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Low Cost Road Surfacing Project Working Paper No 12 © CSIR, TRL, Intech Associates, Sept 2002 Knowledge & Research R7782, Working Paper 12 0 LOW COST ROAD SURFACING (LCS ) PROJECT LCS WORKING PAPER No 12 PAVING THE WAY FOR RURAL DEVELOPMENT & POVERTY REDUCTION by Dr Colin Gourle y, BSc, MSc, PhD, TRL Anthon y Greenin g, BSc, TRL Dr David Jones, PhD, PrSciNat, CSIR Robert Petts, BSc, CEn g, MICE, MIHT, MIA grE, Intech Associates September 2002 Low Cost Road Surfacing Project Working Paper No 12 THE LOW COST ROAD SURFACING INITIATIVE The Low Cost Road Surfacing (LCS) initiative aims to provide documentation and international guidelines on the provision and maintenance of low cost road surfaces an d basic access for rural communities in economically emerging and developi ng countries (EDCs). It is based on a research project funded principally by the British Department For International Development (DFID) under i ts Knowledge and Research (KaR) programme. The initiati ve is led by UK-based specialist consultants Intech Associates. Collaboration is being established with a number of organisations with interests or experience in the sector, including CSIR, TRL Ltd, ILO/ASIST Africa and Asia-Pacific, the ILO-SIDA funded Upstream Project and Ministry of Rural Devel opment Cambodia, WSP International, Ministry of Transport Vietnam, Greater Mekong Sub-region Academic Research Network, The Institute of Technology of Cambodia, Chieng Mai Universi ty Thailand, the Committee C20 (Appropriate Development) of PIARC (World Road Associati on) and the International Focus Group. The LCS programme is being implemented over a 3 year period from 2001 to 2003. The LCS programme is concerned with supporting sustainable improvements in low cost, road surfacing and basic access to support poverty reduction initiatives in rural communities. This implies the effective use of local resources, particularly human resources, loca lly available and alternative materials, and readily available and low cost inte rmediate equipment wherever possible. In the situation of scarce financial resources, it also requires the application of affordable and appropriate standards and adoption of techniques suitable for use by the indigenous private sector (particularly small domestic construction enterprises) and local communities. The applicati on of good management practices coupled with adequate technical inputs are also encouraged. It is intended that dissemination of the guidelines will be through electronic media as well as more traditional publication routes. INTERNATIONAL FOCUS GROUP TRL are currently carrying out a number of research projects on low volu me sealed and unsealed roads for DFID and a number of other Donors. Intech Associates is carryi ng out research on low cost surfacing with a number of partners. As part of these projects, an Inter national Focus Group (IFG) has been established. The main function of the IFG is to thoroughly examine technical, economic and social issues arising from the project work. The group will also provide a focus to improve opportunities for dissemination of project results. The IFG being developed will compr ise technical experts and engineers from a number of African, Asian and other c ountries as well as other international experts. Participation in the IFG will provide opportunities to: • build regional and international partnerships • exchange ideas, experiences, information and data • strengthen local knowledge with new information • build on existing local research • promote wider acceptance of the projects themselves Four projects listed below, are of particular interest to the IFG. Proje cts 1, 2 and 4 are part of the DFID’s Knowledge and Research programme, whilst Project 3, is a colla borative research project involving a number of different donors:- Project 1: Reducing Whole Life Costs: Environmentally Optimised Design Project 2: Minimising the Cost of Sustainable Basic Rural Road Access Project 3: Engineering Standards for Labour-based Roads Project 4: Low Cost Road Surfacing This Working Paper was prepared for the 20 th Conference of the ASEAN Federation of Engineering Organisations (CAFEO-20). The document is intended to inform and provoke discussion, contributions and dissemination regarding surfacing aspects or rural roads. The LCS Project welcomes dialogue with engineers, managers, organizations, communities and individuals active or interested in the rural transport sector with the objective of the promotion of a sustainable ru ral access approach for EDCs. This document is an output from a project funded by the UK Department for International Development (DFID) for the benefit of developing countries. The vi ews expressed are not necessarily those of the DFID. © CSIR, TRL, Intech Associates, Sept 2002 Knowledge & Research R7782, Working Paper 12 1 PAVING THE WAY FOR RURAL DEVELOPM ENT & POVERTY REDUCTION Low Cost Road Surfacing Project Working Paper No 12 First Edition: September 2002 COPYRIGHT © CSIR, Intech Associates & TRL Extracts from this publication may be reproduc ed provided the source is acknowledged as:- “CSIR, Intech Associates, TRL” ACKNOWLEDGEM ENTS Material for this paper has been assembled from assignments and colleagu es working in the appropriate technology roadworks sector in Africa, the Americas, Asia an d the Pacific, as well as available reference documentation. Important c ooperation from engineers and other personnel in the road authorities in these countries has been s upported by a number of agencies and organisations including DFID, BPWA, CIDA, DANIDA, DGIS, EU, Helvetas, KfW, NORAD, SDC, SIDA, USAID, ILO/ASIST (Africa and Asia-Pacific), PIARC (Wor ld Road Association), TRL, UNDP, and the World Bank. Cooperation has been particularly active from the ILO-SIDA Upstream Project and Ministry of Rural Development, Cambodia, and the WSP International-Ministry of Transport V ietnam - DFID Rural Transport Project. The authors wish to acknowledge the cooperation and support received from th ese individuals and organisations, as well as the val uable contributions and comments on the drafts provided by colleagues. THE AUTHORS Colin