Types of Damages on Flexible Pavement for Malaysian Federal Road

Proceeding of Malaysian Universities Transportation Research Forum and Conferences 2010 (MUTRFC2010), 21 December 2010, Universiti Tenaga Nasional. ISBN 978-967-5770-08-1

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TYPES OF DAMAGES ON FLEXIBLE PAVEMENT FOR MALAYSIAN FEDERAL ROAD

Nurul Elma Kordi1*, Intan Rohani Endut1,2, Bahardin Baharom

1,2

ABSTRACT:

Flexible pavements in Malaysia are designed until ten to fifteen years design life to support load. However, sometimes these roads not able to carry the load with the specified design life especially in industry areas because heavy lorries always using these road to move their goods. A lot of distress on the flexible pavement and it become uncomfortable feelings to the driver. A lot of factors contribute the problem of failure to flexible pavement either internal or external factors. Among the heavy trucks' operators, they want to raise the axle loads limit for all trucks to avoid delivery delays and meet higher storage chargers; in fact Road Transport Development (RTD) had given special permission to some 1000 lorries since August 2007 to carry the new maximum load. In order to quantify flexible pavement damages, the impacts of increase axle load on Federal road must identify and evaluate. This paper discusses a type of damages on the flexible pavement, causes of failure to flexible pavement and appropriate structural requirements for pavement performance that can carry the load on a routine basis. With the best understanding of the causes of failure and process to rehabilitation, the responsibilities' authorities will know well the key to proper maintenance of flexible pavement in order to design, manage and maintain the highways.

Keywords: Axle Load, Distress, Flexible Pavement, Rehabilitation

1 Malaysia Institute of Transport (MITRANS), Universiti Teknologi MARA, 40450 Shah Alam, Selangor, MALAYSIA 2 Faculty of Civil Engineering, Universiti Teknologi MARA, 40450 Shah Alam Selangor, MALAYSIA * Correspondence Author: Nurul Elma Kordi, Malaysia Institute of Transport, Universiti Teknologi MARA, Malaysia. Tel: +6003 5521 1492, Fax: +603 5544 2344. E-mail: [email protected]


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INTRODUCTION

Road has played an important role in the trade and transportation system throughout the world, and it become rapid increase in the pavement infrastructure development in Malaysia. Gazette under Federal Roads Ordinance is usually roads linking the state capitals, airports, railway stations and ports. Currently, Malaysia has more than 80,300km roads. The road is divided into three main categories namely toll expressway (1,700km), federal roads (17,500km) and state roads (61,100km) and the life spans are between 10 to 15 years (Zakaria and Hassan, 2005). Local authority road (city mall, municipal or local council) or kampong (district office) road is depending upon jurisdiction and normally maintained by the responsibility local authority (Haron, 2004). In Malaysia, Federal road use the flexible pavement that constructed with asphaltic cement and aggregates and consist of several of layers with the lowest called the subgred which natural soil itself. The next layer is the subbase, which consist of crushed aggregate. The next layer is called road base, which can be made of crushed aggregates with a cementing material. The top layer is called surfacing layer. It is usually made of asphaltic concrete. The structural strength depends on individual material strength characteristic and thickness layer. Some form of deflection within the elastic limit is allowed. Surface readability is good but relatively less durable or susceptible to high temperature (Haron, 2004). Federal road at Malaysia almost used the flexible pavement compare to rigid pavement because flexible pavement more comfortable to the user. Furthermore, flexible pavement can be use by users once ready. Table 1 shows the differences between flexible and rigid pavement. With best design and proper construction method, adequate routine and periodic maintenance are necessary to achieve the determined design life spans and even beyond. The main factors of pavement deterioration due to increasing the number of vehicle and load traffic by the run which is five percent per annum.

