Regional Seminar Papers 1997

Tools and Equipment — Design, Development and Specifications

The MART Questionnaire on Tools and Equipment

Paul Larcher, Management of Appropriate Road Technology (MART), Institute of Development Engineering, Loughborough University, Loughborough, UK. Email: p.a.larcher@lboro.ac.uk

The main objectives of the hand tool and intermediate equipment ILO/MART questionnaire, "Labour and Tractor Based Roadworks: Hand tools and Intermediate Equipment" were to:

• obtain data on hand tools used and their performance
• obtain an indication of commonly used items of equipment and their availability
• investigate countries' equipment manufacturing capacity
• obtain any available standard equipment designs and specifications
• discover the problems associated with the procurement or use of this equipment

The information obtained from these questionnaires would then be used to highlight areas for further work and investigation by the MART programme team, in order to fulfil the project objectives. The results of the questionnaire are discussed below and are a summarised version of MART working papers 2 (equipment) and 8 (hand tools)

There is general agreement that good quality hand tools are very important to achieving good productivity in labour-based roadworks. On the whole the respondents express satisfaction with the productivity of the hand tools used, presumably meaning that task rates can be achieved in reasonable time and comfort. Therefore, to justify better quality tools of higher cost, task rates would need to be increased. It seems likely that when tools are new and in good condition there may be little difference in productivity of different quality tools, provided shapes and sizes are satisfactory, but as tools wear and distort, the productivity of lower quality tools will drop off more rapidly. However, this cannot be assessed from the questionnaire and is currently being investigated by a series of trials with contractors in Ghana and through the Kisii road training centre in Kenya.

The main criterion used in selecting and procuring hand tools is ready "off-the-shelf" availability. Brands chosen therefore tend to be the more popular, less costly ones widely using in agriculture, often from China or India. However, in some countries, such as Tanzania, tools of satisfactory quality are manufactured locally. Where a number of brands are available, if technical staff handle procurement, brands which best meet specifications tend to be chosen, whereas if a tender board is responsible, there is more emphasis on lower cost. If use of better quality tools is to be encouraged they would also need to be readily available "off-the-shelf". This may involve setting up arrangements between suppliers and local stockists and probably guaranteeing a minimum level of sales.

Acceptability testing is generally limited to visual inspection. None of the responses reported any strength or hardness tests as recommended in the ILO Guidelines. In part this was probably due to selection being partly based on previous experience so that there was some knowledge of the performance of the tools. However, if use of better quality hand tools is to be encouraged with more emphasis on meeting specifications, then a higher level of acceptance testing will be needed together with a willingness to reject batches of tools which do not meet specified standards.

The overall impression gained from the questionnaire is that projects "make do" with the hand tools that are readily available and that these are adequate for the task rates set. Assessment of performance may be based on comparisons with what is available rather than against top quality tools. Better quality tools need to be economically justified by:

• a lower "total life" cost (i.e. if the tool costs twice as much, its average life needs to be more than twice as long), and/or
• allowing higher task rates to be set.

The responses to the questionnaire and the discussions at the Accra workshop confirm the serious underdevelopment of the intermediate equipment sub-sector. This significantly constrains the ability of road authorities and contractors to invest in and utilise this type of equipment in the support of labour-based roadworks. The situation is such that many decision makers do not have the knowledge or the supporting environment to make rational and cost efficient decisions regarding whether to use labour, intermediate equipment, or heavy civil engineering plant for each particular activity in the local road sector. Manufacturers and suppliers are also not aware of the exact needs and potential for intermediate equipment to provide optimal solutions for their road authority and contractor clients. The result is that the most cost effective approach is often not achieved.

Furthermore, the natural development progression of a contractor from pure-labour to intermediate equipment to heavy plant, in terms of capital required, management capability, work competence, cash flow and (possibly) profitability is severely constrained.

There is considerable potential for a healthy local industry in the manufacture, fabrication and support of intermediate equipment in many countries (with its related skilled, high-value employment generation) which is currently suppressed by the present situation.

Probably the most serious problem is the lack of cost-awareness regarding the real owning and operating costs of all equipment, and particularly intermediate equipment. Combined with a typical lack of genuine management pressures for cost effective solutions and performance on road authority personnel, there is often little inclination to change to a more rational approach regarding equipment selection and use.

It is apparent that considerable further research, development and promotion of intermediate equipment is required. The principal issues to be addressed from the evaluation of Accra workshop and the equipment questionnaire responses are summarised in the table below.

The range of issues to be addressed and the scale of the task means that the initial MART programme will only be able to take the initial steps towards producing the comprehensive documentation and guidelines required concerning intermediate equipment. Priority will be given to documenting the existing knowledge and experiences and developing preliminary guidelines and cost information on the common and priority items of intermediate equipment. Proposals will be developed to improve the knowledge base and dissemination of issues relating to intermediate equipment and the promotion of its cost-effective use through owning or hiring.

