7 and 8 - Government of Botswana

MINISTRY OF WORKS AND TRANSPORT
Ministry of Works
and Transport
Workshop Proceedings,
Gaborone, 6 th June 2003
Guideline 7
Technical Auditing of Road
Projects
Guideline 8
The use of Silcrets and
Other Marginal Materials
for Road Surfacing
Addendum to publications with reference to
7 an
and 8
February 2004

Workshop Proceedings,
Gaborone, 6 th June 2003
Guideline 7
Technical Auditing of Road
Projects
Guideline 8
The use of Silcrets and Other
Marginal Materials for Road
Surfacing
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8 1

Ministry of Works and Transport
Roads Department
Private Bag 0026
Gaborone,Botswana
Phone +267 -393511
Fax +267 -394278
February 2004
Addendum to publications with reference to
Guideline no 7: Technical Auditing of Road Projects
ISBN 99912 - 0 - 317 - 6
Guideline no 8: The use of Silcrete and Other Marginal Materials for Road Surfacing
ISBN 99912 - 0 - 381 - 8
Reproduction of extracts from this Guideline may be made subject to due acknowledgement of the source.
Although this Guideline is believed to be correct at the time of printing, Roads Department does not accept
any contractual, tortious or other form of liability for its contents or for any consequences arising from its use.
Anyone using the information contained in the Guideline should apply their own skill and judgement to the
particular issue under consideration.
2
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8

ROADS DEPARTMENT
Under the policy direction of the Ministry of Works, Transport & Communications, Roads Department is responsible for providing
an adequate, safe, cost-effective and effi cient road infrastructure within the borders of Botswana as well as for facilitating cross border
road communications with neighbouring countries. Implied in these far-ranging responsibilities is the obligation to:
1. Ensure that existing roads are adequately maintained in order to provide appropriate level of service for road users.
2. Improve existing roads to required standards to enable them to carry prevailing levels of traffi c with the required degree
of safety.
3. Provide new roads to the required geometric, pavement design and safety standards.
The Department has been vested with the strategic responsibility for overall management of the Public Highway Network (PHN) of
some 18,300 km of roads. This confers authority for setting of national specifi cations and standards and sheared responsibility with
the District Councils and Department of Wildlife and National Parks for the co-ordinated planning of the PHN.
Roads Department is also responsible for administering the relevant sections of the Public Roads Act, assisting local road authorities
on technical matters and providing assistance in the national effort to promote citizen contractors in the road construction industry
by giving technical advice wherever possible. This task is facilitated by the publication of a series of Technical Guidelines dealing
with standards, general procedures and best practice on a variety of aspects of the planning, design, construction and maintenance
of roads in Botswana that take full account of local conditions.
� Guideline No. 1: The Design, Construction and Maintenance of Otta Seal (June, 1999).
Addendum to Guideline No. 1 – Seminar Proceedings (June, 2000).
� Guideline No.2–Pavement Testing, Analysis and Interpretation of Test Data (May, 2000).
Addendum to Guideline No. 2 – Seminar Proceedings (January, 2002).
� Guideline No. 3 – Methods and Procedures for Prospecting for Road Construction Materials (December, 2000).
Addendum to Guideline No. 3 – Seminar Proceedings (April, 2002).
� Guideline No. 4 - Axle Load Surveys (December, 2000).
Addendum to Guideline No. 4 – Seminar Proceedings (January, 2002).
� Guideline No. 5 - Planning and Environmental Impact Assessment of Road Infrastructure (September, 2001).
� Guideline No. 6 – The Prevention and Repair of Salt damage to Roads and Runways (September, 2001).
Addendum to Guideline No. 6 – Seminar Proceedings (April, 2002).
� Guideline No. 7 – Technical Auditing of Road Projects (December, 2001).
Addendum to Guideline No. 7 – Seminar Proceedings (February, 2004).
� Guideline No. 8 - The use of Silcrete and other Marginal Materials for Road Surfacing (August 2002).
Addendum to Guideline No. 8 – Seminar Proceedings (February, 2004).
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8 3

FOREWORD
Guideline no 7 Technical Auditing of Road Projects
This guideline document on technical auditing of road projects is a step in the right direction towards ensuring that the road projects
undertaken in Botswana are appropriately designed and constructed.
Financial auditing of public funded projects are done but it is the technical audit which had not received any attention in the past.
The need for producing a guideline on such an important aspect arose from the fact that very recently, some of the road projects
implemented in the country have either failed pre - maturely and/or are in the process of showing distress ultimately leading to
failure in the near future. The irony is that it has not been possible to portion accountability to parties involved in the contract. It
is my hope that Roads authorities, administrators and organizations will start thinking about carrying out Technical Audit of road
projects in order to ensure that the government and public in general get value for investment incurred.
The guideline describes step by step procedures involved in a technical audit process and details the methodology required to conduct
a technical audit. This guideline will certainly go a long way in implementing road projects in the right manner and introduce
accountability on the part of all Stakeholders, the Client, Consultant or the Contractor.
Gaborone
December 2001
Andrew Nkaro
Director of Roads
Roads Department
Ministry of Works and Transport
Guideline no 8 The use of Silcrete and Other Marginal Materials for Road Surfacing
The scarcity of good quality stone, which could be used as road surfacing aggregate in some parts of Botswana, dictated the use of
stones, which marginally meet the conventional specifi cations.
This Guideline on the use of Silcrete and Other Marginal Materials for Road Surfacing is a very useful document in that it captures
the experiences gained, over a period of twenty years, towards utilizing marginal/inferior materials available in Botswana when
constructing road surface treatments.
Experience has shown that under appropriate circumstances the use of marginal stones in surface treatments has produced durable
and cost effective seals, which performed adequately under traffi c and the harsh, semi arid climate that prevails in Botswana.
The Guideline makes the experiences gained over the years readily available for consideration and will act as a practical reference for
engineers and technicians involved in the road building industry in Botswana. The guideline deals specifi cally with the properties,
applications and performance of marginal aggregates in surface treatments.
It is my sincere hope that this guideline will be useful to the road building industry in Botswana and will assist in ensuring that,
under appropriate circumstances, marginal materials will fi nd their optimal use in road surfacing without necessarily compromising
on quality and performance of the surface treatment as well as assist practicing engineers in judicious selection of marginal aggregates
towards their appropriate use in the construction and maintenance of surface treatments in the most cost – effective manner.
Gaborone
August 2002
Andrew Nkaro
Director of Roads
Roads Department
Ministry of Works and Transport
4
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8

