FLEXIBLE PAVEMENT MAINTENANCE ALONG THE NORTH SOUTH INTERURBAN TOLL EXPRESSWAY SOUTHERN REGION EXPERIENCE – A CASE STUDY ON S3- PAGOH TO MACHAP, JOHOR
A compilation based on thesis by Abdul Rahim Mohd Shafie, 2008, edited by Engr Zulkhairi Hasan, P.Eng
Pavement maintenance is very important to prolong pavement life as well as to preserve the road functional in order to provide safe, comfortable riding and reliable passage to all traffics. Generally, neglecting or delaying the road maintenance activities may increase the overall cost of repair and also affect the vehicle operating cost for the road user.
The purpose of this study is to assess the pavement condition and rehabilitation works carried out along the North South Interurban Toll Expressway (NSE) within Section S3 in Southern Region from Pagoh to Machap involving 70 km length. The study focus on visual site assessment for flexible pavement along the mainline and making measurements on the pavement distresses based on Inspection Manual for Pavement Maintenance Management System, PLUS Bhd. as well as Interim Guide To Evaluation and Rehabilitation of Flexible Road Pavements (JKR 20709-0315-94).
From the study, the common type of pavement distress recorded was cracking, rutting, patch, potholes, localized depression and undulation and majority of the distress were occurred along the slow lane, which are 76% cracking, 68% rutting, 18% patches , 9% is potholes and 6% depression and undulation. 67% of the segments assessed having combination of cracking and rutting. There was only minor distress observed along the fast lane that was mainly surface cracks, which is 10%, 2% is depression, 1% is patch and 1% is potholes.
The method of rehabilitation works identified includes reinstatement, overlays, and overlays with pre-treatment, regulating works and partial reconstruction with base stabilization using cement treated base (CTB). Based on year 2006, more than 97% of the rehabilitation works were performed using overlays and overlays with pretreatment.
Right from the very beginning, the structural design of flexible pavement is facing with uncertainties such as traffic prediction and assumptions of pavement layers strength in design methods. During the construction, quality of the road will also depend upon the workmanship on site and supervision competency. Inclement weather also affects quality control by increasing chances of pavement layer contamination, which require special attention by the supervisors.
Finally, after the road is constructed, both environmental and traffic stress will contribute to possibility of the road to be deteriorated. Initial assessment of the physical pavement condition can be carried out through a visual assessment on the flexible surface condition and the main parameters recorded are cracking and rutting.
Section S3 is a 70 km length expressway traversing across varying terrains from mountainous to low laying areas. The construction of this stretch was successfully completed and opened to traffic in 1994. Since its completion, the first major rehabilitation works within this stretch was carried out in year 2003 involving 4.0 km stretch from km114.00 to km110.00 South Bound between Pagoh and Yong Peng. Cement Treated Base (CTB) was used to strengthen the existing base.
After the new flexible pavement had been constructed, both environmental and traffics stress will cause it to deteriorate. The rate of deterioration will depend on the severity of the traffic loads and the variability of the road materials.
Proper evaluation process shall be carried out to identify the pavement distress and possible causes of the failure before any rehabilitation works is carried out. At present, there are many options of pavement maintenance techniques and rehabilitation methods available in Malaysia. However, appropriate techniques of assessment as well as the right choice of the treatment method for rehabilitation works for various types of road pavement failures are significantly issues in many maintenance organizations.
In line with the above, this study is constructed to assess the flexible pavement maintenance activities along the North-South Interurban Toll Expressway (NSE), identifying the various type of pavement distress and the method of rehabilitation works being implemented along the NSE. The results of this study will be beneficial as a knowledge sharing on the maintenance of the NSE with others maintenance organization.
There are two objectives of this paper. They are:-
i) To identify various type of pavement distress along the North South Interurban Toll Expressway, from Pagoh to Machap, Section S3.
ii) To identify pavement maintenance activities and rehabilitation works carried out along the North South Interurban Toll Expressway, from Pagoh to Machap, Section S3.
Assessment of the pavement distress was carried-out using the surface condition survey form modified based on the assessment guide available in PLUS Bhd / Opus(M)-NMM, as well as the Interim Guide To Evaluation And Rehabilitation Of Flexible Pavements, JKR Malaysia.
The condition of the pavement is assessed over 500 meter segment according to its bound directions and lanes (slow lane and fast lane). The visual assessment was done by assessing the type, degree and extent of the pavement distresses for both fast lane and slow lane from the slow moving vehicles travelling on the hard shoulder.
From the study, most of the pavement distress was observed along the slow lane of each bound and this problems mainly related to the excessive traffic loading as the heavy traffics and slow moving traffics are normally travel along this lane. The type of pavement distress identified was cracking, rutting, patch, potholes and depression and undulating. However, the most common distresses were cracking and rutting. Summary of cracks condition is presented in Table 4.
