Development of Pavement Maintenance Management System for Baghdad Urban Roadway Network

The road transportation system is considered as major component of the infrastructure in any country, it affects the developments in economy and social activities. The Asphalt Concrete which is considered as the major pavement material for the road transportation system in Baghdad is subjected to continuous deterioration with time due to traffic loading and environmental conditions, it was felt that implementing a comprehensive pavement maintenance management system (PMMS), which should be capable for preserving the functional and structural conditions of pavement layers, is essential. This work presents the development of PMMS with Visual inspection technique for evaluating the Asphalt Concrete pavement surface condition; common types of Asphalt Concrete distress including (bleeding of Asphalt, patching, block cracking, edge cracking, longitudinal and transverse cracking, rutting, pot holes, longitudinal and transverse deformation) with their various severity and intensity conditions have been included in the system as data base. The surface of the pavement was divided into sections, and the pavement condition is visually evaluated by the raters using specially designed forms, each type of defect was measured, classified, and rated according to type, severity, and extent. Data will be fed to the system using the computer, various types of intensity and severity of distress were analyzed by the system, the present condition rating (PCR) of the pavement section is determined, and the system suggests the required maintenance action. The developed system which is assigned (PMMS-09) was verified in evaluating the pavement surface condition at AL-Jaderiah campus roadway network. The results indicated that the system is sound in evaluation of the pavement condition and in suggestion of the proper maintenance to reserve the pavement condition.


INTRODUCTION
Pavement maintenance management systems are designed to manage maintenance and rehabilitation activities to optimize pavement condition with available funds.The use of (PMMS) is becoming increasingly more prevalent due to benefits achieved.It considers current and future pavement condition, priorities, funding, and can reduce pavement deterioration, this helps maintain pavement structural capacity, and may extend pavement life by slowing or limiting future pavement degradation.Pavement condition can be quantified by the pavement condition rating (PCR) which rates the pavement according to the extent and severity of distress types present (cracking, raveling.bleeding, shoving ...etc).(PCR) ranges from 100 to zero (best to worst).A major goal of (PMMS) is to keep pavement condition in the upper (PCR) range of (60-90) by limiting surface structural degradation to keep down rehabilitation cost.

The Study Area
The road network at AL-Jaderiah campus was constructed and opened to traffic at 1980.It consists of 25cm of compacted sub grade with CBR value ≥5%, 40 cm of sub base type B with CBR value ≥35%, 10cm of Asphalt stabilized base course, 7cm of binder course and 6cm of surface course.The network was subjected to resurfacing with 6cm resurfacing course during the year 2000.Fig. 1 shows the roadway sections at Al-Jaderiah campus, Sarsam (2008).

SECTION LENGTH AND AREA CALCULATION
The actual length of each test section in meters (ACT Length) is calculated by the system using the following equation: ACT Length = End station -Beginning station.
(1) Next, three areas are calculated, the pavement section area (PAV), the wheel path area (WP), and the non-wheel path area (NWP) using the formula below: Plate 1 shows the roadway identification and the section information.
The first step in the procedure starts when the whole Pavement surface was divided into sections of 100 meter length, then it involves identification of both type and severity of the pavement distresses present in the study area of the road sections by establishing the existing pavement condition using the visual walk through survey.Graphic plots of various types of pavement surface distress of each pavement section were obtained from Sarsam,2008 and shown in Plate 2. This procedure was performed with the use of the South Dakota DOT Manual,1997, Miller & Bellinger Manual,2003, WSDOT Manual, 2007, and Mcghee, 2002, Sarsam and Talal,2009 which contains definitions and information concerning pavement distresses.
Table 1 illustrates various types of distress fed to the data base of the software, and the distress types identified at AL-Jaderiah campus.
In the second step, each of the various types of Pavement distresses was identified and measured (i.e. units of linear meter or square meters).In addition, for each distress, a level of severity was determined [low (L), Medium (M), High (H)].
The distresses data were to the Inspection Sheet shown in Plate 3, of the system.Once the visual assessment of the road area was complete, calculations were performed by the system using the data collected in the field, through these calculations, a pavement condition rating (PCR) for the road network was determined.