Gourley is the Group Manager International Division of TRL. e-mail : cgourley@trl.co.uk Tony Greening works for the International Division of TRL. e-mail: tonyg@ecoweb.co.zw David Jones Technical Specialist, Transport Infrastructure Transportek, CSIR: e-mail: djones@csir.co.za Robert Petts is the Principal of Intech Associ ates; Consulting Engineers to the road management and maintenance sector: e-mail: rob@intech-consult.demon.co.uk Abbreviations ASEAN – Association of South East Asian Nations CAFEO – Conference of the ASEAN Feder ation of Engineering Organisations CSIR – Council for Scientific & Industrial Research DFID – Department For International Development EDC - economically Emerging and Developing Country GMSARN – Greater Mekong Sub-region Academic and Research Network IFG – International Focus Group IFRTD - International Forum for Rural Transport and Development ILO/ASIST - International Labour Office/Advisory S upport Information Services & Training programme IMT – Intermediate Means of Transport ITC – Institute of Technology of Cambodia ILO – International Labour Organisation KIHBT – Kenya Institute of Highway and Building Technology KTC – Kisii Training Centre LCS - Low Cost (Road) Surfacing TRL - Transport Research Laboratory vpd - vehicles per day © CSIR, TRL, Intech Associates, Sept 2002 Knowledge & Research R7782, Working Paper 12 2 Paving the Way for Rur al Developm ent & P overty Reduction Gourley, Greening, Jones & Petts CAFEO-20 20 th Conference of ASEAN Federation of Engineering Organisations. Phnom Penh, Cam bodia, 2 – 4 Septem ber 2002 Hosted by the Engineering Institution of Cam bodia. Them e – “Engineering for the alleviation of poverty in ASEAN m ember countries” Sub them e – “Transport: Road, Rail, Water and Air” PAVING THE WAY FOR RURAL DEVELOPMENT & POVERTY REDUCTION Dr Colin Gourley BSc, MSc, PhD, TRL Anthony Greening BSc, TRL Dr David Jones, PhD, PrSciNat, CSIR Robert Petts BSc, CEng, MICE, MIHT, MIAgrE, Intech Associates ABSTRACT Som e of the tertiary road networks in the A SEAN countries are not y et developed to standards appropriate for their vital transport role. Governm ents and international agencies are also com mitted to alleviating poverty , which occurs m ainly in the rural areas of these countries. Im proving rural transport infrastructure will be an essential com ponent of this strategy . The cost of fully developing these networks will be substantial and the process is expected to extend over a tim e span m easured in decades. With such a large com mitm ent of resources in prospect, it will be essential that the policies, standards and arra ngem ents for the developm ent and m aintenance of these networks m ake the m ost effective use of the available constrained resources. Rural com munities require sustainable y ear-round access for their basic social and econom ic needs. This is a fundam ental requirem ent to support govern ments’ efforts to reduce rural poverty . For m any years gravel/laterite has been prom oted as the principal surface for providing road access for rural com munities. Recent research confirm s the particul ar problem s of gravel/laterite surfacing in the ASEAN region. The paper presents the rationale for restricting the u se of gravel/laterite as a road surfacing m aterial in the region. It also proposes a strategy for m ainstr eam ing the application of m ore sustainable surface options for rural roads. The long term objective is the provision of y ear-round access to all rural com munities at low cost and with m anageable m aintenance liabilities. Maintenance should be feasible with the realistic m obilisation of local funding a nd resources and arranged with the involvem ent of local com munities and enterprises. The rural com munities should benefit from both the provision and use of the im proved infrastructure. The paper is based on the work of research progr am mes funded by UK Departm ent for International Developm ent (DFID) with cooperation of the G overnm ents of Cam bodia and Vietnam , and other research on the use of gravel/laterite and low cost surfaces. KEY WORDS : Road Surface Maintenance Sustainable CAF EO-20 September 2002 1 Paving the Way for Rur al Developm ent & P overty Reduction Gourley, Greening, Jones & Petts PAVING THE WAY FOR RURAL DEVELOPMENT & POVERTY REDUCTION Dr Colin Gourley BSc, MSc, PhD, TRL Anthony Greening BSc, TRL Dr David Jones PhD, PrSciNat, CSIR Robert Petts BSc, CEng, MICE, MIHT, MIAgrE, Intech Associates 1. The under-developed state of the tertiary road networks In m any devel opi ng count ries, t he m ain road net work carri es about 80 t o 90 per cen t of passenger and frei ght transport and i t is, therefore, of key import ance t o the econom y. M ain road net works are underst andabl y gi ven high priority in the allocation of m aintenance funds in recognition of th eir econom ic im portance. Conversely, rural roads are given lower priority in the allocation of m aintenance f unding because they carry m uch lower volum es of m otorised traffic. Unsealed rural roads with earth and gravel/laterite su rfaces com prise the greater proportion of the length of public road in rural areas in developing regions. They account for alm ost 60 per cent of the m ain road network, or about 1.2 m illion kilom etres . In addition, there exists an estim ated 5 to 6 m illion kilometres of desi gnat ed m inor roads and m otorabl e track s, and an ext ensi ve net work of undesi gnat ed t racks and pat hs, perhaps several times t he ext ent of t he desi gnat ed net work. Li mited fundi ng avai lable for the maintenance, and ot her fact ors, have m eant that m uch of t he rural road net work has fal len i nto di srepai r. In the South East Asian region two exam ples serve to illustrate the under-developed state of the rural road net works. Cambodia A recent report 1 on t he C ambodi an road net work assessed t hat 75% of t he 4,165 km of nat ional (m ain and provi nci al) roads were not in a m aintainabl e condi tion. A previ ous survey in 1999 assessed t hat of t he approxim ately 28,000 km of rural road network, only about 6,000 km (21%) had been rehabilitated since the severe disruption of the Khm er Rouge regim e. These roads were