ACKNOWLEDGEMENTS
The Workshop Proceedings held in Gaborone 6 th June 2003 is an Addendum to publications with reference to Guideline no 7 Technical
Auditing of Road Projects and Guideline no 8 The use of Silcrete and other Marginal Materials for Road Surfacing.
The production of these Guidelines is one is of a series that is being published under the Institutional Co-operation Agreement
that exists between the Roads Department and the Norwegian Public Roads Administration (NPRA). This agreement falls under a
NORAD Technical Assistance Programme to Roads Department which is co-funded by the Kingdom of Norway and the Government
of the Republic of Botswana.
The various opinions and refl ections given in the Workshop by the participating delegates are highly appreciated and is presented
in the workshop proceedings. The Workshop reporter was Mr. Michael I. Pinard, Infra Africa Consultants.
The production of the Addendum has been a joint effort between the Roads Department and NPRA; its preparation was co-ordinated
by Mr. Charles Overby of the NPRA.
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8 5

TABLE OF CONTENTS
1. INTRODUCTION .......................................................................................................................................................................... 7
1.1 Welcome and Opening ............................................................................................................................................................................ 7
1.2 Seminar Programme .................................................................................................................................................................................. 8
1.3 Attendance ................................................................................................................................................................................................... 8
2 PRESENTATION OF GUIDELINE NO. 8 ............................................................................................................................. 9
2.1 Overview .................................................................................................................................................................................................... 9
2.2 Presentation of Key Aspects .................................................................................................................................................................... 9
2.3 Matters Arising from Discussion .......................................................................................................................................................... 9
2.3.1 General ........................................................................................................................................................................................... 9
2.3.2 Scope and Use of Guideline ..................................................................................................................................................... 10
2.3.3 Properties of Silcretes ............................................................................................................................................................... 10
2.3.4 Surfacing Aggregate Specifi cations ....................................................................................................................................... 11
3. PRESENTATION OF GUIDELINE NO. 7 ............................................................................................................................... 14
3.1 Overview ................................................................................................................................................................................................. 14
3.2 Presentation of Key Aspects ................................................................................................................................................................ 14
3.3 Matters Arising from Discussion ...................................................................................................................................................... 14
3.3.2 Responsibility for undertaking audits ................................................................................................................................... 16
3.3.3 Potential problems of technical auditing ............................................................................................................................... 16
4. SUMMARY AND CLOSURE ..................................................................................................................................................... 17
4.1 Summary of Key Issues .......................................................................................................................................................................... 17
4.1.1 Guideline No. 8 ......................................................................................................................................................................... 17
4.1.2 Guideline No. 7 .......................................................................................................................................................................... 17
4.2 Closing Remarks ...................................................................................................................................................................................... 18
ANNEXES ............................................................................................................................................................................................... 19
Annex 1 - Programme ........................................................................................................................................................................................ 20
Annex 2 - Seminar Attendance List ................................................................................................................................................................ 21
6
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8

1. INTRODUCTION
1.1 Welcome and Opening
The Chairperson, Mr. M. Segokgo, welcomed delegates to the Roads Department seminar on Technical Auditing of Road Projects
(Guideline No. 7) and The Use of Silcrete and Other Marginal Materials for Road Surfacing (Guideline No. 8). He then outlined
the programme for the day which included presentations by the authors of the two Guidelines and discussion periods in which
feedback from the participants was expected as an important objective of the workshop.
The seminar was opened by the Roads Department’s Principal Roads Engineer, Materials and Research Division,
Mrs. N. Mpotokwane, on behalf of the Director of Roads, Mr. A. Nkaro who was unavoidably absent due to other pressing
engagements.
In her opening remarks, Mrs. Mpotokwane expressed her delight at the good turnout to the seminar by a cross-section of stakeholders
- consultants, contractors, academics, testing institutions, professional bodies and other organisations - who provide services
of various kinds to the Roads Department and, as a result, have some form of professional relationship with the department.
The main points made in her speech are as follows:
● Roads Department had embarked on preparing a series of Guidelines under the Institutional Cooperation Agreement between
Roads Department and the Norwegian Public Roads Administration.
● The main objective of the Guidelines was to document best practice and preserve local knowledge in a variety of aspects of
road planning, design, construction and maintenance that have evolved over many years in Botswana.
● The following eight Guidelines had already been produced and are available to all stakeholders. These Guidelines are based
on valuable experiences and knowledge gained by Roads Engineers in the country and incorporate current practices within
Botswana, the SADC region and elsewhere in the world.
■ Guideline No. 1 - The Design, Construction and Maintenance of Otta Seals (June, 1999).
Addendum to Guideline No. 1 - Seminar Proceedings (June, 2000).
■ Guideline No.2 - Pavement Testing, Analysis and Interpretation of Test Data (May, 2000).
Addendum to Guideline No. 2 - Seminar Proceedings (January, 2002).
■ Guideline No. 3 - Methods and Procedures for Prospecting for Road Construction Materials
(December, 2000).
Addendum to Guideline No. 3 - Seminar Proceedings (April, 2002).
■ Guideline No. 4 - Axle Load Surveys (December, 2000).
Addendum to Guideline No. 4 – Seminar Proceedings (January, 2002).
■ Guideline No. 5 - Planning and Environmental Impact Assessment of Road Infrastructure
(September, 2001).
■ Guideline No. 6 - The Prevention and Repair of Salt damage to Roads and Runways
(September, 2001).
Addendum to Guideline No. 6 - Seminar Proceedings (April, 2002).
■ Guideline No. 7 - Technical Auditing of Road Projects (December, 2001).
Addendum to Guideline No. 7 – Seminar Proceedings (February, 2004).
■ Guideline No. 8 - The Use of Silcrete and Other Marginal Materials in Road Surfacing.
Addendum to Guideline No. 8 – Seminar Proceedings (February, 2004).
A number of other Guidelines such as The Use of Kalahari Sands in Road Construction, Operating Procedures for Central
Materials Laboratory and Traffi c Data Collection and Analysis are also being prepared and will be completed during 2004.
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8 7

