labour based road works

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LABOUR-BASED ROADWORKS

John van Rijn

INDEVELOPMENT


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INDEVELOPMENT; Labour-based Road Works

LABOUR-BASED ROADWORKS

Any part of this publication may be reproduced or translated provided that the source and author are fully

acknowledged.

Edition 2005.

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Table of contents:

1 Introduction .............................................................................................................................. 4

2 Selecting technology for public works..................................................................................... 5

2.1 Relevance of economic studies.......................................................................................... 73 Labour-based products............................................................................................................. 9

3.1 Geometric design............................................................................................................... 93.1.1 Roads in hilly terrain..............................................................................................................................93.2 Cross drainage ................................................................................................................. 103.3 Side Drains ...................................................................................................................... 11

3.3.1 Gabions................................................................................................................................................124 Labour-based production technology..................................................................................... 14

4.1 Earthworks....................................................................................................................... 14

4.2 Camber formation............................................................................................................ 18

4.3 Compaction...................................................................................................................... 214.4 Soil stabilisation .............................................................................................................. 23

4.5 Concrete technology........................................................................................................ 244.5.1 Concrete Pavements.............................................................................................................................25

4.6 Bituminious surfacing...................................................................................................... 254.7 Culverts and Sewer Pipes ................................................................................................ 26

4.8 Maintenance activities..................................................................................................... 28

4.9 Selection of materials ...................................................................................................... 284.10 Tools and equipment .................................................................................................... 28

4.10.1 Machine capacities...............................................................................................................................285 Institutional development and organisational strengthening.................................................. 33

5.1 Institutional development ................................................................................................ 33

5.2 Pilot programs/projects.................................................................................................... 345.2.1 Inputs ...................................................................................................................................................345.2.2 Culture .................................................................................................................................................355.2.3 Systems................................................................................................................................................355.2.4 Staff .....................................................................................................................................................355.2.5 Relationship with the contractors.........................................................................................................35

APPENDIX 1: PRODUCTION NORMS OF LIGHT COMPACTION EQUIPMENT.............. 37

APPENDIX 2: PRODUCTION NORMS EQUIPMENT............................................................. 39

APPENDIX 3: GANGFORMATIONS........................................................................................ 43APPENDIX 4: ROADWORKS IN THE HIMALAYAS............................................................. 51

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1 INTRODUCTIONMany manuals for labour-based technology seem to be produced for road

works. However this does not mean that the technology cannot be applied

on any of the other infrastructure works. On the contrary, it is very easy toapply the technology on irrigation, water supply, sanitation, forestry, soil

conservation, building construction works etc. In fact it is usually alreadydone, or it is easier to apply than on the road works.

Most building works are highly labour-intensive in nature. Earthworks inwater supply, sanitation and irrigation projects can almost always easily be

carried out with labour-based technology.In the road sector, the application of labour-based technology is most

challenging. If civil engineers can apply the technology in the road sector,they will be able to apply in any other infrastructure sector.

The following websites presents practical manuals for road works.

http://www.ilo.org/public/english/employment/recon/eiip/asist/asist-ap/download/tmlbt.pdf

www.ruralworks.com

http://www.transport-

links.org/transport_links/filearea/publications/1_816_Labour-Based%20Construction%20Manual.pdf

This document intends to supplement the above-mentioned manuals.

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http://www.ilo.org/public/english/employment/recon/eiip/asist/asist-ap/download/tmlbt.pdfhttp://www.ilo.org/public/english/employment/recon/eiip/asist/asist-ap/download/tmlbt.pdfhttp://www.ruralworks.com/http://www.transport-links.org/transport_links/filearea/publications/1_816_Labour-Based%20Construction%20Manual.pdfhttp://www.transport-links.org/transport_links/filearea/publications/1_816_Labour-Based%20Construction%20Manual.pdfhttp://www.transport-links.org/transport_links/filearea/publications/1_816_Labour-Based%20Construction%20Manual.pdfhttp://www.transport-links.org/transport_links/filearea/publications/1_816_Labour-Based%20Construction%20Manual.pdfhttp://www.transport-links.org/transport_links/filearea/publications/1_816_Labour-Based%20Construction%20Manual.pdfhttp://www.transport-links.org/transport_links/filearea/publications/1_816_Labour-Based%20Construction%20Manual.pdfhttp://www.ruralworks.com/http://www.ilo.org/public/english/employment/recon/eiip/asist/asist-ap/download/tmlbt.pdfhttp://www.ilo.org/public/english/employment/recon/eiip/asist/asist-ap/download/tmlbt.pdf


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2 SELECTING TECHNOLOGY FOR PUBLIC WORKSLabour-based technology is the combination of

product and production process technology for theprovision of infrastructure assets. It uses those

infrastructure products, which fulfils the needs of

the end-users at the lowest total costs. Theseproducts are constructed and maintained with the

cheapest production processes possible. Generallyin low and middle-income countries, where labour

costs are low, the most efficient technology tendsto be more labour intensive than in high-income

countries.

Labour-based technology is not a technology thatonly uses labourers and some tools. In most of the

situations, such production process technologies(labour and tools only) produce outputs of inferior

quality, which results in an increase of the totalcosts to sustain the infrastructure asset.

Allocation of

resources.

A very important aspect of labour-based technology is that assessments are

made of the required technology and the most efficient production process.This means more time and resources are needed before the actual

production/construction. At the same time, more labour-intensiveproduction process needs more management inputs, in particular during

implementation. After all it is more difficult to manage people than it is tomanage machines. Thus labour-based technology requires more- and more

sophisticated management; it requires an organisation with more levels,and finally more- and more formalised communication.

Cost estimating To apply the efficiency rule, cost estimates have to be made. Cost

estimates can be made with various different levels of detail, but three ofthem are more frequently used than others.

Rough estimate

Indicative estimate

Detailed estimate

Which one will be used depends mainly on the purpose of the estimate andrequired accuracy. For selection of products, mostly rough and indicative

estimates are used. If the difference in costs between different alternativesis very obvious, a rough estimate would provide the necessary answer.

When it can be expected that the difference is uncertain, it may be evennecessary to produce a detailed estimate. In particular, when such

uncertain differences could cost the government/client considerable amountof money. Detailed estimates require more information inputs. Thus it maybe even necessary to produce two or more detailed designs in order to

make the final selection. The more expensive the product, the more likelythese situations will occur.

Rough estimate A rough estimate for a building would for example be based on indexes forthe neighbourhood, luxury and quality, area of land and area/ volume of

the building.Indicative estimate An indicative estimate will breakdown the building in different elements,

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like

M2 floor (type a), floor (type b), inner walls, roof etc and multiply these

figures with the respectively unit costs.Detailed estimates To prepare a detailed estimate it will be necessary to break down the

construction process and to budget all the required resources, materials,work force, and equipment.

Product selection The products are designed and selected on basis of three criteria:

1. Terms of reference or schedule of requirements

2. Financial analysis3. Risk analysis

Schedule of

requirements

The schedule of requirements usually consists of four elements:

1. Environmental demands, which can not be influenced by the project2. Functional requirements, related to required impacts/performance

3. Operational requirements/demands, related to the operation and

maintenance of the product4. Design constraints, like time, resources, budget etc.

Financial analysis In general there are two principles of financial analysis:1. Cost-benefit analysis2. Cost analysis

Both analyses should ideally be made over the total required life of the

product. Note that the required life of the product is usually different from

the expected life of a product. For example bridges usually have a longerlife than required, but the asphalt pavement on the deck has a considerable

shorter life than required and needs to be replaced several times before thefinal reconstruction of the bridge.

Cost-benefit analysis Cost-benefit analysis can only be used when it is possible to express the

impacts of the product. A common used technique for cost-benefit analysisis the calculation of the Net Present Value (NPV). The calculation of the NPVis one of the discounted cash flow methods. Note that it is necessary to

discount the cash flows.1Most products have different life expectancies afterconstruction. When comparing products with unequal lifetimes the NPV is

not adequate as a measure. In order to make these products comparablethe uniform annuity series (UAS) can be used. This UAS is defined as the

annuity whose present value equals the NPV.

