---
title: "Basic ingredients of concrete"
subject: "Concrete Technology and Masonry Structure"
chapter: 1
key: "semester_5/concrete_technology_and_masonry_structure:concrete-basic-ingredients"
source: https://www.bctengineer.com/q/semester_5/concrete_technology_and_masonry_structure/concrete-basic-ingredients
site: BCT Engineering
---

# Basic ingredients of concrete

Concrete Technology and Masonry Structure · Chapter 1: Introduction to concrete and concrete materials

- Asked in: 2068 Chaitra, 3 marks
- Video: [Ingredients of Cement Concrete, Civil Engineering and Building materials subject tutorials, lectures](https://www.youtube.com/watch?v=-dBIWObv5KY) — A Universal Truth For You
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/concrete_technology_and_masonry_structure/concrete-basic-ingredients
- Whole chapter: https://www.bctengineer.com/md/semester_5/concrete_technology_and_masonry_structure/chapter-1

## Question

What are the basic ingredients of concrete?

## Short answer

Cement (binder), fine aggregate (sand), coarse aggregate (gravel/crushed stone), water, and optional admixtures. C ement paste glues aggregates; together they form concrete.

## Answer

The basic ingredients of concrete are:

1. **Cement**: the binding material (OPC 33/43/53 grade, PPC). It reacts with water (hydration) to produce the paste that glues the aggregates; typically 10-15 per cent of the concrete volume.
2. **Fine aggregate**: natural sand or crushed stone sand passing the 4.75 mm sieve (IS 383 Zones I-IV). It fills the voids in the coarse aggregate and improves cohesion.
3. **Coarse aggregate**: crushed stone or gravel retained on the 4.75 mm sieve, with a nominal size of 10, 20 or 40 mm. It gives bulk, strength and volume stability. Fine and coarse aggregates together make up 60-75 per cent of the volume.
4. **Water**: clean potable water (IS 456 cl. 5.4) for hydration and workability; the water-cement ratio is normally 0.4-0.6.
5. **Admixtures** (optional): chemical or mineral admixtures to modify the properties of fresh or hardened concrete.

Cement + water forms the paste; paste + fine aggregate is mortar; mortar + coarse aggregate is concrete. Steel bars are added in reinforced concrete.

## Check yourself

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

1. Which is a basic ingredient of concrete?
   A. Steel bars only
   B. Cement, fine aggregate, coarse aggregate, water
   C. Bitumen
   D. Gypsum plaster
   Answer: B. Admixtures are optional. (Key point: Ingredients)

2. Cement + water + fine aggregate is:
   A. Concrete
   B. Paste
   C. Mortar
   D. Grout only
   Answer: C. Paste + fine aggregate = mortar; plus coarse aggregate = concrete. (Key point: Definitions)

3. Fine aggregate passes:
   A. 20 mm sieve
   B. 40 mm sieve
   C. 80 mm sieve
   D. 4.75 mm sieve
   Answer: D. It fills voids in coarse aggregate. (Key point: Fine aggregate)

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