The two Guidelines being presented at the seminar, Nos. 7 and 8, are very important from the overall perspective of construction
and development of effi cient and economical road infrastructure in Botswana.
The principal objective of the seminar was to disseminate the information contained in the Guidelines as well as to solicit the
views and comments of delegates as a basis for engendering their acceptance and subsequent use of these documents.
In concluding her opening remarks, Mrs. Mpotokwane urged delegates to participate actively in the proceedings of the seminar
and expressed the hope that such involvement would lead to the practical take-up of the guidance given in the Guidelines.
1.2 Seminar Programme
The seminar programme was structured into three main components as follows:
i Preliminaries.
ii Presentation of Guidelines.
a. Guideline No. 8 + discussion.
b. Guideline No. 7 + discussion.
iii Summary and closure.
Full details of the seminar programme are given in Annex A while the list of delegates is given in Annex B.
1.3 Attendance
The seminar, which was held at the Tlotlo Conference Centre in Gaborone, was well attended by a cross-section of delegates from
the public and private sectors including Roads Department, City and Town Councils, Consultants, Contractors and Academia
In total, eighty-two delegates attended the workshop of which forty-seven were from the public sector and thirty-fi ve from the
privates sector.
8
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8

2. PRESENTATION OF GUIDELINE NO. 8
2.1 Overview
An overview of Guideline No. 8 was presented by Phil Paige-Green of CSIR and Kabelo Motswagole of Civil and Planning Partnership
who were part of the consultants’ team involved in the preparation of the Guideline.
The importance of the Guideline was placed in the following context:
The scarcity of good quality stone which could be used as road surfacing aggregate in some parts of Botswana has necessitated the
use of materials which are often of “marginal” quality in terms of meeting the conventional specifi cations.
● Experience has shown that, under appropriate circumstances, the use of marginal quality aggregates in surface treatments has
produced durable and cost-effective seals which have performed adequately under traffi c and the harsh climatic conditions
that prevail in Botswana.
● Unfortunately, current aggregate specifi cations for bituminous surfacings are often unnecessarily demanding and exclude the
use of local materials that could be suitable and very cost-effective to utilise.
● Fortunately, the considerable experience gained in Botswana and the SADC region in the past couple decades has allowed
new specifi cations for road surfacing aggregate to be developed that do not compromise on the quality and performance of
surface treatments. The Guideline captures such experience.
● Guideline No. 8 will assist practicing engineers in the judicious selection of marginal quality or non-standard aggregates for
the construction and maintenance of bituminous surfacings in the most cost-effective manner.
2.2 Presentation of Key Aspects
The presentation followed the sequence of main topics included in the Guideline which may be summarized as follows:
1. Introduction.
2. Properties of surfacing aggregates.
3. Surfacing types and their selection.
4. Experience in Botswana.
5. Surfacing aggregate requirements.
6. Material utilization, construction and maintenance aspects.
7. Appendices.
The presentation provoked wide-ranging discussions and comments on a number of issues which are presented in the next section.
2.3 Matters Arising from Discussion
2.3.1 General
A wide range of views, comments and questions were raised by delegates during the discussion of the Guideline. The objective
of this section is to group and synthesise the main issues that were raised and to record the responses given by presenters or the
consensus reached amongst delegates via discussion.
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8 9

2.3.2 Scope and Use of Guideline
10
Issues:
- Does the Guideline apply only to silcrete and other marginal materials or to all types of aggregates. If the
former, then its use would be quite limited.
- What is meant by a “marginal” as distinct from “non-standard” material? Doesn’t the term “marginal”
convey a negative message?
- Very little guidance is given on the design of bituminous surfacings. Is this not a short-coming of the Guideline?
Responses:
- The Guideline applies to all types of aggregates, not only silcrete and other marginal materials. However, the
emphasis is on the use of silcretes and other marginal materials which offer much scope for more extensive use
in bituminous surfacings.
- A “marginal” material is one that is border line with respect to compliance with a given specifi cation. A “non-standard”
material is one that is not traditionally used for a particular purpose. For example, silcrete aggregate is nonstandard
in that, until very recently, it was not normally used as surfacing aggregate. The use of terms such as “
marginal” and “non-standard” convey a negative message. There are many examples of naturally-occurring materials,
such as silcrete and decomposed granite, that have performed satisfactorily despite being “marginal” and/or “nonstandard.”
- The design of bituminous surfacings is an extensive subject on its own and, as indicated in Section 1.2, is well out
side the scope of the Guideline. The Guideline focuses on using “marginal” or “non-standard” materials in bituminous
surfacings and highlights the scope for more extensive use in Botswana despite the fact that their properties
may differ widely from the more “traditional” or “ideal” materials. Useful references on bituminous surfacing
design include:
■ UK Transport Research Laboratory (2000): Overseas Road Note No. 3. A Guide to Surface Dressing in Tropical
and Sub-Tropical Countries. (2nd edition), Crowthorne.
■ Committee of State Road Authorities (1998): Draft TRH3: Surface Seals for Rural and Urban Roads, CSRA,
Pretoria.
■ Ministry of Works, Tanzania (1999): Pavement and Materials Design Manual, Dar es Salaam.
■ NPRA (1999): Publication No. 93: A Guide to the Use of Otta Seals, Oslo.
2.3.3 Properties of Silcretes
Issues:
- The properties of silcrete are not adequately spelt out in the Guideline and should be highlighted at the beginning
of the document. Is this beyond the scope of the Guideline?
- Silcrete properties vary with respect to location and depth. How is this taken into account in the Guideline?
- Silcretes and basalts tend to crush with a high fl akiness index. Should there not be stronger guidance in the
Guideline on the preferred type of crusher to be used?
Responses:
- The properties of various material groups are given in Appendix C of the Guideline. The section on pedocretes deals
specifi cally with the properties of silcretes (ref. Tables C.4 and C.5). However, the mode of formation of silcretes is
not dealt with as it is considered to be outside the scope of the Guideline.
- The properties of most, if not all, tropical materials can vary widely by virtue of their mode of formation and the
infl uence of the prevailing environment. It was not within the scope of the Guideline to deal with the issue of vari-
ation of silcrete properties in relation to their mode of formation and the infl uence of the prevailing environment.
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8

