Concrete is the most common construction material used in the world. Cement is the principal ingredient in concrete. Producing one tonne of cement emits about one tonne of CO₂ resulting from fuel combustion and the calcination of limestone.

Cement manufacturing is a significant source of greenhouse gas emissions, accounting for 8% of global CO₂ emissions.

Cement can be partially replaced in the concrete mix by “Supplementary Cementing Materials” (SCMs) to produce a material with the same or better properties (strength, durability).
Usual SCMs are: fly ash – a byproduct of coal-fired power plants, slag – a residue of steel production, or silica fume. SCM are widely available around the world and are deemed have low or no carbon footprint.

Each tonne of cement replaced by SCM reduces GHG emission by one tonne. The less Portland cement, the better. But this goal has to be placed in the context of the construction industry: from the engineer, the performance and safety of the concrete structure is paramount; for the contractor, the ease and speed of installation is a key economic factor; and for the manufacturer known performance and liability are critical concerns.

Hence the EcoSmart Concrete objectives: Optimizing the amount of SCM in concrete while maintaining or improving performance, cost and constructability.