c. Deformation 1 Slippage Formation of crescent –

shaped cracks pointing in the direction of the thrust of wheels

Usual thrust of wheel in a direction, lack or failure of bond between surface and lower pavement courses

Removal of the surface layer in the affected area and replacement with fresh material

2 Rutting Longitudinal depress ional in the wheel tracks

Heavy channalised traffic inadequate Compaction of pavement layers, poor stability of pavement material, or heavy bullock cart traffic

Filling the depressions with premix material

3 Corrugations Formation of regular undulations

Lack of stability in mix, oscillations set up by vehicles

Scarification and relaying of surfacing, of cutting of high spots and filling of low spots

4 Shoving Localized bulging of pavement surface along the crescent shaped cracks

Unstable mix, lack of bound between layers, or stop type movements and those involving negotiation of curves and gradients

Removing the material too firm base and relaying a stable mix

5 Shallow Depressions

Localised shallow depressions

Presence of inadequately compacted pockets

Filling with premix materials

6 Settlement and upheaval

Large deformation of pavement

Poor compaction of fills, poor drainage, inadequate Pavement or frost heave

Where fill is weeks the defective fill should be excavation and re-done. Where inadequate pavement is the cause, the pavement should be strengthened

D. Disintegration

1. Stripping Separation of bitumen from aggregate in the presence of moisture

Use of hydrophilic aggregate, inadequate mix composition, continuous contact with water ,poor bond between binder and aggregate , poor compaction, etc.

Spreading and compacting heated sand over the affected area in the case of surface dressing ; replacement with fresh bituminous mix with added anti –stripping agent in other cases

2. Loss of aggregate

Rough surface with loss of aggregate in some port -ions

Ageing and hardening of binder stripping poor bond between binder and aggregate insufficient binder , brittleness of binder etc.

Application of liquid deal , fog seal, or slurry seal depending on the extent of damage

3 Ravelling Failure of binder to hold the aggregate shown up by pock marks or eroded areas on the surface

Poor compaction, poor bond between binder and or aggregate insufficient binder, brittleness of binder, etc.

Application of cutback covered with coarse sand or slurry seal, or a premix renewal coat.

4. Pothole Appearance of bowl- shaped holes , usually after rain

Ingress of water into the pavement , lack of bond between the surfacing and WBM base , insufficient bitumen content , etc.

Filling potholes with premix material or penetration patching

5. Edge- breaking Irregular breaker of pavement edges

Water in filtration poor lateral support from shoulders ,inadequate strength of pavement edges ,etc

Cutting the affected area to regular sections and re-building with simultaneous attention paid to the proper construction of shoulders

14.6.1. Annual Calendar of road maintenance activities :

Recommended practice for road maintenance activity is given in table 14.5.

14.6.2. Maintenance method :

Table 14.6. gives an indication of the range of maintenance methods potentially appropriate for use in India.

14.6.3. Output of workman :

To get the desired output from labour, clear-cut directions should be given and tasks to be performed, identified and fixed. Recommended norms for road gangs are given in para 14.6.4. Also, proper tools and plants having multipurpose use, increase efficiencies of the labour. A list of such tools to be kept with each gangman is given in the Table 14.7.

14.6. Execution Schedule and Methods

Table 14.5. Annual Calendar of road maintenance activities :Sr No

Items Jan Feb

Mar

Apr May

June

July

Aug

Sep Oct

Nov

Dec

Remarks

1 Repairs of road berms including jungle clearance

X X X - - - X X X - - -

2 Repairs to side drains - - - - X X X X X - - -

3 Collection of patch of repairs material for WBM roads

- - - - X X - X X - - -

4 Collection of patch repairs matrial for WBM roads

X X X - - - - X X X - -

5 Patch repairs work for WBM roads

- - - - X X - X - - - -

6 Patch repair work for B/T roads

- - - - X X - X X X - -

7 Repairs to sign and caution boards

- - - - - - - - X X X -

8 Painting of km all round the year stone and road marking

- - - - - - - - X X X -

9 Maintenance of T & P

10 Removal of Encroachment -do-

X This shows the recommended period for activity in North India

Table 14.6. Spectrum of Maintenance methods appropriate for use in India

Sr. No

Activity / task Labour Based Methods Intermediate Equipment Based Methods

1. Excavation of soils and rock Soft soil Firm soil Hard soil Soft soil Medium rock

Phowrah *“ Pick Axe *** Crowbar”

Dozer for short leads slips Dozer tipper**

Hard rock for leads of Hand drilling and blasting***

Compressed air/drill blasting

2 Loading handling unloading 0-50 m Phowrah50-100 m animal100-200 m carts

Phowrah PhowrahWheel aninmalBarrow carts

Power dozerWinch wheelWheel loader barrow

3 Heating and mixing bitumen Heat chipping**** and bitumen over open wood fire, mixed by rake

Heat bitumen in tar** boiler, heat chippings and mix with bitumen in small or medium sized mechanical mixer

Integrated hot mix plant*

4 Hauling and Laying bitumen mix Haul by head load or by a bamboo stretcher, lay by rake

Haul by wheel barrow, lay by hand propelled screed board

Tipper and Paver

5 Laying surface Dressing Bitumen Through**** containers with holes, chips from baskets

Bitumen through hand lances** chips from basket

Chip spreader and bitumen distributor

6 Compaction of base material Durmats**** Hand Held Mechanical*** rammers

Vibrating compactors* Rollers**

* Excellent ** Good *** Average **** Poor