---
title: "Factors affecting workability"
subject: "Concrete Technology and Masonry Structure"
chapter: 3
key: "semester_5/concrete_technology_and_masonry_structure:workability-factors"
source: https://www.bctengineer.com/q/semester_5/concrete_technology_and_masonry_structure/workability-factors
site: BCT Engineering
---

# Factors affecting workability

Concrete Technology and Masonry Structure · Chapter 3: Mix design of concrete and property of green concrete

- Asked in: 2075 Ashwin, 1+2 marks
- Video: [Factors affecting Workability of Concrete - Properties of Concrete - Advanced Concrete Technology](https://www.youtube.com/watch?v=9vRlxtnDKeM) — Ekeeda
- 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/workability-factors
- Whole chapter: https://www.bctengineer.com/md/semester_5/concrete_technology_and_masonry_structure/chapter-3

## Question

Define workability. List the factors that affect the workability of concrete.

## Short answer

Workability is the ease with which concrete can be mixed, transported, placed, compacted, and finished without segregation. Factors: water content, w/c ratio, aggregate properties (shape, size, grading), cement fineness, admixtures, temperature, time after mixing.

## Answer

**Workability** is the property of freshly mixed concrete that decides how easily it can be mixed, transported, placed, compacted and finished without segregation (IS 6461).

#### Factors affecting workability
1. **Water content**: more water gives higher workability (the main factor).
2. **Water-cement ratio** and cement content / paste volume.
3. **Aggregate properties**: shape (rounded is better), texture (smooth is better), maximum size (larger gives higher workability), grading (well graded is better), and porosity/absorption.
4. **Aggregate-cement ratio** and fine-to-coarse aggregate ratio.
5. **Fineness and type of cement**.
6. **Admixtures**: plasticisers, superplasticisers and air-entraining agents raise it; accelerators lower it.
7. **Temperature**: high temperature reduces workability (faster hydration and evaporation).
8. **Time**: slump is lost as time passes after mixing.
9. **Method of mixing and compaction** (mixer type, mixing time), and **environmental conditions** such as humidity and wind.

## Check yourself

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

1. The main factor affecting workability is...
   A. Water content
   B. Cement colour
   C. Age of sand
   D. Formwork
   Answer: A. More water gives higher workability. (Key point: Main factor)

2. Which aggregate gives better workability?
   A. Angular rough
   B. Rounded smooth well graded
   C. Flaky
   D. Poorly graded
   Answer: B. Rounded smooth particles need less water for the same flow. (Key point: Aggregate shape)

3. High temperature...
   A. Increases workability
   B. Reduces workability through faster hydration and evaporation
   C. No effect
   D. Doubles slump
   Answer: B. Slump loss is faster. (Key point: Temperature)

4. Which admixture lowers workability?
   A. Superplasticiser
   B. Air-entrainer
   C. Accelerator
   D. Plasticiser
   Answer: C. Accelerators speed setting. (Key point: Admixtures)

## Related in Concrete Technology and Masonry Structure

- [Effect of shape and size of aggregate on workability](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Aaggregate-shape-size-workability) — Concrete Technology and Masonry Structure, chapter 1, asked 2×
- [Workability and its measurement](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Aworkability-measure-methods) — Concrete Technology and Masonry Structure, chapter 3, asked 4×
- [Aggregate shape and texture: strength, workability](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Aaggregate-shape-texture-strength) — Concrete Technology and Masonry Structure, chapter 1, asked 2×
- [Workability and its impact on quality](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Aworkability-impact-quality) — Concrete Technology and Masonry Structure, chapter 3
- [Measures of workability; role of w/c ratio](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Aworkability-measures-wc-role) — Concrete Technology and Masonry Structure, chapter 3
- [Workability and methods to control it](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Aworkability-control-methods) — Concrete Technology and Masonry Structure, chapter 3

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