Summary of Road Conditions

C. Summary of Road Conditions

1. Contract A

3. This heavily traveled 39 km section of two-lane highway is part of NR16W. It begins at the Thai border at Chong Mek and ends at the westerly approaches of the newly constructed Lao Nippon Mekong River Bridge west of Pakse. There is an important intersection with Provincial Road (PR) 902 about midway along this road section near the village of Lak 12. Some logging trucks were observed entering NR16 from PR902, traveling east toward Pakse. Of the four contracts, Contract A shows the greatest degree of pavement deterioration, with an average international roughness index (IRI) of 4.3 as recorded in 2003. Trucks typically queue up approaching the Thai border, parking on the shoulder, which has caused significant excessive breaking up of its outside edge. The easterly 5 km of the section follows a southerly realignment to meet the new Mekong River Bridge thereby avoiding a series of congested, semiurbanized neighborhoods. This realignment was implemented during construction. There

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was no net change in the length of the contract, but additional civil works costs (variation orders 005 and 006) increased the contract by about $585,000, primarily for additional earthworks. Contract A includes four new bridges, the longest being the Phek Bridge, which was inspected by the OEM. Some lengths of this road section were partly resealed in 2003, and additional lengths are scheduled for resealing as part of the Champasack Road Maintenance Fund (RMF) periodic maintenance programmed for 2008/2009.

2. Contract B

4. This 49 km section of NR13S has typically been divided into two sections for analysis: Pakse to km, 8 and km 8 to Phiafay (Km 49+700). The initial section traverses the rapidly developing, urbanized, southern approach to Pakse. The section begins just north of a new roundabout near km 1 and terminates at the new channelized intersection of NR13S and NR16E, the road to Paksong. Traffic is extremely high along this entire section, with the road often operating as a four-lane facility. Some sections, particularly those located near a teacher’s college, are highly congested, with average running speeds during many hours near 50 kilometers per hour. Beyond the intersection with NR16E, the road becomes much more rural, and traffic drops dramatically. Contract B has had virtually no periodic maintenance since it was initially opened more than 5 years ago, and yet the riding quality of the road surface remains high, with an average IRI (2003) for the section before km 8 of only 2.7 and after km 8, 3.2. There are eight bridge structures on the section. The longest bridge of the section (112 m), the Bangliang Bridge, was inspected and found to be well constructed and well maintained.

3. Contract C

5. This contract had a history of problems during construction. After this, the 65 km road section from Phiafay to Nasenphan was sealed with DBST, but before all contract work was completed and accepted, a large degree of severe pavement cracking appeared throughout much of the length. After a series of materials testing programs and other investigations, it was determined that the contractor had used poorly compacted, substandard subbase materials, and 30 km of roadway (km 58 to km 88) had to be completely reworked from the subgrade level up to the DBST pavement. Additionally, some other areas of pavement structural section between km 88 and the end of the section at km 118+800 (primarily between km 88 and km 94, and at km 107) were found to be substandard, but of reportedly less severity than the km 58–km

88 section. The Defects Liability Certificate issued in 2001 excluded the section of pavement between km 88 and km 94, for which MCTPC agreed to receive financial compensation in lieu of the contractor continuing with additional repair works. The monies so received were specifically allocated by MCTPC for periodic maintenance on Contract C. In 2003, DCTPC resealed large sections of this contract under a maintenance contract totaling KN1,518 million (about $152,000). The average roughness for this contract, as measured in 2003 after the completion of this periodic maintenance, was 3.3, which value is quite acceptable. Inspection by the OEM determined that, although there was extensive evidence of resealing and patching, the riding quality of the road was satisfactory, and no extensive cracking of DBST pavement was observed.

6. Another area of concern on Contract C was the Thahou Bridge at Km 50, which in early 2001 showed evidence of extensive cracking in the in-situ concrete deck. This bridge is 1 of

13 bridges on this contract totaling almost 0.6 km in total length. Project correspondence and discussions with DCTPC reported that the crack had been sealed by the contractor using a commercial available adhesive epoxy material specially designed for sealing cracking of concrete structures. The OEM made a thorough visual inspection of this bridge and in particular

Appendix 5

the concrete deck. The cracked areas where the epoxy had been applied were clearly visible. The inspection revealed that the epoxy had worked well, and that no further cracking was readily apparent.

4. Contract D

7. This section of road as originally designed and contracted was from Nasenphan to the Cambodian border, a distance of about 46 km. The southerly terminus of the road improvement was subsequently shortened by about 6 km (variation order D02) to terminate at the access road to the small river port of Veun Kham. The traffic survey taken during the OEM indicated an ADT of only 1,327, with 889 being motorcycles/tuktuks. A bypass around Khinak town was constructed as part of Contract D from km 147 to km 153, shifting the alignment of NR13S away from the moderately congested river town of Khinak to avoid resettlement issues identified at appraisal. The new alignment (variation order D01) was well conceived, passing through flat, lightly forested land approximately 1–2 km east of Khinak. The realignment decreased the cost of civil works by about $390,000. The average IRI for Contract C, as measured in 2003, was a relatively low 3.1, which indicates that the pavement surface was still in relatively good condition. Much of the loan proceeds saved due to the shortening of the road at the Cambodian border was used to design and construct (i) the access road to the Khong Island ferry ramp (4 km), (ii) the ferry ramps on each side of the river, and (iii) approximately 47 km of roads on Khong Island. Also, 2 km of access road to Khone Falls, a rapidly expanding tourist destination, was improved under the Project. The two access roads and the roads on Khong Island were all relatively low-cost construction, i.e., low embankments, 5.5/6.0 m roadway width, and SBST placed on top of granular subbase material. During the OEM, these secondary roads were in fair condition, with little evidence of past maintenance activities.

5. Observations

8. The OEM observed two other issues that will ultimately have a detrimental effect on the road. One observation is that at numerous locations along all sections of the road, there is excessive breaking up of the outside edge of the shoulder. As traffic and roadside development continue to increase along the project road, deterioration of shoulders will accelerate, eventually become widespread, and ultimately become a serious and expensive periodic maintenance problem. The cause of the problem is the basic design, and not a result of any construction or workmanship defect. The design of the 1 m shoulder was based on the inner 0.5 m being SBST on primed base course, with the outside 0.5 m consisting of only primed base course, and with the nominal embankment (2:1) side slopes starting directly at the outside edge of the 1 m shoulder. When vehicles (particularly trucks) cross the shoulder to leave the roadway, the wheel loads directly impact the edge of the shoulder, and there is no embankment material to confine the 0.5 m of primed based course, which causes the edge deterioration. On similar projects in other counties, a 0.5 m “rounding” using embankment material, located between the outside edge of the shoulder and top of the side slope, is often used to support the edge of a primed base course shoulder.

9. The second observation is that at the end of the reconstruction (1999/2000), along the vast majority of this 200 km road improvement project, there was little roadside development. Over the intervening 5 years, there has been a sporadic but significant increase in roadside development, which typically should be confined to construction outside of the 25 m right of way, and well away from shoulders, embankment slopes, and side drainage. Unfortunately, DCTPC has not given any priority to preventing encroachments (both dwellings and small shops) on to the right of way. It is the reality of developing countries that if this typical type of encroachment

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is not properly policed from the opening of a new road, then it is almost impossible to maintain the integrity of the right-of-way in the future.