November 2009

volume 23issue 3

asphaltNEWS

In this issue

CEO comments 3

Sabita's sustainability conference 5

CAPSA'11 programme outline 9

Best practice for LIC methods 10

Sabita's imagery basket refreshed 11

IARC study on bitumen fumes 12

LCWP and Sabita-SALGA cooperation 12

Second trials confirm future for WMA 13

New Graham Ross publication 16

SARF President's award 2009 16

A "sketchy" history of Cape Town's roads 17

New environmental assessment tool 20

Solvents in laboratories: a review urged 22

Reminiscences of a padmaker 24

Sabita publications 26

SAT's landmark membership of the RPF 27

Local and international events 28

Index of asphaltNEWS articles 29

Sabita members 30

Cover picture: Cape cart on Mitchell's Pass (Cape Archives) from Graham Ross'sbook The Romance of Cape Mountain Passes (see page 16)

Asphalt News is published by the Southern African Bitumen Association (Sabita), anon-profit organisation sponsored by its members to serve all stakeholders through

engineering, service and education.

The contents of this publication may be reproduced free of charge provided thesource is asknowledged.

Editorial board: John Fensham and Jeanette Nichol

The last few months have been interesting,

and hectically busy.

The members’ conference on sustainability

matters, held at the Arabella Western Hotel and

Spa in Kleinmond, was attended by 70 delegates

from member companies. Given such an

exquisite setting, the content of the conference

was challenged to attain similar standards.

Suffice to say that there was no disappointment in

this area, nor with any of the arrangements made.

The presentations were all relevant, of world

class standard and engrossing. With the huge

amount of positive feedback from all we spoke

to, the conference can undoubtedly be labeled a

success. The resolutions agreed upon on

conclusion were:

• Industry should take charge of its destiny with

respect to sustainable practices;

• Pursue programmes to improve durability in

asphalt pavements through the introduction of

HiMA and updated HMA and WMA design;

• Develop relationships with client bodies to

assist with and provide input into the

introduction of sustainable practices in

specifications;• Establish an HSE committee to develop best

practice in HSE management;

• The lack of competence in certain areas of the

public sector suggests that the private sector

would have to take the lead where appropriate.

I also had the opportunity to meet with Mr Robin

Carlisle, the MEC for transport in the Western

Cape, to understand how his vision and strategy

would impact the roads industry in the province.

During this session it became clear that one of his

major challenges is funding new development

while struggling to adequately fund the

maintenance of existing infrastructure. This issue

will no doubt feature prominently in the future.

Interest was also shown in cooperating with

Sabita on some of its activities.

Sabita’s membership with SARF has been

upgraded to enable closer collaboration on a

broad front of compatible activities with the

objective of achieving better results - the

engagement with Government being a case in

point.

I was privileged to

attend an IRF

environmental working

group meeting where the

following very pertinent

issues affecting the road

industry are being

tackled:

• Input into the

Future of

Transport

Strategy

launched by the

European

Commission (which normally translate into

legislation).

• Development of the GHG calculator (2 years

in the making) with the first version planned

for completion by year end 2009.

• A study by the tyre industry to assess the

impact of tyre wear particles on roadside soil

and water courses.

• Development of a rating system designed to

distinguish between new or rehabilitated

roads. The system considers only design and

construction and classifies roads on a scale of

silver, gold and evergreen.

WMA trials

The second WMA trial has been concluded

successfully, with the final report being imminent.

Scoping of the third trial with more stringent

monitoring and measurement of certain criteria has

already begun. There is no doubt that WMA will

play a major role in the provision of future

pavements.

At the recent HSE committee meeting, progress has

been made on the adoption of an HSE management

system for Sabita amongst other initiatives which

you’ll hear more of in due course.

This edition of asphaltNEWS is packed with

interesting articles - some old, some new - giving

recognition to the past and current breed of

“Padmakers.”

Do enjoy!