Table 1: The differences between flexible and rigid pavement

No. Flexible Rigid 1 Last for 20 years Last for more than 40 years 2 High cost and schedule maintenance More economic maintenance, no schedule 3 Cheap and easy to get the material Material shortage problem always occurs 4 Low initial cost Higher initial cost 5 Easy to upgrade / stage construction Cannot upgrade / no stage construction 6 Rutting and potholes may occur Free from rutting, potholes and corrugation 7 Less economic for the long duration More economical for the long duration 8 Can be used once ready Traffic disturbance, wait for maximum

strength (28 days) (Source: Haron, 2004)

As a part of the study by research, this paper discusses on failure on flexible pavement, sources failure of flexible pavement and appropriate structural requirements for pavement performance that can carry the loads on a routine basis. This is a preliminary study before conduct the actual study which mapping all the damages along Federal road number one after this.

TYPES OF DAMAGES

According to Highway Research Board, 1970 cited by Pavement Interactive, 2010, pavement distress is "any indication of poor or unfavourable pavement performance or signs of impending failure;


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any unsatisfactory performance of a pavement short of failure". The causes of pavement failures are divided into two categories, which are an internal and external failure. Internal failures of pavement are usually because of the lack pavement mixture, weaknesses of component materials and poor construction. Meanwhile, external failures are due to overloading, diesel spillage, flooding, sink holes and other unforeseen cause such as earthquake, volcanoes and others. The failures of flexible pavement are divided into four categories, which are surface deformation, surface defects, cracking and patching and potholes (Rani, 2007). Tables 2, 3, 4 and 5 below shows the lists the pavement distress groups, possible causes, and the probable treatments that summarized by Rani, 2007 and PFI, 2010.

Table 2: Surface deformation

No. Possible Causes Probable Treatments Shoving

1 Instability mixture of asphalt (course or fine aggregate too rounded or too smooth textured)

Remove surface and base as necessary and replace with a more stable material

2 Low modulus bases course Reconstruction of base 3 Thin wearing course Bituminous overlay 4 Dragging of pavers during laying when

bituminous mix temperatures were low Remove surface and base as necessary and replace with a more stable material

5 High stress due to braking and acceleration movements

Bituminous overlay with the stiffer mix or use the high compaction mix.

Corrugations 1 Inadequate stability of bituminous

surface (excessive moisture) Replace bituminous surface

2 Compaction of base in wave form Base reconstruction 3 Faulty paver behaviour with some

mixes (contamination caused by oil spillage) Replace the faulty mixes and correct the faulty behaviour

4 Heavy traffic on steep downgrade or upgrade Mill off the corrugated surface and replace with the stiffer mix or use hot mix asphalt

5 Stopping at intersection stop lights or roundabout

Mill off the corrugated surface and replace with the stiffer mix or use hot mix asphalt

6 Inadequate stability of base course Base construction. Rutting

1 Inadequate pavement thickness Strengthening overlay or reconstruction 2 Inadequate compaction of structural layers Reconstruction 3 Unstable bituminous mixes Replace or recycle bituminous surfacing or

use the stiffer mix 4 Unstable shoulder material which does not

provide adequate lateral support Shoulder improvement and overlay rutted area with bituminous surfacing

5 Overstressed subgrade which deforms permanently

Reconstruction

6 Unstable granular bases or subbases Base or sub base strengthening Depression 1 Differential settlement of

subgrade or base materials Subgrade or base reconstruction

2 Settlement of services and / or widening trenches

Reconstruction of services and/or widening trenches

3 Volume change of subgrade due to environmental influences

Improve sub-soil drainage and reconstruct

4 Settlement due to instability of embankment Embankment stabilization


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(Source: Rani, 2007 and PFI, 2010)

Table 3: Surface defect

No. Possible Causes Probable Treatments Bleeding / Flushing 1 Excessive asphalt in the surface layer. On hot

days the binder expands into air voids; if the volume of air voids is too low, continued expansion results in lower stability of the mix with the consequence that traffic will force out excess binder to the surface.

Apply hot sand to blot up the excess binder to the stone size.

2 Paving over flushed surfaces. The excess bitumen on the old surface may be pumped up through the new paving over period of time.

Apply hot sand or aggregate seal coat.

