20320140503005

International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print),
ISSN 0976 – 6316(Online) Volume 5, Issue 3, March (2014), pp. 50-59 © IAEME
50
REHABILITATION STUDY OF ALTAJI – BAGHDAD HIGHWAY
THROUGH THE 8.00 KM SECTION LENGTH
ABDUL KAREEM NAJI ABBOOD
University Lecturer, Babylon University College of Engineering Civil Department
ABSTRACT
The processes perform maintenance for different types of highways and intersections must be
done according to the scientific methodology in order to minimize structural and functional failures
of asphalt pavement layers which require a process of rehabilitation inclusive of the whole section of
the roadway, and more cost, effort as well as the time. The study had been done rehabilitation
process for the roadway which is started from Baghdad north Gate to the south of Al Taji area with
(8.00 Km) section length, based upon the basis of the survey included the condition of the roadway,
areas of failure, the shoulders conditions, the effects on the roadway, type of traffic characteristics
used the roadway, and engineering survey, this information's detailed with traffic volume study on
the basis of peak-hour volume (PHV). The study used a method of (Full Depth Asphalt) published by
(Asphalt Institute Manual for Flexible Pavement) to design the thickness of the overly layers
required for the rehabilitation of the roadway. The study concluded that the thickness of the overlay
layers (105mm) where it is implemented by following steps:
- Scraping and cleaning rutting failure areas using mechanical skimmer.
- Construction and compaction a leveling asphalt layer 50 mm thickness along roadway section,
taking into account the slope and elevations after treated of all pot holes in the study area.
- Construction and compaction a surface course asphalt layers (55mm) thickness under (SORB)
specification.
- Construction and compaction a layer of type (B) subbase thickness ranges (10-15cm) compacted
well to avoid the difference in the elevation between shoulders and the roadway edge, taking into
account the leveling and elevations.
It was found that when the rehabilitation study have been done for this section of roadway the
operational speed will be increase thus the level of service (LOS) increase too and rise from type (E)
to type (C) through the analysis of the traffic data using (Highway Capacity System 2000) (HCS)
program, this gives a great benefits to the passengers and frights.
Key words: Rehabilitation, Highway, AlTaji, Baghdad.
INTERNATIONAL JOURNAL OF CIVIL ENGINEERING
AND TECHNOLOGY (IJCIET)
ISSN 0976 – 6308 (Print)
ISSN 0976 – 6316(Online)
Volume 5, Issue 3, March (2014), pp. 50-59
© IAEME: www.iaeme.com/ijciet.asp
Journal Impact Factor (2014): 7.9290 (Calculated by GISI)
www.jifactor.com
IJCIET
©IAEME

51
INTRODUCTION
Baghdad is a strategy and mission city , not for being the capital of Iraq only , but for her
historical , geographical , cultural in the Middle East and the world , in addition to being the central
for many of the activities such as government , cultural, economic , trade and others , all that calls us
to attention and developed in terms of environmental, social and Urban , for the priority and
necessity which requires the relevant authorities and decision-makers observed , a network of roads ,
bridges and interchanges in the city and through the development and improve the performance of
existing roads and raise the level of service (LOS) in order to provide safety , convenience and
efficient for road users as well as reducing a travel time between the origin and destination trips
according to economic studies and traffic maintenance .The rehabilitation of roadways and
intersections implemented throughout the city require brushes and adding pavement layers to the full
path of the road as well as the high costs and technical working compared to the costs of
maintenance because the different type of failures covers most parts of them, while different types of
highway operation maintenance are made for a specific area of the road path or intersection and
sometime have been done before the failure appear .So a scientific and programmed maintenance of
highway is very importance in order to rationalize of costs , time and manpower.
1- DEFINITION OF STUDY AREA
This study was conducted to the highway section length (8.00 Km) joint between Baghdad
north Gate stations (0+00) to the south of Al Taji area station (8+00). This section classify as multi-
lanes highway with two-lanes in each direction, separated by a median. The rehabilitation study were
done to the arrival direction, which suffer from several distresses and damage in several parts of it
,while the departure direction did not show any cases of failure thus the level of service is
acceptable, as indicated due to reconnaissance survey. The roadway width is (7.00) m in each
direction, the average median width (6.00) m and (2.50) m shoulders width stabilized with granular
materials. The study noted many of the failures causes in the pavement asphalt layer as follows:-
1-1- Rutting
Rutting is defining as a decline in the roadway pavement surface and channels in the path of
vehicles tires. Rutting is a functional failure in the asphalt layers and be a construction failure in case
of rutting reach high intensity. Rutting has been appeared with respect to the axial load, compaction
and pavement layers thickness which transverse due to flexibility of layers .Rutting can be show
clearly after falling rain causing danger to the movement of vehicles. (Fig.1)
Figure (1): Rutting Failure in Study Area (Baghdad-Iraq)