CEO's COMMENTS

Busy times as Sabita continues to

underpin members' interests

Sabita CEO Saied Solomons

3

Sabita’s members’ conference at the Arabella

Western Hotel and Spa in Kleinmond in August,

which focused sharply on sustainable practices,

identified a strong need for South Africa’s

bituminous products industry to adopt a more

proactive approach to a wide range of issues to

maintain sustained growth and development.

Hosted by Sabita to celebrate the association’s 30th

anniversary, the conference was attended by 70

delegates representing 35 companies, and concluded

with resolutions identifying crucial actions required to

underpin the sustainability of the industry. These were:

• Industry should take charge of its destiny with

respect to sustainable practices, and should get

involved proactively;

• The lack of competence in the public sector

suggests that the private sector might have to take

the lead where appropriate;

• Sustainability in the bituminous products industry

can be further advanced through:

� Technology to improve the durability of

asphalt in terms of extended pavement life;

� The development of formal relationships with

road authorities and other bodies to introduce

sustainable practices in specifications;

� The establishment of an HSE committee to

develop best practice in HSE management;

� Further development and implementation of

practices that will reduce energy consumption:

The keynote address, one of eight invited presentations,

was delivered by SANRAL CEO Nazir Alli on the

theme Advancing sustainable practices within the

context of the Kyoto protocol. Noting that South Africa

was one of 183 signatories to the protocol, Alli analysed

the compliance requirements of both government and

industry. These included:

• Better land usage and planning, leading to:

� higher density with good public transport;

� reduced congestion and emissions to improve

air quality.

5

Conference speakers (l-r): Consultant Tony Lewis, Nico Pienaar (ASPASA), Benoit Verhaeghe (CSIR BuiltEnvironment), Etienne le Bouteiller (Colas International), Nazir Alli (SANRAL), Mike Zacharias (Shell Oil Products

Africa), Arthur Taute (Vela VKE), Saied Solomons (Sabita), Les Sampson (Asphalt Academy)

Sustainability conference highlights

industry’s need for proactive approach

• Direct measures such as

legislation, fuel taxes and

greater use of renewable

energy sources;

• Indirect measures

including:

� switch to fuel efficient

vehicles;

� measures to improve traffic

flow;

� improved traffic demand

and management;

� greater use of technology.

To implement these measures, Alli said government

had already initiated a long term mitigation scenario

study, and had committed to a fair global climate

change agreement in Copenhagen in 2009, leading to

six broad policy direction themes:

• reduce greenhouse gas emissions;

• build on, strengthen and/or scale up current

initiatives;

• implement the “business as usual” call for action;

• prepare for the future;

• vulnerability and adaptation;

• alignment, coordination and cooperation.

He added that industry’s response should be to reduce

energy inputs, reconfigure manufacturing processes

and recycle reusable materials, use renewable energy

sources and support research and development to

reduce costs or broaden alternatives.

“What is required is a revolutionary approach to

infrastructure that supports life on earth while

safeguarding the rights of the poor. The individual

element is that of choice, the collective element that of

management. The outcome of this interaction, in

context, is essential life support without prejudice to

the requirement of quality infrastructure,” he

concluded.

Assessed impacts

The presentation by Mike

Zacharias of Shell Oil

Products Africa was entitled

Sustainability in the Asphalt

Industry - Eurobitume activity.

He noted that environmental

awareness had, in recent years,

expanded considerably, raising

concerns about the safety of

people and the environment,

and also about global

sustainability. Society and

public authorities were also

increasingly demanding

information on the

environmental impacts of products and industrial

activities.

“This has led to growing regulation and taxation, to

new projects being blocked and products being

rejected if assessed impacts are considered too high.

Financing and insurance costs are rising, and a poor

environmental image makes it difficult to attract new

people to the sector.