Table 4: Summary of cracks conditions – Slow Lane
Out of 263 segments assessed along the slow lane, 200 segments or 76% is experiencing cracking problems and remaining 63 segments or 24% segments are still in satisfactory condition with no cracks observed. Further assessment on the cracks conditions was noted that 67% was identified as a crocodile cracks, 5% is block cracking and 4% is surface cracks. This indicates that the deterioration for slow lane is largely influence by heavy loading from the traffics. There are only localized block cracking between km 72.00 and km 74.00 South Bound (SB) were found between warning and severe condition which require attention for rectification works. Overall cracks condition is presented in Figure 1 and Figure 2.
Figure 1: Cracking condition slow lane.
Based on the assessment, 180 out of 263 segments or 68% is having rutting. Further assessment on the degree of the rutting identified that 49% of the rutting is identified under degree 1, 21% is degree 2, 29% is degree 3, 1% is degree 4. There has been no degree 5 rutting identified during the site assessment. In addition, there has been no rutting observed along the fast lane. Overall rutting condition along the slow lane is presented in Figure 3
Figure 3: Pavement rutting – Slow Lane
The Maintenance and Rehabilitation works
The rehabilitations of the flexible pavements are carried out to address the defects highlighted or detected during the inspection as well as after a detailed evaluation has been conducted. Based on the findings, the rehabilitation treatment for flexible pavement can generally divided into reinstatement, overlays, overlays with pre-treatment, structural overlay and regulating works. The type of treatment and common condition of use is tabulated in Table 5.
Table 5: Treatment type and conditions of use
Generally, the rehabilitation works coverage has increased over the years to address to pavement failures not only because of the ageing of the pavement but also do to overall consideration such as cost, coverage and treatment needed to overcome the issues which are some times global but some time local.
Although very stringent maintenance and inspection strategies have been implemented, some pavement failures are still occurring even when design optimization has been considered, there were other factors that may not be predicted and foresee during the planning and design stage as well as after the construction stage. Figure 4 indicates the pattern of rehabilitation activities carried from year 2002 until year 2006.
Figure 4: Rehabilitation works carried out from year 2002 to year 2006.
a. Pavement distress
Results of the study indicated that cracking are the most common type of the failures occurred along the North South Interurban Expressway that is (76%), followed by rutting (68%), patch (18%) potholes (9%) and depression and undulation (6%). The slow lane was found to have majority of defects as heavy traffics and slow moving traffics are the most common users that travelled along this lane, which is the auspicious factor to higher percentage of defects observed. A detailed pavement evaluation is normally required to optimise the budget especially when the particular sections of the pavement require major rehabilitation or upgrading.
b. Pavement Maintenance and Rehabilitation Works
A forward planning software to determine the need of the pavement maintenance and rehabilitation were normally used to not only determine the locations of the rehabilitation work but also to determine the life-cycle of the pavement in future, such that the design life of the pavement can be further stretched to ensure its usage can be extended and enhanced.
On the other hand, a medium term plan which will alleviate the distress and rehabilitate the pavement can be implemented and can generally be divided into reinstatement, overlays, overlays with pre-treatment, structural overlay and regulating works.
In year 2006, more than 97% of the rehabilitation works were performed using overlays and overlays with pretreatment as this method provide not only medium term which is 6 months two 1 ½ years free of maintenance but also a ‘feel good’ view of the completed section. In addition, the regulating treatment normally applicable to address to pavement depression and undulation especially at bridge and culvert approaches. Preventive maintenance such as overlay shall be carried out effectively at the beginning stage when the distresses were identified to avoid further failure that would increase cost of repairs.
1) Jabatan Kerja Raya (April 1994). Interim Guide To Evaluation And Rehabilitation of Flexible Road Pavement JKR 20709-0315-94 , Cawangan Jalan Ikram Series (Pavement) ISP-2
2) Malaysian Highway Authority (September 1996). Maintenance Manual and Guideline (Civil Works).
3) Inspection Manual, Pavement Maintenance Management System, PLUS BHD. July 2000.
4) Jabatan Kerja Raya (December 1992). A Guide To Visual Assessment Of Flexible Pavement Surface Conditions. JKR 20709-2060-92.
5) Assoc. Prof. Dr. Meor Othman Hamzah, USM (2006). Pavement Design. IEM’s Course on Asphalt Material and Pavement Design, 19 December 2006, Kuala Lumpur.
Photo of Pavement cracks
Photo Of Pavement undulating
Photo of potholes
Photo Of Patching Work
PAVEMENT REHABILITATION WORKS
Photo of Pavement regulating
PAVEMENT REHABILITATION WORKS
Photo Of Milling work
PAVEMENT REHABILITATION WORKS
Photo Of Overall completed section