--- title: "Tests on bituminous binders" subject: "Transportation Engineering I" chapter: 6 key: "semester_6/transportation_engineering_i:bitumen-tests-list" source: https://www.bctengineer.com/q/semester_6/transportation_engineering_i/bitumen-tests-list site: BCT Engineering --- # Tests on bituminous binders Transportation Engineering I · Chapter 6: Highway Materials - Asked in: 2079 Ashwin, 3 marks; 2078 Chaitra, 2 marks; 2078 Poush, 3 marks; 2073 Magh; 2072 Magh; 2071 Bhadra; 2070 Magh, 8 marks; 2062 Jestha (old course), 10 marks (asked 8 times) - Video: [All Types of Tests on Bitumen | Civil Engineering Lab Tests Explained](https://www.youtube.com/watch?v=8DkY55EKKR4) — REINFORCE - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_6/transportation_engineering_i/bitumen-tests-list - Whole chapter: https://www.bctengineer.com/md/semester_6/transportation_engineering_i/chapter-6 ## Question What are the tests to be conducted on bituminous binders (consistency tests) to judge their suitability in road construction? ## Short answer Consistency tests: penetration classifies grade, softening point indicates temperature susceptibility, ductility measures cohesion, viscosity gives grade and compaction temperatures. Additional tests: flash point (safety), solubility (purity) and loss on heating (ageing). These ensure binder stiffness, flexibility and durability for the climate and traffic. ## Answer Bituminous binders are tested to check that they have the right consistency, safety, purity and durability for the climate and the traffic. The tests are given in IS:73 / IS:1201-1220 and adopted in NRS 2070 and IRC:SP:53. #### Consistency tests (main) 1. **Penetration test** - depth in units of 0.1 mm to which a standard needle (100 g, 5 s, 25 degrees C) penetrates; it classifies the grade (30/40, 60/70, 80/100). 2. **Softening point test (ring and ball)** - temperature at which bitumen softens; shows the temperature susceptibility. 3. **Ductility test** - distance in cm to which a briquette of bitumen can be stretched (27 degrees C in IS:1208, 25 degrees C in ASTM; 50 mm/min) before breaking; shows cohesion and flexibility. 4. **Viscosity test** - flow time in seconds (Saybolt, orifice/tar viscometer) or absolute and kinematic viscosity; gives the grade (VG-10, 20, 30, 40) and the mixing and compaction temperatures. #### Other tests 5. **Flash and fire point** - safe heating temperature. 6. **Specific gravity** (about 0.97-1.02) - for mix calculations. 7. **Loss on heating (thin-film oven/RTFOT)** - ageing and volatile loss. 8. **Solubility in trichloroethylene** - purity (at least 99%). 9. **Float test** - consistency of tars, cutbacks and thick liquid binders. 10. **Water content, Fraass breaking point, elastic recovery** (modified binders), and **adhesion/stripping** with aggregates. #### Why needed Penetration and viscosity indicate stiffness at service/mixing temperatures, softening point shows high-temperature behaviour, ductility shows cracking resistance, flash point gives safety, and solubility and loss on heating show quality. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. In the penetration test, what is measured and what does it classify? A. Depth in 0.1 mm of a 100 g needle in 5 s at 25 degrees C; it classifies the grade B. Temperature at which bitumen softens C. Distance a briquette stretches D. Flow time in seconds only Answer: A. Penetration gives consistency and the grade names such as 60/70. (Key point: Penetration test) 2. What does the softening point show? A. Cohesion B. Temperature susceptibility and high-temperature behaviour C. Purity D. Safe heating temperature Answer: B. The ring and ball temperature shows how bitumen behaves as it warms. (Key point: Softening point) 3. What does ductility indicate? A. Cohesion, flexibility and resistance to cracking B. Fire hazard C. Water content D. Specific gravity Answer: A. Stretching distance before breaking shows how well the binder resists cracking. (Key point: Ductility) 4. Which pair of tests is matched correctly with its purpose? A. Flash point - purity; solubility - safe heating B. Flash point - safe heating temperature; solubility in trichloroethylene - purity C. Float test - purity; flash point - grade D. Ductility - safety; penetration - purity Answer: B. Flash point gives the safe heating limit, and solubility (at least 99%) shows purity. (Key point: Flash point and solubility) ## Related in Transportation Engineering I - [Why different consistency tests, ductility](https://www.bctengineer.com/question.md?key=semester_6%2Ftransportation_engineering_i%3Aconsistency-tests-why-ductility) — Transportation Engineering I, chapter 6 - [Tests on road aggregates](https://www.bctengineer.com/question.md?key=semester_6%2Ftransportation_engineering_i%3Aaggregate-tests-list) — Transportation Engineering I, chapter 6, asked 8× - [Macadam road construction method](https://www.bctengineer.com/question.md?key=semester_6%2Ftransportation_engineering_i%3Amacadam-construction) — Transportation Engineering I, chapter 1 - [Types of bitumen and bituminous materials](https://www.bctengineer.com/question.md?key=semester_6%2Ftransportation_engineering_i%3Abitumen-types) — Transportation Engineering I, chapter 6, asked 6× ## Related in other subjects - [Road construction activities; plants for bituminous and CC](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Aroad-construction-activities-plants-bituminous-cc) — Transportation Engineering II, chapter 3 - [Bituminous premix carpet construction](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Apremix-carpet-construction) — Transportation Engineering II, chapter 3, asked 3× - [Bituminous pavement types; asphalt concrete construction](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Atypes-bituminous-pavement-ac-construction) — Transportation Engineering II, chapter 3 - [Road construction equipment and mass haul characteristics](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Amass-haul-diagram-equipment-plants) — Transportation Engineering II, chapter 3, asked 3×