- As indicated in Section 2.4.4, jaw crushers are the least suitable for materials prone to producing fl aky material. The
use of impact or gyratory crushers reduces the tendency to produce fl aky material and should thus be used for crush-
ing silcretes or basalts intended for use as surfacing aggregate. Also, the crushing process itself, it terms of whether the
crusher jaws are fully or partially fed during operation, will infl uence the fi nal product. In general, for best results, the
crusher jaws should always be fully fed during operation.
2.3.4 Surfacing Aggregate Specifi cations
Issues:
- Why is there a need for different specifi cations for marginal or non-standard materials as compared with
conventional materials?
- The Guideline recommends a relaxation in the 10 FACT requirement for surfacing aggregate. On what basis is
this being recommended?
- Many of the traditional sources of aggregate in Botswana exhibit a 10% FACT value of about 180 kN.
Although such stone has been used successfully in Botswana, the current Roads Department specifi cation still
requires 210 kN.
- Government, through the Roads Department, is currently paying a premium for including a 10% FACT
requirement of 210 kN when a lower value would be acceptable. Why is there a reluctance to lower the
specifi cation requirement?
Responses:
- Conventional specifi cations apply to “ideal” materials and originate from situations very different to those prevail-
ing in Botswana and, when applied, often preclude the use of many non-standard, so-called marginal materials such
as silcrete. However, on the basis of research undertaken in Botswana and elsewhere, appropriate, performance-
related specifi cations have been derived which allow local materials to be used with little, if any, risk.
- The 10% FACT value was derived more than 20 years ago on the basis of the crushing strength required by sur-
facing aggregate to withstanding the stresses imposed by steel-wheel rollers that were used to roll in the aggregate.
Today, rubber-tyred pneumatic rollers are generally used for rolling the aggregate. Consequently, a much lower
aggregate crushing strength is required to resist the stresses imposed by this type of roller compared to a steel-wheel
roller. Countries such as Australia, New Zealand and Zimbabwe have longer ago specifi ed much lower 10% FACT
requirements than those specifi ed by Botswana. For example, Australia requires a minimum 10% FACT of 150 kN,
Zimbabwe 120 kN and Tanzania 160 kN (AADT > 1000 vpd) or 120 kN (AADT < 1000 vpd). The general consensus
of workshop delegates was that a reduction in 10% FACT was justifi ed along the lines recommended in the Guide-
line, i.e. 150 – 180 kN depending on the level of traffi c.
- The 10% FACT requirement as currently specifi ed in the BRDM and Standard Specifi cation is agreed by many
practitioners to be unnecessarily high. The BRDM, which is over 20 years old, is soon to be revised and updated to
take account of developments in road technology, including specifi cations for surfacing aggregates. The on-going
Pavement Monitoring programme will provide feedback for updating the BRDM and, subsequently, revising the
Standard Specifi cation. One of the purposes of the Guideline is to raise awareness of the need to revise the 10%
FACT requirement for Chip Seals for inclusion in the revised BRDM and the Standard Specifi cation.
- Until the Standard Specifi cation for Road and Bridge Works is offi cially revised, its requirements should be adhered
to in principle. However, changes to particular specifi cations can and, in fact, are made on a case-by-case basis. How-
ever, it is important that such changes be agreed at the time of design and not after the contract is let when contrac-
tual problems can arise. Thus, the onus is on the design engineer to ensure that all possible “relaxations” are built
into the contract before it is tendered.
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8 11