3 Paving over excessively primed surfaces Apply hot sand 4 Lack of proper rolling during placement Resurfacing the asphalt 5 Failure to protect a newly constructed surface

from traffic until the asphalt cured sufficiently. Resurfacing the asphalt

Ravelling 1 Insufficient bitumen content Thin bituminous overlay 2 Poor adhesion of bitumen binder to aggregate

particles due to wet aggregate Thin bituminous overlay

3 Inadequate compaction or construction during wet weather

Thin bituminous overlay

4 Deterioration of binder and/or aggregate Thin bituminous overlay Polishing 1 Inadequate resistance to polishing of surface

aggregates particularly in areas of heavy traffic movements or where high stresses are developed between surface and tyres

The bituminous overlay of use of stiffer mix

2 Use of naturally smooth uncrushed aggregates Thin bituminous overlay. Delimitation / Surface Lifting /Seal Break 1 Inadequate cleaning or inadequate tack cot

before placement of upper layers Mill off and re-lay upper layers.

2 Seepage of water through asphalt, especially in cracks, to break the bond between surface and lower layers.

Replace wearing course or thin bituminous overlay

3 Weak, loose layer immediately underlying seal Reconstruction of weak layers 4 Adhesion of surface binder to vehicle tyres Thin bituminous overlay



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Table 4: Cracking crack

No. Possible Causes Probable Treatments Fatigue (alligator/crocodile) crack

1 Inadequate pavement thickness Strengthen the pavement or reconstruction 2 Low modulus base Strengthen the base or reconstruction 3 Brittle base Base recycling or reconstruction 4 Poor base drainage Improve the drainage and reconstruct 5 Brittle wearing course Replace or treat wearing course

Block cracking 1 Joints in underlying layer Crushed aggregate overlay 2 Shrinkage and fatigue of underlying

cemented materials Replace underlying cemented materials

3 Shrinkage cracks (due to bitumen hardening) in bituminous surfacing

Seal cracks or replace bituminous surfacing

4 Fatigue cracks in embrittled bituminous wearing course

Cut and patch or crushed aggregate overlay

Longitudinal cracking 1 Reflection of shrinkage cracks Cut and patch 2 Poorly Constructed paving lane in bituminous

surfacing Replace bituminous surfacing

3 Displacement of joints at pavement widening Reconstruction of joints 4 Differential settlement between cut and fill Crushed aggregate overlay or reconstruction

of joints. Transverse (Thermal) Crack

1 Reflection of shrinkage cracks Cut and patch 2 Construction joint in bituminous surfacing Crack sealant 3 Structural failure of Portland Cement Reconstruction of base 4 Shrinkage crack bituminous surfacing Seal cracks or replace bituminous surfacing 5 Reflection of joints in the underlying base Crushed aggregate overlay or reconstruction

of joints Edge cracks

1 Excessive traffic loading at the pavement edge

Widen the pavement or strengthen the pavement edge

2 Poor drainage at pavement edge and shoulder Improve drainage and shoulder 3 Inadequate pavement width which forces

traffic too close to the pavement edge Widen treatment

4 Insufficient bearing support Reconstruction Edge breaks

1 Inadequate pavement width Widen the pavement 2 Alignment which encourages drivers to

travel on the pavement edge. Pavement widening and realignment

3 Inadequate edge support Shoulder strengthening 4 Edge drop-off Strengthening and leveling of shoulder with

road surface 5 Loss of a adhesion to base Cut and patch or bituminous overlay.

Edge drop-offs 1 Inadequate pavement width Widen the pavement 2 Shoulder material with inadequate resistance Replace shoulder material and reconstruct


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to erosion and abrasion. 3 Resurfacing of pavement without

resurfacing of shoulder Leveling of shoulder with road surface

Crescent shaped cracks / parabolic / slippage / shear cracks 1 Lack of bond between wearing course and

the underlying layers Cut and patch

2 Low modulus bases course Reconstruction of base

Reconstruction of base

3 Thin wearing course Bituminous overlay 4 Dragging of pavers during laying when

bituminous mix temperatures were low Cut and patch

5 High stress due to braking and acceleration movements

Bituminous overlay with the stiffer mix or use the high compaction mix.


Table 5: Patching and Potholes

No. Possible Causes Probable Treatments Patch/Patch Deterioration 1 Inadequate cleaning or inadequate tack cot

before placement of upper layers Mill off and re-lay upper layers.