m ostly re built to gravel/laterite standards. However m aintenance funding is only available for a sm all portion of the rehabilitated network. There is thus justifiable concern for the sustai nability of a ‘gravel-only’ strate gy for rural roads in Cam bodia 2. Vietnam Vi etnam has a road net work of approxi mately 210,000 km , this represent s a densi ty that is twice t hat of Thai land or Malaysia. However, only 13.5% of the road network is considered to be in good condition, just 26% has two or m ore lanes, and 29% is bitum inised. Over 10% of v illages are inaccessible by road for at least one m onth of the year 3. Whilst fundi ng is a major i ssue, quest ions are bei ng rai sed regardi ng whet her provi sion and m aintenance of l arge unpaved networks is sustaina ble using the traditional strategies from a financial, resource m anagem ent (gravels are a non-renewabl e nat ural resource) or envi ronm ent al perspect ive. 2. The link between rural accessibility and poverty reduction If rural roads are poorl y m aintained, t his can have a l arge negat ive soci o-econom ic impact on t he livelihoods of local com munities and the econom y as a whole. Networks that deteriorate quickly put an untenable dem and on the lim ited m aintenance resources, reduce access to a le vel that severely restri cts social and econom ic development an d can put liv es at risk in ru ral co mmunities. It is th e ru ral ro ad netwo rk th at serv es th is popul ation and t hus i t has an i mport ant rol e in prom oting t he devel opm ent of t he rural econom ies and t he livelihoods of the local people. Problem s are often m ultip lied for vulnerable groups in society such as wom en, 1 Cam bodian Rural Transport Infrastructu re Program , A Sub-Sector Overview, Minist ry of Rural Developm ent, Decem ber 2001. 2 Sem inar on ‘Surface Options – Policy and Strategy for Sust ainable Access’, MRD, ILO, P hnom Penh, 11 – 13 Decem ber 2001. 3 Vietnam Countr y repor t 2001 CAF EO-20 September 2002 2 Paving the Way for Rur al Developm ent & P overty Reduction Gourley, Greening, Jones & Petts subsistence farm ers, landless poor, the sick, disabled and elderly. Although all sectors of rural com munities benefit from im provem ents in accessibility, wom en are often the greatest beneficiaries. Reliable rural road access improves: • Marketing opportunities for subsistence farmers. Impassable r oads lead to loss of market opportunities, spoi ling of crops, reduced or l ost income. Agri cul tural input to the economy i s hi ghest duri ng or short ly after the rai ns and i t is essent ial to move produce at this time. • Ru ral co mmu nity h ealth through better access to health care. Main taining wet season access is important because i t is at this time that instances of mal aria, dengue and ot her w ater borne di seases are at their peak. • Educat ion through better access to schools and shorter travel times. • Social welfa re. Maintaining inter-community a ccess to family and friends has important social benefits, which help promote a better quality of life for the rural poor. Ru ral co mmunities are o ften left iso lated wh en th eir ro ads b eco me im passab le d uring th e rain s. Often it is o nly rel atively short road sect ions t hat are affect ed. Thi s is norm ally caused by poor m aintenance, whi ch has al lowed roads and st ruct ures t o fal l into such a st ate of di srepai r that they can no l onger funct ion. Both the Cam bodian and Vietnam ese governm ents see l ack of access to local tran sport infrastructure and servi ces as one of t he cent ral feat ures of povert y. 3. The previous focus on gravel roads and the associated problems in S. E. Asia Natural gravel (or laterite) surfacing is generally used as a so-called “low-cost” solution to rural access problem s in m any developing and em erging econom ies. This m aterial provides an interm ediate surface between basic engi neered eart h and hi gher cost , usual ly bi tuminous pavi ng. Gravel is appropri ate where sui table m aterial is avai lable and l aid to surfaci ng speci ficat ions, gravel haul di stances are short (i.e. < about 10 km ), road gradi ents are l ess t han about 6%, rai nfal l is low or m oderat e (i.e. < about 700 m m/annum ), t raffi c is rel atively low (i .e. < about 200 m otorised vpd), fi nance resources and m anagem ent capaci ty are avai lable for rout ine m aintenance (incl udi ng gradi ng/ reshapi ng), and peri odi c regravel ling, and dry season dust gene rat ion i s not severe. Unfort unat ely, these condi tions cannot be achi eved i n m any locat ions i n Sout h East Asi a. Nat ural ly occurri ng lateritic and other suitable gravels are usually lim ited in occurrence; the good quality deposits still left unused are often located far from the roads requi ring regravel ling. Gravel is a ‘wasting’ surface. Material is lost from the surface of the road due to the action of traffic and rainfall; gravel loss i ncreasi ng approxi mately proport ionat e to bot h. Som e regi ons of Sout h East Asi a experi ence part icularl y hi gh vol um e and i ntense rai nfal l, whi ch l ead s to severe erosi on of gravel roads and oft en al so impassabl e condi tions. In t he dry season t he bi ndi ng effect of th e fin es is red uced due to m oistu re lo ss an d th ey are ‘sucked’ out by traffic in the form of dust, lead ing to surface ravelling. Annual rates of gravel loss can exceed 5cm of surface thickness. Losses are higher if poor gr avel is used, or if it is not properly constructed. Gradi ents are oft en st eep on l ow vol um e roads t o m inimise eart hworks and overal l const ruct ion cost s. Gravel loss increases on steep gradients. Gr avel surfaces also disintegrate if they are subjected to flooding. Maintenance of gravel is expensi ve, especi ally for peri odi c regravel ling, whi ch is typical ly requi red at 3 t o 5 y ear interval s. R out ine m aintenance of a gravel road can be achi eved for US$250 - 650/ km /year, dependi ng on t he method used. However the need to replace the surface lo sses by periodic m aintenan ce re-gravelling can cost a further US$400 - 2,000/km /year. These levels of funding are difficult fo r governm ents or com munities to provide. There is an inevitable increas e in gravel haulage distances over tim e as deposits are worked out. Due to the foregoing, gravel roads are rarely m aintain ed system atically an d m any rev ert ev entually to earth ro ad standard. The provision, and then deprivation of access to com munities has serious social im plications. 