2.3.5 Bituminous Surfacings
12
Issues:
- A lot of money is expended on maintaining gravel roads. Would it not be more cost-effective to seal these
roads with a low-cost surfacing using relaxed specifi cations?
- What are the criteria for determining the suitability of aggregates for use in a bituminous surfacing?
- Why do the aggregate specifi cations vary in relation to the type of surfacing?
Responses:
- Gravel is a fi nite resource which is being depleted in many areas of Botswana with the result that haul distances
are getting longer. In the long term, the continued use of gravel for regravelling purposes is unsustainable. Thus,
the use of low-cost surfacings using non-standard or so-called marginal aggregates in the form of Otta or Sand Seals
becomes an attractive option. Research in the region has shown that, in appropriate circumstances, it is can be cost
effective to provide a sealed road surface for a low-volume road at traffi c levels often below 100 vehicles per day. In
fact, in Botswana, in the early 1980s it was cost-effective to surface the Sehitwa-Tsau road at traffi c levels of less than
50 vpd. However, the sustainability of this solution, in terms of assured funding for maintenance, becomes a critical
consideration.
- The criteria for determining the suitability of aggregates for use in bituminous surfacings are well spelt out in Section
2.2.2 of the Guideline and include strength, durability, bitumen adhesion, water and bitumen absorption, polishing
and mineralogical composition. Importantly, it is the type of seal that dictates the criteria for selecting the aggregate.
For example, because of the difference in mechanism for dispersing traffi c stresses, the aggregate selection criteria for
a Chip Seal would be quite different to that for an Otta Seal.
- In some surfacings, e.g. the traditional chip seal, the aggregate is in direct contact with the vehicle tyres and requires
relatively high resistance to crushing and abrasion to disperse the stresses without breaking down. In contrast, other
types of surfacings, e.g. the Otta seal, acts as a stress-dispersing mat under traffi cking and the aggregate, which is
inter-locked, is not in direct contact with the vehicle tyre and, as a result, does not require to have as high a crushing
strength as if it were in direct contact with the vehicle tyre.
2.3.6 Construction and Maintenance of Surface Treatments
Issues:
- Joints in single seals often give rise to maintenance problems. It is often better to construct unequal widths when
surfacing, e.g. for a total sealed width of 6.0 m, it is preferable to construct seal widths of 2.5 m + 3.5 m rather
than 3.35 m + 3.35 m. In this way, when re-sealing, the joint can be displaced by reversing the seal widths, i.e.
sealing 3.5 m then 2.5 m.
- When remarking roads, it would be advantageous, where possible, to move the centerline so as to shift the wheel
track and, in so doing, spread the wheel loads more evenly across the carriageway, thereby kneading the surfacing
more evenly across the carriageway.
- Since seal life is related, amongst other factors, to the stiffness of the pavement/ subgrade support, would it not be
preferable to compact to refusal with the heaviest plant available rather than to a pre-determined percentage of
Mod AASHTO compaction?
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8

Responses:
- Agreed.
- Agreed
- Agreed. It would be preferable to compact to refusal with the heaviest plant available rather than to a pre-determined
percentage of Mod AASHTO compaction. However, this approach may not always be appropriate, particularly where
the material breaks down under compaction which, if it did, would make it even more diffi cult to attain the normally
specifi ed relative compaction.
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8 13

3. PRESENTATION OF GUIDELINE NO. 7
3.1 Overview
An overview of Guideline No. 7 was presented by Phil Paige-Green of CSIR who was part of the consultant team involved in the
preparation of the document.
The importance of the Guideline was placed in the following context:
● Whilst fi nancial auditing of public funded projects is commonly undertaken, little attention has been given to the
complementary activity of technical auditing.
● In recent years, a number of road projects have either failed pre-maturely, are exhibiting distress that will ultimately lead to
failure in the near future or have experienced signifi cant cost overruns. In the absence of a Technical Audit, it is often not
possible to fairly apportion accountability to the parties involved in the contract.
● The production of a Guideline on technical auditing of road projects is a step in the right direction in terms of putting in place
a process that should enable any problems that occur to be adequately and transparently diagnosed as a basis for apportioning
responsibility, where appropriate.
3.2 Presentation of Key Aspects
The presentation followed the sequence of main topics included in the Guideline which may be summarized as follows:
14
1. Introduction.
2. Technical Audits: General procedures.
3. Data requirements.
4. Scope of post construction audit.
5. Post construction audit procedure.
6. Assessment of audit results.
7. Reporting.
As was the case with the presentation on Guideline No. 8, the presentation on Guideline No. 7 provoked wide-ranging discussions
and comments on a number of issues which are presented in Section 3.
3.3 Matters Arising from Discussion
3.3.1 Specifi c concerns of the Association of Building Contractors (ABCON)
Issues:
- If the parties carrying out the contract and, more especially, the Supervising Engineer are competent then we
question the need for a third party to carry out the technical audit either during or post-contract.
- The client has his own lab and, as such, as is done in South Africa, he can collect samples for check testing on
a regular basis. In South Africa this is normally done on a quarterly basis.
- If there is any doubt of the veracity of results from any site, an independent check of laboratory procedures
should be more than adequate.
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8

Responses:
- The competency or otherwise of the parties carrying out the contract is beside the point. The technical auditing of
public funded projects is no different, in principle from the current fi nancial auditing of public projects. Such auditing
is often carried out in commercialized roads agencies as part of their accountability obligations to the general public
for expenditure of public funds.
- Apart from the fact that the client often does not have the human resources to undertake laboratory check testing, as
suggested, the client cannot audit himself – an independent body, the Technical Auditor, must do so. The client, as a
party to the contract, is also subject to auditing.
- Independent checking of laboratory procedures is but one of many aspects undertaken in a technical audit. By itself,
it serves a limited purpose within the broader context of a more comprehensive technical audit.
Issues:
Should the client wish to involve a separate body to audit the contract then he is free to do so, but:
- Is the cost justifi ed?
- What responsibility does the Client have?
- What responsibility does the Auditor have?
- How will the audit affect the already cumbersome process of disputes where decisions are affected by fi ndings
of the Auditor.
- Whilst we as competent contractors have no objection to our work being subject to scrutiny the following must
be borne in mind.
- Nothing should be set up such that if diminishes the contractors responsibility for his workmanship.
- Any report which is submitted either only to or fi rstly to one party and not to all three simultaneous will
be viewed with suspicion no matter the source.
Responses:
- The cost of a Technical Audit is relatively small in relation to the potential benefi ts and to the overall cost of the
project. In the context of formalised technical auditing, the cost of carrying out the audit may be viewed as an
“unavoidable” cost.
- The Client’s main responsibility is to ensure that a competent, independent, fully qualifi ed Technical Auditor is
appointed in a proper manner and is subjected to clear Terms of Reference. These Terms of Reference are published
in the Roads Department’s publication Model Terms of Reference for Technical Audits, dated December 2001. Once
the audit is underway, the Client has no role to play in the process as he is also subject to the same audit scrutiny as
the Contractor and the Engineer.
- The Auditor has the primary responsibility of carrying out the Technical Audit in a transparent, unbiased and inde-
pendent manner, as spelt out in the Section 2.2 of the Guideline.
- The fi ndings of the audit allows the Roads Department to identify whether the parties involved in the contract
(including the client) have given the Government and people of Botswana what they paid for. These fi ndings will
often facilitate the resolution of disputes that might otherwise go to mediation or arbitration.
- It is fully agreed that no part of the audit process should diminish the contractor’s responsibility for his workman-
ship. The Auditor should in no way interfere with the construction process.
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8 15