“It is therefore important that the industry demonstrates

its understanding of the safety issues and environmental

impacts of its products and processes throughout the

existence of those products and processes,” Zacharias

said. “There is an increasing emphasis on green

credentials in the EU, although the main focus at present

is on collecting information on end-user requirements

and reviewing existing documentation. The development

of lifecycle inventory (LCI) information resulting from

this information gathering is considered essential.

Sustainable technologies

Sustainable technologies were covered in three

presentations:

Long life asphalt pavements to

reduce traffic disruption –

Benoit Verhaeghe:

Verhaeghe made the point that

whereas in 1998 less than 10% of

South Africa’s national and

provincial surfaced roads were in

poor to very poor condition, that

percentage had risen to 60% by

2008. Conversely, while 30% of

those roads were in very good

condition in 1998, less than

10% were in that condition by

2008. At the same time traffic

volumes and heavy vehicle loadings had increased

significantly.

“This makes it vital that South Africa introduce well

constructed pavements (HiMA) to meet the demands of

long-life, high volume roads,” he said. “

From a cost perspective well constructed pavements built

above a threshold strength are not likely to exhibit

structural damage when subjected to very heavy traffic

for a very long time, and would also equate to infinite

life or non-maintenance pavements requiring only the

periodic replacement of wearing courses. In addition, the

use of long-life pavements may generate substantial

savings, particularly when road user costs are

considered.”

Innovative technology for improved durability: a global

perspective – Etienne le Bouteiller:

Road professionals globally are taking heed of an

increasing expectation on the part of road customers and,

more broadly, of the public, that road provision and

maintenance should be supportive of sustainable

practice. Consequently, innovative efforts are constantly

underway in support of the preservation of raw

materials, reduced reliance on non-renewable energy

6

SANRAL CEONazir Alli

Mike Zacharias ofShell Oil Products

Africa

Benoit Verhaeghe,CSIR Built

Environment

resources, the limitation of

green house gas emissions and

increased pavement life and

durability.

Raw materials

Preservation of raw materials

– typically aggregate and

bituminous and cementitious

binders – is routinely

addressed by selection of

binders and recycling. The

latter is carried out in a

number of ways – in place, in plant, cold and hot.

Generally plants are dedicated to handle recycling of

asphalt. Also, binder containing materials from the agro

industry is increasingly used with due consideration of

cost and performance.

Energy savings

Energy used in both the transportation of materials and

heating can be reduced through in-place recycling, cold

techniques incorporating bitumen emulsions, warm

asphalt mixes and a combination of these, e.g. warm

mixes incorporating reclaimed asphalt.

A variety of techniques used in the production of warm

mix asphalt, in terms of process and products, is now

well established and deemed as being reliable.

Conventional plants and equipment are used and the

process is pursued even where energy is cheap.

Generally, in the manufacture of asphalt, a temperature

reduction of 40�C is targeted, which yields significant

reductions in combustion materials and emissions.

In terms of a recent agreement in France between the

ministry for the ecology, energy and sustainable

development (MEEDAT) and the road industry the aim

is to recycle 60% of reclaimed asphalt by 2012 and to

reduce carbon dioxide emissions by 33% by 2020.

A recent development is software to assess comparative

savings in energy consumption and greenhouse gas

emissions associated with various measures. Examples

of typical energy savings and reductions in greenhouse

gas emissions are illustrated on page 21, where the

software is explained in greater detail.

Extended pavement life

Construction periods of up to 30 years, during which

limited intervention is required, dictate that stronger

pavement structures are required. In the asphalt domain,

high modulus asphalt, as developed in France, has

proved to ensure high durability through its high

modulus, hence load spreading capacity, as well as

deformability that underpins fatigue strength.

To facilitate the technology transfer associated with

the proposed introduction of high modulus asphalt in

South Africa, Colas France have been conducting

tests on materials prepared from South African

aggregates and bitumen. The bitumen has been used

in some 300 000 tons of asphalt base on Reunion

Island and is deemed to be suitable. Some fine tuning

of aggregate selection and design appears to be

indicated to ensure that all mix design criteria are met.

