---
title: "Asphalt versus tar"
subject: "Civil Engineering Materials"
chapter: 10
key: "semester_3/civil_engineering_materials:asphalt-vs-tar"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/asphalt-vs-tar
site: BCT Engineering
---

# Asphalt versus tar

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

- Asked in: 2080 Bhadra, 2 marks; 2076 Asoj, 2 marks; 2073 Shrawan, 2 marks (asked 3 times)
- Video: [What’s the Difference Between Tarmac and Asphalt?](https://www.youtube.com/watch?v=l0l5EKEy7oM) — History of Simple Things
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/asphalt-vs-tar
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-10

## Question

Differentiate between asphalt and tar (with respect to their properties and uses).

## Short answer

Asphalt is a mixture of bitumen and mineral matter, less temperature-sensitive and durable, used for road surfaces and waterproofing. Tar is a dark viscous liquid from coal/wood distillation, more brittle in cold, weathers quickly, and is used for priming, surface dressing and timber preservation.

## Answer

**Asphalt** is a mixture of bitumen and mineral matter, found naturally or made artificially. **Tar** is a dark viscous liquid obtained by destructive distillation of coal, wood or other organic matter.

| Point | Asphalt | Tar |
|---|---|---|
| Source | Natural deposits or petroleum refining (with aggregate) | Destructive distillation of coal, wood or peat |
| Composition | Bitumen + mineral matter | Complex mix of aromatic hydrocarbons, phenols |
| Solubility | Bitumen part dissolves in carbon disulphide and in petroleum solvents | Dissolves in toluene; only partly soluble in petroleum oils |
| Temperature susceptibility | Less sensitive to temperature | More sensitive; becomes brittle in cold, soft in heat |
| Weathering | Resists ageing better | Weathers quickly |
| Adhesion with aggregate | Good | Good; wets and coats aggregate quickly |
| Toxicity and odour | Low | Strong smell and harmful (carcinogenic) |
| Colour | Brown to black | Black |
| Uses | Wearing courses, mastic roofing, waterproofing | Surface dressing, priming coat, preservatives for timber, pipe coating |

## Check yourself

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

1. How is tar obtained?
   A. From petroleum residue
   B. By destructive distillation of coal, wood or peat
   C. From lake deposits
   D. By mixing bitumen with sand
   Answer: B. Tar comes from destructive distillation of coal, wood or similar organic matter. (Key point: Source of tar)

2. Which statement on temperature behaviour is right?
   A. Tar is less sensitive than asphalt
   B. Both are insensitive
   C. Tar is more sensitive: brittle in cold and soft in heat
   D. Asphalt is more sensitive
   Answer: C. Tar is more temperature sensitive and weathers quickly. (Key point: Temperature susceptibility)

3. Which has strong smell and is harmful?
   A. Asphalt
   B. Tar
   C. Neither
   D. Both equally
   Answer: B. Tar has a strong smell and is harmful (carcinogenic); asphalt has low toxicity. (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 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×
- [Properties and uses of tar](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Atar-properties-uses) — Civil Engineering Materials, chapter 10
- [Compare asphalt, bitumen and tar](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Aasphalt-bitumen-tar-comparison) — Civil Engineering Materials, chapter 10, asked 2×
- [Define asphalt, bitumen and tar](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Adefine-asphalt-bitumen-tar) — Civil Engineering Materials, chapter 10, asked 2×
- [Asphalt versus bitumen](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Aasphalt-vs-bitumen) — Civil Engineering Materials, chapter 10, asked 4×

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