Assessment of the Functional Performance of Mohammed Al-Qasim Expressway Pavement Surface

To achieve these requirements need to assess the pavement surface condition (Functional Performance). The pavement surface damage that frequently happens has an effect on the safety and comfort of road users. Pavement condition assessment is the basic step to select a suitable type of maintenance and rehabilitation program. This study aims to estimate the functional condition of the Mohammed Al-Qasim Expressway pavement surface by the Pavement Condition Index (PCI) assessment with data collected throughout 2017. The result showed that the AC pavement surface condition assessment is equal to 70 based on PCI value, and rated as fair, and the transverse tining PCC pavement surface condition is rated as satisfactory and PCI value equals 77.


Introduction and Literature Review
The transportation systems aim to provide the safe and efficient movement for people and goods [4].To achieve these requirements we needs to assess the pavement condition or performance.The pavement failure can be classified into functional and structural failure.Functional failure is the failure of the upper layer of pavement (surface) and will often affect comfort and safety of the roads users and it can be treated with periodical maintenance.Structural failure represents the most serious type of failure that occurs in all the layers of pavement, thus, the pavement is unable to withstand the traffic loads and rehabilitating is the only treatment possible [8].
Pavement damage frequently happens and has an effect on the safety and comfort of roads' users as mentioned earlier.It could be caused by several conditions such as the age of the pavement, a presence of water on the pavement surface, excessive traffic load and repetition of load, inappropriate planning, and poor monitoring of the road.Moreover, the lack of maintenance, delays in financing, inappropriate handling, and climate change [7] can be further causes of pavement damage.
Thus, the condition of the pavement needs to be monitored periodically according to both sin terms of structural and functional conditions, and this is known as pavement condition monitoring.The data obtained from the pavement condition monitoring surveys play a vital role in selecting maintenance and rehabilitation activities [6,7], as well as the pavement condition rating, which gives an indication of the type and prioritizing maintenance and rehabilitation projects, in other words, gives a more objective comparison of two or more pavement sections.
The data collection and pavement condition rating activities are carried out to provide an indication of the serviceability and physical conditions of the pavement and known as Pavement Condition Surveys.One of the common techniques to assess the pavement surface condition (pavement distress) is the Pavement Condition Index.It is one of a measured condition rating technique developed by the US Army Corps of Engineers and adopted by the American Public Works Association and American Society for Testing and Materials (ASTM) [6].
Previous research has been done to relate the PCI and the service life of pavement, as well as the correlation between pavement distress and the rate of traffic [7], and there is a similarity in the determination of the pavement condition by the PCI method and that by the laboratory tests [1].
The operation and maintenance problems of the highway network in Iraq become worse in up-keeping and serviceability offered, although the doubling of efforts and financial allocations to improve the serviceability of the pavement and increase the design age, the main reasons for highways network failure are the rapid occurrence and increase in the intensity of deformation, lack of periodical maintenance to the pavement surface [3], in addition to the lack of control of traffic load with the temperature that exceeded the 50°C [5].
The objective of this study is assessing the existing pavement surface condition for two sections of Mohammed Al-Qasim Expressway which is considered the first highway in the middle region of Iraq.The surface of existing pavement can be assessed by visual condition survey (distress type, density and severity) based on a pavement condition index (PCI) criteria with aiding PAVER 5.2 software for both AC and transverse tining PCC pavement surfaces and storing the collected data in Geographical Information Systems (GIS) to indentify the condition of every pavement surface with details.Moreover, these data can be used later for the pavement maintenance program.

