---
title: "Define clinker in brief"
subject: "Civil Engineering Materials"
chapter: 5
key: "semester_3/civil_engineering_materials:define-clinker"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/define-clinker
site: BCT Engineering
---

# Define clinker in brief

Civil Engineering Materials · Chapter 5: Cement

- Asked in: 2072 Chaitra, 1 marks; 2066 Shrawan (old course), 2 marks (asked 2 times)
- Video: [How Is Cement Made? The Manufacturing Process from Limestone to Clinker ](https://www.youtube.com/watch?v=cK1F18YKe8c) — Neo Explainer
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/define-clinker
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-5

## Question

Define clinker.

## Short answer

Clinker is the nodular, dark grey product (5-25 mm) formed by burning limestone and clay at 1400-1500°C, consisting mainly of C3S, C2S, C3A, and C4AF. It is ground with 3-5% gypsum to produce cement.

## Answer

**Clinker** is the hard, dark grey, nodular (5-25 mm) material obtained by burning a finely ground mixture of limestone and clay at about 1400-1500 C in a rotary kiln, until partial fusion occurs. It consists mainly of the four compounds C3S (tricalcium silicate), C2S (dicalcium silicate), C3A (tricalcium aluminate) and C4AF (tetracalcium aluminoferrite). Cement is obtained by grinding clinker with 3-5% gypsum.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What is clinker?
   A. Finely ground cement powder with gypsum
   B. Raw meal before the kiln
   C. Hard nodular material from burning limestone and clay at 1400-1500 C until partial fusion
   D. Gypsum blocks
   Answer: C. Clinker is the nodular product of partial fusion in the rotary kiln. (Key point: Definition)

2. Which set of compounds forms clinker?
   A. CaO, MgO, SO3, gypsum
   B. Lime, sand, water, gypsum
   C. C3S, C2S, gypsum, fly ash
   D. C3S, C2S, C3A, C4AF
   Answer: D. Clinker consists mainly of the four Bogue compounds. (Key point: Composition)

3. How is cement obtained from clinker?
   A. Grinding with 3-5% gypsum
   B. Mixing with 3-5% water
   C. Burning again at 1450 C
   D. Mixing with sand
   Answer: A. Clinker plus 3-5% gypsum is ground to give cement. (Key point: Cement from clinker)