Cost-benefit analyses are usually only used for the identification andranking of the infrastructure asset. It is less common to use this technique

for selecting the production process technologies.Cost analysis Most often the financial analysis can be limited to cost comparisons. Costs

are all the expenditures made in order to provide the product during the

total required life. Thus it contains, investment (construction costs),operation costs, maintenance costs and replacement costs (usually thesame as the investment costs). The product with the lowest total costs

during the total required life will be ranked as number one.

Indirect cost In theory governments could take into account indirect costs and tax

1Discounting is the technique of reducing the nominal (numerical) value of future sums of money to their

present worth.

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returns in their cost analysis. For example assume that a government uses

capital-intensive approaches instead of labour-based technology, because

when comparing the direct cost of construction, labour-based technologywas found to be more expensive. But when the government also provides a

social benefit to the un/underemployed; its total expenditure using capitalintensive methods may be higher than when it would have used labour-

based technology and provided employment to a portion of the un/underemployed. In addition many countries have to import heavy equipment

items and their fuel affecting the foreign exchange and governments

foreign cash reserves negatively. Various studies have proven the positivemacro-economic impacts of labour-based technology over equipment-based

technologies. Additional economic growth leads to additional income (taxes)for the governments and in theory the cost comparisons could take these

financial benefits into account.Although the theory is simple there are quite some constraints to adjust the

cost comparisons. To start with, usually civil engineers prepare the cost

comparisons. They do not have economic data and are not trained in thiskind of analysis. Gathering the necessary information is costly and difficult

(if at all possible for the economic growth aspects). But probably more

important, infrastructure providing actors do not receive the additionalbenefits or they are not paying for the additional costs. These come and gofrom other (government) pockets. Without strict instructions and control on

these instructions, infrastructure-providing agencies will not take intoaccount these indirect costs or incomes in their cost estimates.

Risk analysis Risk is the change of damage multiplied with the damage. Breakdowns ofsome infrastructure products are more likely to occur than other products.

If the damage is very high in financial or social-economic terms, theproject/client may want to select the product with lower change of

breakdown.

2.1 RELEVANCE OF ECONOMIC STUDIESIn many middle-income countries, labour-based (equipment-supported)technology and equipment-based technologies may be in the same price

range. Labour-based (equipment-supported) technology has a number ofeconomic advantages over equipment-based technologies, like:

Income effects

Backward linkages

Forward linkages

Reduction foreign cash flowIncome effects The immediate purpose of the ILO is to maximise short-term employment

opportunities and alleviate transient poverty. Employment creation is seenas one of the most effective means to alleviate poverty.

Backward linkagesBackward Linkages relate to the expenditures for local produced andpurchased materials, tools and equipment. The costs for the project are

then income for the providers. The providers on their turn will buyproducts. In other words the expenditures are recycled in the local

economy and contribute the GNP.Forward linkages Forward linkages, as defined here, derive from the spending of earnings

during construction, most significant of which are wages paid to workers.Foreign cash flow When imported equipment is replaced by local available labour, economies

will reduce their foreign cash flow.

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Studies? The question arises; is it relevant to conduct ex ante evaluations,

quantifying these impacts, for each project? Such studies are usually very

expensive and the outcomes are very predictable. The above statementsare common sense, widely accepted and go without saying. Quantifying the

macro-economic impacts however is a different matter. In fact it is verydifficult and seems always to be subject to discussion. Such studies may

only contribute if more alternatives are studied. For example if labour-based technology is 20% more expensive would its indirect effects be

higher or lower than investing these 20% additional resources in other

public service delivery like, education and health?

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3 LABOUR-BASED PRODUCTS3.1 GEOMETRIC DESIGNThe cost of new roads can be enormously reduced through setting theoptimal geometric design standards. Too often road width and gradients are

over designed, resulting in unnecessarily costs. TRL provides someguidelines to set appropriate design standards.

Geometric standards TRL states: Each inter-urban road may be classified as being arterial,

collector or access in nature.Arterial Arterial roads are the main routes connecting national and international

centres. Trip lengths are likely to be relatively long and levels of traffic flowand speeds relatively high.

Collector Collector roads have the function of linking traffic to and from rural areas,either direct to adjacent urban centres, or to the arterial road network.

Access Access roads are the lowest level in the network hierarchy. Vehicular flows

will be very light. TRL designed the below presented table:

Road function Traffic flow (ADT) Width Maximum gradient %

Carriage way Shoulder

5000-15000 6.5 2.5 8Arterial

1000-5000 6.5 1.0 8

Collector-Arterial 400-1000 5.5 1.0 10

Collector-Access 100-400 5.0 1.0 10

20-100 3.0 1.5 15Access


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mass.

Retaining walls limit the height of the cuts and fills on slopes. They

therefore reduce the area of disturbance of the soil and rock cover and canalleviate the aesthetic impact of a road in its landscape.

Source: ITECO; A Guide to Proper Design, Construction and Maintenance, TechnicalSheets, 1993.

3.2 CROSS DRAINAGEAlmost always it is necessary to apply cross drainage on a road, because

the water from higher ground on one side of the road has to be lead to thelower ground on the other. Cross drainage is also required where the road

goes downhill from both directions to a low point. At this point, watercollects and cross drains are needed.

A number of structures can be used as cross drains. The amount of waterexpected to flow during a bad flood determines the structure to be selected.

Drifts Drifts allow water to cross the road on the surface. Drifts are cheap andeasy to construct and are well suited to roads with relatively little traffic

crossing riverbeds that are dry for most of the year. But drifts may also beused in more challenging situations with more water flow during the year.The main advantages of drifts over culverts are that they cause less

erosion, they are simple to construct, the required amount of excavation isrelatively small and culverts may be blocked and therefore cause local

floods.Culverts Culverts are usually made of a single line of concrete pipes, placed in

trenches and covered over to carry the water under the road. Culverts

require sufficient space between the bottom of the watercourse and floor ofthe road deck. Often culverts require erosion protection on the downstream

side. It should be kept in mind that they require regular routinemaintenance.

Vented drifts are usually needed where large flows ofwater are likely. It is made of a number of culverts

imbedded in concrete. Most of the time water flowsthrough the pipes and during peak flow the water will also

run over the road. As they are designed to be overtopped,

it is necessary to protect the water-bank structure in thedirect vicinity of the structure.

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Bridges The last option to arrange cross drainage is a bridge.

The location of river crossings is an important step in

the design process. Preferable the angle between the

road and the river would be close to 90o

. The rivershould not be crossed in its curves. Because due toerosion it is likely that the river will change position

over the years. Subsequently the river crossing should

not be located at places where silting or scouring takesplace. Steep banks and steep approaches require a lot

of expensive earthworks. The ideal slope for a driftapproach is about 5 %.

3.3 SIDE DRAINSThe side drains need to have sufficient capacity to collect all rainwater from

the road carriageway and dispose of it quickly and in a controlled manner tominimise damage. Sides drains can basically be constructed in three forms:V-shaped, rectangular or as a trapezoid.

The V-shape is the standard shape for ditches constructed by a motor-

grader. It can be easily maintained by heavy equipment, however it carriesa low capacity. The rectangular shape requires little space but needs to be

lined to maintain its shape. When using labour-based methods, it is

possible to construct a trapezoid shaped side drain. This shape carries ahigh flow capacity and by carefully selecting the gradients of its side slopes,

will resist erosion.

Flow velocity A velocity of 0.6 to 0.8 m/s is often quoted a minimum that will not resultin heavy siltation and will reduce weed growth. In earth canals, however,

this velocity requires a steep longitudinal bottom slope, which is seldompossible in flat areas. The maximum permissible velocity should not cause

erosion of the bottom and side slopes. The table below present the

maximum permissible velocity in earth canals.

Materials Flow velocity (m/s)

Fine sand 0.45

Non-colloidal sandy loam 0.55

Non-colloidal silt loam and alluvial silts 0.6

Firm loam, volcanic ash 0.75

Shift clay and colloidal alluvial silts 1.10In windy sections the permissible velocities are reduced by 10 to 20%.