Study area
Mohammed Al-Qasim Expressway is the first highway in the middle region of Iraq, and due to a heavy traffic volume passing it and the expansion of population density on both sides around the road, two sections were chosen to examine the functional performance of existing pavement surfaces.It is a multi-lane road with three lanes in each direction.Section No.1 is transversely textured PCC pavement surface about 1000 m from Toyota SAS Baghdad Automotive service to Sulaikh bridge, and section No.The minimum sample units (n) required for an adequate estimation of the PCI value of the sections and the (n) parameter can be calculated by following equation: Where: N: Total number of sample units in the pavement section, e: Permitted error in the estimate of the section PCI, S: Standard deviation of the PCI between sample units in the section.
Based on equation ( 1) the (n) parameter of PCC pavement surface is equal 11.29 ≈ 12 samples, and for AC pavement surface it equals 9.5 ≈ 10 samples.
Then determine the sampling interval (ί) by using the following equation: So that, the sampling interval (ί) for PCC pavement surface equals 1.3 ≈ 1 sample, and for AC pavement surface it equals 2.2 ≈ 2 samples.
The final step of hand calculation is a random start (s) where there is arbitrary choice between sample unit 1 and the sampling interval (ί).Then the sample units to be surveyed are identified as s, s+ ί, s+2ί, etc. PAVER5.2software used to calculate PCI value for AC pavement surface is shown in figure (4), ( 5) and ( 6) after calculating the PCI for each sample unit where the section (880 m) was divided into 22 samples; each sample area equals 288  2 .The eleven sample units were surveyed starting with sample unit 2 (random start (s)) and then 4, 6, 8, etc.PCC pavement section (1000 m) is divided into 16 sample units; each sample consists of 20 slabs in each lane in one direction.After calculating the PCI for each sample starting with sample unit 1 and then 2, 3, 4, etc., the PCI was calculated for the whole section as shown in figure (7), ( 8) and (9).The dividing process of the section into sample units also are illustrated using GIS as it is shown in figures ( 16) and ( 17) where the selected sample units are in blue color with illustration of their lengths, widths, area and PCI values of each inspected unit.

Results Analysis
PCI value for AC pavement surface is equal to 70 as it is presented in figures (4) and ( 18).The condition of pavement is rated as fair as mentioned in ASTM D6433-07 due to several causes of distress.Some of the distress related to traffic load (Cracks for example) represents the ratio equals to 13% .While 87% of the distress is due to the climate condition such as weathering.For transverse tining PCC, the PCI value is equal to 77 and rated as satisfactory.Moreover, 30% of causes of distress are related to traffic load, 45% are due to climate condition and 25% are due to other causes presented in figures (7) and (19).Figure (19b) shows some of the distress types that have been observed on the PCC pavement surface, such as large patching, corner break, shrinkage crack, map crack and joint spalling in the middle lane with varying severity levels, and some low patching, corner break and joint spalling at right lane.From figure (20), it can be observed that out of the eleven examined sample units only seven units are rated as fair while others are rated as satisfactory for AC pavement surface.AS for transverse tining PCC, one the sixteen examined sample units rated as fair.In addition, two sample units are rated as poor while the remaining are units are rated in satisfactory and good condition as it is shown in the figure (21).

Conclusion
The assessment pavement surface condition of Mohammed Al-Qasim Expressway shows the following conclusions: 1.The value of the AC pavement surface condition assessment is equal to 70 based on PCI value, and it is rated as fair.The transverse tining PCC pavement surface condition rated as satisfactory with PCI value is equal to 77. 2. The causes of distress for AC pavement surface exhibited by PAVER software related to traffic load represents the ratio equal to 13% and 87% due to climate condition.3. Five types of distress are observed on AC pavement surface; they are alligator crack (Alligator CR), longitudinal crack (Long.CR) and rutting in the right lane as well as longitudinal and transverse joint reflection cracks (JT REF.CR) at both right and middle lanes.4.About 30% of causes of distress for PCC pavement surface are related to traffic load, 45% are due to climate condition and 25% due to other causes.5.The ten types of distress which are observed on the PCC pavement surface include large patching, corner break, shrinkage crack, map crack and joint spalling in the middle lane with varying severity levels, and with some low patching, corner break and joint spalling at right lane. abdulhaq1969@uomustansiriyah.edu.iq 2 is an AC pavement surface about 880 m after Al-Nidaa bridge as it is shown in Figure (1), and Figure (2) shows AC and PCC.

Figure ( 10 )
Figure (10) Database of distresses for sample unit 13 of Trans.Tining PCC Pavement Surface

Figure ( 14 )
Figure (14) Connect Digital Image to Failure Exist in the Trans.Tining PCC Pavement Surface

Figure ( 16 )
Figure (16) Information of Sample Units of Trans.Tining PCC Pavement Surface Figure (18) PCI for AC Pavement Surface with Surface Distress.
Figure (19) PCI for Transverse Tining PCC Pavement Surface with Distress Types PAVER software additionally displays the condition of each sample unit, where the sample units entered in GIS program with their PCI values as it is shown in the following figures.

Figure ( 20 )
Figure (20) AC Sample Units in GIS Program with PCI Range Color Suggested by ASTM D6433-07