52
1-2- Lane Shoulder Drop: it is define as the different in elevation between pavement layer and
shoulders surface, often surface shoulder less than road path elevation. It has been observed that this
kind of failure in most of the road section, while the. Fig (2).
Figure (2): Lane Shoulder Drop Failure in Study Area (Baghdad-Iraq)
1-3- Alligator/Fatigue Cracking
They are a nested cracks occurred as a result of the fatigue collapse of asphalt pavement layer
under the influence of higher axial loads .Cracks starting under the asphalt surface layer then appear
on the surface while continue in all directions in form of sharp angles. Our study has been spotted
that the appearance of these cracks in term of heavy vehicles path in the study area. Fig. (3).
Figure (3): Alligator Cracking Failure in the Study Area (Baghdad-Iraq)
1-4- Reveling and Weathering
Reveling is a gradual disintegration of the pavement surface layer, followed by the expulsion
of the gravel place turn out led to disjoint in mixture materials like a dismantled stone materials.
Weathering is the loss of overlying asphalt material in the pavement surface. These failures indicate
that the material has hardened asphalt or asphalt concrete which used is weak in quality and
workability. This types of failure have been observed in the study area. Fig. (4).

53
Figure (4): Reveling and Weathering Failure in the Study Area
1-5- Pot holes
It is a grooves show on the road surface, vary in terms of the depth and width, and occur as a
result of the broken or disintegration of asphalt pavement surface, potholes will be widening due to
the presence of moisture and vehicles loads. Fig (5).
Figure (5): Potholes Failure in the Study Area (Baghdad-Iraq)
The presence of many failures as above for the full path of the road indicate the need to
conduct scientific studies for the rehabilitated in the study area , especially if we take into account
the economic importance of the roadway, as well as, the failure cases indicate increased in axial
loads for heavy vehicles used for the roadway section and lack of maintenance operation further
exacerbating the failures and distortions surface layer of asphalt ,thus lower level of service (LOS)
provided by the road for users result in reduce operational speed and increase the travel time for
passengers and goods.

54
2- DATA COLLECTION
Data has been collected through field survey and traffic study include the condition of the
road, area of failure, types and classification of vehicles due to number and types of axles. Stations of
traffic count have been made in order to estimate peak hour volume (PHV),percentage of heavy
vehicles (HV%) and average annual daily traffic (ADT) .Photograph Technique Method (Ibrahim
A. B.&A.Naji A. 2009). were used during October 2013for seven days , 9 hours a day , the future
traffic for coming 15 years is estimated , while the growth rate has been calculated on the basis of
(6%) as taking into consideration the social and economic conditions of the roadway environment.
Calculating of (ADT) based on the specifications of the General Authority for Roads and Bridges
according to type of roadway with K coefficient (0.12). Table (1).
Table (1): Average Traffic Volume in Study Area (Baghdad-Iraq).
ADT = K*DHV ------------- (Highway Design Manual 2005)
3- REHABILITATION OF THE SECTION LENGTH
The main purpose of the rehabilitation study for a roadway is conclusion thickness and type
layers of overlay according to the scientific and technique study based on traffic volume
characteristics and analysis of the axial loads for heavy vehicles, taking into account the traffic
generated, traffic attracted due to rate of traffic flow and the design life of the road. Rehabilitation
study takes into account the economic factors in order to determine the thickness of the layers as well
as the safety and convenience for road user .Test pits of (50*50) cm for full depth pavement course
and sub grade was done for each (1.50)Km to determine thickness of existing pavement for the
purpose of rehabilitation study. Sample of all pit holes sent to the civil engineering department
laboratory to carry out some of the characteristics in terms of depth, type, class, proportion of
asphalt, stability as well as California Bearing Ratio (CBR) for sub base and subgrade layers. Figure
(6).show test pit holes, while results of test pit show in Table (2).
TrucksBusPc
TotalType
3-S3
Type
3-S2
Type
2-S2
Type
3
Type
2
1325933445975131092
Hourly Volume
(Veh. /hr.)
752753664916251099100ADT*
0.6792.493.334.455.700.98
percentage of
trucks for each
type %
17.70
Total percentage
of trucks %

