Clinker
Definition
The nodular intermediate product of Portland-cement manufacture, consisting of C3S, C2S, C3A and C4AF mineral phases before grinding.
- Form
- Greyish nodules produced in the cement kiln
- Mineral composition
- Four crystalline phases: alite (C3S), belite (C2S), aluminate (C3A), ferrite (C4AF)
- Forensic value
- Mineral ratios and crystal structure allow comparison of cement samples for source identification
Common questions
What exactly is clinker in cement?+
Clinker is the nodular intermediate product made during Portland cement manufacturing. It consists of four mineral phases: alite (C3S), belite (C2S), aluminate (C3A), and ferrite . These phases exit the kiln in greyish nodule form.
Why does clinker matter in forensic evidence?+
Forensic analysts examine clinker nodules and their mineral composition to identify the cement source and determine whether samples came from the same batch or manufacturing run. The specific ratio and crystal structure of the phases can link materials at a crime scene.
What happens to clinker after the kiln?+
Clinker is ground into fine powder to produce the final Portland cement product. Before grinding, it is purely the intermediate crystalline form.
Related terms
- 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...
- Alite (C3S)
- Tricalcium silicate, 3CaO.SiO2. Dominant clinker phase (50 to 70 percent). Hydrates fast, gives early strength up to 28 days.
- Aluminate (C3A)
- Tricalcium aluminate, 5 to 10 percent. Reacts violently with water, attacked by sulphate. SRC cement is low in C3A.
- ASTM C150
- US standard specifying Portland-cement composition limits and performance requirements by type (I through V); referenced in forensic mineral-phase characterisation.
- 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.
- Calcium Sulphate Hemihydrate
- CaSO4 . 1/2 H2O; produced by heating gypsum, rehydrates to gypsum on setting; the basis of plaster of Paris and most interior...
- ENFSI ENG-FG1
- The European Network of Forensic Science Institutes' guidelines for forensic geological evidence, published in 2018 by the Expert Working Group on Forensic...
- FTIR (Fourier Transform Infrared Spectroscopy)
- A vibrational spectroscopy technique used in toner analysis to identify the polymer backbone and functional group composition of toner binder material; ATR...
- Pozzolan
- A silica- or alumina-rich material (fly ash, silica fume, volcanic ash) that reacts with portlandite to form additional C-S-H gel; used as...
Explained in these topics
- Cement, Mortar and Concrete: Composition and Forensic AnalysisGreyish nodules leaving the kiln, made of four crystalline phases: alite (C3S), belite (C2S), aluminate (C3A) and ferrite (C4AF).
- Cement, Plaster and Building-Material EvidenceThe nodular intermediate product of Portland-cement manufacture, consisting of C3S, C2S, C3A and C4AF mineral phases before grinding.