Retained on 45 micron IS Sieve)Max 20 percent

Practical Notes

Handling alkaline activators like Sodium Hydroxide and Sodium Silicate requires strict safety precautions (gloves, goggles, apron) as they are highly corrosive.

The properties of GPC are highly sensitive to the source and quality of fly ash and GGBS; trial mixes are essential for every new batch of materials.

Unlike Portland cement concrete, GPC often requires heat curing (e.g., at 60-80°C) to achieve high early strength, which must be planned for at the precast yard or site.