Assessment Calculations:
Using the data obtained through the assessment procedure shown in Plate1, the following calculations were performed by the system to determine the pavement condition rating (PCR) for the road network.For each of the different types and severity of distresses, a distress density (extent) was calculated by the system.The following are the formulas Eqs. 5 through 7 that were fed and used to calculate the distress densities:

Distress Severity Assessment
The most common form used for the knowledge representation of the system is (IF-THEN) rule; such forms are fed to the system as described below.

Rutting, Bleeding, Raveling, Polished Aggregate and Shoving
Record maximum rut depth in millimeters, and number of occurrences and square meters of affected area, severity level is not applicable.

Fatigue Cracking (in the wheel path)
IF an area of cracks with few fine parallel cracks connected, THEN severity is low.IF interconnected cracks forming alligator pattern, THEN severity is moderate IF interconnected cracks forming alligator pattern with sapling and distortion, THEN severity is high Record square meters of affected area at each severity level.

Edge Cracking (area within 0.6m of the pavement edge)
IF cracks are light with no breakup or loss of material, THEN severity is low.IF cracks are well defined with some breakup and loss of material, THEN severity is moderate.IF cracks are well developed with significant breakup and loss of material, THEN severity is high.

Transverse Cracking
IF crack spacing > 15 m, THEN extent is low.IF crack spacing > 7.5 m and < 15 m, THEN extent is moderate.IF crack spacing < 7.5 m, THEN extent is high.

Fatigue Cracking
IF crack is 1% to 9% of wheel path, THEN extent is low.IF crack is 10% to 24% of wheel path, THEN extent is moderate.IF crack is 25% to 49% of wheel path, THEN extent is high.

Patching
IF patching is 1% to 9% of section, THEN extent is low.IF patching is 10% to 24% of section, THEN extent is moderate.IF patching is 25% to 49% of section, THEN extent is high.

Block Cracking
The values for the densities (extent) were recorded.Next, using the calculated densities and the severity (i.e.L, M, or H) a deduct value for each distress type was determined.The deduct values were determined through the use of the "Deduct Value Curves" for each of the various distress types identified.The curves are part of the U.S. Army Corps of Engineers Technical Report TR97/104.The mathematical models for each multiplying the unite cost of the selected alternative by the area of the defected section.The unite cost data must be upgraded periodically.

Software Environments
Microsoft ACCESS 2003 (which was selected for the development of PMMS for Baghdad urban roadway network) employs three programming languages to enable user to add finetuning to an application.The Structured Query Language (SQL) is the language access used behind the scenes in queries that can extract, manipulate and relate data from one or more tables.Macros consist of list of actions that execute in response to an event such a button click or data in a form changes.The developed system processes in four steps, the first step involves field data collection and tabulation while the second step involves creating the table definitions and key field requirements, and data validation rule, define tables linked to look up.Finally data were added to tables to be able to test application thoroughly.The third step is the data entry form, the fields in the form carefully arranged in logical order and with meaning full label to help prevent entry errors.The fourth step considers macros and event procedure , function were added to the form design that it would be perform appropriately to user action as shown in plate 6.

ANALYSIS AND DISCUSSION OF VISUAL ASSESSMENT OF PAVEMENT SURFACE CONDITION
The original raw data that was collected in the field and the results of the calculation described in the previous section are included in Plates 2 and 5 which is a summary of the data and results.As shown, there were different types of distresses identified during the inspection of the representative area.The levels of severity for the distresses identified ranged from low severity (L) to high severity (H).The total amount of "deduct" and the corrected deduct value "CDV" was calculated by the system and illustrated in Plate 4. The pavement condition rating (PCR) was determined to be in the range of (99-45) % which results in a rating of "poor to very good" for the road sections based on the rating index provided.

CONCLUSIONS AND RECOMMENDATIONS
This paper has produced a methodology that can use the visual data obtained in the field and perform analysis of distress using an expert system.The developed system was tested in a small project that include most of distress types, it could provide a better environment to assess and analyze data about the condition and maintenance of Asphalt concrete pavement, it combines detailed inventory and evaluation procedures with analytical software routines.It is simple to perform, use less expensive techniques and individuals to subjectively rate Asphalt pavement sections based on observed distress, provides job opportunities for Engineers and technicians.Based on the information obtained during this evaluation, it is recommended to consider using the software, and it should be tested in bigger project to evaluate whether it will be labor intensive.