2 Seepage of water through asphalt, especially in cracks, to break the bond between surface and lower layers.

Replace wearing course or thin bituminous overlay

3 Weak, loose layer immediately underlying seal Reconstruction of weak layers Pothole 1 Loss of surface course Patching 2 Moisture entry to base course through a

cracked pavement surface Cut and patch

3 Load associated disintegration of base Base reconstruction (Source: Rani, 2007 and PFI, 2010)

From the table, it shows most of the possible causes damages of pavement are due to of imperfection during construction. This failure will give uncomfortable to the users during their driving. Either responsibility contractor does their work perfectly or not during construction of the road need to investigate.

CHARACTERISTICS EFFECTING FAILURE OF PAVEMENT

Truck factors

Most comment from the users of the road about the vehicle that carries the heavy load that makes the pavement damage. On behalf of heavy truck operators, they want to increase the axle load limit to avoid delivery delays and meet higher storage chargers. Table 6 below shows the comparison weight limit of the truck among various countries.


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Table 6: Comparison Weight Limit of Truck among Various Countries

Country Type (load+vehicle) Weight limit (maximum)

Malaysia Two-axle-fixed truck Three-axle-fixed truck Four-axle-fixed truck

16 tons 21 tons 25 tons

Thailand Two-axle-fixed truck

Three-axle-fixed truck Five-axle-fixed truck

12 tons 21 tons 39 tons

Singapore Two-axle-fixed truck

Three- axle-fixed truck Four-axle-fixed truck Articulated truck

16 tons 24 tons

- 24 tons

ASEAN Standard Two-axle-fixed truck

Three-axle-fixed truck Four-axle-fixed truck Articulated truck

16 tons 21 tons

- 38 tons

(Source: MRTV3, 2010)

Table 7 show the comparison of axle load among various countries. Axle load and total truck load limits are also an important factor, which can determine the efficiency of the road system and competitiveness of the countrys logistics system. Thailands maximum axle load limit is 8.2 tons while the truck limit had increased to 25 tons from 21 tons in 2006. Thailands axle load limit is lower than other countries. Truck load limit and axle load limit will have impact on Thailands long-run freight transport cost and road maintenance cost, which need to be balanced. Different load limits among Thailand and neighboring countries might also cause problems for transshipment of goods across national borders and complicate international trade negotiations (Transport Sector, 2008).

Table 7: Comparison of Axle Load among Various Countries

Country Axle Load Limit (Ton) Malaysia 12 Thailand 8.2 Singapore 10 Japan 11 Europe 10-13 The Peoples Republic of China 10 ASEAN member countries 10

(Source: Transport Sector, 2008)


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Heavy vehicle also contributed to deterioration of the road, there were 19.3 million registered vehicles on the Malaysias road, and the government spent RM5 billion between 2001 and 2010 to keep sustaining all the Federal roads (New Strait Times, June 2010). Heavy vehicle has been banned during morning peak hours started 2 August 2010 from certain stretches to avoid traffic congestion on the North-South Expressway. Federation of Malaysian Manufacturer presidents, Tan Sri Mustafa Mansur (2010) said the move would not cause much impact as lorries could still use other alternative roads to get their destination. This rule is applied after investigations have been done. The result shows the total of heavy vehicle breakdown three times more than light vehicles and this situation will give big impact on traffic congestion (Berita Harian, 2010). However, Pan Malaysia Lorry Drivers Association president, Er Sui See, unhappy with the ban because it unfair and absurd to expect them apply for temporary permits each time they need to use the highway during the ban time (The Star, July 2010).

Pavement and environmental factors

The other factor of pavement damages is due to extra ordinary weather such as heavy rain and flooding. It is bringing on water absorption to pavement and weakened the structural pavement base. The pavement will weaken and fail due to increasing moisture content of the subgrade. Therefore, drainage is very important in the roads' system to keep the low water table. In Malaysia, RM220 million was spent every year on repairing road damages by rains and floods (New Strait Times, 2010). In general, conventional asphalt easy to damage when exposed to water and high incidences of flooding. The used less quality of material, non effective construction, construction procedure without control and overweight commercial transports also as sources of failure pavement.