To tackle the crucial issue of increasing cost-awareness and increase general awareness regarding intermediate equipment, a reference document (Intermediate Equipment Handbook) will be developed in the basic format of one double sided A4 sheet for each item of equipment. On the front side of the page will be descriptive details (including illustration/photograph) and recommended procurement specifications for the item including advice on capabilities/limitations and sourcing. On the reverse side will be guidelines on costing. These will be divided into owning costs and operating costs. The owning costs will be set out in a matrix format so that planners, owners or users may select appropriate values of assumed economic life, annual utilisation and finance interest rate to select a corresponding ownership cost per hour or day of use. The operating costs will be calculated separately.

The sheet-per-item format should assist dissemination, training and everyday use of the information, and will ease updating. Contractors, manufacturers or suppliers could request the provision of only the sheet or sheets of immediate interest to them. It should be possible to mail, fax or e-mail this information at very low cost. There is potential to have this information downloadable from the Internet.

It is envisaged that the initial document will be a basic "core" issue. Interested parties will be encouraged to contribute to, expand and refine the data in subsequent issues. The document should help promote the awareness of the potential market with equipment manufacturers. Further funding will be sought to develop the document from the core initial issue.

Appropriate Hand Tools for Labour-based Roadworks

Gary Taylor, I.T. Transport, The Old Power Station, Ardington, Near Wantage, OX12 8QJ, Oxon, UK. Email: ittran@rmplc.co.uk

Experience shows that labour costs are typically around 40% of the total construction costs in labour-based (LB) roadworks, so that the productivity of the labour force obviously has a significant impact on the cost effectiveness of LB methods.

The main factors governing productivity are the effectiveness of organisation and supervision of LB activities, motivation of the workforce, and the quality and efficiency of the tools and equipment used. The cost of hand tools usually represents 2 to 5% of the total project costs so that a relatively small investment in this element has a substantial impact on the overall cost-effectiveness of the project.

Although accepted standards and specifications for hand tools are available,^1,2 experience shows that poor quality hand tools are still being widely used in LB projects with a consequent loss of labour productivity. This indicates a need to improve procurement policies and procedures and the ready availability of acceptable quality tools. For instance: increasing awareness of the need for good quality tools; making specifications more readily available and accessible; advocating wider use of simple acceptance tests to check quality; and promoting improved availability of suitable quality tools. These are the aims of the hand tool component of the MART initiative.

This paper reviews the factors affecting hand tool quality and the influence of tool quality and condition on the productivity of LB works. This includes a review of results on the effect of tool wear on productivity from recent tests in Ghana and Kisii, Kenya.

Although there seems to be general agreement by LB practitioners that hand tool quality is very important to the cost-effectiveness of LB work, there appears to be virtually no documented experience to substantiate this view. Hard evidence is needed to prove the case for better quality hand tools to those responsible for procuring and purchasing tools. This seminar brings together a wealth of experience on LB work and the paper would like to take the opportunity to document some of your field experience with hand tools. A questionnaire is included in the paper which it is hoped will draw out some of this valuable experience through responses and additional comments and observations. This kind of evidence is an essential input to promoting the case for good quality hand tools.

There are three main factors which affect the quality of hand tools:

1. Ergonomic efficiency:

This is the efficiency and convenience of use of the tool. It is influenced by the shape, size, weight and quality of finish of the tool. For instance, the angle between the blade and handle of a hoe is an important ergonomic factor since it affects the angle at which the blade strikes the soil and hence the efficiency of chopping out the soil.

2. Strength of the tool:

This is the capacity of the tool to perform its required function without deforming excessively or breaking. The important factors are shape, size, material and material treatment (hardening and tempering). The latter is particularly important for impact tools such as hoes and pickaxes since it can double the effective strength of the tool (i.e. the force needed to cause permanent deformation). If tools bend too much or are deformed they do not work as efficiently. If they break then time is lost in repair or replacement. In the worst cases workers may have to restrict their rate of work because of inadequate strength of the tools.

3. Wear and durability

Wear reduces the size of working edges and surfaces and may damage or blunt cutting edges. This reduces the efficiency and productivity of the tools. Durability against abrasive wear appears to depend mainly on the carbon content of the steel, improving with increased carbon content up to about 0.8%. Initial hardness of the metal has less effect.

Table 1, derived from an analysis of a number of LB projects in Ghana, Lesotho and the Philippines shows a typical breakdown of LB costs to activities.

This shows that labour costs typically account for about 40% of total LB costs, with at least half from earthworks. The productivity of earthworks and gravelling activities, making up over 80% of labour costs, is clearly very important to the cost-effectiveness of LB work. The impact of quality on the productivity of the main tools used - hoes, shovels, pickaxes/mattocks, wheelbarrows and rakes/spreaders - is therefore very important. Since the cost of hand tools typically makes up only 2 to 5% of overall construction costs, the labour productivity achieved with the tools is likely to have a significantly greater impact on overall costs than the purchase cost of the tools. This is illustrated by the following simple examples:

1. A heap shovel typically costs about $4 and a good quality shovel 2 to 3 times more, say $10.

A typical life of a shovel is 100 days, and if the labour cost is $2 per day the labour cost for the life of the shovel is $2 x 100 = $200.