55
Figure (6): Method of taking the Test points in the Study Area (Baghdad-Iraq).
Table (2): Laboratory Test Pits Results
Asphalt layer
Subbase
Subgrade
Station
Binder CourseBase Course
CBR
Thick(cm)
CBR
Asphalt
Content
(cm)
Stability
KN
Thicknes
s
cm
Asphalt
Content
(%)
Stability
KN
Thick
cm
4.605.207.504.204.11148355.400+001
5.805.505.004.223.6950306.701+502
4.555.605.004.154.37939355.503+003
4.495.806.004.164.51244337.504+504
4.605.706.504.184.61150406.006+005
5.005.706.004.204.001041315.108+006

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4- CALCULATION OF EQUIVALENT AXIAL SINGLE LOAD(EASL)
The study was evaluated the effect of axial loads thus knowing standard coefficient of
equivalent axial single load by using method (Asphalt Institute Manual Method for Flexible
Pavement) then determine (Overlay) thickness. Table (3) shows the distribution of loads according to
the vehicles axial load while tables (4, 5) indicate (ESAL) for all types of heavy vehicles in the study
area.
Table (3): Legal Load due to Truck Types
Maximum Axle Load (Ton)
Truck Type No. of Axles
654321
137Type-2
207Type-3
20137Type2-S2
20207Type 3-S2
27207Type 3-S3
Table (4): Traffic Volume for Heavy Vehicles
(EASL)ADTTruck
Types
(Legal Load
Trucks)
Equivalent Factor
Legal Load Trucks)
**
(Empty
Trucks)
Equivalent
Factor
(Empty
Trucks)
**
47007.5243.750.07625Type2
2047.474.1749.10.1491Type3
4051.6211.0767.710.185366Type2S-2
3532.37512.84548.1250.175275Type 3S-2
811.5010.82150.2075Type 3S-3
15142.965223.685Total
**AASHTO 2002 Axle Load Equivalency Factor for Tandem & Single Axles.
Assuming that (60%) of heavy vehicles using the road which are loaded while (40%) an
empty. So
EASL/Day = 15142.965*0.60 + 223.685*0.40
= 9175.253 Veh/day
= 9175.253*365
= 3348967.345
As mentioned that the roadway design life (15) years and rate of growth (6%).
Annual growth rate from table (5).

57
Table (4): Annual Growth Rate (Nicholas J. Garber 2002)
Annual growth rate = 23.28
EASL = 3348967.345*23.28
= 77963959.79
Assume that the the percentage of heavy vehicles in the design lane = (50%)
=77963959.79 * 0.5
= 38981979.9
The percentage of heavy vehicles in the design lane = (50%)
= 38981979.9*0.5
EASL = 19490989.95
5- DESIGN OF OVERLY THICKNESS LAYERS
According to the (Asphalt Institute Manual) (MS-17). The thickness of asphalt overlay
layers is calculated by using the following equation.
To = Tn – Te
Where:
To = Thickness of overlay (mm).
Tn = Thickness that a new pavement (after overlay) would require for expected traffic (ESAL) and
subgrade resilient modulus (MR). (mm).
Te = Effective thickness of the existing pavement structure (mm).
In order to get the value of (Tn) used (Figure 7) based on the value Resilient Modulus (MR) for
subgrade layer (MPa) which is calculated as following :-
MR = 10.30* CBR
From laboratory tests the value of (CBR =6.033) for (Subgrade)
MR = 10.3 * 6.033
= 62.1399 MPa
Enter the figure (9). Using the value of EASL and MR in order to determine (Tn).

