Helping Vietnam to Achieve Success as a Middle-Income Country 92065 Improving Vietnam’s Sustainability Key priorities for 2014 and beyond Rural Road Pavement and Surfacing Options The Rural Road Surfacing Research Programme . trial roads have been constructed within a range of The Rural Road Gravel Assessment Programme road environments in 16 provinces, from which a (RRGAP) comprised the evaluation of a representative 123 sections of between 80m to representative selection of 269 WB-funded road 200m in length have been selected for ongoing links from 16 provinces. performance monitoring. Between 2003 and 2012 three phases of trial road selection, design and construction were undertaken The condition monitoring of the Vietnamese trials under the RRST programme. The objective was to has resulted in the assembly of a significant compare new pavement options in terms of amounts of data on the performance of a wide construction and in-service performance against a variety of pavement and surfacing types. number of standard Vietnamese “control” sections, Monitoring of the trial sections commenced as soon as construction was completed. A total of 156 km of Research Outcomes Sustainability of Unsealed Gravel Surfaces Phase I comprises the identification of appropriate pavement types compatible with the road The RRGAP studies showed that unsealed gravel is environment and may be considered as a not a sustainable option in many of Vietnam’s road progressive screening operation aimed at environments. More than 60% of the analysed road identifying one or more options that are compatible sections indicated gravel loss of greater than the with the road task and its environment. The second 20mm/yr taken as the limit of loss sustainability. phase is the detailed design of the selected pavement option compatible with engineering Pavement and Surfacing Selection and Design requirements; primarily traffic, axle load and sub- A two-phase pavement selection and design grade strength. approach has been developed, based on the experience gained with the RRST programme Strengthening Competitiveness, Improving Sustainability, Increasing Opportunity Helping Vietnam to Achieve Success as a Middle-Income Country Phase II of the selection and design process involves Specifications the detailed design of the general options identified under Phase I. The RRSR programme has prepared a library of relevant rural road pavement specifications in The Comparison of Engineering Performance English and Vietnamese. These have been updated The rural road performance data enables based on experience gained during RRST comparative analysis to be made of different construction and monitoring phases. pavement and surfacing options. Figure 1, for Quality Control example, compares options in a single very high rainfall environment. Existing supervision arrangements in the rural road sector do not appear to be sufficiently effective. Figure 1 Performance of Different Options on a Single Trial Road: Visual Assessment. Pavement Drainage Although drainage was not a direct component of the pavement trials its impact on the performance of the pavements was assessed and the following general conclusions arrived at: • Side drainage was often poorly constructed and frequently omitted altogether. • Missing or ineffective drainage is directly linked to poorly performing or failing pavements. Environmentally Optimised Design Whole Life Costs The principles of Environmentally Optimised Design A simplified Whole Life Asset Cost (WLAC) (EOD) and Spot Improvement allow for the approach, assessing both maintenance and adoption of variable surfacing options along the construction costs over road design life period, has length of rural road links. The appropriate adoption been developed for use in the RRSR programme. of this strategy allows a more focussed use of limited construction resources. .. Maintenance The lack of routine or periodic maintenance deterioration patterns of the trial options over 6-7 undertaken on the RRST roads since 2005 reflects years it has been possible to assess the relative the general position in the rural road sector as a maintenance costs. whole in Vietnam. However, by analysing the Strengthening Competitiveness, Improving Sustainability, Increasing Opportunity Helping Vietnam to Achieve Success as a Middle-Income Country Pavement and Surfacing Performance Unsealed Granular Pavements Stone Block Pavements Analysis of the trial control section data confirmed The performance of the two stone cobble or stone the conclusions from the separate gravel studies sett trial pavements is good and they have been (RRGAP) that even in low traffic environments shown to be highly resistant to rain-storm and flood unsealed gravel wearing course (GWC) or water- erosion. bound macadam (WBM) surfacings are not The pavement is effective in providing a sustainable sustainable options in areas of flood, high rainfall, surface/road-base in mountainous