Therefore to justify changing from a cheap to good quality shovel, a cost increase of $6, the labour cost would need to be cut by $6 i.e. a 3% increase in productivity.

This is a relatively small increase in productivity which would need to be achieved by increased worker output using the better quality tool and reduced time lost from tool breakages.

2. If the tools are changed twice as frequently, i.e. every 50 days, to reduce losses in productivity from using worn tools, an extra $10 has to be justified over a period of 50 days i.e. an average increase in productivity of 10%.

The extent to which the potential improvements in productivity can be achieved on site depends on labour relations, effectiveness of supervision and the way in which labour is paid:

• Daily paid: the output of work completed per day should increase provided there is effective supervision;
• Task rate: to achieve improved productivity the daily task rate needs to be increased. The potential for this depends on labour relations and the effectiveness of supervision. Usually there is some flexibility in the daily task rate to allow for variation in soil conditions so that increasing the daily task rate may not be a problem. The Ghana contractor felt that it would be difficult to justify the increase to the workers but other site supervisors have suggested it would not be a problem;
• Piece work: improved productivity will increase the volume of work completed per day, but for direct cost savings the unit rate ($ per m or $ per m³) would need to be reduced. This may be difficult to justify to the workers.

Although the use of better quality tools may not always produce cost savings from improved productivity, workers will benefit from the reduced time and effort needed to complete their work which should lead to a more contented and better motivated workforce. In addition, there should be savings in site overhead costs from completing work in less time.

Most of the documented information on hand tools is concerned with specifications and procurement. No information has been found in project reports reviewing the performance of hand tools and their impact on productivity and project costs. The only documented field experience of the effect of hand tool quality on productivity appears to be from the following test programmes.

A series of tests was carried out by de Veen³ and others to compare the ergonomic efficiency and strength of farm quality tools with construction quality tools. The only significant difference found in worker productivity with the two types was for hoes, where the construction type hoes gave a 12% higher productivity than the farm type, possibly because they were 25% lighter. However, considerable differences were found in the strength of the two types, the farm type experiencing far more failures, particularly of handles during the tests. Losses in productivity due to broken tools vary very much with working arrangements and availability of replacement tools and are difficult to generalise. However, they are likely to be significant where failure or damage of tools occurs frequently. For instance, in the tests at Kisii (below) it was reported that on some occasions up to 25% extra labour had to be used to go over work which could not be completed to a satisfactory standard on the previous day because of poor quality of tools. Also, in the gravel loading tests, a team of five was reduced to three or four on three out of the nine days because of failure of shovel handles.

These tests were carried out as part of the MART programme by a master's student with considerable support and assistance from a local contractor. The measurements were made in actual site work using shovels and pickaxes in ditching and sloping activities. The working force of 12 was split into two groups of six, one group having new tools and the other badly worn tools (about 80 to 90% of maximum wear before the tools would be discarded). The tools are illustrated in Figure 1 and 2. Workers with new and worn tools were located alternately to standardise soil conditions and the new and worn tools were alternated between the groups from day to day. The time to complete the daily task for each worker was recorded, and workers asked for comments on tiredness, the difficulty of the task and the performance of the tools. Three days testing was completed for each task. The average results were as follows:

• Ditching: average increase in time for daily task using worn tools = 22%
• Sloping: average increase in time for daily task using worn tools = 6%

Ditching is a much more strenuous activity than sloping, involving considerable breaking up of the soil surface, whilst one of the main complaints about the worn tools was the bluntness of the cutting edge of the pickaxes. These factors would explain the greater loss in productivity in the ditching activity.

These tests have recently been carried out as part of the MART programme to follow up the tests in Ghana. They were implemented by staff at the Kisii Training Centre. In these tests, three groups of tools were compared - new, part worn (about 40% of full wear) and badly worn (80 to 90% of full wear). Two series of tests have been completed as outlined below:

The tests followed the same basic procedure as those in Ghana. The workers were divided into two groups of 10, workers with new and worn tools located alternately and tools exchanged between groups on a daily basis. six days of testing were carried out to compare new and worn tools, and 6 days to compare new and part-worn tools. The main tools used were hoes (jembes) and shovels, with support from mattocks and forked jembes. The average results were as follows:

Part-worn tools +2.5%

Badly-worn tools + 7%

It was clear in these tests that competition between the workers has a significant effect on the results, with those using the worn tools working considerably harder to keep up with those using the new tools. A scale of tiredness allocating 0 to not tired and 3 to very tired showed a consistent average of +4 "tiredness units" for the Group using worn tools, and +1.8 units for the Group using part-worn tools. The results also showed a clear relationship between "tiredness units" and the time taken to complete the task. Using this relationship 4 units is equivalent to about 52 minutes per worker and 1.8 units to 23 minutes per worker. It therefore seems likely that without the competition (i.e. all workers using worn or part-worn tools) the increase in task time would have been 15 to 20% for the worn tools and 5 to 10% for the part-worn tools.