The side slopes also have a maximum slopes, these are presented in thefollowing table:

Material Side slope canal

Rock 1:0

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Stiff clay 2:1

Cohesive medium soils 1:1 or 2:3

Cohesive sandy soils 1:2

Fine sand 1:3

Typical side slopes for canals

Longitudinal gradients on all roads should preferable not exceed 12%. If the

longitudinal gradient of an earth or gravel road is higher than 10% it isadvisable to protect the road surface with a protective layer (asphalt,

concrete, bricks or stone pitching). Otherwise it rills will be formed. If thelongitudinal gradient is higher than 7%, the rainwater will not flow from the

road but on the road. It is therefore important to minimise the amount ofwater entering the road. Therefore drains, gullies are constructed on the

mountainside to prevent rainwater accessing the road surface. Mountain

drains are also recommendable along rice fields, natural springs and othermoist areas.

One of the considerations during defining the road alignment is avoiding offalling objects from the mountainside on the road. Often the road will

zigzag and different road segments may be located above or on top of eachother. Note that uphill roads discharge water and other debris. It may be

necessary to divert the water with drains from the uphill road to avoid

disturbances on the downhill segment of the road.

3.3.1 GabionsThis product can be well constructed with labour-based (equipment-supported) technology. Many web pages provide information about

gabions:

http://www.gabions.net/

http://www.maccaferri-usa.com/

http://www.terraaqua.com/

http://www.markham.com.pg/Culverts/gabions.htm www.fao.org/ag/magazine/9812sp2.htm

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http://www.gabions.net/http://www.maccaferri-usa.com/http://www.terraaqua.com/http://www.markham.com.pg/Culverts/gabions.htmhttp://www.fao.org/ag/magazine/9812sp2.htmhttp://www.fao.org/ag/magazine/9812sp2.htmhttp://www.markham.com.pg/Culverts/gabions.htmhttp://www.terraaqua.com/http://www.maccaferri-usa.com/http://www.gabions.net/


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4 LABOUR-BASED PRODUCTION TECHNOLOGY4.1 EARTHWORKSEarthworks involve the loosening, removal, disposal and handling ofearthen materials in the construction process-excavation of cutting and

construction of embankment.The principal activities are:

Excavation which includes levelling, cut to crossfill, U-cut and borrowexcavation

Loading, hauling and unloading

Filling, including spreading and compaction

Levelling Levelling of bumps and depressions is necessary to provide a sufficientwidth for the road at uniform level. Levelling is best carried out with hoes,

rakes and shovels. The bumps and ridges are cut and the soil is raked,

pushed or thrown into the holes and depressions with the hoe. Deep hoesshould be compacted in layers with hand-rammers.

Cut to cross fill Cut to cross fill means that the soil is excavated (cut) from one side of the

road and used as fill material at the other. If the excavated soil is not used,it is going to spoil. It is dumped outside the embankment.

High cuts In high cut, excavation is more difficult to organise. It is especially difficult

to allow the workers enough space to work. It is, therefore advisable toexcavate in steps. Providing a bench for the next days work. The number

of steps depends on the total height. The best excavation height is between1 and 1.5 meters.

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U-cut The U-cut is a cut, which is roughly U-shaped. The road is cut through a

hillcrest in order to reduce the gradient. If U-cuts are deeper that one-

meter the excavation should be organised in several steps.


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Borrow When sufficient suitable material is not available from the roadway

excavations, additional material must be obtained from sources situated

beyond the site. Borrow area parallel to the road should be drainedwherever possible to ensure that pounded water will not seep through and

weaken the embankment or fill.

Work in Quarries A good quarry is one, which requires the minimum work for the maximumoutput. In selecting a quarry the following aspect should be considered:

Quality of material

Depth of soil over the wanted material

Cost of excavation and transport

Hauling distance Availability of access road

Finally, it is important to establish whether or not the quarry is located in

low-lying terrain. If so, this may well cause the quarry to become floodedand un-workable when it rains.

The quarry layout should allow the vehicles and carts to enter and leavewithout being in each others way. A circular traffic flow, requiring only

single lanes is ideal.

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4.2 CAMBER FORMATIONAfter the alignment is cleared from bushes, grasses, roots, othervegetation, boulders and setting out has taken place than the bulk

excavation to achieve the level terrace can be carried out. The terrace fill

needs to be compacted to ensure good geometric quality for the following

operations, see also the section on compaction.

Ditching The materials of the side drains usually can be used to construct the

camber. The camber is nothing more than sloping of the road. Sometimesadditional materials for the camber production need to be transported to

the site. The excavated materials may not be enough or of poor quality.

The set of drawing2 below present a methodology to produce the camber.Note that precise production of the camber depends on the compaction

methodology, terrace level with regard to original ground level and soiltype.

2Andersson, Beusch and Miles: Road Maintenance and Regravelling using Labour-Based Methods,

Handbook

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Presented drawings were first published in Road Maintenance and Regravelling (ROMAR) using labour-based methods Handbook, Cleas-Axel Andersson, Andreas Beusch and Derek Miles, ILO 1996.

4.3 COMPACTIONCompaction is a vital part of road construction. Efficient

compaction makes it possible to substantially improve the bearingcapacity and stability of a fill, to increase the impermeability and,

in most cases, to practically eliminate settlement. Consequently,compaction makes the soil sufficiently stable to withstand

permanent loads and traffic, so maintenance costs are greatly

reduced. Compaction costs represent only a comparatively smallshare of the total construction costs, normally less than 5%. The

compaction criteria are deduced from the Proctor curve, which isdetermined by either the Standard or the Modified Proctor test.

This curve shows the relationship between the dry density and themoisture content.

With a given amount of compaction each soil has an "optimum moisturecontent" at which a maximum dry density is obtained. The compaction

energy used in the Modified Proctor test is 4.5 times larger than in the

Standard Proctor test, which results in the maximum dry density being 5 to10% higher than obtained with the Standard Proctor test.

For rural roads compaction can be specified in terms of values of drydensity varying between maximum dry density of Standard Proctor and

that of Modified Proctor tests. Accordingly, the variation of moisturecontent is specified at approximately the optimum value.

The average Proctor curves are all rather similar in shape. Generallyspeaking, a flat curve denotes a closely graded soil, and a curve with a

pronounced peak denotes a well-graded soil. On the right-hand side all thecurves approach the saturation line and the peaks all occur at an air voidcontent of approximately 5%.

In the field, soils are compacted by applying energy in one of three ways,

which are, in order of duration of the stresses which they apply: Pressure (rolling)

Impact (ramming)

Vibration.

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The types of compaction equipment that are available can be listed under

these three headings as follows:

Rollers: Smooth-wheel, pneumatic-tyre, or sheep foot rollers, lorries,pneumatic-tyre construction machinery and track-laying vehicles.

Rammers: Dropping weight (including piling equipment), internalcombustion type and pneumatic type.

Vibrators: Out-of-balance weight type and pulsating hydraulic type(mounted on screeds, plates or rollers).

In general, smooth-wheel rollers are most suited for crushed rock,hardcore, mechanically stable gravel and sands; pneumatic-tyre rollers for

closely graded sands and fine-grained cohesive soils at a moisture contentapproaching the plastic limit; and sheep foot rollers for fine-grained

cohesive soils at moisture contents from 7 to 12% below the plastic limit.Heavy vibrating rollers compact the surface not very well, therefore often

the last passes are done with dead-weight rollers. Dead weight rollers are

also more appropriate in cohesive soils.The dry density of compacted soil decreases with depth as the thickness of

the layer compacted is increased. With normal compaction equipment, this

reduction is not very great up to a loose thickness of about 20-cm, butabove 25 cm it is considerable. When thinner layers are used, theentrapped air can be driven out much more easily with a smaller amount of

compaction energy.

The usual method of measuring compaction in the field is to determine thedry density of the compacted soil in-situ. The sand-replacement method

and the rubber-balloon method are the most widely applied methods. Theprocedure in both cases is to determine the weight and moisture content of

soil removed from an approximately cylindrical cavity, whose volume isthen measured. The rubber-balloon method is faster than the sand-

replacement method and it generally gives a somewhat more accurate

value.