16
- It is fully agreed that the audit report should be issued to all parties simultaneously to avoid any suspicion that one
party is being shielded from the fi ndings of the audit..
3.3.2 Responsibility for undertaking audits
Issues:
- Is there really a need in principle for carrying out an audit?
- Shouldn’t Roads Department staff be monitoring and following-up the on-going construction rather than an
Auditor? Or, should an in-house Auditing Unit not be set up rather than appointing an external auditor?
- What kind of institution and staff will be responsible for carrying out an audit?
- In appointing an Auditor, will it not be a case of one consultant auditing another?
Responses:
- As indicated previously in response to ABCON, a Technical Audit is an instrument of accountability pertaining to
expenditure of public funds. It is complementary to a Financial Audit which is currently carried out in Botswana on
major public funded projects, such as roads. Also, the Client cannot say beforehand that the Consultant and the
Contractor will perform well. By the time things go wrong, as has happened in a number of cases recently, it is too
late to rectify the problem. Thus, there is a need, in principle, for carrying out Technical Audits.
- The Roads Department staff should be monitoring and following-up the on-going construction as part of their
normal duties by appointing a Project Engineer. However, this is a quite separate role and function to that played by
the Auditor. An in-house Audit Unit is an option but Roads Department does not have such capacity currently,
neither is likely to have it in the near future. In addition, the prospect of one arm of the department auditing another
raises a number of diffi culties, including confl ict of interest.
- The institution selected for carrying out a Technical Audit could range from a large to a small consulting/research
organisation comprised of appropriately qualifi ed professional staff with at least 15 to 20 years of experience
covering among other disciplines, highway design and construction and contract management.
- In appointing an Auditor, it will NOT be a case of one consultant auditing another. The Auditors role is quite diffe-
rent to that of the Supervising Engineer. Moreover, the Auditor should be totally independent. Ideally, it would be
desirable to appoint an Auditor who is not directly involved in design and construction work in Botswana, but this
may not always be possible.
3.3.3 Potential problems of technical auditing
Issues:
- What happens in the event that there is a dispute between the Technical Auditor and the Supervising Engineer,
both of whom are providing advice to the Client?
- Is there not confl ict of interest when one consultant (the Auditor) is auditing another consultant (the Super-
vising Engineer)?
- Is there not repetitive work in carrying out a Technical Audit, i.e. both the Auditor and the Supervising
Engineer are undertaking the same kinds of checks on site?
Responses:
- It may well be the case that the Technical Auditor and the Supervising Engineer fi nd themselves in a dispute over
the fi ndings of the audit. In such a case, they may well be providing confl icting advice to the Client. This is an inevit-
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8

able possibility in Technical Auditing. In such a case, it will be up to the Client to weigh up the advice of both
parties and to reach his own, independent conclusions.
- As an independent professional carrying out his duties in an impartial manner and in accordance with his prescribed
Terms of Reference, the Auditor’s role should not be in confl ict with the Supervising Engineer. The Auditor’s report
should be objective and fully quantifi ed. All parties should be provided with an opportunity to respond to the Audit
Report. In principle, the Auditor’s role vis-à-vis the Supervising Engineer is no different from that of one consultant
reviewing the design of another.
● The type of investigations undertaken by the Auditor and the Supervising Engineer are, in general, quite different. There may
be some areas of overlap, for example, check testing of materials and assessment of workmanship, but the Auditor’s role goes
well beyond check testing of materials and includes checks on compliance with a range of technical and contractual matters,
including.
■ Initial audit: - project management issues and construction methodologies.
■ Intermediate audit - conformance with specifi cation and matters of effectiveness.
■ Final audit – conformance with all aspects of the contract.
4. SUMMARY AND CLOSURE
4.1 Summary of Key Issues
The summary of key observations and issues emanating from the workshop was presented by the Workshop Facilitator, Mr. Mike
Pinard, and are as follows:
4.1.1 Guideline No. 8
● The use of certain terminology, such as “marginal” “non-standard” or “relaxed standards”, as applied to local surfacing
aggregates, can convey negative signals which can be very misleading. For example, a material that is marginal in terms of
strength may fail when carrying high traffi c volumes with a high percentage of heavy vehicles, but may often perform entirely
satisfactorily in a low volume road situation in a rural area. Ultimately, the selection of aggregate should be based on the
concept of its “fi tness for purpose”.
● Many of the current specifi cations for surfacing aggregate apply to “ideal” materials found in the temperate climates where
conditions are very different to those prevailing in Botswana. Rigid application of these specifi cations often rules out the use
of many satisfactory local materials. Thus, careful selection and testing of local materials is required in order to obtain a basic
understanding of their properties as a basis for applying appropriate specifi cations as recommended in the Guideline.
● Pending the revision of the BRDM and the Standard Specifi cation for Road and Bridge Works, deviation from the current
specifi cations, for example the 10% FACT, should be considered on a case-by-case basis during the design stage and not after
the project has been let when contentious contractual issues pertaining to a change of project specifi cation can arise. The
workshop concluded that a 10 % FACT of 150 – 180 kN (depending on traffi c) would be appropriate for most of the roads in
Botswana.
● Environmental issues are assuming greater importance and the continued use of gravel for re-gravelling purposes is unsu-
stainable. This will engender a need to consider carefully the use of low cost surfacings in which aggregates of relatively low
quality can be used with an appropriate type of seal. This ahs proved to be the case on many road projects in Botswana.
4.1.2 Guideline No. 7
● Technical Auditing of road projects is assuming greater importance in Botswana than hitherto and complements the Financial
Auditing that is currently undertaken of publicly funded projects. It seeks to ascertain whether the Government and the
general public get “value for money” and, in so doing, engenders greater accountability in the expenditure of public funds.
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8 17

