Page 144 - Lecture Notes DCC3113

10.1.2 The maintenance techniques for flexible pavement

Road maintenance is a continuous process that involves keeping and repairing the existing road.
It is carried out to control the rate of damage and to ensure the safety towards the road users or the
public. The rehabilitation techniques for flexible pavement that are listed below:

Restoration

 Is designed to restore the surface to suitable condition and best applied to pavement with
distress limited to the surfacing.
 Techniques include rejuvenation, crack sealing, patching and thin bituminous overlay.
 Rejuvenating: spraying a layer of bitumen or polymer modified bitumen onto the
hardened/aged bituminous surface.
 Crack sealing: seal the cracks from ingress of water to reduce water infiltration into pavement
.Small cracks may be filled with crack filler.
 Cutting and patching: replacement of deteriorated asphalt surface with new bituminous mixture
placed and compacted to the same level with the surrounding surface to maintain the riding
surface.
 Thin bituminous overlay: improves the surface riding quality and can extend the pavement
service life. Commonly methods are surface dressing, slurry seals and thin hot mix overlay.

Resurfacing

 For pavement with severe and extensive structural damage.
 It involved placement of fresh material on an existing surfacing to increase its structural strength
and improve the riding quality of the surface.
 Necessary to carry out a proper overlay thickness design to achieve the desired design life.
 Two methods for resurfacing: thick asphalt overlay with or without granular overlay.
 With granular overlay – involves construction of a crushed aggregate layer on the existing
pavement prior to laying the asphalt layer. Without granular overlay – require pre-treatment such
as crack sealing, application of hot sand, cut and patch, reconstruction and the use of
geosynthetic material have to be carried out at localized failed areas.

Recycling

 Has long been practiced in developed countries.
 Is essentially old pavement that is reclaimed for use
 Material collected in loosed granular from as a by product of pavement.
 Pavement can be recycled via hot or cold methods or in plant or in place
 The benefits are lost cost maintenance, reuse existing material effectively and avoid costly
construction.

Reconstruction

 2 categorized : Full and Partial reconstruction
 Needed when all pavement layers including subgrade have deteriorated
 Removal and rebuilding of all or part of the pavement using new material & construction
specification
 Partial reconstruction : needed when pavement layers (except subgrade) have lost their stability
and strength
 If the failure of the road base is too extensive , recycling of the surfacing usually carried out
 The surface and road base are pulverized, additional aggregate or stabilizers may be added &
laid as a new road base

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