---
title: "Field tests of bricks"
subject: "Civil Engineering Materials"
chapter: 3
key: "semester_3/civil_engineering_materials:field-tests-of-bricks"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/field-tests-of-bricks
site: BCT Engineering
---

# Field tests of bricks

Civil Engineering Materials · Chapter 3: Clay Products

- Asked in: 2081 Baisakh, 2 marks; 2072 Chaitra, 2 marks; 2068 Baisakh, 2 marks; 2065 Shrawan (old course), 6 marks; 2074 Chaitra, 3 marks (asked 5 times)
- Video: [What are the tests performed on bricks?|How to Check the Quality of Bricks on site?|Tests on Bricks](https://www.youtube.com/watch?v=UkHIaI9lPSc) — Civillogy (Study of Civil Engineering)
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/field-tests-of-bricks
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-3

## Question

What are the field tests (standard tests) to determine the quality of bricks?

## Short answer

Field tests: uniform colour, standard size 240×115×57 mm, metallic ringing sound, no nail scratch, compact structure, water absorption <20%, slight efflorescence, and no break from 1 m drop.

## Answer

The following tests are done at the site to check the quality of bricks.

1. **Colour:** should be uniform, bright and cherry red (or as required).
2. **Shape and size:** bricks should be rectangular with sharp edges and straight faces. The Nepal Standard size is 240 × 115 × 57 mm (the IS modular brick is 190 × 90 × 90 mm). Size is checked by measuring 20 bricks laid in a row.
3. **Soundness test:** two bricks are struck together; a clear metallic ringing sound shows good quality, while a dull sound shows a poor brick.
4. **Hardness test:** a scratch with a fingernail should leave no impression on a good brick.
5. **Structure:** a broken brick should show a uniform, compact, fine-grained structure without voids, lumps or cracks.
6. **Water absorption test:** a dry brick is weighed, soaked in water for 24 hours and weighed again. Absorption should not exceed 20% of its dry weight for first class bricks (15% for facing bricks).
7. **Efflorescence test:** a brick is kept in a dish of water for 24 hours and then dried; white patches should be no more than slight.
8. **Drop test:** a brick dropped from about 1 m onto a hard surface should not break.
9. **Compressive strength:** done in the laboratory; minimum 3.5 N/mm² for common bricks as per NBC.

## Check yourself

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

1. Maximum water absorption of first class bricks after 24 hours soaking:
   A. 5% of dry weight
   B. 20% of dry weight
   C. 50% of dry weight
   D. 2% of dry weight
   Answer: B. First class bricks absorb not more than 20% (15% for facing). (Key point: Water absorption)

2. Two good bricks struck together give:
   A. A dull thud
   B. A cracking noise
   C. A clear metallic ringing sound
   D. No sound
   Answer: C. A dull sound shows poor burning. (Key point: Soundness)

3. In the hardness test a good brick:
   A. Is scratched easily
   B. Crumbles
   C. Leaves powder
   D. Shows no impression when scratched with a fingernail
   Answer: D. A good brick is hard and resists the fingernail. (Key point: Hardness)

4. In the drop test, a brick dropped from about 1 m on hard ground should:
   A. Not break
   B. Break into two
   C. Produce dust
   D. Bounce
   Answer: A. A sound brick withstands a 1 m drop without breaking. (Key point: Drop test)

## Related in Civil Engineering Materials

- [Standard tests of cement](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Astandard-tests-cement-field-lab) — Civil Engineering Materials, chapter 5

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- [Field tests and SPT corrections for sand](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Afield-tests-spt-corrections) — Foundation Engineering, chapter 2, asked 2×
- [Field tests for sand and clay](https://www.bctengineer.com/question.md?key=semester_4%2Fsoil_mechanics%3Afield-tests-sand-clay) — Soil Mechanics, chapter 3
- [Drilling type and field tests, Kathmandu core](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Adrilling-field-tests-kathmandu) — Foundation Engineering, chapter 2