Pavements incorporating high modulus asphalt also

offer substantial savings, particularly as a result of

reduced pavement thickness. Case studies have

revealed that 24% reduction of asphalt base thickness

is achievable.

Progress made with the

introduction of warm mix

asphalt and re-use of

bituminous mixes – Tony

Lewis.

Consultant Tony Lewis’s

presentation focused on

the warm mix asphalt

trials carried out in

KwaZulu Natal by the

eThekwini Municipality in

2008. The detail of these

trials, and their outcomes,

were extensively reported in AsphaltNEWS

(Volume 22, Issue 3, 2008, and Volume 23, Issue 1

and 2, 2009).

The presentation by Arthur Taute of Vela VKE, Well

planned urban development and transport as a means

of ensuring poverty alleviation, safety and mobility,

outlined the non-sustainability of current urban

development systems and transportation.

“Sustainability is more than simple performance

improvements, and will require a significant change

in the minds and hearts of the people. Urban sprawl

continues with little regard for improved

sustainability, and transport continues to consume an

ever greater share of fossil fuels,” he said.

Sustainable communities

“We need to be aware that our business is inherently

unsustainable with the current fuel usage of transport,

and that alternative fuels would improve

sustainability, but at an increased cost of transport.

We also need to look at our urban form as soon as

possible. Existing urban development patterns leave

much to be desired in terms of safety, accessibility,

7

Environmental issues are becoming increasingly hard to ignore these days. For manycompanies, it has become a licence to operate. Those who don’t consider the environmental

impact of their operations will find themselves at a disadvantage, not just because their

competitors are doing it, but also because the public demands it.

Etienne le Bouteiller,Colas International

Tony Lewis,Consultant

addressing the comprehensive

range of needs of the

inhabitants, energy

consumption and acceptable

lifestyles. We need to build

sustainable communities, not

just cities.”

Asphalt Academy (AsAc)

CEO Les Sampson’s

presentation, A proactive

approach to redress skills

deficiencies in the roads

industry, listed the problems

currently faced by the

industry. These included:

• Capacity shortages at provincial and municipal

levels, including limited capacity and ability to

manage the road system and implement

programmes;

• Lack of leadership from the Department of

Transport;

• Capacity shortages at tertiary institutions and FET

colleges;

• Inappropriate qualification standards at CETA

levels 1-4 and HET levels 5-10;

• Fluctuating funding; and

• Outdated technical documentation.

Proactive solutions

“These problems present the roads industry with a

pressing need to develop proactive solutions, and

AsAc is poised to facilitate broader industry

participation in skills development.

“Possible solutions include an industry coordinated

website for skills training, linked to tertiary

institutions for accreditation. Improved training

materials and methods of teaching need to be

developed, probably based on distance learning

through the web.

Through an industry driven, proactive initiative South

Africa’s current skills deficiencies can be reversed.”

The conference concluded with a wide consensus that

South Africa’s bituminous products industry must take

proactive responsibility for its future, and should initiate

actions to underpin sustainability. A critical element of

this strategy would be to entrench links between the

public and private sectors, at all levels, to maintain

continuity of delivery and to ensure that South Africa’s

road system, and the personnel responsible for its

provision and maintenance, are able to meet the

requirements of society at large, now and in the future.

8

Sabita chairman Phillip Hechter addressingguests at Sabita's 30

thanniversary dinner

Some of the guests at Sabita's commemorative dinner

Les Sampson,Asphalt Academy

Sabita honorary life member Garth Green, Piet Myburghand Saied Solomons

Since the turn of the century global awareness of the threat

posed by the greenhouse effect induced by human

activities has led to widespread understanding and

awareness of the importance of sustainability.

To be in step with this compelling imperative, the Steering

Committee of CAPSA’11 has agreed that the conference should

advance sustainable practice, and has adopted the theme: Roads

of the future - living within the carrying capacity of the planet.

