Road maintenance and Repair
Measures intended to keep the pavement structure in serviceable
condition as best as practicable and as long as possible is known as
maintenance.
Types of Maintenance:
(1) Routine Maintenance
(2) Recurrent Maintenance
(3) Periodic Maintenance
(4) Emergency Maintenance
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(1) Routine Maintenance:
Routine maintenance is carried out daily at road, below road or
above road.
The works done in routine maintenance are grass cutting of shoulders,
cleaning of road & drain, cleaning of sign post, pot holes repair of
earthen and gravel road, etc
(2) Recurrent Maintenance:
Recurrent maintenance is carried out at the interval of 6 months to 2
years.
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The works done in routine maintenance are pot holes repair of
bituminous road, painting of road marking & sign posts, repair of
drainage , etc
(3) Periodic Maintenance:
It is carried out at the interval of 5 to 7 years.
The works done in periodic maintenance are overlaying of road, Bio-
Engineering, installation of cross drainage structures like culverts , etc.
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(4) Emergency Maintenance:
It is also known as special maintenance.
It is carried out in a emergency situations.
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Q. Maintenance of Earthen and gravel road comes under:
(a) Routine Maintenance
(b) Recurrent Maintenance
(c) Periodic Maintenance
(d) Emergency maintenance
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Q. Maintenance of Bituminous road comes under:
(a) Routine Maintenance
(b) Recurrent Maintenance
(c) Periodic Maintenance
(d) Emergency maintenance
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Xm 2080-Mangsir
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Q. Pot hole maintenance incase of bituminous road is:
(a) Routine Maintenance
(b) Recurrent Maintenance
(c) Periodic Maintenance
(d) Special maintenance
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Q. Maintenance of road comes under:
(a) Routine Maintenance
(b) Recurrent Maintenance
(c) Periodic Maintenance
(d) Emergency maintenance
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NEC Exam Asked Question (1 mark)
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Q. Maintenance operation done at interval of 6 months to 2 years is
known as:
(a) Routine maintenance
(b) Recurrent maintenance
(c) Preventive maintenance
(d) Periodic maintenence
Er. Sabin Pokhrel
NEC Exam Asked Question (1 mark)
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Q Thin overlay lies under:
(a) Routine maintenance
(b) Recurrent maintenance
(c) Periodic maintenance
(d) Emergency maintenance
Er. Sabin Pokhrel
NEC Exam Asked Question (1 mark)
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Q Improving the structural strength of the pavement is considered as:
(a) Rehabilitation
(b) Reconstruction
(c) Maintenance
(d) Repair
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Typical Flexible Pavement Failure
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(1) Alligator (Map) Cracking
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The main cause of alligator cracking is temperature stress.
Consolidation of Pavement Layers occurs due to repeated actions of
load on the pavement.
Longitudinal cracking is the cracking along the length of the road.
Frost heave is caused due to frost actions on the roadway.
Waves and corrugation are formed due to inadequate compaction
and composition of various soil types at the base of the road.
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(2) Consolidation of Pavement Layers
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(3) Longitudinal Cracking
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(4) Frost Heaving
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(5) Lack of Binding with lower layers
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(6) Reflection Cracking
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(7) Formation of waves and corrugation
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Q. Which of the following is typical types of flexible pavement failure?
(a) Mud pumping
(b) Alligator cracking
(c) Scaling of cement concrete
(d) Spalling of joints.
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Xm-2080 Mangsir
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Q. The type of flexible pavement failure shown in the figure denotes:
(a) Longitudinal cracking
(b) Rutting
(c) Shear failure
(d) Bleeding
Er. Sabin Pokhrel
Xm-2080 Mangsir
22
Q. The longitudinal depression in the wheel path in bituminous pavement
is:
(a) Longitudinal cracking
(b) Rutting
(c) Shear failure
(d) bleeding
Er. Sabin Pokhrel
Xm-2080 Mangsir
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Q. One of the probable causes of rutting on flexible pavements is:
(a) Excessive stripping of binder material from the wearing course
(b) Use of flaky aggregates in the wearing course
(c) Inadequate compaction of pavement layers
(d) High wind speed
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Typical Rigid Pavement Failure
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(1) Scaling of Cement Concrete:
This is mainly due to deficiency in the mix or presence of chemical
impurities.
(2) Shrinkage Cracks:
During the curing operation of cement concrete pavements
immediately after the construction these cracks develop both in
longitudinal and lateral direction.
(3) Spalling of Joints : It is the dislocation of the joints
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(4) Warping Cracks: It is the failure at edge and corner of the pavement
due to difference in temperature.
(5) Mud Pumping: It is the process of upheaval of mud below the
pavement from the joints.
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Prime Coat
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It is the first application of low viscosity liquid bituminous material and is
applied to the existing base.
In average 7.3 to 14.6 kg/10 m2 (@ 1kg/m2) prime coat is sprayed
during the road construction.
Functions:
(1) To develop adhesion between the wearing course and base course.
(2) To seal the pores thus making it water proofing.
(3) To bind together any loose aggregates on the existing surface.
The primed surface is allowed to cure for at-least 24 hours during which
period no traffic is allowed.
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Tack Coat
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It is application of bituminous material on existing pavement surface.
Rate of application is 4.9 to 9.8 kg/10 m2 road surface
Functions:
(1) To ensure adhesion between the existing surface and the new
bituminous surface.