areas, albeit with or steep gradient. Monitored trial sections in the high roughness consequences. lower rainfall, flatter, regions in the Vietnam Central Plateau have shown satisfactory performance in Brick Pavements similar traffic environments when well-constructed with appropriate materials. Although the single sand seals placed over brick options have performed very poorly, the brick Concrete Pavements pavements themselves have continued to perform satisfactorily with little or no maintenance. The concrete trial roads are generally performing well. Even on the sections exhibiting some cracking, Carriageway Shoulders the great majority of the pavement slabs are still performing adequately in a zero-maintenance Road shoulders were constructed with a variety of regime. The exceptions are where significant materials. In general the shoulders were very problems with the quality of concrete were poorly maintained and deteriorated to poor recorded during construction. condition. In many cases the erosion of shoulders was impacting on the performance of otherwise Sealed Flexible Pavements sound pavements. Coarse quarry-run materials were clearly the best performing shoulder materials The combination of emulsion double chip seal on with sealed WBM/DBB a second best. Full-width dry-bound macadam base/sub-base is performing construction should be considered where the as well or better than the Vietnamese standard additional costs are justified. option of hot bitumen seal over water-bound macadam base/sub-base. Key Recommendations 1. The design and construction of rural road  Design must be suitable for the local networks should be founded on four key environment. principles:  Materials must be locally available.  Roads must suit their function. Strengthening Competitiveness, Improving Sustainability, Increasing Opportunity Helping Vietnam to Achieve Success as a Middle-Income Country  Roads should be constructed with whole life 5. The use of technical standards and costs that will not place excessive burdens specifications that are focussed on up-to-date on the local management budgets. regional or national requirements is essential. 2. It is not possible for local authorities, designers 6. The RRSR has shown that unsealed granular or contractors to accept research outcomes roads are not a sustainable option in many of without their being adopted by Ministries for the road environments of Vietnam, especially if inclusion in official standards and specification. no effective maintenance programme is in 3. Suitable rural road classification is a necessary place. step in providing the context and design control 7. Spot Improvement solutions may be effectively framework. applied in cases where there is insufficient 4. For rural roads a key initial question should be- budget to supply a sustainable whole road link “What roads can I build with the locally solution. available materials?” Further Discussion Phuong Thi Minh Tran is a Senior Transport (Intech-Associates), David Salter (ADB, formerly Specialist in the East Asia and Pacific Sustainable SEACAP Manager). Department of the World Bank in Vietnam. This note is part of a series of Vietnam Transport Jasper Cook is a Geotechnical and Road Engineering Notes to share experience on the transformation of Short Term Consultant with the World Bank in the Vietnamese transport sector. It is built on a Vietnam and Lao PDR. combination of the outputs from the DFID funded South East Asia Community Access Programme Pham Gia Tuan is Vietnam based Road Engineering (SEACAP) and the World Bank Rural Transport 3 Short Term Consultant with the World Bank. Project (RTP3) and the RTP3 Additional Financing with additional support from GFDRR with respect to Acknowledgements climate resilient issues. For comments, please The achievements of the RRSR project are due to the contact Tran Thi Minh Phuong contributions of a large number of persons over an (ptran1@worldbank.org); World Bank in Vietnam. extended period of time. Simon Ellis (Lead Transport Specialist, Former Transport Coordinator, WB in Viet Any findings, interpretations, and conclusions Nam), Peter O’Neill and Simon Lucas of DFID played expressed herein are those of the authors and do key roles in setting up the project. The support and not necessarily reflect the views of the World Bank. commitment of the Ministry of Transport and the Neither the World Bank nor the authors guarantee Steering Committee has been a vital facilitating framework for the research and dissemination work. the accuracy of any data or other information The efforts of the various project teams from Intech- contained in this document and accept no TRL; ITST; TDSI and OTB Engineering have ensured responsibility whatsoever for any consequence of the successful project delivery. In particular the their use. fundamentally important contributions of Rob Petts Strengthening Competitiveness, Improving Sustainability, Increasing Opportunity