Hand rammers Hand rammers are normally used for compaction fairly restricted areasparticularly those inaccessible to plant. If it is not possible to transport

compaction plant to the construction site the gang of labourers equippedwith hand rammers can be positioned to cover the width of the formation.

Effective compaction is possible if the material layers are restricted to amaximum of 100-150 mm.

Power rammers Power rammer: Even relatively light power rammers can produce a high

degree of compaction either by using a small area rammer of a relatively

fast stroke. Power rammers and falling weight compactors produce greatcompactive effort at depth, but have an inherently low output. They are

used on all types of soil usually for reinstatement of trenches and

compaction in confined area such as bridge abutment.

Light vibrating

equipment

Vibrating plate of less than 450 kg is only suitable for granular soils.

Heavier compactors are suitable for most other soils with the exception ofheavy clays.

Vibrating rollers, less than 2 tons are only suitable for granular soils.Heavier compactors are suitable for most other soils with the exception of

uniformly grade sand. In general a vibrating roller will compact to a greater

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depth and to higher degree than a much heavier dead-weight roller.

Heavy vibrating rollers do not compact the surface very well, therefore it is

recommended to do last passes with a dead weight roller. Towed vibratingrollers affect the surface in a negative way and have less compaction

density to deeper parts of the layer. Driven vibrating rollers result in adeeper compaction and result in a smooth surface.

Work procedure To produce a good quality road, it is important that all soils are properly

compacted. Compaction should be carried out along the road line starting

at the shoulder of the road and gradually working towards the centre line.Appendix 1 presents production norms of light equipment items.

4.4 SOIL STABILISATIONSoil stabilisation offers one of the best forms of base or sub-base and

surfacing for road construction in tropical and sub-tropical countries. Awide variety of soils may be used. The soil can be stabilised either

mechanically or chemically.Mechanical stabilisation consists of mixing two differently graded soils in

order to obtain a well-graded and therefore more suitable road aggregate.The mixing procedure is done at a mixing plant and is almost

impracticable by hand. Chemical stabilisation makes use of admixtures orbinding agents. The mixing procedure is very easy to do by hand and is

therefore widely applied.

In the majority of cases of chemical stabilisation, cement, lime, orbituminous products are used as binders. The bearing capacity of

stabilised soil is determined with the unconfined compressive strengthtest, as described in TRIZIL (1957). Cement is used to stabilise a wide

variety of soils, but preferably for course-grained materials. Well-gradedsoils with maximum 15 to 35% of silt and clay give the best result.

With lime stabilisation, clay minerals are necessary for a chemical reactionwith the soil. The proportion of cement or lime is normally between 3 and

7% by weight of the dry soil. Bitumen is used mostly to stabilise sandysoils.

The mix-in method The mix-in-place method is possible with various types of implement. The

primary requirement is to achieve an even mixing of the correctproportions of soil and stabiliser. Soil stabilisation is seldom an entirely

manual operation because of the difficulty of ensuring an even distributionof the stabiliser throughout the soil. The same difficulty limits the

usefulness of graders and some types of agricultural equipment.

To mix soil and stabiliser thoroughly it is often necessary to break the

former down into a fine tilt.

PulverisationWith enough passes animal drawn rotary and disc harrows and thetractor-drawn discs harrow will produce the required degree of

pulverisation, but they are designed mainly to reduce the soil lumps onthe surface only and their depth of penetration is limited. The tractor-

powered devices operate at a faster rate and produce a greater depth ofpenetration than those drawn by animals.

The various types ofrotavator are designed to produce a high degree of

pulverisation in relatively few passes. Those mounted on four wheeledtractors operate at a faster rate, and produce a greater depth of

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penetration, than those powered by single axle tractors.

The most recent development has been the tractor-mounted rotary

harrow with the soil contacting components attached to a vertical shaft.The vertical rotors are directly followed by a crumbler roller, which not

only packs the tilt evenly, but also controls the harrowing depth. Theperformance of the rotary harrows for soil stabilisation has not been

evaluated, but should be similar to that of a rotavator.

In mix-in-place stabilisation with cement or lime the stabiliser can be

spread on the loose soil either by hand or by a mechanical spreader. Toobtain an even distribution when spreading cement or lime stabiliser by

manual methods requires strict continuous supervision. When stabilisingsoils with cement or lime it is usually necessary to add water to the

pulverised soil to bring it to the correct moisture content for compactionand provide adequate water for hydration. The water is sprayed on to the

loose soil with water bowsers in mix-in-place operations. However, most

purpose-made mix-in-place pulvimixers have provision for adding anaccurately controlled amount of water through a metering pump and

spray bar. Similar spray bars are used for adding the bitumen when the

mix-in-place method is employed for bituminous stabilisation. Thus mix-in-place bituminous stabilisation is only possible where low viscositybinders, i.e. cut backs or emulsions, are available.

The compaction and shaping of stabilised road bases is carried out with

normal plant. Soil- bitumen mixtures are compacted most effectively bythe kneading action of rubber or pneumatic-tyre rollers.

Manual operation If spreading of the stabiliser is to be done manually then the boundaries

of the area to be stabilised should be set out using pegs and string lineswith suitable permanent reference marks placed well clear of the area

being processed. Then the bags of cement or lime should be placed atpredetermined intervals in a number of longitudinal rows. The positioning

of each bag is such that its contents are the correct amount required forthe depth of soil layer to be stabilised and the surrounding square area.The bags are split open and the stabiliser raked and shovelled or hoed

uniformly over the area being processed.If mixing is to be carried out manually this should be done by first dividing

the soil, spread with stabiliser, into convenient areas of a few squaremetres. Labour should then be instructed to collect the enclosed material

into a heap, which is then turned with a shovel or hoe, and re-spread.

Studies in India show that if the material is heaped and turned a minimumof four times, 70-75 per cent of the strength obtained with machine

rotavating can be achieved. Mixing more than four times will furtherincrease the soil strength.

4.5 CONCRETE TECHNOLOGYConcrete is a mixture of aggregate, sand, cement and water.

Impurities All sands contain a percentage of impurities. It is inevitable and a

maximum of 5 percent of silt can be allowed. However sand used inreinforced concrete should not contain particles of shell or coal residues,

which have a corrosive effect on the reinforcement. The sand is often

found in rivers. It should be smaller than 7 mm and therefore is should besieved on a sieve of 80x150 cm with a wire mesh of 7 mm diameter. The

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steeper the sieve is held, the finer the sand will be. Heavy weight sand in

generally is more suitable for concrete construction.Cement bags Cement (bags) should be stored in a dry room on a raised wooden

platform approx. 20 cm above ground level and not less 30 cm away from

the walls and roof. Air circulation should be avoided by placing the bagsclose to each other and make the storage place airtight. The maximum

amount of bags to be stapled on top of each other is seven or eight.Water Water must be clean and do not contain salt. Dirty water should be stored

in drums and allowed to settle before it can be used for mixing. The

amount of water should be the minimum necessary for sufficientworkability.

Hand- versus machine

mixing

When concrete is mixed by hand it requires more water than when it ismixed by machines, respectively 19 and 16 litres per bag of cement.

4.5.1 Concrete PavementsThe success of the construction of concrete pavements depend mainly onfive criteria:

1. The roughness or smoothness of the sub-base

2. Planning and implementation of the formwork3. Compacting of the concrete

4. Roughening of the surface5. Curing process

Smooth sub-bases save a lot of expensive concrete. It is also easier toensure that the pavement itself will be smooth if the sub-base is smooth.

Often projects spend too much on their formwork. By proper planningimplementer of the project can save considerable amount of money.

The concrete can be compacted by a vibrator or with wooden tamping

beam. The tamping beam is a beam of 75 mm wide, 225 mm deep andthe length equal the width of the section plus 300 mm. The underside of

the beam has a metal plate. By using a back and forward sawingmovement in combination with series of lifts and drops of 1 cm each the

concrete is compacted. The concrete is sufficiently compacted when themortar mix begins to work up the surface.