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Xm-2080 Mangsir
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Q. The bitumen layer spread over old pavement to bind newer
pavement layer together is:
(a) Seal coat
(b) Prime Coat
(c) Tack Coat
(d) Otta Seal
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Seal Coat
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Seal coat is very thin surface treatment which is applied as a final step.
Function:
(1) To seal the surfacing against the ingress of water.
(2) To increase resistance to skidding.
Types of Seal Coat:
(I) Type-A
It consists of bituminous binder and stone chippings (hot metal chips)
(II) Type B
It consists of bituminous binder and fine aggregates.
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Construction Procedure of Penetration Macadam:
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Penetration Macadam is used as base or binder course.
The coarse aggregates are first spread and compacted in dry state.
After that hot bituminous binder of high viscosity is sprayed in large
quantity.
The bitumen penetrates into the voids from the surface.
Depending upon the quantity of bitumen spread and the extent of
penetration, it is classified as full grout and semi-grout.
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(I) Thickness: 50 mm to 75 mm
(II) Materials requirement:
Bitumen grade: 80/100, 60/70 and 30/40
Aggregates should be hard, strong, durable and clean with the
following specifications:
(a) Los Angeles Abrasion (LAA) = 35 %
(b) Aggregate Impact Value (AIV) = 30 %
(c) Flakiness Index (FI) = 25 %
(d) Water Absorption = 1 %
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For the thickness of layer having 75 mm, the course aggregates used
are 63 mm down.
For the thickness of layer having 50 mm, the course aggregates used
are 50 mm down.
(III) Plants and Equipments:
(a) Bitumen heating device
(b) Bitumen sprayer
(c) Aggregate spreader
(d) Pneumatic roller
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Construction Steps:
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(a) Preparation of existing surface
(b) Application of binder and prime coat
(c) Application of stone chippings (Coarse aggregates)
st
(d) Rolling of 1 coat with 6 to 8 tonnes roller
(e) Application of binder and stone chips (Smaller size)
(f) Rolling of second coat
(g) Application of seal coat
(h) Finishing
(V) Opening to traffic:
The road section is opened to traffic after 24 hours.
Er. Sabin Pokhrel
Xm-2080 Mangsir
34
Q. In the penetration macadam construction, the bitumen is:
(a) Sprayed after the aggregates are spread and compacted
(b) Premixed with aggregates and then spread
(c) Sprayed before the aggregates are spread and compacted
(d) None of the above
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Construction Procedure of Bitumen Bound Macadam:
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It is premixed construction method consisting of one or more size of
compacted crushed aggregates premixed with bituminous binder.
It is used in base course or binder course.
(I) Thickness: 50 mm to 75 mm
(II) Bitumen Grade: 80/100, 60/70 and 30/40
Aggregates used for this construction should be hard, strong,
durable, clean , etc with the following specifications:
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(a) LAA = 50 %
(b) AIV = 35 %
(c) FI = 15 %
(III) Plants and Equipments:
Bitumen Heating device
Bitumen sprayer
Mechanical mixer
Aggregate spreader
Roller
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Construction Steps:
(a) Preparation of existing surface
(b) Application of prime coat or tack coat
(c) Premix preparation
(d) Placement of mix at site
(e) Rolling and finishing the paving mix.
(f) Application of seal coat
(g) Opening of traffic
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Xm-2080 Mangsir
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Q. Which premix is used in the base course?
(a) Otta Seal
(b) Bituminous concrete
(c) Bituminous Bound Macadam
(d) Surface dressing
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Construction of Plain Cement Concrete Pavement:
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The construction of cement concrete pavement is divided into two
ways:
(a) Construction of pavement slab
(b) Construction of Joints
(A) Construction of Pavement slab:
(I) Materials:
Cement : Ordinary Portland Cement (OPC)
Coarse Aggregate = The maximum size of coarse aggregates
should not exceed 1/4th of slab thickness.
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The desirable properties of coarse aggregates are:
(a) Aggregate Crushing Value = 30 %
(b) AIV = 30 %
(c) LAA = 35 %
Fine Aggregates : Generally, natural sand is preferred.
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(II) Plants and Equipments:
(a) Concrete mixer
(b) Batching plant
(c) Wheel barrow
(d) Vibrator
(e) Float
(f) Straight edge
(g) Pan
(h) Belt
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(III) Construction steps:
(a) Preparation of sub-grade and sub-base.
(b) Placing of formworks
(c) Batching of materials and mixing
(d) Transporting and placing of concrete
(e) Compacting and finishing
(f) Curing of cement concrete
(IV) Opening of Traffic:
The roads are opened to traffic after proper curing (28 days)
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(B) Construction of Joints:
Joints are provided in cement concrete roads for expansion,
contraction and warping of the slab due to variation in temperature.
The main function of these joints are to minimize the temperature
stresses induced in the pavement slab.
Er. Sabin Pokhrel
NEC Model Question (1 mark)
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Q Which of the following joint is not a road joint?
(a) Tyton
(b) Expansion
(c) Construction
(d) Warping
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Xm-2080 Mangsir
45
Q. Tie bar in rigid pavements provide across:
(a) Contraction Joint
(b) Expansion Joint
(c) Longitudinal Joint
(d) Construction Joint
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