4. The health and environmental issues of gravel Num erous consequences are a ssociated with gravel roads 4. In dry condi tions, dust generat ed by traffi c, and t o a lesser ext ent wi nd, resul ts in increased gravel loss (40m m/annum vs 10m m/annum where dust cont rol was practiced), safety hazard (fatalities on dry gravel roads are disproportionate to the num ber of vehicles using 4 Doctor ate T hesis, David Jones CAF EO-20 September 2002 3 Paving the Way for Rur al Developm ent & P overty Reduction Gourley, Greening, Jones & Petts them ) health hazard, discom fort and nuisance, air pollution, a nd reductions in agricultural yields and livestock health . Du st sp read over p eople, v illag es, in homes an d field s has m any im pacts an d co sts, m any of wh ich have yet to be quant ified. Food st ores and wat er resources can be pol luted . Heal th risks associ ated wi th m ineral airborne dust are well known. Particles finer than 10 m icrons are highly respirable and can result in bronchitis, em physem a, silico sis an d pneumoconiosis, effects id entified in vario us earlier research stu dies. Th ere is also evi dence of i ncreased l ung and ski n cancer associ ated wi th hi gh ai rborne dust concent rations. Dust ent ers machinery and electrical equipm ent, usual ly leadi ng t o subst antially reduced l ife and/ or great er servi cing frequency and m aintenance cost s. Research 5 has shown t hat typical ly 30% of am bient part iculate m atter is attribut ed t o road dust . One vehi cle travelling one kilom etre once a day ever y day of the year will typically gene rate between 0.2 and 0.6 tonnes of fines, t his bei ng l ost from the road and causi ng t he impact s descri bed above. Put anot her way , in a dry season, vehi cles and wi nd can rem ove of t he order of 25 t onnes of dust per ki lometre of unseal ed road every year. During rain periods, runoff of fines into stream s has serious im pacts on water quality. Runoff siltation causes a high m aintenance requi rem ent in the drai nage sy stem . R oads al so becom e slippery leadi ng t o increased safet y hazards. Grav el p it ex cav atio ns can ev entually fill with water an d beco me lo ci fo r d isease. Th ey are d angerous fo r chi ldren and l ivest ock and i nevi tably becom e dum ping si tes for garbage, bui lding rubbl e and scrap. Perhaps the biggest environm ental issue associated with gravel roads is that of sustai nability of a non-renewable reso urce. Su itab le g ravel is b eco ming a scarce co mmodity an d its in judicio us use will ev entually lead to th ere bei ng no such m aterial for any form of road const ruct ion. 5. New Strategies - A Paradigm Shift In Thinking Despite the im pact that the poor cond ition of rural roads can have on liveli hoods, few countries are likely to be able to provide sufficient funding to fu lly im prove and m aintain networks to an acceptable paved standard in the foreseeable future. Rural Authorities, Non-Governm ental Organisations and the local com munities, need methods whereby all weather access can be m aintained at reasonable cost. W ith very restricted resources and on very su bstan tial n etwo rks th is o bjectiv e is im possib le to achi eve usi ng current road provi sion and m aintenance strategies. About fifty years ago a ‘rul e of thum b’ was est ablished whi ch stipulated that roads carrying m ore than 50 m otorised vehi cles per day merit upgradi ng from eart h to gravel, and from gravel to a first generation bitum en surface at 200 vehi cles per day . These rough and ready figures were based on assessm ents of whole life costs (the total o f co nstru ctio n, m ainten ance, and road user costs). However, condi tions have changed. Technol ogy , research and knowledge have m oved on apace. Un fortu nately th is o utdated ‘ru le o f thumb’ still p ersists in th e m inds of ma ny. Traditiona l Appr oach 0 50 100 150 200 250 300 350 400 450 500 Traffic (Vpd) Whole Life Cost Earth Roads Gravel Roads Convent ional Paved R oads Rule of Thum b Upgrade from Earth to Gravel at 50 vehicles per day and above. Upgrade form Gravel to a Conventional Paved R oad at 200 vehicles per day and above. So what are the options? • Adopting a flexible, realistic and innovative approach to access n eeds, provision and maintenance, CAF EO-20 September 2002 4 5 US E nvir onm ental Pr otection Agency Paving the Way for Rur al Developm ent & P overty Reduction Gourley, Greening, Jones & Petts • Maximising the use of earth (provi sion of good camber, drainage and tra ffic control can often extend the serviceability of earth roads) wh ere in-situ soils are suitable, • Spot improvement s where l imited avai labl e resources are t arget ed t oward appropri ate improvement measures at strategic points on th e route to ensure an optimal level of access. These would include: - Judi cious use of gravel (if resources are scarce) - Provi sion of short sect ion of bitumi nous or non-bi tumi nous surf aci ngs. By prom oting i nnovat ion, usi ng l abour-based and l ight equi pm ent technol ogi es and devel opi ng desi gn approach es an d m ainten ance strateg ies th at wo rk with th e en vironment, b oth th e in itial co nstru ctio n co sts an d longer t erm m aintenance dem and can be si gni ficant ly reduced (see Fi gure bel ow). Recent research 6 has shown t hat in som e circum stances bi tumen seal ing of gravel roads i s econom ical ly just ified at traffi c level s as l ow as 40 t o 70 vpd, and wel l engi neered eart h roads on good subgrade soi ls can provi de adequat e servi ce at traffi c level s of bet ween 70 t o 100 vpd and bey ond. Si tuations requi ring a gravel surfaci ng need careful consideration particular ly as better engineering approaches, including increased attention to surface maintenance (often m axim ising use of labour and light equipm ent), can increas e the serviceability of earth roads. Local ised ‘spot improvem ents’ such as i mprovi ng drai nage or provi ding gravel or ot her pavi ng opt ions over key short len gths can en hance th e u tility o f earth ro ads b y ex ten ding th eir ab ility to carry traffic in wet weath er condi tions. Asi de from econom ic consi derat ions, concerns are bei ng voi ced regardi ng t he dwi ndl ing availab ility o f su itab le g ravel resources and the increasing cost of longer haul di stances. The l ocal cap acity to ach iev e re-g rav ellin g target s, t he cont inuous m aintenance burden, and soci o-envi ronm ent al issues, notably the adverse effect on air q uality o f dust raised by vehicles usi ng gravel roads, are al l provi ding impet us to prom oting pol icy change and provi sion of al ternat ive surfaci ng t echnol ogi es. Revi sed Thinking 0 50 100 150 200 250 300 350 400 450 500 Traffic (Vpd) Whole Life Cost Engineer ed E arth Roads Extend Serviceability of earth roads by improved en gineering and spot improvement approaches. Increased attention to surface maintenanc e of earth roads is needed Low Volume Paved R oads Appropriate desi gn and construction technologies including labour based a nd intermediate bituminous surfacings and other alternative surfacings 6. The proven alternatives to gravel It is necessary to be m ore rigorous in evaluating the options for rural and access road surfacing. Gravel will probably be found to be suitable in fewer locations th an previously thought. The fo regoing diagram s illustrate the reduced ‘window of suitability’ of gravel. Poor peopl e oft en rel y on non-m otorised t ransport , m otorcy cles and si mple trucks for t heir transport needs. On many soils, an engineered earth road is sufficient to provide basic access fo r these vehicle types, provided that specific, lim ited constraints such as wat ercourse crossi ngs and st eep gradi ents are adequat ely engi neered wi th spot improvem ents. The cam ber and drai nage m ust of course be m aintained. However i n som e circum stances t he in-si tu soi ls are just too weak t o support any traffi c in the wet , and m ust be covered . Fo rtu nately, th ere is a ran ge of altern ativ e surfaci ng and pavi ng opt ions al ready proven i n vari ous countries that could provide appropriate, econom ical and sustainable alternatives to gravel. Suitability will depend on l ocal circum stances. These al ternat ives, i nvol ving t he appropri ate use of avai lable m aterials, m ay be cheaper i n whol e-l ife-cost term s. M any can be carri ed out by sm all local ent erpri ses usi ng l ow-capi tal, labour based and l ight equi pm ent m ethods. They coul d have l ower m aintenance requi rem ents than gravel , not onl y in term s of cost but also by reduci ng t he need for (i mport ed) heavy equi pm ent to transport and com pact . Thei r envi ronm ent al impact coul d be subst antially less. CAF EO-20 September 2002 5 6 Secondar y and Feeder Road Developm ent Pr ogr amme Final r epor t, Depar tment of State Roads, Ministr y of T ranspor t and Energy, Gover nment of Z imbabwe. Novem ber 1995. Paving the Way for Rur al Developm ent & P overty Reduction Gourley, Greening, Jones & Petts The opt ions for roadbases and surfaci ng are sum marised i n Tabl e 1 7. Gu idelin es o n th e u se o f th ese altern ativ e surfaces and pavem ent layers have been com piled a nd successfully im plem ented in a num ber of African count ries. Si milar docum ent s are current ly bei ng com piled for Sout h East Asi a. 7. The experiences of Southern Africa Comprehensi ve research i nto low-cost surfaci ng as an alternat ive to gravel roads has been undert aken i n southern Africa in recent years 8 9. R esearch has i ncluded just ificat ion for upgradi ng (consi deri ng i ssues ot her than traffic alo ne), m aterial sp ecificatio ns (layers a nd su rfacin g), su rfacin g typ es (d ust p alliativ es, san d seals, singl e seal s, graded seal s, t hin concret e and bl ock pavi ng), const ruct ion m ethods (i ncl udi ng l abour-based) and life-cy cle cost s. The research has shown t hat, provi ded t raffi c charact eri stics and growt hs are underst ood, sound construction practices are followed and adequate m ainte nance is carried out, m ajor im provem ents in access can be achi eved and si gni ficant savi ngs i n whol e-l ife cost s are recorded. Sm all cont ract ors, usi ng l abour-based methods throughout the construction process, have produced good quality work m eeting all the necessary specificatio ns. Im proved ro ads h ave resu lted in notable d evelopments in th e co mmunities, in clu ding in creased tourist traffic, co mmercial ag ricu ltu re and forest ry and sm all m anufact uri ng busi nesses. As part of t he research, training courses and appropri ate docum ent ation (i ncl udi ng cont ract ual docum ent ation) has been devel oped t o facilitate th e d evelopment o f sm all co ntracto rs. There are a num ber of l ow-cost surfaci ng t ypes t hat lend t hem sel ves t o bot h l abour-based, si mple equi pm ent operat ions 10. These include: • Sand seal s • Chip seals • Slurry seals • Otta seals TRL in collaboration with ANE in Mo zam bique recently constructed a range of bitum inous seals to dem onstrate the feasib ility, ap plicab ility an d potential fo r co nstru ctio n of bitu menised seals (Otta seal, p rem ix, p enetratio n macadam , and single/double surface dr essing and sand seal) us ing labour. Em ulsions, applied at am bient temperat ure were used i nstead of hot bi tumens. 