Alite (C3S)
Definition
Tricalcium silicate, 3CaO.SiO2. Dominant clinker phase (50 to 70 percent). Hydrates fast, gives early strength up to 28 days.
- Chemical name
- Tricalcium silicate
- Formula
- 3CaO.SiO2
- Clinker share
- 50 to 70 percent
- Hydration speed
- Fast
- Strength contribution
- Early strength up to 28 days
Common questions
Why does the proportion of alite in a clinker matter forensically?+
The relative proportions of clinker phases like alite reflect the specific cement formulation and manufacturing process used, so comparing phase composition between a questioned concrete sample and a reference source can support or exclude a common origin.
How does alite's role differ from the other main clinker phase, belite?+
Alite hydrates quickly and drives early strength gain within the first month, while belite hydrates more slowly and contributes strength over a longer term, so the ratio between the two phases affects how a concrete's strength develops over time.
Related terms
- Aluminate (C3A)
- Tricalcium aluminate, 5 to 10 percent. Reacts violently with water, attacked by sulphate. SRC cement is low in C3A.
- Belite (C2S)
- Dicalcium silicate, 2CaO.SiO2. 15 to 30 percent. Hydrates slow, gives long-term strength beyond 28 days.
- C-S-H Gel
- Calcium silicate hydrate, the main hydration binder. Amorphous, broad hump on XRD.
- Clinker
- The nodular intermediate product of Portland-cement manufacture, consisting of C3S, C2S, C3A and C4AF mineral phases before grinding.
- Ettringite
- A calcium sulfoaluminate hydrate that forms early in cement hydration and can re-form later from delayed sulfate attack; its presence or alteration...
- Portland Cement
- A hydraulic binder produced by firing calcium and silica sources at 1450°C; the four clinker phases (C3S, C2S, C3A, C4AF) hydrate on...
- Portlandite
- Calcium hydroxide (Ca(OH)2) crystallised during cement hydration; a bright birefringent phase visible in thin section that dissolves progressively as concrete carbonates, providing...