--- title: "Highway maintenance and causes of pavement failure" subject: "Transportation Engineering II" chapter: 4 key: "semester_7/transportation_engineering_ii:maintenance-flexible-failures" source: https://www.bctengineer.com/q/semester_7/transportation_engineering_ii/maintenance-flexible-failures site: BCT Engineering --- # Highway maintenance and causes of pavement failure Transportation Engineering II · Chapter 4: Highway Maintenance, Repair, and Rehabilitation - Asked in: 2074 Asoj, 8 marks; 2071 Chaitra, 8 marks (asked 2 times) - Video: [Flexible pavement failures and maintenance](https://www.youtube.com/watch?v=kKmG5qMZcAc) — lohit talawar - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_7/transportation_engineering_ii/maintenance-flexible-failures - Whole chapter: https://www.bctengineer.com/md/semester_7/transportation_engineering_ii/chapter-4 ## Question What is highway maintenance? Explain the general causes of pavement failures. ## Short answer Highway maintenance preserves roads in safe condition through routine, recurrent, periodic, and emergency works. Pavement failures are mainly caused by overloading, poor drainage, weak subgrade, design defects, inferior materials and workmanship, climatic effects, ageing, and delayed maintenance. ## Answer #### Highway maintenance **Highway maintenance** is the work done to keep a road, its pavement, shoulders, drainage, structures and furniture in a safe and serviceable condition and to preserve the investment, without changing the original design standard. Classification (Nepal DoR practice and IRC:82): 1. **Routine maintenance** - small, regular, yearly works such as patching potholes, cleaning drains and culverts, clearing slips, cutting grass, repairing shoulders and signs. 2. **Recurrent maintenance** - works repeated at intervals within a year or two, such as resealing cracks and shoulder re-gravelling, drain repair. 3. **Periodic maintenance** - works at intervals of several years (3 to 8) like resealing, regravelling, surface dressing and thin overlay to restore the surface. 4. **Urgent (emergency) maintenance** - immediate works to reopen the road after landslides, floods or accidents. #### General causes of pavement failure 1. **Traffic factors** - overloading, more repetitions than designed, high tyre pressure, channelised traffic. 2. **Poor drainage** - the main cause. Water in the subgrade and base reduces strength, causes pumping, ravelling, potholes and edge failure; blocked side drains and culverts, high water table. 3. **Weak subgrade** - low CBR, expansive or soft soil, poor compaction, inadequate sub-base. 4. **Design defects** - thin pavement, wrong assumed traffic or CBR, no allowance for climate, poor geometric and drainage design. 5. **Poor materials and workmanship** - inferior aggregate or binder, wrong mix proportions, segregation, low compaction, poor joints and bond between layers, low temperature during laying. 6. **Climate and environment** - temperature extremes (bleeding, cracking), rainfall and floods, freeze-thaw in hills, landslides. 7. **Ageing** - oxidation and hardening of bitumen with time. 8. **Lack of timely maintenance** - small cracks and potholes grow rapidly into major failures when not repaired. 9. **Utility cuts and other external causes** - trenches, spillage of oil. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Works such as resealing, regravelling, surface dressing and thin overlay at 3-8 year intervals are: A. Routine maintenance B. Urgent maintenance C. Periodic maintenance D. Recurrent maintenance Answer: C. Periodic maintenance is done at intervals of several years (3 to 8) to restore the surface. (Key point: Periodic maintenance) 2. Reopening a road after a landslide or flood is: A. Routine maintenance B. Urgent (emergency) maintenance C. Periodic maintenance D. Rehabilitation only Answer: B. Immediate works to restore access after landslides, floods or accidents are urgent maintenance. (Key point: Urgent maintenance) 3. The main cause of pavement failure is generally: A. Poor drainage B. Pavement colour C. Excess shoulder width D. Low traffic Answer: A. Water in subgrade and base reduces strength and causes pumping, ravelling, potholes and edge failure. (Key point: Main cause of failure) 4. What happens when small cracks and potholes are not repaired in time? A. They heal by themselves B. They grow rapidly into major failures C. They have no effect on structure D. They only affect appearance Answer: B. Lack of timely maintenance lets minor defects grow quickly into major failures. (Key point: Lack of maintenance) ## Related in Transportation Engineering II - [Maintenance vs rehabilitation; flexible failure causes](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Amaintenance-vs-rehabilitation-flexible-failure-causes) — Transportation Engineering II, chapter 4 - [Bituminous maintenance and rigid pavement failures](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Abituminous-maintenance-rigid-failures) — Transportation Engineering II, chapter 4, asked 2× - [Pavement evaluation; flexible failure types and causes](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Apavement-evaluation-flexible-failure-causes) — Transportation Engineering II, chapter 4 - [Flexible pavement failures: causes and remedies](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Aflexible-pavement-failure-cause-remedy) — Transportation Engineering II, chapter 4 - [Maintenance, rehabilitation, reconstruction; rigid failures](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Amaintenance-rehab-reconstruction-rigid-failures) — Transportation Engineering II, chapter 4 - [Failures of rigid pavement](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Arigid-pavement-failures) — Transportation Engineering II, chapter 4, asked 2× ## Related in other subjects - [Causes of foundation failure](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Afoundation-failures) — Building Technology, chapter 2, asked 2× - [Equipment for highway and pavement construction](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Ahighway-pavement-equipment) — Construction Management, chapter 4, asked 3× - [General, local and punching shear failure](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Amodes-shear-failure) — Foundation Engineering, chapter 6, asked 4× - [Causes of slope failure](https://www.bctengineer.com/question.md?key=semester_4%2Fsoil_mechanics%3Aslope-failure-causes) — Soil Mechanics, chapter 11, asked 4×