8. Spot Improvement Strategies Earth and gravel roads are particularly suscept ible to envi ronm ent al dam age. Oft en, just short sect ions of road are affected but th ese can have a serio us im pact o n passab ility, esp ecially d uring th e wet seaso n, th us red ucing the benefits for rural com munities, which they were de signed to provide. In respons e to these conditions, spot im provements targ eted at p roblem sectio ns of ru ral ro ad netwo rks can give larg e b enefit/co st ratio s. Th e fo cus on road provi sion i n rural areas i s m ovi ng away from the convent ional concept of benefi ts from reduced vehi cle operating costs to that of providing all weather access for the m odes of transport used. W hen access is treated as a priority (i.e. to schools, clinics, markets etc), it is likely that there w ill be an increased focus on localised improvem ent opt ions. If t hese ‘spot improvem ent’ works are t o be carri ed out , then t he convent ional large contracto r-eq uipment b ased ap proach can beco me prohibitiv ely ex pensive an d cu mberso me fo r th e sm all sections of road to be tackled. However, this can create opportunities for locally ba sed sm all contractors using labour-based or i nterm edi ate technol ogi es. These spot improvem ents can t ake m any form s, i ncludi ng t he surfaci ng of sect ions of road t hat are l ikely to requi re excessi ve recurrent m aintenan ce. Low-cost seal ing as an opt ion for spot improvem ent works can be 7 Low Cost Sur facing, Working Paper No 1 - Rationale for the com pilation of international guide lines on low-cost, labour-based, alter native & sustainable r oad sur facings, R C Petts, March 2002. 8 Perf orm ance of low-volum e sealed road s: Results and r ecom mendations fr om studies in souther n Afr ica. TRL Project Repor t PR/OSC/167/99. Transpor t Resear ch L abor ator y, Crowthor ne, Be rkshir e, UK, CS Gour ley and PAK Gr eening, Novem ber 1999. 9 New appr oaches for the pr ovision of low volum e sealed r oads. 20th Annual South Afr ican T ranspor t Confer ence. Pretor ia, South Afr ica, PAK Gr eening and CS Gour ley, July 2001. 10 Increasing skills of labour-based cont ractors through transfer of appropriate road surfacing technology , 7th Conference on Asphalt Pavem ent for Souther n Afr ica ( CAPSA) , Zimbabwe , PAK Gr eening, CS Gour ley & JM Tour nee, July 1999. CAF EO-20 September 2002 6 Paving the Way for Rur al Developm ent & P overty Reduction Gourley, Greening, Jones & Petts carried out by labour-based methods utilising a range of relatively low- cost equipm ent. Much of the equipm ent requi red for t he bi tuminous surfaci ng i s part of t he st andard plant used by sm all cont ract ors i n the const ruct ion of rural roads. M any sm all cont ract ors are usi ng t ract or-bas ed or l ocal vehi cle/equi pm ent technol ogy and t his opens up t he opport uni ty to invest igate the scope of usi ng rel atively low-cost equi pm ent and at tachm ents for seal ing works. Purchase of hand-l ances and t ract or at tachm ents shoul d be wi thin the range of t he capi tal invest ment expected by sm all–scale contractors or local equipm ent hire enterprises. Labour–based or i nterm edi ate approaches are seen as an i mport ant rout e to allow t he ent ry of em ergi ng contractors into the road sector. The main reason for the success of this appr oach is th at a m uch lo wer lev el o f invest ment is requi red by labour-based cont ract ors t han for m ore equi pm ent intensi ve operat ions. Thi s has enabl ed cont ract ors t o ent er the roads sect or at di fferent level s rangi ng from pet ty cont ract ing for rout ine mainten ance to perio dic m ainten ance, reh abilitatio n an d ev en larg er co nstru ctio n projects. One of the identified risks for ensuring the long-term viability of sm all contract ors is that they have a relatively narrow skills base and are therefore extrem ely vulnerable to any discontinuities in th e funding for road works. Opportunities for work are also likely to be restricted if contractors ha ve lim ited skills. If these contractors are to rem ain viable, it is arg uable th at th ey m ust wid en th eir sk ills an d clien t base so th at th ey can diversify th eir operat ions when part icular t ypes of work are scarce and al so be ab le to co mpete with th e m ore well estab lish ed contractors for bitum enised work. Ther e m ust also be opportunities for som e diversification into other activities. Typical exam ples would be sm all bitu menised areas in schools, clinics, roads in sm all m unicipalities, rural district ro ads, ro ads in villag es, car an d bus parking areas, an d other su rfacin g tech niques in th e ro ads, b uild ings, agriculture and water sectors. It is also im portan t th at th e u rban an d ru ral au thorities h ave a co ntractin g cap acity th at can operate at th e lo cal level without incurring large m obilisation costs for rela tively sm all road works th at would be necessarily incurred by larger scale contractors. Th is is p articu larly relev ant to th e co nstru ctio n an d m ainten ance o f th e relatively short lengths of surfaced roads for which m any of these local authorities are becom ing responsible. The devel opm ent of l ocal ly based (di strict and provi nce l evel ) cont ract ors can assi st in spreadi ng t he em ploym ent opportunities into all areas of the country, and also provide capacity at the local level for the implem ent ation of road m aintenance and i mprovem ent works. 9. Current initiatives in Cambodia and Vietnam In C ambodi a, t he excessi ve rat es of gravel loss experi enced on rural roads and general ly long haul di stances for gravel contribute to the very high m aintenance burden for this type of surf ace. It is assessed that the typical cost of m aintaining a gravel/laterite rura l road in Cam bodia is US$1,625/km /year 11. There are also significant dust probl em s associ ated wi th the local ly avai lable m aterials in the long dry season; this is part icularl y evi dent due t o the tendency for the population to construct their housi ng im mediately adjacent to the road alignm ents. Co sts an d su stain ability co ncern s reg arding gravel ro ads led to an in itiativ e to arran ge trials o f altern ativ e surfaces for rural roads in Kam pong Cham and Siem Reap provinces. These trials have been arranged by Ministry of R ural Devel opm ent and ILO Upst ream Project in cooperat ion wi th Int ech Associ ates under t he DFID funded Low Cost Surfacing for Poor Com munities research program me. Techni ques being investigated include hand placed and packed st one, dressed stone, water-bound m acad am , sand-aggregate, aggregate stabilised laterite, arm oured laterite , bitum en em ulsion chip and sand seal s, and bam boo reinforced concrete pavi ng 12. A surfacing policy and strategy workshop in Decem ber 2001 led to the inclusion of a m ore rigorous approach t o eval uat ion of surfaci ng opt ions i n the revi sed C ambodi an nat ional rural roads pol icy. Vietnam also experiences considerable variability in natural gravel quality and extrem ely long m aterial haul distances in som e provinces. Rainfall intensity and volum e also causes high rates of su rface gravel loss. In som e del ta areas gravel or hard st one m aterials have t o be haul ed up t o 200km . The concerns for t he m aintenance liabilities and sustainability of grave l/laterite surfacing in som e locations led to a national workshop on rural road surfaci ng opt ions 13. Further initiatives are planned to trial a nd dem onstrate alternative surface options for rural roads. 