Source: M. Allal and G.A. Edmonds: Manual on the Planning of Labour-Intensive RoadConstruction, 1977, ILO

Brooming with a stiff fibre brush ideally roughens the surface.It is important to ensure proper curing of the pavement. Curing requires

moist concrete and therefore it is recommendable to cover the pavementwith bags, sand or water. After the curing period the top 75 mm of the

expansion joints between the sections are filled with bitumen.

4.6 BITUMINIOUS SURFACINGTRL published a manual on labour-based construction of bituminous

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surfacing on low-volume roads. The document can be downloaded from

the following web address:

http://www.transport-links.org/transport_links/filearea/publications/1_816_Labour-

Based%20Construction%20Manual.pdf

4.7 CULVERTS AND SEWER PIPESCulverts of concrete pipes give passage to water under roads or otherobstructions. On condition that the pipes are laid correctly this type of

culvert is very reliable and cheaper than box culverts and bridges.

Pipes should be placed level and should have and internal diameter of 0.4

m or more. Smaller pipes block up easily. Above the crown of the pipe asoil cover is needed to spread the concentrated forces by trucks and carts.

The thickness of the cover should at least be 0.4 m or 0.75*Diameter,whatever is higher. In countries where the soil cover will be frozen during

the winter, the minimum soil cover is at least 1 m or 0.75*Diameter.To avoid erosion under the exit of the culvert, the invert of the pipe is

placed at least 0.1 D, maximum 0.5 D below the downstream canal bed.Some sedimentation in the pipe is normal and can be allowed. The flow

capacity should be based on the reduced cross section. In earth canals the

flow velocity in the pipes should be limited to 1.7 times the permissiblecanal velocity.3

It is important not to raise the level of the road at the location of the

culvert. When a (part) of the culvert is laid above the level of thesurrounding road, the changes are that excess water will overtop the road.

The flow section of the culvert is reduced considerably. Furthermore this

type of construction results in additional tensions within the pavement,

often resulting in damages. The level of the pavement above bridges maybe raised to create the necessary headroom, when the channel operatesas a fairway.

Foundation In most cases the pipes are laid directly in the undisturbed soil. However

when the soil is to weak it may be necessary to construct a foundation,like reinforced concrete slabs, or a piled foundation.

3T.K.E. Meijer: Design of Smallholders Irrigation Systems, Wageningen Agricultural University, 1993.

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Nowadays most

concrete pipes have

bell and spigot joints.

A conic shaped spigot

Spigot with groove

There are various techniques to make the joints impervious, but the use of

clay or mortar is not one of them. Both materials are not flexible andeasily crack to settings and temperature. The most common solution is the

use of rubber rings. The spigots are either conic shaped or contain agroove to fix the ring. Alternatively the bell may be conic shaped. The ring

is put at the very end of the spigot. While the spigot enters into the bell,

the rubber rings rolls into the groove or to the position where it is clampedbetween the spigot and bell.

Furthermore, it is possible to use a sealant prepared of bitumen and

asbestos fibres. Some sealants require heating while others can be applieddirectly.

A waterstop strip is also a bituminous product, but unlike sealants it is

solid. With aid of a burner it is sealed on the spigot and subsequently

made even more flexible after which the bell side is moved over thespigot.

It is also possible to put a strip of expanded polyurethane (plastic foam)

between the joints, after which the pipes are pushed together to close thejoints.

To protect the joints against damages it is possible to use a bandage of

jute drenched in bitumen or glass fibres.

The pipes should be placed in a trench that is cut after the excavation of

the drains. Preferably the whole trench is cut first prior the pipes are laid.However due to traffic conditions, ground water conditions and limited

storage capacity of the soil it may be necessary to cut the trench inpiecemeal and lay just a few pipes at the time. However the latter method

is more difficult and requires extra attention during setting out.The bed width of the trench is usually the pipe diameter plus 1 meter. The

pipe is laid in the middle. The extra meter allows workers to compact the

refill properly. Trenches often easily calve in. Therefore heavy equipmentand the materials should not be placed near the edges to the trench.

The edges of the concrete pipes break easily if they are not laid in the

exact same line (both horizontal and vertical directions). The workersshould therefore be experienced in this activity and appreciate that laying

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pipes is a time-consuming activity. Concrete culvert inlets are usually laid

after the laying of the pipes is completed. The inlet is moved over or in the

pipe, depending on the design of the inlet.

PVC pipes are more flexible, but their ends also easily break when theworkers push the pipes with to much pressure. The most common

construction method is to connect three pipes at the same time.

4.8 MAINTENANCE ACTIVITIESThe following websites contain information about maintenance activities:

www.ruralworks.com

http://www.transport-

links.org/transport_links/publications/publications_search.asp

4.9 SELECTION OF MATERIALShttp://www.ilo.org/public/english/employment/recon/eiip/asist/document.

htmCheck this web site for more information on this subject.

4.10 TOOLS AND EQUIPMENT4.10.1 Machine capacitiesTo obtain acceptable machine performances it is necessary to fulfil certain

prerequisites. These are:

Availability of a good workshop with skilled mechanics; Good management;

Availability of skilled operators; A continuous supply of spare parts, fuel and lubricants.

When one of these requirements is not met, machine work always leads todisappointment and financial losses.

Factors governing

performance

Even when these requirements are fulfilled to capacity performances willvary a great deal, depending on the circumstances. To arrive at the

capacity appraisal it will be first necessary to know the theoretical

capacity, which should then be corrected by numerous factors. To arrive atthe real capacity from the theoretical capacity, the following factors for

reduction have to be applied. They can be divided into non-controllableand controllable factors.

The most dominant non-controllable factors are:Non-controllable

factors

Climate. With extended freezing and rainy periods it is impossible to

maintain mechanical work performance at an acceptable level.

Soil. Climate and soil problems often occur at the same time. Clay soils inwet periods result in muddy conditions and in less bearing capacity. Long

rainy periods can result in water logging and unworkable conditions. Ingeneral, heavy clay requires more traction power than sandy soils.

Altitude. The higher the altitudes above sea level the thinner the air,resulting in a lower engine performance. For every 100 m of additional

height a reduction of 1 -1.5% has to be applied. For altitudes up to 500 m

there are hardly any noticeable reductions in engine performance.Topography. Flat and gently sloping areas make efficient work possible.

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Hilly and/or gullied areas result in a considerable reduction of work

efficiency.

Plot size. Small plots drastically reduce work efficiency. Depending on theplot size and slope a reduction factor of 40% may have to be introduced.

Obstruction. Stumps, rock and hills, etc. may have to be reckoned with.Visibility. Dust storms, rain, snow and fog will result in much lower

performances. Despite good lighting on the machines and a moreagreeable temperature (in the tropics) night work will reduce the work

output.

Controllable factors The following factors can be controlled:

Machine and equipment capabilities. The selection of the right equipmentfor the right job is of utmost importance. This is also true for the type of

machine and its capacity.Work organisation. Proper planning, the right working method and a

proper organisation of the work is a prerequisite in order to achieve

acceptable work efficiency.The operator. Skill, efficiency and motivation of the operator are probably

the most important controllable factors. A good operator should also be

able to avoid unnecessary mechanical breakdowns. Yet if an unavoidablebreakdown does occur he should notify the proper officials.However, it has to be kept in mind that even the best operator can only

achieve a work efficiency of 50 minutes per hour, due to all kinds of minor

operating adjustments. Therefore, in many instances the theoreticalperformance is defined as the working speed, times the working width,

times 5/6 (83%).Machine and equipment availability. Availability means that a machine can

do the job when it has to be done. It is true that even a new engine canbreak down, but as a machine depreciates the chances of a breakdown

increase. With regard to seasonal work a 90% machinery availability canbe realised. Also here it is generally assumed that the work efficiency will

drop.Other factors In addition there are factors which do not fit in the above mentionedclassifications:

Rest. During rest periods, sometimes required by law, the operator musttake care of his personal needs.

Starting and finishing. Every day certain delays occur in the starting andfinishing of the work; this can be observed in the workshop and in the

field.

