Cement Chemistry
C3A (Tricalcium Aluminate)
// Definition
The fastest-reacting aluminate phase in cement. C3A controls initial setting and is responsible for flash setting unless tempered by gypsum.
C3A forms 5-12% of clinker. It generates significant heat in the first hours and is the phase most susceptible to sulfate attack — limited in sulfate-resisting cements (SRC).
// Related Indian Standards
IS 12330IS 269
// Cross-references
C4AF (Tetracalcium Aluminoferrite)
Ferrite phase in OPC. Contributes little to strength but gives cement its grey colour and improves resistance to chemical attack.
Heat of Hydration
The heat released as cement reacts with water. Important for thermal control in mass concrete to avoid cracking from temperature gradients.
Setting Time
The time it takes cement paste to lose plasticity and harden. Measured as Initial Set (start of stiffening) and Final Set (no longer deformable).
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