Tolled expressways are better maintained than Federal roads because government has to take care of more roads, which are 16,500km of federal roads compared only 1,360km that managed by private highway concessionaires (The Star, 2010). Contact condition and configuration of tire

The consensus is clear which the details of the contact conditions such as the exact area, pressure

and pressure distribution, effect stresses and strains near to the surface of the pavement, whereas the response in the lower layers depends mainly on the overall load. Haas and Papagiannakis, 1986 (as cited in Cole & Cebon, 1997) showed that increasing the tyre inflation (contact) pressure from 415 kPa to 830 kPa at constant load will increase the theoretical vertical compressive strain near to the surface of a 200mm thick asphalt layer by up to a factor of eight, but hardly affected the strain at the bottom of the layer. In 1963, Zube and Forsyth (as cited in Cole & Cebon, 1997) performed an experimental comparison of the vertical deflections and transverse strains of a flexible pavement surface, to wide-base single tyres and dual wheels. Their results indicated that pavement deflection was equivalent to 27 kN carried on a single tyre or 40 kN carried on a dual pair.

Cole and Cebon, 1997, conclude that fatigue cracking failed due to wide single tyres cause up to seven times more damage than dual tyres carrying the same total load for the relatively thin asphalt pavements (minor roads). For thicker pavements, where permanent deformation is the main mode of failure, wide single tyres are likely to cause one and half to two times more damage than dual tyres. Dadoo and Thorpe (2005) identify the main factors responsible for pavement damage caused by heavy vehicle such as dynamic axle load, number and type of axles (e.g. single, tandem), tyre properties (e.g. wide-base, dual) and pavement properties (e.g. pavement type, thickness, temperature and roughness). This research will discover which these factors have the greatest influence on pavement response. Marshek et al. (1986) lists of the possible damage or defect on the pavement are shown in Table 8. It can be concluded that, pavement damage will be increased due to less of contact area of tires to road. The higher pressure of tires is one of the factor's pavement damages because small of contact area between tires and pavement.


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Table 8: Summary of characteristics influencing pavement damage

Characteristic Decrease in Pavement Damage Increase in Pavement Damage

No. of Tires per Axle

More Tires per Axle (Tandem Axle) Less Load per Tire Less Load per Unit Contact Area Decrease in Pavement Damage

Fewer Tires per Axle Greater Load per Tire Greater Load per Unit Contact

Area Increase in Pavement Damage

No. of Axles

More Axles Less Load per Axle Less Load per Unit Contact Area Decrease in Pavement Damage

Fewer Axles Greater in Load per Axle Greater Load per Unit Contact

Area Increase in Pavement Damage

Load Distribution

Load Distributed Evenly Among Axle Less Load for the Most Heavily

Loaded Axle Group Decrease in Pavement Damage

Load Not Distributed Evenly Among Axles Greater Load for the Most

Heavily Loaded Axle Group Increase in Pavement Damage

Speed / Congestion Higher Speeds Decrease in Load Duration Decrease in Pavement Damage

Lower Speeds Greater Load Distribution Increased Pavement Damage

Tire Pressure

Lower Tire Pressure Greater Surface Contact Area

between Tire and Pavement Less Load per Unit Contact Area Decrease in Pavement Damage

Higher Tire Pressure Smaller Surface Contact Area

between Tire and Pavement Greater Load per Unit Area Increase in Pavement Damage

EFFECTS OF INCREASED LEGAL LOAD LIMITS

Studies of the effect of increasing the legal load limit from 18,000 to 20,000 pounds for single axles and from 32,000 to 36,000 pounds tandem axles were made by the California Transportation Department. According to a study by Smith (1973) cited by Matthews and Baumeister (1976), if half load trucks which hauled legal limit loads were to increase axle loads to the proposed limits, the decrease in fatigue life of existing pavements is predicted to be between 20 and 25%. The effect of this decrease in pavement life will be to increase maintenance costs on existing pavements considerably over what they have been in the past and require reconstruction and rehabilitation at an earlier date. Findings from the study indicate that an 11% increase in legal load limits appears to reduce service life in years approximately 20% (Matthews and Baumeister, 1976).