11 Rural Road Investm ent, Maintenance and Sustainability , A Cases Study on the E xperience in the Cam bodian Province of Battam bang, D Johnston and D Salter , May 2001. 12 Bam boo Reinfor ced Concr ete Pavem ent, Mustafa I. Azam , Sam er Al- Fayadh, Fer gus Gleeson, 2002. 13 Rur al Road Sur facing W orkshop, Hanoi, Septem ber 2001, Ministr y of T ranspor t (MOT ) CAF EO-20 September 2002 7 Paving the Way for Rur al Developm ent & P overty Reduction Gourley, Greening, Jones & Petts 10. A proposed strategy for providing basic access for the poor in ASEAN cou ntries An engineered earth road will provi de adequate access throughout the year for a rural com munity in m any situations, if it is adequately maintained. The suitability of this standard of access will depend on:- • The characteristics of the in-s itu soi l (type and st rengt h) • Crossfal l and drai nage arrangem ents • The rainfall characteristics • Th e typ es an d lo ading of traffic in th e critical season (usually the wet season) • Feasib le arran gements fo r m ainten ance The lim iting circum stances for the use of engineered earth road surfaces n eed to be determ ined based on the above param eters. Prel iminary work has al ready been carri ed out by TR L, Int ech Associ ates (Roads 2000 ) in Keny a and t he C SIR in Sout h Afri ca i n areas of m edium rai nfal l and convent ional traffi c. Thi s work requi res t o be veri fied and ext ended t o the hi gh rai nfal l regi ons of S out h East Asi a where a range of Int erm edi ate M eans of Transport (IM T) i s the preval ent transport m ode for t he rural poor. Intern atio nal Gu idelin es o n th e ap plicatio n of En gineered Eart h R oads are requi red. Thi s is the hi ghest pri ority for research, recently confirm ed by the Greater Me kong Sub-Region Academ ic Research Network (GMSARN) Rural Transport W orkshop i n Cambodi a (M ay 2002). With the successful application of such guidelines, the m ajority of funds curre ntly wasted on gravel/laterite roads in unsui table ci rcum stances coul d be saved by the provi sion of engi neered eart h roads i n appropri ate condi tions. These subst antial savi ngs coul d be re-depl oyed t o provi de bet ter, l ow cost and l ow m aintenance pavi ng i n those circum stances not suitable for engineer ed earth surfaces, using spot im prove ment strategies where appropriate. In practice, the sam e overall funding currently deployed would produce m ore sustainable access to m ore poor peopl e on a gl obal basi s. Research wo rk is cu rren tly p rogressin g on lo w co st su rfacin g by CSIR, TRL an d In tech Asso ciates wh ich will lead to im proved recom mendations on the use of stone, bitum en and concrete based surfaces. Draft guidelines are alread y av ailab le fo r th e u se o f gravel/laterite 14. To provide essential basic access to poor com munities, it is envisaged that surface selection will in future consider engineered earth road as th e first o ptio n in th e circu mstances where they are appropriate 15. It will b e necessary to ensure t hat they can be m aintained usi ng l abour and si mple equi pm ent and t he fi nanci al resources availab le. Fo r h igher g rade su rfacin g, gravel/laterite wo uld be just one of t he opt ions eval uat ed usi ng t echni cal feasibility, whole life costing, socio-ec onom ic and environm ental evaluations. As with engineered earth roads, a real istic assessm ent of m aintenance fundi ng and capaci ty m ust be an i ntegral part of t he eval uat ion and deci sion process to ensure a sust ainabl e sol ution. The above research initiatives need to be coordinated and coupl ed to dissem ination and m ainstream ing strategies which will ensure that policy m akers, practising engineers and the education system adopt appropriate rural road surfacing strategies that will be m eet the rural access a nd transport needs of the poor and will be sustainable wi thin the fi nanci al and m anagem ent resources avai lable. It is likely that these in itiatives will be facilitated by dialogue a nd involvem ent of re gionally and globally orientated institutions such as AFEO, GMSARN, PIARC (W orld Ro ad Association), ISOHDM and the Int ernat ional Focus Group (IFG) for rural transport res earch, as wel l as nat ional publ ic and pri vate sect or institu tio ns. Th e targ et in stitu tio ns are th ose o rganisatio ns th at will b e better ab le to ad vise o n, ed ucate an d dissem inate fo r, plan or im plem ent road investm ents, hence the initiatives will contribut e to im proved governance. The m ain beneficiaries will be those com munities who are curren tly affected by the adve rse econom ic, social and environm ental effects of unreliable access, dust, eros ion, and high transport co sts, and which have high proport ions of poor, i solated and vul nerabl e peopl e. 14 DFI D Transpor t Links website: www.transport-links.org , Resear ch, R7782. 