In this test the new, part-worn and worn shovels were compared in loading gravel in two quarries. Two teams of five were used in each quarry, one using new shovels and the other part-worn or worn shovels. The tools were exchanged between groups on a daily basis. The total "loading" time during the day was recorded for each group, which comprised 13 trailer loads per group in one quarry and 14 in the other quarry.

The average results were as follows:

Part-worn shovels +1%

Badly-worn shovels +28%

Shapes and sizes seem to be reasonably the same for most hand tools regardless of quality and it appears that ergonomic efficiency may not be a significant factor affecting productivity.

The main problem experienced with poor quality tools is probably inadequate strength, usually because the tool heads are made of an inferior steel and are not properly hardened and tempered. Inadequate strength may show up as excessive bending or deformation of the tool head or cracking and breaking. Breaking of cheap handles is also a considerable problem. The loss of productivity due to damage and breakages of poor quality hand tools cannot be measured in tests and it is therefore important to collect and collate typical field experience on this issue.

The results of the tests investigating the effect of wear of hand tools on productivity show a consistent pattern. Over the first half of the life of the tool there is little loss in productivity and in fact there may be some benefits from polishing of the surfaces and self-sharpening of cutting edges. In the second half of tool life there is a substantial drop in productivity due to reduced area of working surfaces and damage to cutting edges. It seems that there would be benefits from changing tools at about 60 to 70% of their present life (e.g. at 60 to 70 days instead of 100 days).

For example, consider that three tools costing $10 are used over 200 days instead of two. The increased tool cost of $10 would be justified by an increased productivity of about 7% over the final a of present tool life (i.e. final 33 days of a 100 day life). The tests indicate that increases in productivity of at least 15% are likely.

The MART programme proposes three steps to encourage the wider use of good quality hand tools in LB roadworks:

1. Production of an illustrated brochure to promote the advantages of good quality tools, particularly in terms of cost effectiveness. This will be distributed to organisations and contractors involved in LB work, and especially to individuals and departments involved in the selection and procurement of hand tools. It is essential to collate field experience to substantiate the brochure.
2. Preparation of hand tool specifications in a clearer and more accessible form. This is likely to be a two page data sheet containing all essential information. It will include details of simple tests that can be carried out on site to check compliance with specifications - a visual inspection to check important features; and a strength test for blade and handle.
3. Informing hand tool suppliers of the potential increase in demand for good quality tools which should be generated by the promotional campaign. It is clear that one of the reasons that projects use lower quality tools is that good quality tools are not always readily available from local suppliers. Promotion of the wider use of good quality tools must therefore be backed up by encouraging suppliers to make the tools readily available.

New and worn shovels

New and worn pick-axes

ILO (1981) Guide to tools and equipment for labour-based road construction. International Labour Office, Geneva

Coukis, Basil (1983) Labour-based construction programmes. The World Bank; Oxford University Press, Oxford, UK

Veen, de J (1981) In collaboration with J Boardman and J Capt: productivity and durability of traditional improved hand tools for civil construction. ILO/FAO

I.T. Transport (1997) Effects of worn hand tools on worker productivity in labour-based roadworks for MART. I. T. Transport, Oxon, UK

We need to collate field experience on the impact of hand tool quality on LB productivity and costs to substantiate the case for good quality hand tools. We have been unable to find any documented information and we would therefore be very grateful for any help you can give in providing information from your own experience of LB work through responding to the following questions or through your own comments.

(job title or responsibility)

Contact details would help us if we wish to follow up any responses:

Could you please give details of any documented information that you are aware of on the following topics:

1. Feedback from LB projects on the quality and performance of hand tools:

If the information is contained in project reports, could you please suggest where these may be obtained from.

The following refers particularly to problems found with poor quality tools and their impact on productivity.

4. Can you provide any information on the comparison of "total life" costs of good and poor quality tools? i.e. costs over the life of the tools taking into account initial cost, costs of repair and replacement and differences in productivity.

5. Do you think the approach outlined in Section 5 of the report to promote the wider use of good quality tools is appropriate/effective?

Do you have any comments on the approach or on the need to promote the use of better quality tools?

6. Do you think good quality tools are important to the productivity and cost-effectiveness of LB roadworks:

If yes, on what do you base this opinion? Can you give any practical experience which supports this opinion?

Increase in productivity to justify spending $6 more on good quality shovel

= 6 x 100 = 3%

200

If shovel is changed at 1/3 of present life (67 days instead of 100 days) then 3 shovels are used in 200 days instead of 2

Extra cost of shovel = $10

Increase in productivity needed over final 1/3 of present life i.e.

