---
title: "Elastic deformation, shrinkage and creep"
subject: "Concrete Technology and Masonry Structure"
chapter: 4
key: "semester_5/concrete_technology_and_masonry_structure:elastic-deformation-shrinkage-creep"
source: https://www.bctengineer.com/q/semester_5/concrete_technology_and_masonry_structure/elastic-deformation-shrinkage-creep
site: BCT Engineering
---

# Elastic deformation, shrinkage and creep

Concrete Technology and Masonry Structure · Chapter 4: Properties of hardened concrete

- Asked in: 2074 Ashwin, 2+2+2 marks; 2068 Chaitra, 2+2+2 marks (asked 2 times)
- Video: [Difference between Shrinkage and Creep](https://www.youtube.com/watch?v=xLUsS7XKgDk) — Civil Engineering
- Answer checked by Claude Sonnet 5.5 on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/concrete_technology_and_masonry_structure/elastic-deformation-shrinkage-creep
- Whole chapter: https://www.bctengineer.com/md/semester_5/concrete_technology_and_masonry_structure/chapter-4

## Question

Explain elastic deformation, shrinkage and creep in concrete.

## Short answer

Elastic deformation is immediate strain on loading with modulus Ec=5000√fck. Shrinkage is time-dependent volume reduction without load, causing cracks; design strain0.0003 per IS456. Creep is gradual strain under sustained stress, increasing deflection and prestress loss, with coefficients1.1–2.2.

## Answer

#### Elastic deformation
Immediate strain that appears on loading and disappears on unloading. For concrete it follows a curved stress-strain path, but within working stress it is treated as linear with $E_c = 5000\sqrt{f_{ck}}$ N/mm$^2$ (IS 456, Cl. 6.2.3.1). Elastic strain $\varepsilon_e = \sigma/E_c$.

#### Shrinkage
**Shrinkage** is the time-dependent reduction in volume of concrete, without any applied load, caused by loss of moisture and by chemical reaction (hydration and carbonation). Typical long-term values are 0.0003 to 0.0008 (300 to 800 microstrain).
Main types are plastic, drying, autogenous and carbonation shrinkage. It is reduced by low W/C, large aggregate, good curing and joints. IS 456 (Cl. 6.2.4.1) gives design strain of 0.0003.

#### Creep
**Creep** is the gradual increase in strain of concrete with time under a constant sustained stress, over and above the instantaneous elastic strain. It is caused mainly by seepage of gel water out of the C-S-H layers and by slip of gel particles. Creep continues for years, with about 50% occurring in the first 3 months and 75 to 80% in the first year.
Creep coefficient values are 2.2, 1.6 and 1.1 for loading at 7 days, 28 days and 1 year (IS 456, Cl. 6.2.5.1). Creep raises deflections and causes loss of prestress; part of it is recoverable on unloading.

## Check yourself

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

1. Elastic strain under working stress is calculated as:
   A. sigma x E_c
   B. sigma / E_c with E_c = 5000 sqrt(f_ck)
   C. E_c / sigma
   D. sigma / 5000 f_ck
   Answer: B. Strain = stress / modulus. (Key point: Elastic strain)

2. Shrinkage of concrete is:
   A. an increase in strain with time under constant sustained load
   B. an instantaneous strain that disappears on unloading
   C. a loss of strength under repeated loading
   D. a time-dependent reduction in volume without applied load, due to moisture loss and chemical reaction
   Answer: D. Shrinkage occurs with no load; the other options describe creep, elastic strain and fatigue. (Key point: Definition of shrinkage)

3. Creep is caused mainly by:
   A. seepage of gel water out of the C-S-H layers and slip of gel particles
   B. growth of ice crystals in capillary pores
   C. carbonation of Ca(OH)2 in the paste
   D. expansion of aggregate under heat
   Answer: A. Gel water seepage and gel particle slip give the time-dependent strain; about 75 to 80% occurs in the first year. (Key point: Cause and time of creep)

4. IS 456 creep coefficient values for loading at 7 days, 28 days and 1 year are:
   A. 1.1, 1.6 and 2.2
   B. 2.2, 1.1 and 1.6
   C. 2.2, 1.6 and 1.1
   D. 1.6, 2.2 and 1.1
   Answer: C. Earlier loading gives larger creep, so theta falls from 2.2 to 1.6 to 1.1 as loading age rises. (Key point: Creep coefficient)

## Related in Concrete Technology and Masonry Structure

- [Shrinkage and creep of concrete](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Ashrinkage-and-creep) — Concrete Technology and Masonry Structure, chapter 4, asked 6×
- [Define shrinkage, creep, segregation, bleeding](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Ashrinkage-creep-segregation-bleeding-define) — Concrete Technology and Masonry Structure, chapter 3
- [Shrinkage types; creep and recovery graph](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Ashrinkage-types-creep-recovery) — Concrete Technology and Masonry Structure, chapter 4
- [Maturity; shrinkage and creep](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Amaturity-shrinkage-creep) — Concrete Technology and Masonry Structure, chapter 4
- [Creep phenomenon with time-dependent graph](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Acreep-phenomenon-graph) — Concrete Technology and Masonry Structure, chapter 4, asked 2×
- [Hardened concrete properties; elastic behaviour](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Ahardened-properties-elastic-behaviour) — Concrete Technology and Masonry Structure, chapter 4