15 Design and Appraisal of Rural Trans port Inf rastructure. Ensuring basic access f or rural com munities. World Bank Technical Paper No. 496, Lebo J and Schelling D, 2001. CAF EO-20 September 2002 8 Paving the Way for Rur al Developm ent & P overty Reduction Gourley, Greening, Jones & Petts Table 1 - SCHEDULE OF ALTERNATI VE ROAD SURFACE IMPROVEMENTS Road Surface Improvemen t Option s Description (A roadbase option m ay need to be used in com binat ion with the selected surface im provem ent) C1 Dragging Road Surface Smoothing out minor defects on an earth or gravel road surface and redistribut ing loose material on the surface, using ty re or blade drag. C2 Light Grading/Reshaping of Surface Minor reshaping of an earth or gravel surface to restore correct camber using labour or light/heavy grading equipment. C3 Natural Gravel Surface A lay er of compacted natural gravel w ear ing course (ty pically 15 – 20cm thick) C4 Lime Stabilization of Existing Surface Addition of and mixing of quicklime or hy drated lim e to a soil or surface material, w atering and compaction to increase its strength and reduce its su sceptibility to the w eakening effect of increasing moisture content. This is achieved by chemical reaction of the lime with the clay particles. Mixing and compaction by light or heavy equipment. C5 Stone Chippings Surface A lay er of single sized (ty pica lly 20mm) crushed stone chippings. C6 Hand Packed Stone Surface A lay er (ty pically 20 – 30cm thick) of large br oken stone pieces, tightly packed and w edged in place with stone chips rammed by hand into joints, w ith remaining voids filled w ith sand. The Hand Packed Stone is normally bedded on a thin lay er of sand/gravel. C7 Dressed Stone Surface A lay er (ty pically 15 – 20cm thick) of stone blocks cut (dressed) to a cubic shape by hand, laid by hand. Joints mortared/sealed or tightly packed and wedged w ith stone chips rammed into place w ith remaining voids filled w ith sand. The Dressed Stone is normally bedded on a thin lay er of sand/gravel. C8 Stone Sett Surface (Pavé) As dressed stone, how ever stone blocks are sma ller; ty pically about 10cm x 10cm x 10cm w ith mortared joints. C9 Concrete Block Surface A lay er of concrete blocks (ty pically each 10cm x 20cm and 7 – 10cm thick) laid by hand on a thin (3 – 5cm) sand bed w ith joints also f illed w ith sand and lightly compacted. C10 Clay Brick Surface A lay er of high quality clay bricks (ty pically eac h 10cm x 20cm and 7 – 10cm thick) laid by hand on a thin sand bed w ith joints also filled w ith sand and lightly compacted, or bedded & jointed w ith cement mortar. C11 Bamboo Reinforced Concrete Surface Jointed slabs of structural quality concrete reinfo rced w ith a split bamboo rod grid. Joints w ith steel weight transfer dow els and bitumen seal. C12 Steel Reinforced Concrete Surface Jointed slabs of structural quality concrete reinforc ed w ith a mild steel rod grid. Joints w ith steel weight transfer dow els and bitumen seal. C13 Bituminous/Tar Sand Seal Surface A seal consisting of a hand or machi ne applied film of bitumen (straight run, cutback or emulsion) or road tar follow ed by the application of excess angular sand or fine crushed stone, lightly rolled into the bitumen/tar. C14 Ottaseal Surface A lay er consisting of a hand or machine applied film of relatively soft bitumen (usually straight run or cutback) follow ed by the application of graded nat ural gravel or crushed stone aggregate (ty pically 16mm dow nw ards), rolled into the bitu men using heavy pneumatic ty red rollers. C15 Bitumen/Tar Surface Dressing Surface A seal consisting of a hand or machi ne applied film of bitumen (straight run, cutback or emulsion) or road tar follow ed by the application of a single la yer of single sized (6 – 20mm) stone chippings, lightly rolled into the bitumen/tar. C16 Bitumen Slurry Seal Surface (and "Cape" Seals) A seal consisting of fine graded aggr egates (ty pically 10mm dow nw ards), w ater, bitumen emulsion, cement, and sometimes an additive, mixed in a conc rete mixer or other machine and spread on the road surface by hand or machine. Cape seals are co mbinations of Surface Dressing and Slurry Seal. C17 Bituminous Premix Macadam Surface Graded crushed stone material (ty pically 28mm dow nw ards) usually derived from fresh sound quarried rock, boulders or granular material and mi xed w ith a bituminous binder (straight run, cutback or emulsion) and laid and compacted. Material may be hand or machine mixed and laid. Compaction by light or heavy equipment. C18 Penetration Macadam Surface Tw o or three lay ers of single size crushed st one (of decreasing nominal aggregate size, e.g. 63 mm dow nw ards) each compacted and w ith bitumen (strai ght run, cutback or emulsion) or road tar spray ed betw een each stone application. C19 Water Bound Macadam Roadbase A lay er of nominal single sized (ty pically up to 50mm) crushed stone compacted and fully blinded with w ell graded fine aggregate w hich is w atered into the voids and compacted to produce a dense stable material. Lay er thickness up to tw ice the nominal stone size. Material may be hand or machine crushed and laid. C20 Dry Bound Macadam Roadbase A lay er of nominal single sized (ty pically up to 50mm) crushed stone compacted and fully blinded with angular sand or fine crushed stone material w hich is then vibro-compacted to produce a dense stable material. Lay er thickness up to tw ice the nominal stone size. Material may be hand or machine crushed and laid. Suitable in areas short of w ater. C21 Slurry Bound Macadam Roadbase A lay er (about 7cm thick) of single size aggregat e (ty pically 50mm) blinded w ith smaller aggregate (typically 25mm), plate compacted and grouted w ith bitumen emulsion slurry before final compaction. C22 Crushed Stone Roadbase A lay er (usually up to 20cm thick) of graded cr ushed stone material (ty pically 50mm dow nw ards) usually derived from fresh sound quarried rock, boulder s or granular material. The angular material derives its strength primarily from mechanical interlock. Material may be hand or machine crushed. C23 Mechanically Stabilised Roadbase Addition and mixing of granular materi al such as crushed stone or sand to a material to increase its strength and achieve the properti es required of a roadbase. C24 Chemical or Emulsion Stabilized Roadbase Addition and mix ing of a stabilizer such as lime, cem ent, or ion ex change chemical s, to a material to increase its strength and achieve the properties required of a roadbase. Mixing and compaction by light or heavy equipment. C25 Improvement using Recy cled Mater ials Use of recy cled road pavement materials, brick k iln w aste, broken brick, demolition materials, industrial slags, etc. C1 & C2 are m aintenance/surface im provem ents, C3 – C18 are surface options, C19 – C25 are lower pavem ent layer options. CAF EO-20 9