Pavement Maintenance & Repair
TL;DR
Pavements deteriorate faster and more visibly than bridges, so they dominate day-to-day road maintenance. On 7/23 at Komatsu you’ll watch an actual pavement repair. Know the distress types, the condition indices, and the repair ladder below.
Pavement types
- Flexible (asphalt): most roads; surface course over base/subbase. Repaired by milling & overlay.
- Rigid (concrete): longer life, used on heavy-load/expressway sections; repaired by slab replacement, joint repair.
Common distress types
| Distress | Looks like | Typical cause |
|---|---|---|
| Cracking (fatigue/“alligator”, longitudinal, transverse) | Networks of cracks | Repeated loading, aging |
| Rutting | Wheel-path depressions | Heavy traffic, hot weather, weak mix |
| Potholes | Bowl-shaped holes | Water + traffic on cracked pavement |
| Ravelling | Loss of surface aggregate | Binder aging, poor compaction |
| Subsidence | Settlement / dips | Subgrade failure, utilities, disaster |
Condition evaluation
Indices you'll hear
- IRI (International Roughness Index): ride roughness — the global standard.
- MCI (Maintenance Control Index): Japan’s composite pavement score from cracking + rutting + roughness; drives repair timing in a PMS.
- Surveys via profilometers, road-survey vehicles, and increasingly AI/image methods.
The repair ladder (light → heavy)
- Crack sealing / fog seal — preventive, cheap.
- Patching — fix potholes/local failures.
- Milling + overlay — grind off the worn surface, lay new asphalt.
- Reconstruction — rebuild the structural layers (when the base has failed).
- In-place / plant recycling — reuse old material (sustainability angle).
Why it matters for this workshop
Pavement is where the preventive-vs-corrective argument is most tangible: seal a crack for cents, or rebuild for thousands later. It’s also the most relatable repair for every participant country. At Komatsu, note the materials, machinery, traffic management, and how repair timing is decided — and ask how it’d transfer to a lower-budget context.
Sources
- Japan PMS research: JSCE PMS (PDF)
- General pavement asset management & IRI literature.