= 2 x 33 = 66 days

is 10 = 7.5%

2 x 66

Main Tools : Hoes (jembes); shovels

Support Tools : Forked hoes; mattocks

Part-Worn (about 40% worn) 2.5%

Badly-Worn (about 80-90% worn) 7%

Taking into account effect of "competition" between workers, estimated losses in productivity are:

Part-Worn : 5 to 10%

Badly-Worn: 15 to 20%

Part-Worn Shovels 1%

Badly-Worn Shovels 28%

MART Working Paper No 7: Agricultural Tractors in Roadworks

The Management of Appropriate Road Technology (MART) initiative aims to reduce the costs of constructing, rehabilitating and maintaining road infrastructure, and vehicle operations in economically emerging and developing countries (EDCs). It is based on a research project funded principally by the British Department For International Development (DFID) under its Technology Development and Research (TDR) provision. The initiative is led by the Construction Enterprise Unit of Loughborough University's Institute of Development Engineering, in association with two UK-based specialist consultants Intech Associates and I.T. Transport. The MART programme is currently implementing its initial three year programme.

The MART programme is concerned with supporting sustainable improvements in road construction and maintenance in developing countries. This implies the effective use of local resources, particularly human resources and readily available intermediate equipment (especially wheeled agricultural tractors and related ancillary equipment). To optimise the use of scarce financial resources, it also requires the effective mobilisation of the indigenous private sector (particularly small domestic construction enterprises), and the application of good management practices in both contracting and employing organisations.

The current phase of the MART programme will inter alia draw together existing expertise in labour - and intermediate equipment-based technology and the development of private construction enterprises to produce a series of guidelines on the four priority topics of:

• hand tools;
• intermediate equipment;
• private sector development; and
• institution building.

The MART initiative is strongly research-based, and both DFID and the MART partners see its main impact as providing analysis and codification to support practical project initiatives. Thus much of the output will be in the form of journal papers and other formal publications suitable as reference material and providing an independent and reliable record of the advancing state of the art.

This Working Paper is intended to inform and provoke discussion and dissemination. MART welcomes dialogue with engineers, equipment designers and manufacturers regarding designs, products or experience of intermediate equipment with the objective of the promotion of a sustainable road sector technology and management 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 views expressed are not necessarily those of the DFID.

Material for this paper has been assembled from assignments and colleagues working in the appropriate technology roadworks sector in Africa, Asia and the Pacific, as well as available reference documentation. Important co-operation from engineers and other personnel in the road authorities in these countries has been supported by a number of agencies and organisations including DFID, BPWA, CIDA, DANIDA, DGIS, EU, Helvetas, KfW, NORAD, SDC, SIDA, USAID, ILO, TRL and the World Bank. The author wishes to acknowledge the co-operation and support received from these individuals and organisations, as well as the valuable comments on the drafts provided by colleagues.

Robert Petts is the Principal of Intech Associates, Consulting Engineers to the road management and maintenance sector.
Robert Petts, Intech Associates, 53 The Park, Great Bookham, Surrey, KT23 3LN, UK.
e-mail:- rob@intech-consult.demon.co.uk

This working paper reviews the role of and potential for the wheeled agricultural tractor for roadworks in economically emerging and developing countries. It considers the rationale for, and range of activities suitable for, tractor applications in paved and unpaved road works.

While heavy plant may be appropriate for some large road construction and rehabilitation projects where the huge investment may be justified, for most roadworks, and particularly maintenance, tractor technology can offer a capable, cheaper and more flexible investment which is better suited to the situation of emerging and developing countries and their local contractors.

The paper demonstrates that tractor technology should be part of a natural progression from purely labour operations through to sophisticated heavy equipment roadworks, particularly with respect to capital requirements. It also shows that the owning and operating costs of tractor equipment can be considerably lower than those of heavy plant used to achieve the same work output.

The paper suggests that support for intermediate equipment hire organisations could help to establish tractor technology and reduce road infrastructure provision and maintenance costs.

The needs of the intermediate equipment sub-sector have been identified through the MART initiative and these are discussed.

Economically emerging and developing countries (EDCs) vary enormously in their economic, resource, industrial, service sector and social circumstances. This suggests that the technologies and methods used for road construction, rehabilitation and maintenance should also vary and be appropriate for their individual circumstances. Unfortunately, it is not always immediately obvious that the "state-of-the-art" technologies used and taught in developed country organisations and institutions are often not appropriate, economic nor sustainable in most situations in many other countries. What is required is an appropriate technology and management approach.

Economically emerging and developing countries (EDCs) are usually characterised by a resource base that is very different from that found in economically developed countries. For example, in developed countries, labour wage rates are typically in the range of US$40 to 150 per day equivalent (Figures 2 and 3). In comparison, EDCs may have abundant low cost and under-utilised labour (wages often less than US$5/day equivalent), particularly in the rural areas (Figure 3). Furthermore, they have local traditions and procedures, and a fledgling or intermediate-technology industrial and service sector base^1-3 which are substantially different from the industrialised countries. It makes economic and management sense to seek an optimal use of these lower cost, locally available resources, including local skills and traditions, before resorting to importing expensive (and often extremely problematic) heavy equipment and expertise on a large scale.

