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

# Asphalt properties and uses

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

- Asked in: 2076 Chaitra, 2+2 marks; 2068 Chaitra, 5 marks; 2057 Chaitra (old course), 6 marks; 2065 Shrawan (old course), 8 marks (asked 4 times)
- Video: [Everything You Need to Know About Bitumen: Types, Uses, and Properties Explained!](https://www.youtube.com/watch?v=qxyI_0fCcWw) — Aashmi Classes (Dr.Sovan)
- 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-properties-uses
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-10

## Question

Define asphalt. Give the properties and uses of (different types of) asphalt.

## Short answer

Asphalt is a dark, sticky, waterproof mixture of bitumen and minerals. It is thermoplastic, highly adhesive, durable, elastic, and resists acids and weathering. Natural rock or lake asphalt is used for floors; mastic asphalt for waterproofing; hot-mix for highways; cut-back and emulsion for tack coats; asphalt felt for damp-proof courses.

## Answer

**Asphalt** is a dark brown to black, sticky, waterproof material made of bitumen mixed with mineral matter (sand, stone chips or filler). It is obtained from natural deposits or made artificially.

#### Types of asphalt

1. **Natural asphalt:** Rock asphalt (porous limestone or sandstone soaked in bitumen, e.g. from Switzerland), lake asphalt (Trinidad lake) and asphaltic sand.
2. **Artificial (refined) asphalt:** Made in plants by mixing refined bitumen with graded aggregates and filler: hot-mix asphalt, mastic asphalt, cut-back and emulsified asphalt.

#### Properties

- Dark colour, solid or semi-solid at normal temperature.
- Binds well to aggregate and is highly adhesive.
- Waterproof and durable under weather.
- Thermoplastic: softens when heated, hardens on cooling.
- Resists acids, alkalis and weathering; not affected by moisture.
- Elastic and flexible; does not crack easily with small movements.
- Good electrical and sound insulation; low cost.
- Burns slowly with smoke.

#### Uses

| Type | Uses |
|---|---|
| Rock asphalt | Road surfaces, footpaths, floors |
| Mastic asphalt | Waterproofing flat roofs, basements, tanking, floors of warehouses |
| Hot-mix asphalt | Wearing course of highways and airport runways |
| Cut-back and emulsion | Tack coat, prime coat, patching and surface dressing |
| Asphalt felt | Roofing sheets, damp-proof courses |
| Asphalt paint | Protect steel and pipes from rusting |

## Check yourself

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

1. What is asphalt?
   A. Distillate of coal
   B. Pure petroleum residue with no minerals
   C. Resin in spirit
   D. Bitumen mixed with mineral matter, natural or artificial
   Answer: D. Asphalt is bitumen with sand, chips or filler, from natural deposits or made artificially. (Key point: Definition)

2. Which is a natural asphalt?
   A. Mastic asphalt
   B. Hot-mix asphalt
   C. Lake asphalt (Trinidad)
   D. Cut-back asphalt
   Answer: C. Rock asphalt, lake asphalt and asphaltic sand are natural; hot-mix, mastic, cut-back and emulsion are artificial. (Key point: Types)

3. Asphalt is thermoplastic. What does this mean?
   A. It softens when heated and hardens on cooling
   B. It sets permanently when heated
   C. It burns quickly
   D. It is brittle always
   Answer: A. Thermoplastic means softens on heating and hardens on cooling. (Key point: Thermoplastic)

4. Which asphalt type is used for waterproofing flat roofs and basements?
   A. Hot-mix asphalt
   B. Mastic asphalt
   C. Rock asphalt
   D. Asphalt felt only
   Answer: B. Mastic asphalt waterproofs flat roofs, basements and tanking; hot-mix is for highway wearing courses. (Key point: Uses)

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