The conference, to be held from 11 – 14 September 2011 at the

Champagne Sports Resort in the foothills of the Drakensberg

range in KwaZulu-Natal, will examine and demonstrate the

commitment and capacity of producers and users of bituminous

products to advance sustainable practice through reduced

reliance on non-renewable resources, care of the environment

and by assisting in the sound development of society.

Industry commitment

Led by Sabita, the bituminous product industry will view

CAPSA’11 as an opportunity to set the achievement of

commercial goals and profitability side by side with sound

practice in which quality is pursued without compromising

human wellbeing or damaging the environment. Sabita will

therefore explore opportunities to:

• Establish contact and interaction with international

experience, policy and legislation;

• Examine means whereby the use and application of

bituminous products can be exploited as being conducive

to sustainable practice;

• Foster an awareness of the need to be legally compliant,

with a duty of care towards employees, society and the

environment; and

• Develop and support sustainable human capacity building

programmes in the roads industry.

Environmental stewardship

Three key aspects of environmental conservation that will be

specifically targeted by CAPSA’11 are:

• Reduced energy consumption in the construction of

bituminous layers;

• Mitigating the impact of road building activities on the

environment; and

• Extending the life and durability of bituminous products

and flexible pavements.

Focus areas and topics for the plenary sessions will cover:

Focus area 1 - Reduced energy consumption in the

construction of bituminous layers

• Lower temperatures in the mixing and laying of durable

asphalt and bitumen stabilised materials;

• Re-use and recycling of asphalt;

• Potential for the use of industrial waste in road layers.

Focus area 2 – Reducing the impact of road building

activities on the environment

• The development and use of life cycle inventories and life

cycle assessments for bituminous pavement layers;

• Reduction and management of harmful emissions;

• Pavement material selection to lessen the depletion of

natural resources;

• Asphalt surfaces for improved fuel economy and

mitigation of road noise.

Focus area 3 – Designing for extended performance of

asphalt

• The introduction of mix design procedures for improved

durability and performance characteristics of asphalt;

• Ultra thin asphalt layers, spray seals and microsurfacing

for high performance areas;

• Designing wearing courses to meet road user needs in

terms of comfort and safety.

Focus area 4 – Flexible pavement systems for extended life

• Balanced structural pavement design procedures;

• Optimal design or rehabilitation strategies and total whole

life cost assessments for roads on fixed alignment;

• Methods and procedures for assessing the costs of

periodic interventions;

• Impact of climate change on road pavements and

evolving adaptation strategies;

• The introduction of high modulus asphalt to minimise

frequent interventions and disruptions to traffic flow.

Human wellbeing

Addressing the wellbeing, competence and advancement

potential of those persons employed in the industry on the one

hand, and the safety of those affected by the operations of the

roads industry on the other, accounts for the core objective of

the fifth focus area as follows:

Focus area 5 – Meeting the needs of society

• Exploiting bituminous product technology to provide

sustainable employment;

• Economic sustainability through the procurement and

management of bituminous roads;

• Meeting the needs for capacity and skills development;

• Bituminous roads and pathways as a means to advance

equity in the production and sale of goods and services;

• Ensuring the safety of road users and employees.

A number of additional topics including measures to assess the

vulnerability of road networks in terms of climate change and to

develop adaptation strategies that will ensure their long-term

viability are being considered for parallel workshops and

speciality sessions.

More detail can be found on the CAPSA'11 website,

www.capsa11.co.za

CAPSA'11 to focus on advancing

sustainable practice

9

10

To underpin the drive by government to improve

job creation, skills development and

empowerment in the road sector, Sabita has

initiated a project to identify and describe best

practice methods for Labour Intensive Construction

(LIC) related to bituminous products. The undertaking,

being conducted by Barry Pearce, is now well under way

and will be posted on the Sabita website once completed.