Maintenance. Daily maintenance has to take place; sometimes moreextensive maintenance work is also required. This influences the

availability and/or the hourly work performance.In-field service. Every operation needs time for minor adjustments during

the work, thereby reducing the output.

Overlap. Mechanical operations always have a certain overlap, resulting inlower performances than are theoretically possible.Turning. Every mechanical operation requires turning room for the

machine and equipment. The reduction factor is more or less dependent onthe size and shape of the plot.

The performance reduction of these various factors is as follows:

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Item Range of reduction

Climate 1.00-0.75

Soil 1.00-0.80

Altitude 1.00-0.75

Topography 1.00-0.85

Plot size and turning 0.9-0.5

Visibility 1.00-0.80Machine suitability 1.00-0.70

Work Organisation 1.00-0.70

Operator 1.00-0.50

Availability 0.80-0.40

Rest 0.95-0.85

Start and finish 0.97-0.90

Maintenance 1.00-0.85

Infield-service 0.98-0.90

Overlap 0.95-0.90

The reduction factors are multipliers of each other, resulting in a situationwhere the total fleet of machines may have to be three to four times as

large as would follow from the theoretical capacity.It has also to be kept in mind that the given list of reductions can be

changed, depending on local conditions. This could result in further

performance reductions.In the following sections, capacities of machines will be given. One must

keep in mind that these performances are achieved under conditions havingcertain requirements. On account of the reduction factors mentioned above,

the given capacities will have to be reduced in many countries by a factorbetween 2 and 4.

Draglines Draglines are normally used for excavation of canals. They are available

with bucket sizes ranging from 400 to 2000 litres. A bucket size of 800

litres is frequently used. The production depends on the type of work, sizeof canal and whether the excavated earth has to be loaded in vehicles orcan be dumped on the banks. If all other conditions are optimal it ranges

from about 30 M3/h for small machines to close to 200 M3 /h for largemachines. For the 800 litre bucket size the production ranges from 40 to

100 m3/h.Bulldozers Bulldozers are used for moving earth over not too large distances, not more

than 100 m for the smallest type to about 180 m for the heaviest types.

There are track-type and wheel type bulldozers.Optimum production depends on type of machine and the distance the

earth has to be moved. It ranges for a D3 type bulldozer from 120 to 30 m3/h for distances from 15 to 90 m. For a D1 0 type the range is from 2000 to

400 m3/h for distances between 30 and 180 m

Scrapers Scrapers are used for moving earth over somewhat larger distances than ispractical with bulldozers. Scrapers are used for distances up to about 2000

m. The capacity of the machines available on the market ranges from 10m3 to 25 m3. By heaping this capacity can be increased by about one-third.

The optimum production depends on the load time (0.5 to 1 minute), timeneeded for unloading (0.7 minute) and the travel time (loaded and

unloaded).On horizontal land the speed is about 1.5 minutes per km. Loaded or

unloaded does not make much difference. On sloping land the speed is

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reduced considerably; 4 minutes per km on 10% slope. The resistance of

the road surface further reduces these velocities.Hydraulic excavators Hydraulic excavators are used for excavation of canals and trenches, and

are available with bucket sizes from 300 to 1500 litres. A bucket size of 700

litres is frequently used. As with draglines, optimum production depends onthe type of work, size of canal or trench, and whether the excavated

material has to be loaded on a vehicle or can be dumped freely. It rangesfrom 30 m3 /h for small machines to 150 m3/h for large machines. For the

700 litre bucket size the production ranges from 40 to 90 M3/hLoaders There are wheel loaders and track-type loaders. Both are used for loading

material (earth, sand, gravel, and rock) from a quarry stockpile onto

vehicles.Track-type loaders are available with bucket sizes ranging from 1 to 5 m3,

while the bucket sizes of wheel loaders are up to 10 m3. Optimumproduction of track-type loaders ranges from about 100 m3 /h for the 1 m3

bucket size to 600 m3/h for the 5 m3 bucket size. For wheel loaders thesefigures range from 100 m3 /h for the 1 m3 bucket size to 1000 m3 /h for

the 10 m3 bucket size.Graders Graders are not normally used for moving earth. Their principal use in rural

development projects is for maintenance of earthen roads. Their productionis normally expressed in m2/h. Working width (blade base) is about 2.5 m.Top speed is in the order of 40 km/h; working speed is considerably less.

Production in m2/h also depends on the number of passes required to dothe work as specified.

Appendix 2 presents for a number of activities the production norms for

activities carried out with equipment.Land levelling with

bulldozers

For earth-moving operations involving about 200 m3 /ha the following

performance can be obtained1200-1600 m2/h for a maximum transportation distance of 60 m. For 35-50

kW bulldozers the figures at the lower end of the scale apply, while for 65-90 kW bulldozers the figures at the upper end of the scale apply. (Note: 1

kW -- 1.34 hp).For earth-moving operations involving about 500 m3/ha:1,000 m2/h with 65-90 kW bulldozers having a maximum transport distance

of 60 m.

By land plane (tractor plus implement)

1,000 M2 /h for minor earth-moving operationsSub soiling Ripping and sub soiling activities with narrow tines and 'goose feet' mostly

have a working depth of about 80 cm. Greater depths require more power. Depth kW Performance Machine

1 -00 m 120 0.25 ha/h 1 D 7

1.25 m 225 0.25 ha/h 1 D 8

Deep ploughing The following table indicates the furrow depths, the ploughing width, and

performance per hour, the kilowatts and the types of machines needed fordeep ploughing.

Furrow Ploughing Performance

Depth (cm) width (m) per hour (he) kW Machines

40 0.70 0.15-0.2 95-105 1 D 6c

40 1.00 0.15-0.2 185 2 D 6c

50 1.25 0.11-0.2 210-225 D6+1D7

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50 1.50 0.1-0.15 375-410 2 D 8

Mixing For mixing depths with a rotator up to 1 m, 185 kW is required, giving a

performance of 01-0.15 ha/h.

Data on productivity

norms labourers

http://www.ilo.org/public/english/employment/recon/eiip/asist/publ/techbrf

/techbrf2.pdf

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5 INSTITUTIONAL DEVELOPMENT ANDORGANISATIONAL STRENGTHENING

Many infrastructure agencies are, in contradiction to what you may expect,

not organised in a way that they select the most efficient productiontechnology or product. This chapter provides information to those agencies

that would like to develop their organisation towards a user of labour-basedtechnology.

5.1 INSTITUTIONAL DEVELOPMENTMore and more work is contracted out to the private sector all over the

world and in particular in Asia and Africa. Where civil works are to becontracted out, clearly the line agencies should not only build up there own

capacity but also that of the consultants and more important thecontractors or community contractors. These partners need to be educated

in aspects of technology choice and labour-based execution of works.Important for contractors is the availability of qualitative site-management-

and engineering staff. After all labour-based technology requires moremanagement and more preliminary design work.

Institutional development means also to build up the education and training

capacity in the country. Line agencies are often not willing to keep ontraining engineers over and over and would expect universities,

polytechnics and vocational training centres to fulfil a demand for staff withsufficient knowledge in labour-based technology. Unfortunately most

education organisations are not that market oriented and sufficient lobbyingfrom high officials is required, like permanent secretaries.

Unfortunately too many countries have adopted standard specifications andcontracting procedures that are constraining technology choice and

technology development unnecessary.

Technology choice and development, with an eye on efficiency, benefit ofperformance specifications. Performance specifications do not specify the

construction technology, but actually specifies only the quality requirementsof the product. It goes without saying that it should be possible to carry out

all the necessary tests. If such tests cannot be carried out performancespecifications may not be applicable. It should also be noted that

specifications are management tools. In countries or situations with mature(integer and qualified) contractors, the client would benefit most of

performance indicators. Not only do contractors have the most accurate

information on technologies and costs, but also do they have all theincentives to produce the required products against the lowest possible

costs. In countries where such contractors are insufficiently forthcoming,the client could adopt specifications that describe the production

technology. The standard specifications however should describe the wholerange of technologies and not only the mechanised version. The contract

itself could indicate which technology should be implemented.Not only the specifications can hamper free technology choice. Contractors

have to register themselves and are often classified into groups. For each

group standards have been set with regard to turn over, manpower,experience and unfortunately also equipment. Often these requirements

with regards to equipment include items, which favours equipment-basedconstruction, like bulldozers and graders. Once invested in these equipment

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items, contractors shall utilise these equipment items, after all if not used

they are still deteriorating. It should be noted in this context that in high-

income countries most large contractors rent most of their equipment onproject-to-project basis.