Heavy construction plant will still continue to be justifiable on many large, paved main road, reconstruction and rehabilitation projects where the factors of high road traffic, high technical specifications, high guaranteed plant utilisation, economies of scale, intensive management, rapid implementation and relatively simple logistics can support a large-contractor, capital-intensive approach. However for most other roadworks the use of intermediate equipment and labour is often cheaper and more appropriate. There are also strong political and social arguments for adopting a more local-resource orientated approach.

Many problems encountered in the road sector in EDCs can be attributed to the application of inappropriate technology, as well as problems of inadequate policy guidance, insufficient funding, inadequate institutional arrangements, poor manpower development and motivation, and inadequate decision making arrangements^4-9.

This paper reviews the experience and potential role of tractor technology in the development of an appropriate and sustainable road sector in EDCs. By adopting the most appropriate technology in each situation (whether labour, intermediate or heavy equipment) it should be easier to tackle the other (equally important) issues of finance, institutional arrangements and management.

Experience with Tractors

The use of wheeled agricultural tractors is well established in the private and public sectors in many EDCs for road, agricultural and water sector works.

Even on many of the labour based (LB) road programmes, tractors and fixed dump body trailers are used for hauling natural gravel for the running surface of roads; with excavation, loading and unloading achieved by manual labour. Gravel road construction/ rehabilitation is typically achieved for a cost of US$10,000 to 20,000 per km using tractor and labour technology (with labour wage rates of between US$1 and 3.5 per day)^10.

On conventional capital intensive road projects, wheeled agricultural tractors are normally used for tasks such as towing compaction rollers and water bowsers, and sweeping.

In the UK, some contractors still use tractor technology for rehabilitating thin-surfacing paved minor roads using bitumen emulsion technology, and for laying thin bituminous overlays (Figures 4 & 5). The operations include ripping, pulverising, mixing and spreading by tractor equipment. The bitumen roadworks viability of tractor technology in the relatively high wage environment of the UK presents the prospects of tractor technology being attractive in a far greater range of economic circumstances than pure labour technology when the wage rates in Figures 2 and 3 are considered.

Many of the LB road programmes in EDCs have concentrated on road construction or rehabilitation, rather than maintenance. The method of implementation has focused on works management using a civil service organisation, with the notable exception of the Ghana, Lesotho, Tanzania and Indonesia projects ^{11-14, 22.} The programmes have usually concentrated on gravel roads (unpaved roads often constitute between 80% to more than 90% of national road networks in EDCs¹⁵).

Despite this encouraging experience with agricultural tractors, most roadworks in EDCs are still carried out by civil service organisations or large contractors using traditional heavy equipment technology.

There is now widespread pressure, particularly from the international agencies and some governments, for a move away from implementation using the problematic civil service machinery, towards works carried out by the private sector. In addition, more attention is being paid to road maintenance. There is also strong argument for better use of local resources^6,7,9,15,16. It is argued that with the expected commercial pressures, more attention will be paid to cost awareness and the adoption of the most appropriate technology.

Unfortunately, the road contracting sector is poorly developed in many of these countries after decades of 1 force account road maintenance operations. Typically, major road schemes are carried out by international contractors, a few large indigenous contractors, or a partnership of both. However, the majority of roadworks (smaller schemes and most maintenance) is suitable for lower cost appropriate technology implementation by small domestic contractors using simple equipment and local labour. There should also be scope for sub-contracting to the larger projects. Unfortunately, the appropriate standards, documentation, procedures, awareness and training, and supporting institutional and management framework to use an appropriate technology approach are usually deficient.

Intermediate equipment often is, or can be, manufactured locally to meet some of the needs of the roadworks sector. It can be tractor-based, self propelled, animal drawn or hand operated. Capital costs of local manufacture can be significantly lower than imported sophisticated equipment. Other potential benefits include easier maintenance, simpler spares requirements leading to less downtime (i.e. higher availability), lower operating costs and the added advantage of the local manufacturing capability (which creates local employment). This should encourage greater sustainability compared with sophisticated imported equipment (Figure 6)^2,17,18.

Experience has shown that the use of heavy plant for road maintenance works in EDCs leads to extremely low utilisation rates for the equipment due to a range of factors listed in Figure 6. Annual utilisation can often be in the region of 200-500 hours per year ^19,27. At this level of utilisation, the overall costs of ownership in EDCs is extremely high (Figure 7) and uneconomic.

In contrast, tractor equipment is likely to achieve far higher availability in any particular mechanical support environment ²⁷. Slightly reduced hourly output by lower-powered tractor equipment can be more than compensated with higher availability and overall output, and far greater utilisation due to flexibility of applications.