Jarviss (2008) opinion the increasing of truck Gross Vehicle Weights (GVW) on the federal highway system, while keeping individual axle weight limits at the current level, will improve productivity, fuel conservation, air quality, infrastructure conservation, and public safety, while reducing carbon emissions and traffic congestion. While Eason and Greene (2008) explained by providing fuel-cost savings, increasing the allowable GVW also would streamline trucking across national borders. Current maximum GVWs allowed by Mexico and Canada are 106,920 pounds and 95,900 pounds, respectively. According to the Americans for Safe and Efficient Transportation (ASET), the payload increase would make trade more parallel and obtain $14.5 billion of potential savings in shipping costs. For an individual truck, ASET also states that tractor-trailers (with six axles rather than five) can reduce vehicle miles


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travelled (VMT) by 11% and reduce fuel usage by 6%. Accidents would decrease as well, as fewer trucks driven by a smaller pool of more highly qualified drivers would be on the road. With the increasing prices of fuel, the haulier needs to improve their trucking system because fuel costs will reduce the profit margins on every industry in the economy, and logging is certainly no exception. APPROPRIATE STRUCTURAL REQUIREMENT

The rehabilitation of flexible pavements encompasses a broad range of activities, which could be grouped into three categories namely; restoration, resurfacing (structural) and reconstruction (Caltrans, 2000). In order to prevent failure flexible pavement, the polymer-modified asphaltic (PMA) concrete has started used in several project road upgrading by Work Ministry. The National Economic Action Council had agreed that PMA be used on five per cent of new projects as a part of the 10th

Figure 1 below illustrates the alternatives of pavement maintenance and rehabilitation. This figure is helpful in understanding the aim for which a given treatment.

Malaysia plan. PMA is a mixture of natural or synthetic polymer materials with conventional bitumen. Their rubberlike surfaces are highly resistant against rutting and cracking and absorb little water, which is the cause of cracks in roads. PMA has a lower life cycle cost and can admit the higher axle load, also, with using PMA it can save until RM200,000 for every kilometer of the road in yearly maintenance work, although the cost PMA is 1.7 times more than conventional (New Strait Times, 2010). A study was completed for the Affiliate Committee of the Asphalt Institute on the use of PMA for reducing distress in flexible pavements and hot mix asphalt (HMA) overlays. The results from that study found that the use of PMA reduced pavement distress and increased the life of flexible pavements by two to ten years (Asphalt Institute IS-215, 2005).

Figure 1: Alternatives of Pavement Maintenance and Rehabilitation

(Source: Monismith, 1979)

Pavement maintenance and Rehabilitation

Maintenance Rehabilitation

Surface Subsurface

Overlays

Recycling Reconstruction

Combination of recycling and overlays

- Preventive - Corrective


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There are differentiated between preventive and corrective approaches preventive strategies for pavement surface include fog-seal asphalt, rejuvenators, joint sealing, seal coat (with aggregate) and thin blanket. For surface corrective there are patching, crack filling, joint sealing, seal coat, friction course, grooving, thin blanket, surface recycling, cold planning and drainage. For subsurface, there have drainage for preventive maintenance and sub-sealing, in-situ stabilization and drainage for corrective maintenance. CONCLUSSION

The failures of pavement have increased significantly over the year. The effect of axle load plays an important role in the deterioration of flexible pavements. Although the Association of Malaysia Hauliers (AMH) and truck operators want to raise the lorry load limit for all as similar size vehicles have been transporting heavier loads at overseas, the responsibilities' authority still needs to investigate carefully the effect to the road and users. Damaged roads need to repair immediately as they can cause accidents and traffic congestion. The study that was conducted and discussed in this paper show that the possible causes of flexible damages mostly did not cause by heavy truck. Therefore, the further research needs to conduct to check whether the responsible contractor done their work properly or not and the other factor of flexible pavement easy to damage need to consider and investigate. New road construction will involve big investment. Therefore, to ensure life span of the road that constructed more durable, comfortable and safe to the user, construction and maintained of the road need to be done effectively.

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Nurul Elma KordiP0F P*, Intan Rohani EndutP1,2P, Bahardin BaharomP1,2

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Types of Damages on Flexible Pavement for Malaysian Federal Road