---
title: "Properties and uses of tar"
subject: "Civil Engineering Materials"
chapter: 10
key: "semester_3/civil_engineering_materials:tar-properties-uses"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/tar-properties-uses
site: BCT Engineering
---

# Properties and uses of tar

Civil Engineering Materials · Chapter 10: Asphalt, Bitumen, Tar and Miscellaneous Materials

- Asked in: 2081 Chaitra (new course), 2 marks
- Video: [What is Tar | Can Tar Be Used in Highway Construction | Uses of Tar](https://www.youtube.com/watch?v=hx0tfKWU1vg) — Bridge Construction Training Institute
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/tar-properties-uses
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-10

## Question

Write a short note on properties and use of tar.

## Short answer

Tar is a dark viscous liquid from destructive distillation of coal, wood or peat. It has good adhesion, penetrates surfaces, is waterproof and preservative, but is highly temperature-sensitive and ages faster than bitumen. It is used for road priming and surface dressing, timber preservation, coating iron pipes, and tarred felt roofing.

## Answer

**Tar** is a dark, viscous liquid obtained by destructive distillation of coal, wood or peat.

#### Properties

- Black to dark brown viscous liquid, more fluid than bitumen, with a strong odour.
- Good adhesion to aggregate, and quickly penetrates surfaces.
- Waterproof, and resists decay by insects and fungi (acts as a preservative).
- Highly temperature-sensitive: soft in heat and brittle in cold.
- Weathers and ages faster than bitumen; toxic and harmful if inhaled or touched.
- Cheap.

#### Uses

- Priming and surface dressing on roads, and road patching.
- Preservative on timber poles, sleepers and fence posts.
- Coating on iron pipes and tanks to prevent rust.
- Tarred felt and waterproof coating for roofs.

## Check yourself

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

1. Tar is how sensitive to temperature?
   A. Not sensitive
   B. Highly: soft in heat and brittle in cold
   C. Only in cold
   D. Only in heat
   Answer: B. Highly temperature sensitive. (Key point: Temperature sensitivity)

2. Tar resists what?
   A. Decay by insects and fungi
   B. Fire
   C. Heat
   D. Weathering better than bitumen
   Answer: A. Acts as preservative; weathers faster than bitumen. (Key point: Preservative)

3. Tar's hazard is what?
   A. Harmless
   B. Toxic and harmful if inhaled or touched
   C. Radioactive
   D. Explosive
   Answer: B. It is toxic with strong odour. (Key point: Health)

## Related in Civil Engineering Materials

- [Uses of asphalt, bitumen, tar](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Auses-asphalt-bitumen-tar) — Civil Engineering Materials, chapter 10
- [Asphalt versus tar](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Aasphalt-vs-tar) — Civil Engineering Materials, chapter 10, asked 3×
- [Asphalt properties and uses](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Aasphalt-properties-uses) — Civil Engineering Materials, chapter 10, asked 4×
- [Types of lime, properties and uses](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Atypes-of-lime-uses) — Civil Engineering Materials, chapter 4, asked 3×
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- [Properties and uses of lime](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Aproperties-uses-of-lime) — Civil Engineering Materials, chapter 4, asked 2×

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