SEACAP Programme Update: Sustainable Rural Roads Access in Lao PDR
The South East Asia Community Access Programme (SEACAP) aims to support the uptake of low cost sustainable solutions for rural access. The overall goal is to leverage pro-poor growth and poverty alleviation through improved access to economic opportunities and public services (eg. health and education) for poor rural communities.This news update highlights the work of SEACAP 17, a programme based in Lao PDR, which is focusing on low-cost locally resourced rural road improvements to improve rural access. SEACAP 17 has been implemented in conjunction with the ADB Northern Economic Corridor Project (NEC) and is carrying out research on a group of rural access roads in Houay Xai district. Lao PDR in the heart of the Mekong region of South East Asia is an agrarian economy with more than three-quarters of the population living in rural areas. An estimated 90% of poverty in Lao PDR is rural-based and there is a strong correlation between access to basic infrastructure services and poverty.
The SEACAP 17 approach is to replace the standard NEC gravel pavement with a SEACAP trial pavement at specific locations along the access roads. The trial pavement types were selected from those presented at a Knowledge Exchange Workshop (December 2004) and the specifications were developed from similar projects in the region and worldwide. The trials include the following pavement types:
- Bamboo Reinforced Concrete, a bamboo reinforced surface consists of a layer of concrete, reinforced with strips of bamboo, and laid upon a compacted base.
- Otta Seal, this surface comprises of a layer of binder followed by a layer of aggregate that is rolled into the binder using a roller or loaded trucks. It is different to surface dressing in that an 'all in' graded gravel or crushed aggregate is used instead of single sized chippings.
- Geocell, manufactured plastic formwork is used to construct in-situ concrete paving. The plastic formwork is sacrificial and remains embedded in the concrete.
- Hand Packed Stone, this surface consists of a layer of large stones into which smaller chips are packed. Remaining voids are filled with sand or gravel to form a strong and semi-impervious matrix.
- Mortared Stone, this surface consists of a layer of large stones, placed closely together to form a tight surface. The voids are filled with mortar to form an impervious layer.
- Concrete Paving Blocks, the blocks are precast in moulds and then laid side by side on the road. Gaps between blocks are filled with fine material to form a strong and semi-impervious layer. A variation of this is to use Fired Clay Bricks where these are available.
- Engineered Natural Surface, this construction is used where the existing subgrade material comprises natural gravel with the same characteristics as the pavement layer.
In order to monitor the pavement trials various data has been collected, specifically:
- The bearing capacity of the road foundations.
- The gradients and alignment.
- Predicted traffic loading.
- Climatic data.
This data is stored in a database (developed in Microsoft Access) which is used and owned by the Ministry of Communication, Transport, Post and Construction (MCTPC).
On completion of the trial sections a base condition monitoring will be conducted and monitoring will be continued over the long term. Condition monitoring will comprise:
- Visual inspection and surface condition logging.
- Photographic recording.
- Surface deformation recording (dipped levels and rut measurement).
- Surface roughness using a MERLIN apparatus.
- Surface texture (sand patch test).
- Classified traffic counts.
- Structural integrity using a Dynatest 3031 LWD Light Weight deflectometer.
The records will be collected in a similar method to other SEACAP projects and stored in an identical database to enable comparisons to other trial section projects.
One of SEACAP 17's key objectives is to disseminate the findings from the trials to regional and international agencies. Forthcoming workshops and seminars will enable practitioners to share the experiences from this project and other similar projects within Lao PDR, South East Asia and worldwide.
SEACAP 17 research is being implemented in 4 modules as follows:
- Module 1 - Project planning and initiation
- Module 2 - Representative data capture
- Module 3 - Data interpretation
- Module 4 - Information dissemination and training
For more information about SEACAP 17 please contact:
Safety and Security
Regional East and South Africa
Mobility as a Human Right
Transport services IMTs
Regional Latin America
Regional West and Central Africa