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Bituminous maintenance and rigid pavement failures

Short answer

Bituminous surface maintenance includes patching potholes, sealing cracks, surface dressing for ravelling, spreading chips on bleeding, and periodic overlay. Typical rigid pavement failures are transverse cracking, corner breaks, faulting, pumping, spalling, blow-ups, and scaling.

Explain the maintenance of bituminous surface. Describe the typical types of rigid pavement failure.

Maintenance of bituminous surface

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.

Maintenance of a bituminous surface (IRC:82 and Nepal DoR maintenance manuals) depends on the defect:

DefectMaintenance treatment
PotholesMark a square or rectangular patch, cut vertical sides down to sound base, remove debris, apply tack coat, fill with hot or cold premix, and compact (roller or hand rammer) to finish 5-6 mm above the surface
Cracks (hairline/fine)Seal with bitumen emulsion or slurry seal; for wider cracks, clean and fill with bitumen and sand or crack sealant
Fatigue (alligator) crackingRemove and replace failed area including base; overlay
Ravelling / loss of aggregatesSurface dressing or seal coat; fog seal for light cases
Bleeding / fatting upSpread hot coarse sand or 6.7 mm chips and roll; or remove excess binder
Corrugation, shoving, ruttingScarify, add or remove material and recompact; level with a bituminous levelling course and overlay
Edge breakingRepair shoulders, widen the pavement or re-gravel; improve drainage
DepressionsFill with premix levelling course
Worn surfacePremix carpet, surface dressing, slurry seal or thin overlay (periodic maintenance)

Drainage (cleaning side drains and culverts) and shoulder maintenance are essential, because water is the main cause of failure.

Typical failures of rigid pavement

Typical types of failure of a cement concrete pavement:

FailureDescriptionCause
Transverse crackingCracks across the slabLate sawing of joints, joint spacing too long, thin slab, restrained shrinkage
Longitudinal crackingCracks along the laneDifferential settlement, warping, thin slab, poor subgrade support
Corner break (corner crack)Triangular piece at the corner within 1.5 m of jointLoad at unsupported corner, loss of support (pumping), poor load transfer
Diagonal crackingCrack at about 45 degreesHeavy corner loads, settlement
Punch-out / shattered slabSlab breaks into many piecesHeavy repeated loads, weak sub-base
FaultingStep between slabs at a jointPumping, poor load transfer (dowel failure)
PumpingEjection of water and fines at jointsWater under slab, loose subgrade, heavy traffic
SpallingBreaking of joint edgesIncompressible material in joints, weak concrete, dowel misalignment
Blow-up (buckling)Slab lifts and shatters in hot weatherBlocked expansion joints, insufficient expansion gap
Scaling and crazingFlaking and map cracks on surfaceOver-finishing, poor curing, freeze-thaw
Joint seal failureSealant loss, weedsAged sealant, poor installation
 Faulting at a joint        Corner break
        ______              +-------------+
 ______|  step              |             |
     joint                  |             |
                            |   crack ->  /
                            +-----------/-+

Remedies include full-depth repair, slab replacement, dowel retrofit, grinding of faults, crack and joint resealing, undersealing (grout) to fill voids, and improving drainage.

✓ Answer checked by Claude Opus 5.5 (high effort)

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