● The Technical Audit is carried out by an independent, appropriately qualifi ed and experienced organisation in a manner
prescribed in the Guideline and according to the requirements of the Model Terms of Reference for Technical Audits. All
parties to the contract are audited and there must be no interference by any party to the audit process.
● Technical Auditing does not duplicate the role or function of the Supervising Engineer. The audit process entails undertaking a
number of prescribed activities that are carried out intermittently during the course of the project from pre-construction (review
of tender documentation, design and drawings, specifi cations and BoQ) to post-construction (certifi cates, fi nal measurement
and fi nal certifi cates.).
● An option to the appointment of an external Technical Auditor would be the establishment of an in-house Technical Audit
Unit. However, Roads Department does not currently have the resources for such a unit and recourse to the use of an external
auditor will be necessary in the short to medium term.
4.2 Closing Remarks
Mr. Pinard’s closing remarks may be summarized as follows:
● Attendance: Some eighty-two delegates have attended the seminar. This is testimony not only to the importance that they
attach to the subject matter of the Guidelines, but also a demonstration of their wish to interact with other stakeholders in the
roads sector in a manner that can only be benefi cial to all.
● Constructive dialogue: There has been open and constructive dialogue and interaction amongst all stakeholders. A number of
important issues have been raised which is a refl ection of the knowledge base of the delegates. This has engendered much
discussion in the course of which consensus has been reached on most, if not all, of the issues raised.
● Use of the Guidelines: The real value of the Guidelines will only be realised if they are properly used by stakeholders. In this
regard, the initiator of the Guidelines, the Roads Department, has an important role to play in terms of continually promoting
the use of these Guidelines amongst all stakeholders.
● Tribute to organizers: Finally, the organizers must be commended for their foresight in convening what all would agree has
been a worthwhile, benefi cial seminar for all stakeholders.
18
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8

ANNEXES
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8 19

ANNEX 1
PROGRAMME
20
�������� �� ����� ��� ���������
Ministry of Works
and Transport
Roads Department Seminar
Guidelines Nos. 7 and 8
Technical Auditing of Road Projects
and
The Use of Silcrete and Other Marginal Materials for Road Surfacing
0800-0830 Registration of Delegates
Held at the Tlotlo Conference Centre, Gaborone
Friday 6th of June 2003
Chairperson M.E. Segokgo
Principal Roads Engineer II -Materials
0830-0840 Welcome address and brief introduction to Ms. N. Mpotokwane
the Seminar Principal Roads Engineer -Materials and Research
Division
0840-1000 Presentation of Guideline No. 8 “The Use of Dr. Phil Paige-Green
Silcrete and Other Marginal Materials for Road CSIR-Transportek, Pretoria (RSA)
Surfacing” Mr. Kabelo Motswagole
Civil & Planning Partnership Botswana
1000-1030 Coffee/Tea Break All
1030-1130 Discussion on Guideline No. 8 Chaired by Mr. M. B. Kowa
Senior Roads Engineer -Training Division
1130-1300 Presentation of Guideline No. 7 “Technical Auditing Dr. Phil Paige-Green
of Road Projects” CSIR-Transportek, Pretoria (RSA)
Mr. Kabelo Motswagole
Civil & Planning Partnership Botswana
1300-1400 Lunch All
1400-1500 Discussion on Guideline No. 7 Chaired by Mr. B.M. Sharma
Senior Roads Engineer-Materials and
Research Division
1500-1530 Coffee/Tea Break All
1530-1600 Seminar Wrap Up Mr. Mike Pinard - InfraAfrica Consultants
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8