With the grading application shown in Figure 7, it should also be recognised that typical (and adequate) motorgrader specifications in the period 1945-55 were only 75-100 hp (56-75 kW) and 10 tonne operating weight (e.g. Caterpillar 12) ^29. This is comparable to the larger tractor-based combinations now available (5 tonne 100 hp tractor and 5 tonne towed grader) which can achieve both light and heavy grading.

Based on 12 year economic life for the motorgrader and 10 years for the tractor equipment. Calculated on an interest rate of 20%. For detailed assumptions and calculations see Annex 2. Motorgrader hourly output on light and heavy grading expected to be 20% higher than towed grader.

Wheeled agricultural tractors are the simplest, most robust and versatile mobile power source; furthermore the proven uses in the road sector are extensive (Figure 8). Applications cover bitumen, gravel and earth roads. Even where the tractors are not manufactured or assembled locally, the attachments usually can be. Tractor technology suffers much less from the problems summarised in Figure 6. Figures 9 to 20 illustrate some of the tractor equipment applications in roadworks.

Service and repair facilities for agricultural tractors are far more common in rural areas than for heavy civil engineering plant. This contributes to better reliability and availability of the equipment.

Recent experience in Kenya¹⁹ has shown that a team of three No. 100hp 4wd tractors working in association with two 5 tonne heavy towed graders (Figure 14), a towed compaction roller and local unskilled labour can rehabilitate the camber and drainage system on earth and gravel roads for direct costs of less than US$2,000 per km. The rate of work output was more than 2 km of rehabilitated road per week.

Subsequent routine maintenance can be established for between US$250 - 750 per km per year, depending on towed grading frequency, also using labour and tractor technology. These costs are substantially below those of using a heavy plant approach.

This basic provision of camber and drainage system and regular low-cost routine maintenance can provide an adequate standard of low traffic road in low-moderate rainfall climates (<2,000 mm/year). Spot gravelling, or even more extensive gravelling where traffic and resources permit, can also be provided at costs lower than those incurred using heavy plant.

Tractor technology offers local entrepreneurs a lower risk and more flexible investment than traditional heavy roadworks plant. The latter will require investments in specialised equipment with a new procurement cost of about US$1 million or more (Figure 21), even to achieve just a full regravelling capability (with high associated running costs).

In practice, contractors will often purchase second-hand plant from larger contractors or overseas sources. Nevertheless, the risks from undocumented previous use and abuse are obvious, with the potential for poor availability of spares and expensive repairs for the new owner.

However, from as little as US$30,000, a contractor or subcontractor can buy (new) into tractor technology with the versatility to carry out a range of operations and serve clients in the road, agriculture, water and municipal sectors (Figure 22). An extensive roadworks, water and agricultural sector capability using tractor technology can be achieved with an investment of less than US$250,000 (new). This is equivalent to the cost of just one new motorgrader. The tractor based equipment substantially reduces the risks and increases business opportunities compared to a ‘one client' relationship using single-function items of plant. Nevertheless, the development of an effective multi-sector tractor-based contracting sector will require improved understanding, liaison and co-operation between road authorities, agricultural organisations, land users, equipment owners, suppliers and manufacturers.

Tractor technology also creates a natural development path for successful pure-labour contractors, who can be established for capital sums of about US$12,000 (Figure 23), when they come up against the management constraints of large unskilled labour forces.

1. Basic tractor equipment for routine maintenance

2. Basic tractor equipment for earth/gravel road reconstruction

When considering adoption of an intermediate equipment approach, a frequently voiced concern is what to do with the existing fleets of problematic heavy plant which are still viewed as a resource, despite their high operating costs and downtime. The rational approach would be to consolidate the remaining serviceable items on closely supported road construction/rehabilitation sites where the necessary support and the logistical problems are minimised. Replacement of the heavy plant should only be considered when the numbers reduce to a level that matches the market and economic requirements.

Wheeled agricultural tractors have been used independently for all of the key activities required for reconstruction of a deteriorated paved road with a thin bituminous surfacing^{2,17,18,20,21}. There is potential for contractors to carry out these works using tractor based equipment for ripping up the existing pavement, pulverising the existing materials, applying and mixing in a stabiliser such as bitumen emulsion binder, shaping and rolling, then sealing with a conventional surface dressing. The approach would optimise the use of the existing pavement materials, have the energy and environmental attractions of a cold, low waste process and should have capital requirements and overall costs significantly below those of traditional heavy plant, hot-mix reconstruction processes.

Figures 24 and 25 demonstrate how tractor technology fits into the natural progression from pure labour technology through to sophisticated equipment while still providing the flexibility provided by labour to carry out a range of operations.

Tractor towed equipment can also be used to provide thin (up to 50mm) bituminous overlays using the equipment shown in Figure 5.

