Understanding why AJCC’s green cement program is technically significant requires understanding the chemistry it is built on. Clinker production is the most carbon-intensive stage of cement manufacturing, because the calcination of limestone at temperatures exceeding 1,400 degrees Celsius releases CO2 as an unavoidable process emission, regardless of the fuel used to generate the heat. Every ton of clinker replaced by a supplementary cementitious material eliminates the corresponding process emissions entirely, not merely reduces them.
Natural pozzolana is a siliceous or siliceous-aluminous volcanic material that reacts chemically with calcium hydroxide, the by-product of Portland cement hydration, to form additional calcium silicate hydrate (C-S-H). This secondary pozzolanic reaction does not generate heat, which reduces the heat of hydration in large concrete pours. It densifies the cement paste microstructure, reducing permeability and improving resistance to sulfate attack, chloride ingress, and alkali-silica reaction. The concrete produced from pozzolanic cement performs better over its full service life than OPC concrete in aggressive environments, making it not just more sustainable but technically superior for demanding applications.
AJCC’s local black pozzolana achieves a combined SiO2 plus Al2O3 plus Fe2O3 content of 71.93 percent, above the minimum 70 percent threshold specified by international standards. Its fineness at 45 micrometers is 1.8 percent, far below the 34 percent maximum. The Strength Activity Index, the standard measure of pozzolanic reactivity, reaches 92.9 at 7 days and 93.2 at 28 days against a minimum requirement of 75 at both ages. Water requirement is 102 percent against a maximum of 115 percent. These are not marginal compliance figures. They represent a high-reactivity pozzolana that performs at the upper end of what is available commercially anywhere in the world.