58
Figure (8): Show How to Choose the Thickness of the Rehabilitation Layers in the Study Area
(AASHTO 2002)
From figure (8). Tn =325 mm.
In order to calculate (Te), a conversation factor must be calculated too, so the conversation
factor for sub base (0.2), while for asphalt course (0.9). (Asphalt Institute Manual 1981).
Te = 350*0.2+170*0.6
= 223 mm.
T0 = Tn - Te
= 325 – 223
= 102 mm
Use T0 = 105 mm.
6- CONCLUSIONS
6-1- The study have been concluded that the (Full Depth Asphalt) method by (Asphalt Institute
Manual for Flexible Pavement) is an efficient way to calculate and design thickness of overly layers
which is built on the basis of field studies and laboratory analytical as well as it is an appropriate way
to provide safe in the implementation.
6-2- According to the study of traffic characteristics, analysis of axial loads for heavy vehicles
and calculation of (ESAL) under the above method that the thickness of the layers of rehabilitation
layer for a section length of study area (105 mm) Implemented as follows:-
6-2-1- Scraping and cleaning rutting failure areas using mechanical skimmer.
6-2-2- Clean up the failure areas of roadway section using compressed air.
6-2-3- Spray tack coat according to road and bridge organization specification (SORB).
6-2-4- Construction and compaction a leveling asphalt layer 50 mm thickness along roadway
section, taking into account the slope and elevations after treated of all pot holes in the
study area.
6-2-5- Construction and compaction a surface course asphalt layers (55mm) thickness under
(SORB) specification.

59
6-2-6- Construction and compaction a layer of type (B) subbase thickness ranges (10-15cm)
compacted well to avoid the difference in the elevation between shoulders and the roadway
edge, taking into account the leveling and elevations.
6-3- It was found that when the rehabilitation study have been done for this section of roadway the
operational speed will be increase thus the level of service (LOS) increase too and rise from (E) to (C)
through the analysis of the traffic data using the program (Highway Capacity System 2000) (HCS) which
get a great benefits to the passengers and frights.
7- RECOMMENDATION
7-1- Establishing of specialized departments concerned with traffic maintenance it provides material,
equipment's and human resources needed, its staff must be characterized by expertise, skill and through
training and development.
7-2- Establishment of a database for each roadway includes the name, kind, date of completion,
contract amount, date of last maintenance, cost, type of failure quotient, the type of maintenance and
treatment with the development of programs, objectives and precedency under the standards
specifications and scientific planning for this purpose.
7-3- The study monitored heavy vehicles loaded with illegal Load, so it is suggested to establishment
of weight stations for heavy vehicles at the entrances to the highways with the activation of laws and
regulations to keep the roadways away from the effect of illegal axial loads.
8- REFERENCES
1- Asphalt Institute Manual, Series No.17 (MS-17), 1981, "Asphalt Overlays for Highway & Street
Rehabilitation.
2- Asphalt Institute Lexington, Ky, (1993) , "Soil Manual For The Design Of Asphalt Pavement
Structure ", (MS-10) , 5th
ed.,
3- AASHTO, 2002, "Geometric Design of Highways and Streets”, Suite 249, Washington DC,
20001.
4- AASHTO, 1993, "Guide for Design of Pavement Structures" N.W, Suite 249 Washington DC,
20001.
5- Dr.Ebraheem A.&Naji A. (2009) , "Evaluate and Design some Intersection in Al Hilla City", The
Iraq Journal For Mech.& Mat.Eng. Special Issue For The Paper Presented 1st
Annual Scientific
Conference Of The College of Engineering (17-18) May Part (C).
6- Ajam H. K., (1999)," Development of an Expert System to Investigate The Problems of Failure in
Flexible Pavement " MSc Thesis university of Technology " .
7- Ministry of Construction & Housing, 2005, “State Corporation for Road & Bridges Studies
Section”, “Highway Design Manual”, 2nd
Edition.
8- Nicholas J. Garber & Lester A. Hoel, (2002), "Traffic & Highway Engineering" Thomson,
international student edition. P.p. 963 – 989.
9- Transportation Research Board, 2000, “Highway Capacity Manual”, Special Report (209),
Washington DC.
10- Transportation Research Record 1524, Transportation Research Board, (1996), National Research
Council, Washington, D.C.
11- Hameedaswad Mohammed, “The Influence of Road Geometric Design Elements on Highway
Safety” International Journal of Civil Engineering & Technology (IJCIET), Volume 4, Issue 4,
2013, pp. 146 - 162, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.
12- Abdul Kareem Naji Abbood, “A Comparative Technical and Economical Study to Different
Options Location for Bridge and Its Approaches” International Journal of Civil Engineering &
Technology (IJCIET), Volume 4, Issue 6, 2013, pp. 214 - 229, ISSN Print: 0976 – 6308,
ISSN Online: 0976 – 6316.

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