The works themselves are usually also divided in groups. These groupsrelate to the classes of the contractors. Thus class A contractors can bid for

class A works, class B contractors for class B works, etc.Because smaller contractors have not yet invested in large equipment fleets

they have more freedom to select to most efficient and appropriate

technology. In quite a few countries, small contractors can form a jointventure on project-to-project basis and tender for larger sized works than

their original class. Such organisational freedom tends to favour labour-based technology.

5.2 PILOT PROGRAMS/PROJECTSThe first step, infrastructure agencies usually want to take is to test the

technology. Labour-based technology may be unknown or the agency is nolonger experienced with this technology. Therefore they usually undertake a

pilot-project.Project type The project type can highly influence the technology choice. Certain

products can only be produced in a limited number of ways. In some cases

there is no other option than to use a technology with a high capital/labourratio, like underwater excavation, deep pile driving and high quality

pavement surfacing.

Availability of

labourers

Although it may sound very obvious but a labour based project can be onlysuccessful if labourers can be attracted to work on the site. Therefore is

necessary to make an estimate of the most likely supply of labourers. Thesupply may fluctuate over the seasons. In particular in the agricultural

areas the supply may decline due to the labour requirements in the

agricultural peak seasons. In Muslim countries in the month of fasting,

Ramadan, it may be very difficult to motivate labourers to do hard work.Another aspect to take into account during the project formulation stage isthe issue of labour migration.

Statistics Additionally shortcomings in statistical data about individual and householdincomes, actual hours of work already occupied, and demand for additional

income are usually lacking.Deployable surplus

labour

However deployable surplus labour is often visible through:

1. Registration of the unemployed

2. Visible unemployed persons during site visit3. People employed in establishment with very low productivity

4. Surplus of new entrants into the labour market over persons leavinglabour market.

If the pilot project is evaluated positively the agency could start withformulating a strategy to develop the organisation in the labour-based

direction.

5.2.1 InputsReference materials To allow engineers to make technology choices they require reference data

on costs, production norms, expected lives of products, etc. The agency can

either buy all this information, or assign a certain section of its manpowerto gather and present this information.

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Allocation of time and

funds

As stated earlier in this document to increase the efficiency of the total

product, the agency has to allocate more time and budget during the design

and preparation stages of the project. After all it is in these stages that thedecisions have high impacts on the cost of the products. Furthermore the

required amount of supervision seems to correlate with labour/capital ratioof the technology. Thus in other words more time and funds should be

allocated when production technologies require high labour inputs.Equipment, tools Labour-based technology usually uses a lot of tools with certain forms of

equipment. When however the market does not provide these tools and

equipment, they can obviously not be used. The agency could considersetting up hire and purchase units. These units of course have to operate as

independent private enterprises. Thus they should aim to break even withinthe lives of the equipment and tools.

5.2.2 CultureThe culture of an organisation is defined as the shared values and norms of

people in the organisation. It is important that the employees are taughthow they are expected to think and behave within the organisation and in

this case with regard to the subjects technology choice and labour-basedtechnology.

5.2.3 SystemsThe aspect of systems compromises the internal processes that regulate thefunctioning of the organisation. It is a set of agreements that aims to

regulate the activities of management and staff with one or more related

organisational processes, like imbedding technology choice.Control processes An important process is the control on the process technology choice.

Decision taking, monitoring and providing feedback all these processesneed to be arranged. However the control should not lead to a lame

organisation. The best approach is control afterwards through internalaccounting processes. If it appears the procedures where not obeyed,

sanctions will follow.

5.2.4 StaffThe component staff refers to all activities, rules and regulations related tostaff motivation and utilisation and development of staff capacity.

Training As technology choice and labour-based technology are fairly new processes,most of the staff most likely will require additional training on these

subjects.

5.2.5 Relationship with the contractorsWhen the agency has the policy that it contracts out most of the works to

the private sector the question arises who should make the technologychoice. The overall aim to reduce the total costs and assures the quality of

the products.In countries where contractors have abundant experience with labour-based

technology, the implementers of the works can best make the technologychoice. The contract procedures should therefore focus on fair changes for

all contractors without hampering the quality of the works. Smaller

contractors usually lack the capital to invest in heavy equipment andtherefore tend to use more labour-intensive technologies than the bigger

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contractors. The contractor procedures should enable the smaller

contractors to compete with the bigger contractors for the works. On

condition that the contractors are motivated and capable to deliver qualityproduct, the specifications are best performance orientated. This means

that the specifications are formulated in a way that quality will beafterwards tested. The decision freedom for the contractor is the largest in

that case. If the agency is not particular sure about the motivation orcapability of the contractors it could still issue performance based

specifications but require a description of the proposed production

processes for their review.In those countries where the contractors do not have abundant experience

with technology choice and labour based technology, it is unlikely that thecontractors are able to select the most efficient production technology.

Therefore the technology choice has to be made by the agency themselves.The agency also needs to specify the production technology in the

specifications. The specifications describe the work methods to be used and

are more presented as detailed work manual than description of theperformance requirements.

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APPENDIX 1: PRODUCTION NORMS OF LIGHT COMPACTIO

EQUIPMENT

Type Width of

compacted area

(m)

Speed of rolling

(m/min)

Number of

passes required

Area compacted

per hour (m2)

Depth of

compacted layer

(mm)

Out

com

per

100 kg power

rammer

0.05 m2 60 blows/min 6 blows 25 150 3.8

55 kg vibrating

rammer

0.28 5 3 23 100 2.3

75 kg vibrating

rammer

0.28 12 4 42 150 6.3

100 kg vibrating

rammer

0.4 8 3 53 200 11

200kg vibrating

plate compactor

0.38 10 3 63 150 9.5

450kg vibrating

plate compactor

0.61 20 12 51 130 6.6

660kg vibrating

plate compactor

0.61 15 4 110 200 22

700kg vibrating

plate compactor

0.61 15 2 230 150 35

200 kg vibrating

roller

0.61 10 8 38 80 3.0

350 kg vibrating

roller

0.71 20 12 59 150 8.9

1.0 tandem

vibrating roller

0.81 20 4 200 150 30

2.8 tonne smooth

wheeled roller

1.30 50 8 410 130 53

Table 1: Production norms light compaction equipment

(Source: Guide to tools and equipment for labour-based road construction)

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Type of plant Compacted

width (m)

Speed of

rolling

(m/min)

Number of

passes

required

Area

compacted per

hour (sq.m/hr)

Max. depth

compaction

layer

Output of

compacted

soil per hour

(cu.m/hr

8t smooth

wheeled roller

1.78 50 4 1320 150 198

13.5t gridroller with 60

kW track

laying tractor

1.6 125 7 1715 200 343

13.5t grid

roller with 112

kW wheeled

tractor

1.6 250 8 3000 200 600

12t

pneumatic-

tired roller

2.08 50 4 1560 130 203

46t

pneumatic-

tired roller

2.36 50 3 2360 250 590

1.7t double

vibrating

roller

0.84 15 4 189 110 21

3.8t towed

vibrating

roller

1.83 40 6 730 250 180

7.7t self-

propelled

vibrating

roller

1.83 80 6 1460 150 220

12t towed

vibrating

roller

2.08 40 3 1660 300 498

2t vibrating

plate

compactor

0.86 10 2 258 300 77

Table 2: Production norms heavy compaction equipment(Source: World Bank; Labour-based construction Programs, 1983)


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INDEVELOPMENT: Multi-Sector Planning Approaches

APPENDIX 2: PRODUCTION NORMS EQUIPMENT

Production norms (M3/hour) for hauling trucks with capacity of 3 m3 for transport of

grassland.