Bank interest rates in developing countries are usually high (15 - 48% in the countries surveyed by MART Working Paper No 2 ²⁸ ). The high cost of (and problems of securing) finance in emerging and developing countries and the utilisation-cost relationships shown in Figure 7 demand that any equipment (whether heavy or intermediate) must be highly utilised to have a chance of paying back its investment and for the contractor to make a profit. The market for contract roadworks in most developing and emerging countries is particularly variable and precarious. Contractors must minimise the eventualities of having serviceable-but-idle plant. There is therefore potential for the provision of intermediate equipment hire services. This could be provided by dedicated plant hire firms or by contractors hiring out their equipment when they have insufficient work themselves. This flexibility should increase the utilisation of individual items of plant and therefore lower the overall costs. Initiatives will probably be required to convince road authorities, contractors and international agencies of the potential benefits of such an approach using intermediate equipment. Pilot schemes should allow the potential, technicalities, costs and benefits of such an approach to be established.

Figure 24 – Construction of New Road Base Layer from Existing Base and Bituminous Surfacing*

Paved Road Reconstruction – Technology Options for Each Operation – Tractor Options Shown Emboldened

Cold Process Emulsion Technology: Options shown generally in increasing complexity of technology down each column

Source: Intech Associates
* The process can also be applied to the upgrading of an existing gravel surface of suitable material characteristics.
** Depending on deadweight per unit width of roll and layer thickness.
*** Assumes that subgrade and/or sub base are of acceptable characteristics and any necessary repairs to the drainage system are carried out.

Figure 25 – Surfacing of Reconstructed Road Base Layer

Paved Road Reconstruction – Technology Options For Each Operation – Tractor Options Shown Emboldened
Cold Process Emulsion Technology

Options shown generally in increasing complexity of technology down each column

* The process can also be applied to the maintenance resealing of an existing bituminous surfacing (usually only one of the coats will be applied in this case).
* Time periods between roadbase construction and each seal, and trafficking, to depend on curing times.

The MART initiative has been investigating the needs of the intermediate equipment sub-sector through questionnaires to users in developing countries. Furthermore a workshop in Accra in 1996 ²⁶ involved road and equipment engineers, contractors, consultants, academics and equipment manufacturing representatives to identify and enumerate the needs of the sector in more detail. These requirements are summarised in Figure 26.

The MART initiative is preparing guidelines from available sources in consideration of the above sub-sector needs.

The MART investigations have shown that there is still a need for widespread enlightenment regarding the capability of intermediate equipment, including tractor applications. Furthermore, there is prevailing lack of knowledge regarding the real costs of owning and operating any type of equipment, be it sophisticated or simple.

There is a need to highlight the real costs of financing and ownership which are neglected in many equipment management systems, and which can dwarf operating costs in a high-cost-finance environment; thus possibly adversely affecting management decisions on choice of technology or equipment.

Heavy construction plant will still continue to be justifiable on many large, paved main road, reconstruction and rehabilitation projects where the factors of high road traffic, high technical specifications, high guaranteed plant utilisation, economies of scale, intensive management, rapid implementation and logistics can support a large-contractor, capital-intensive approach.

However, the use of intermediate technology equipment and labour has particular advantages for road authorities and smaller contracting enterprises on more modest road construction/rehabilitation works and on the secondary and minor roads which comprise the majority of the rural road networks. This approach is also appropriate for most road maintenance operations on paved, gravel and earth roads.

The wheeled agricultural tractor is a proven technology for a wide range of roadworks in economically emerging and developing countries (and even for some applications in economically developed countries). However, the application and benefits of tractor technology are not widely recognised or utilised. The principal attractions are lower operating and overall works costs due to reduced capital requirements and risks, higher potential utilisation through a range of applications, potential clients and workload in various sectors. Tractor technology represents the natural progression (in terms of affordability, management and business development) for authorities and contracting enterprises from pure labour operations through to the capability to utilise sophisticated heavy equipment. It should however be questioned whether most local enterprises need to complete the progression beyond tractor technology because of the costs, risks and market characteristics discussed in this paper.

There are potentially considerable benefits to be gained from encouraging the establishment of local plant hire companies providing intermediate equipment based on tractor technology. This would further assist small local contractors in reducing their capital or borrowing requirements so that they would use and pay for specific tractor equipment items only when they have secured work contracts. Contractors could also be encouraged to hire out serviceable-but-idle equipment to other contractors.

Better understanding of the capabilities, flexibility, actual costs and advantages of this technology is necessary, particularly by the engineers, contractors, suppliers of tractor based equipment, academics and trainers. Where necessary, contract procedures and documentation need to be adapted to accommodate the use of local contractors and appropriate technology. As well as adopting the most appropriate technology in each situation (whether labour, intermediate or heavy equipment) attention must also be paid to tackling the other (equally important) issues of finance, institutional arrangements and management in the roadworks sector.

The MART initiative is assisting in these endeavours by codifying and disseminating the experiences and potential of intermediate equipment technology and local contracting.

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