Low-carbon materials
Geopolymer Concrete
Concrete in which Portland cement is replaced by an alkali-activated aluminosilicate binder — often made from fly ash, slag, or calcined clay — potentially cutting embodied CO2 by more than 80%.
Definition
Geopolymer concrete is concrete whose binder is an inorganic aluminosilicate polymer formed by activating materials such as fly ash, ground granulated blast-furnace slag, or metakaolin with an alkaline solution, rather than ordinary Portland cement. The term "geopolymer" was introduced by Joseph Davidovits in the late 1970s; substituting such binders for Portland cement can reduce concrete's CO2 emissions by more than 80%.
References
definition and climate rationale
mechanism and reduction potential
Overview
What it means
Cement production accounts for roughly 8% of global anthropogenic CO2, driven by limestone calcination and kiln fuels. Geopolymerisation avoids both: the binder hardens at ambient temperature through polycondensation of aluminosilicate precursors, frequently industrial by-products, delivering comparable or superior strength, durability, and chemical resistance.
How it is used
Geopolymer concrete is deployed in precast elements, pavements, and demonstration structures; barriers to scale include activator cost and handling, variable feedstocks, and the absence of harmonised standards and design codes.
Why it matters
Concrete is the most-used material on Earth after water; a credible low-carbon binder is one of the largest single levers for cutting construction emissions.
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