ANNEX 2
SEMINAR ATTENDANCE LIST- Guidelines No 7 and 8
Tlotlo Conference Centre, Gaborone
Friday 6th of June 2003
Name Organisation Postal Address E. mail Address Phone/Fax
E. Masuku BOTEC Bag 0082, Gabs Masuku @ botec.bw 3914161/3974677
Z. Svetozar ROADS Bag 0026, Gabs Szzrilic @ gov.bw 3913511
M. Batlhotlhe ROADS Bag 004, Masunga 2489861
PPR Oosthuizon MTS Box 2069, Gabs MTS info.com 3913285
T. Modise ROADS Box 40893, Gabs Tmodise@gov.bw 3914151
S. Khunou Gantsi Council Bag 015, Gantsi GDC roads@Botsnet.bw 6596360/211
K. Wah MOA Bag 003, Gabs kwah@gov.bw 3950672
M. Dihutso INGEROP AFRICA BOX 404577, Gabs bibots@global.bw 3905535/3902317
J. Maabong Gaborone City Council Bag 0089, Gabs 3657523/3900141
Tony Rees Haas Consult Box 201640, Gabs tonyrees@global.bw 3121088/3121667
H. Alemayehou BCL Consult Box 1892, Gabs 71672718/3912969
B. Sile BCL Consult Box 1892, Gabs 72104360
S. Gobhgoba CCP BR 121, Gabs sgobhgoba@
O.S. Dijokota ROADS Bag 0026, Gabs odijokota@gov.bw 3913511
B.M. Mokgethi Roads Bag 0026, Gabs bmokgethi@gov.bw 3913511
N. Ramasia GCC Bag 08, Gabs 308951
S. Rankgate Sedudu Pty Ltd Box 201848, Gabs 580931/72167016
M. Kenaope Weaver Bird Holdings Box 46393, Gabs 3162286/72213364
K. Malendeja Roads Bag 0026, Gabs rmalendeja@gov.bw 71778298
J. Versteeg Asphalt Botswana Box 1041, Gabs 3902420/3902418
A. Kgosi CPP Bag BR 121, Gabs akgosi@cpp.bw 3951654/3912890
R. Islam Roads Bag 0026, Gabs 3913511
V.K. Rajawat Roads Bag 0026, Gabs 3913511
J. G. Durairai Local Government Box 00338, Gabs jdurairaj@gov.bw 3658446
A.D. Mkinga Central District Council Bag 001, Serowe vrajawat@gov.bw 4630411
M.E Segokgo Roads Box 40893, Gabs msegokgo@gov.bw 3914151
D.U. Ndwapi Roads Box 40893, Gabs dndwapi@gov.bw 3914151
G. Chammas Consolidated Contractors Box 905, Gabs cccbots@botsnet.bw 3937733/4
N. Rajela Consolidated Contractors Box 905, Gabs cccbots@botsnet.bw 3937733/4
B.M. Sharma Roads Box 40893, Gabs 3914151
A.T. Tema Roads Bag 0026, Gabs atema@gov.bw 3913511
K. Solomon Roads Box 40893, Gabs ksolomon@gov.bw 3914151
K.L. Bale Roads Box 40893, Gabs kbale@gov.bw 3914151
M.D. Sarma Roads Box 40893, Gabs mdsarma@gov.bw 3914151
R. Nduna Roads Box 40893, Gabs 3914151
M. Rahman Roads Box 40893, Gabs 3914151
O. Glendinning Excavator Hire Box 2402, Gabs glendinning@it. 3928392
D. Well Sands Civil Services Bag 00379, Gabs ssands@global.bw 3909867
C.N. Evans Grinaker LTA Box 1301, Gabs 3933819
S. Semetsa Agriculture Bag 003, Gabs ssemetsa@gov.bw 3950471
E. Rametse Roads Bag 0026, Gabs erametse@gov.bw 3913511
E. Botshomanyane Roads Box 40893, Gabs ebotshomanyane@gov.bw 3914151
Dr P. Paige Green CSIR Pretoria Box 395, Pretoria ppaigegr@cisr.co.za (012) 8412924
R. Gobotsamang Roughton Box 601945 roughton@info.bw
K.R. Ntabota Roads Box 40893, Gabs rntabota@gov.bw 3914151
M. Moile CPP Bag BR121 3951654
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8 21

Name Organisation Postal Address E. mail Address Phone/Fax
W. Dong China State Bag 00335 5915511
G. Mohiuddin Bothakga Burrow Bag 380, Gabs 395181
Seth O. Okyere Kgalagadi District Council Bag 005, Tsabong sookyere@yahoo.com 6540061
G. Solomon Roads Box 40893, Gabs gkeakeditswe@gov.bw 3914151
B.T. Phiri MWT Bag 007, Gabs btphiri@gov.bw 3958536
G.S. Motshome MWT Bag 007, Gabs gmotshome@gov.bw 3958536
B.T. Mathibidi Kgatleng D.C. Bag 11, Mochudi 3163431
M. Lekoa Excavator Hire Box 2402, Gabs 3928392
M. Kowa Roads Box 10105, Gabs mkowa@gov.bw 3912755
M.I. Pinard InfraAfrica Consultants Bag 00426, Gabs mipinard@global.bw 71311629
S.S. Modise Southern D.C. Bag 002, Kanye 5442442
B. Derera CPP Botswana Bag BR 121, Gabs 4900375
J. Raphalane Roughton Botswana Box 601945, Gabs roughton@info.bw 3180078
P.D. Monametsi Roads Box 40893, Gabs pmonametsi@gov.bw 3914151
M. Besta Tanroads-Tanzama Box 9452, Gabs +255 744272098
Shao Gang CSCEC P/Bag 00335, Gabs 71867566
A.A. Phosa DLGD P/Bag 00338, Gabs aphosa@gov.bw 3658448
G.R. Ndoo CCP Box 41643, Gabs 4900375
T. Freestone Hillary Construc. Box 1966, S/Phikwe hillarytrev@it.bw 2600745
I.S. Kuppan Matrolab Botswana Bag 0026 Mogoditshane 3930838
M.S. Chowdary GDC P/Bag 0015, Gantsi 6596360
N. Nduku Roads Box 40893, Gabs 3914151
K. Kasatu Bothakga Burrow Box 380, Gabs 3951891
R. Laher WSP (Botswana) Box BO 21049, Gabs wspbot@it.bw 3188140
R. Thekiso RTM Soils Box 20170, Gabs 3903168
K. Spackman NMA Bag 1791, Gabs spackman@global.bw 71316207
Dr N.T. Rao Roads Box 10105, Gabs trao@gov.bw 3912755
K. Sabokone CDC Bag 001, Serowe sre@botsnet.bw 4600603
E.T. Phang Roads Box 40893, Gabs ephang@gov.bw 3914151
K.J. Motswagole CPP Bag BR121, Gabs kabelo@cpp.co.bw 3951654
S. Kapundanga Stewart Scott Box 1 517, Gabs 3952557
B.S Alemarumo CPP Botswana Bag BR 121, Gabs balemar@botsnet.bw 3951654
N.N. Naidu Roads Bag 0026, Gabs nnaidu@gov.bw 3913511
C. Overby NPRA P.O.Box 8142, Oslo, Norway charles_overby@hotmail.com +47 90592182 or
71302778
P. Ododah CSIR Box 17001, Durban pododah@csir co.za 0312618161
K.C. Jain GCC Bag 89, Gabs kjain@gov.bw 3974576
22
Proceedings of Roads Department Workshop June 2003, Guidelines 7 and 8