Distance in meters

Soil condition 100 200 300 400 500

Poor 9 8 6.25 5.2 5

Medium 14 12.5 10.6 8.9 8.0

Good 17.6 17.0 14.3 12.9 12.5

Production norms (M3/hour) for dumpers with capacity of 3 m3 for transport of grassland.

Distance in meters

Soil condition 100 200 300 400 500

Poor 11.5 7.6 6.25 5 3.8Medium 15 11.25 8.8 7.6 7

Good 20 15.7 12.8 11 10

Production norms (M3/hour) for dumpers with capacity of 1.75 m3 for transport of

grassland.

Distance in meters

Soil condition 100 200 300 400 500

Poor 6.25 4.5 3.7 2.6 2.4

Medium 10 6.8 5.2 3.7 3

Good 13 9.1 7.2 5.9 5

Production norms (M3/hour) for Draglines excavating a layer with an equal depth and

loading it into a truck, tipper etc. Note if clay is excavated reduce capacity with 10%

Bucket capacity (litres)

Depth (meter) 400 500 600 700 800

0.2 32.3 36 42.4 43.2 49

0.4 35.5 42.5 48.2 52.6 57.4

0.6 38 45 53.2 57.6 63.2

0.8 40 47.5 55.5 61.2 67

1.0 40.5 48 57.5 63.7 68.5

1.2 41.5 49 58 65 70

1.4 42.4 50 58.5 66 71

1.6 42.5 51 59 67.5 71

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Production norms (M3/hour) for Draglines excavating a layer with an equal depth and

putting it in depot etc. Note if clay is excavated reduce capacity with 10%


Depth (meter) 400 500 600 700 800

0.2 26.5 31 34 35.5 37.5

0.4 35.5 40 46 47.5 550.6 40 45 51.7 54 61

0.8 42.5 47.5 54 57.2 65

1.0 43 45 52.5 55 67.5

1.2 44.5 46.2 56 58 70

1.4 45 47.5 58 61 71.5

1.6 45 48.5 61.5 63.2 72

Production norms (M3/hour) for Draglines loading dumpers, tippers etc from a depot.

Note if clay is excavated reduce capacity with 10%


Volume per running meter(M

3/m)

400 500 600 700 800

1 22.5 25.5

2 25 28.5 32

3 27.5 31.3 35.5

4 30 35 37.5 42 43

5 32 37.5 40 42 48

6 33.5 39 42 48 52.5

7 34.8 40 43.5 52 55.5

8 35.5 41 44 54.5 58

Production norms (M3/hour) for Draglines for transporting soil from a depot to another

depot. Note if clay is excavated reduce capacity with 10%


Volume per running meter

(M3/m)

400 500 600 700 800

1 24 28

2 32 36 40

3 34 40 45

4 37 43 47.5 51.5 53.2

5 38 45.5 52.5 55 57.5

6 39.5 48 55 58 57.6

7 41 51 58 61.5 64

8 42.5 54 61 64 66

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Production norms (M3/hour) for Draglines for excavating canals and put soil in a depot.

Note if clay is excavated reduce capacity with 10%



(M3/m)

400 500 600 700 800

1 15 15.5

2 23 27 32.53 28 32.5 38

4 32.5 37 42 45 47.5

5 35 39 45.5 49 52.5

6 37.5 41 48 53 56.6

7 40 43 50 56 60

8 41 45 52.5 59 62.5

Production norms (M3/hour) for Draglines for excavating canals and loading of

dumpers/tippers. Note if clay is excavated reduce capacity with 10%



(M3/m)

400 500 600 700 800

1 18.7 202 22.5 26.2 28.7

3 25 30 34

4 27.5 32.5 37.5 42 42.6

5 29 35 40 45 46

6 30 37.5 42.5 47 48

7 31 39 44 48 51

8 32 40 45 50 52.5

Production norms (M3/hour) for Draglines for widening/deepening canals and put soil in

a depot. Note if clay is excavated reduce capacity with 10%


Volume per running meter(M

3/m)

400 500 600 700 800

1 12

2 20 22 23

3 25 28 31

4 29 33 37 40 42.5

5 33 38 40 42.5 45

6 35.5 40 42.5 50 52

7 37.5 42.5 47.5 54 55

8 38 45 50 57 58.5

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Production norms (M3/hour) for Draglines for widening/deepening canals and loading of

tippers/dumpers. Note if clay is excavated reduce capacity with 10%



(M3/m)

400 500 600 700 800

1 14.5 152 19.5 22 22.5

3 22.5 27 33

4 25 30 37 38 40

5 27.5 32.5 40 41.2 44

6 29 35 42 45 47

7 30 37 42.5 47 48

8 30.5 38 42.5 48 50

Production norms (M3/hour) for Mencken scraper-dozer.

Type

Distance (m) D4+ 3.4m3

D6+ 5m3

D7+ 6.7m3

D8+ 7.5m3

D8+ 10m3

50 25 38 48 56 69

100 20 32 41 45 60150 16 26.5 35 37.5 52

200 13 22 30 32.5 44.5

250 11 18 25.5 29.5 38

300 9.5 16 23 27 34

350 8.9 13 19 25 30

400 7.5 12 17 22.5 27.5

450 7.5 11 15 22 25

Production norms for bulldozers (Caterpillars) (M3/hour)

Type

Distance (m) D6 D7 D8

25 100 125 170

50 60 75 11575 45 55 85

100 35 45 68

125 26 35 55

150 20 26 45

175 1 20 39

Productivity data for excavation by hand (M3 /man-day)

Excavation loading at given loading

height (m)

Material

0 0.5 1.0 1.5 2.0

Soft, very loose soil 6.5 5.5 4.5 3.7 3

Firm loss soil 4 3.7 3.25 2.8 2.4Stiff/compact soil 3

Very stiff/dense soil 2.4

Hard/very dense soil 2

Soft rock 1.7

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APPENDIX 3: GANGFORMATIONS

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APPENDIX 4: ROADWORKS IN THE HIMALAYASThe Himalayas is a relatively young mountain range. It covers countries like Bhutan, Nepal,

India, Pakistan and China and contains the highest peaks in the world. In addition to the white

peaks it also contain countless numbers of so-called hills. Many of these hills are higher than

2000 meters but are nonetheless considered hills. Population densities at high altitudes are

usually low but are of moderate level at the lower levels of the mountains. Most of the villagesin this mountain range are only connected through tracks with the outside world. The

governments and donors in this region make major efforts to reduce the isolation of the villages

and to connect them with a road network.

The mountain slopes of the Himalayas are known for its instability. The mountain range is the

result of two continental plates moving together. The movement is perhaps only a few

centimetres per year and run through a series of earthquakes. It is on these slopes that

governments and donors are trying to build roads. Many of the roads are characterised by

landslides and are often temporarily closed during parts of the year.

Over the years several techniques were developed to mitigate the risk of landslides. Nepal

developed extensive knowledge in bio-engineering to stabilise the slopes and furthermore it

developed a phased labour-based road construction method. This appendix provides a synopsisof the latter.

One of the important design criteria of rural road construction in mountains or hills is balancing

of earth. Older techniques would cut and spoil the road in the slope of the mountain or hill. This

old technique has number of negative consequences, like:

Damage of vegetation down hill

Slope is more instable and risk of landslide is higher and the cost to reduce the risksare considerable

Loss of earth materials to build the road

Clogging of irrigation canals and polluting other streams, affecting fish populations

Etc.

This picture gives an example of mass balancing.The so-called cut and fill techniques. Although it is

possible to carry out this technique with equipment

in many low and middle-income countries it is

usually cheaper to use more labour-intensive

techniques. The downhill part is build up with small

layers, of 15 to 20 cm. Every layer needs to be

properly compacted. The application of small

compacters is very useful for these kinds of

constructions.

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Often it is necessary to strengthen the fill side and

protect it against erosion. When the risks are of

moderate levels, it is only necessary to protect the

downhill against erosion, e.g. with a stone riprap. In

situations where the risk of collapsing downsides is

high it is necessary to strengthen its bearing

capacity. Dry stone retaining walls or gabions are

often applied techniques. Both dry stone retaining

walls and gabions allow excess groundwater

labour based road works

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