Various LIC activities applicable to bituminous practice

have been identified. These broadly cover layer works,

spray applications, hot mix asphalt (HMA), and seals, as

well as routine repair and maintenance operations. The

method descriptions were reviewed by industry experts

to ensure that the information was up to date and aligned

with current best practice.

The methods covered are included in Table 1.

Table 1: LIC methods covered

Although all possible alternative means are not

covered, the above methods represented the

mainstream operations best suited to LIC methods in

bituminous product technology. For example, the

options available for repairing an edge-break may

include the use of hot or cold mix asphalt for

surfacing, HMA, gravel or bitumen stabilised

materials (BSM) as a basecourse before overlaying

with an appropriate wearing course.

Options

This results in six possible options for tackling the

repairs. Although all these applications are covered in

the various methods, they may not be grouped in a

sequence as specified in the contract documents or as

dictated by factors such as material availability. The

combination of methods actually required on a project

may need to be extracted from two or more of the LIC

methods to complete the operation with readily

available materials and in

accordance with contract

specifications.

To ensure that each method or

part thereof does not contain too

great a volume of information,

some were broken down into

various operations. An example is

the seal process, which was

divided up into the following

activities:

• spray operations (including

priming, tack coats,

penetration coat and cover

spray; and

• chip application.

The above activities are each

covered separately and the

information can be drawn on as

and when required to make up the

complete operation.

The various chipping operations

were also kept separate although

the operation of chipping is

essentially the same whether it is

a single, double or Cape Seal

application. Other additional and

equally relevant activities include

sweeping of the base (which is

included in the priming operation)

and traffic control, which is

applicable to almost all repair or

maintenance activities.

Although traffic control is not

covered in detail, its vital

Best available practice identified for labour

intensive construction methods

Layer works Remarks

Foamed bitumen gravel

Slurry-bound macadam By concrete mixer

Spray seals

Single seal (new construction or reseal)

Cape Seal (new construction)13,2mm

19,0mm

Double seal (new construction or reseal)

Graded crushed stone seal

Spray application

Prime coat (inverted emulsion or low

volatile emulsion prime)

Tack coat

Fog spray

Asphalt

HMA surfacing

Cold mix asphalt Cold mix (bags)

Cold mix with emulsion

Slurry-bound macadam surfacing Concrete mixer

Repairs and maintenance

Potholes (small repairs)HMA/cold mix

Road patch

Patching (larger repairs possible with two

layers)HMA

Surface repairs (ravelling repairs with

graded aggregate)

BSM, cold mix

Chip and spray

Edge break HMA, BSM, cold mix

Crack sealing

Hot modified binder

Cold modified binder

Paving fabric

Road patch

importance to all operational aspects requires mention.

Such signage as is necessary must comply with the

minimum requirements of the South African Road

Traffic Sign Manual (SARTSM) as detailed in Chapter 13

and illustrated in Appendix B for traffic deviations and

lane restrictions to ensure the safety of the repair team.

SANRAL's Routine Road Maintenance Manual - 2009

version also refers to the SARTSM for such deviations

and lane closure signage.

Production figures

In some cases production figures have been provided to

assist with the estimation of work rates. These

production figures may vary from those achieved,

typically depending on the experience of the team

undertaking the operation. In some cases however, it is

very difficult to provide production figures due to the

variables in the methods. This is particularly relevant to

repair and maintenance methods such as crack sealing

and pothole repairs. Users

should therefore view these

rates with the necessary

caution.

Once the LIC methods are

published on the Sabita

website, users will be invited

to review the methods and to

forward any comments,

additional points or revisions

to Sabita. This will enable

refinement of the methods,

keeping them up-to-date and

ensuring maximum benefit is

derived from their use.

Additional photographs that

users believe will improve the illustrations would also be

welcomed and should be forwarded to info@sabita.co.za.

for inclusion on the website.

Acknowledgements

Sabita acknowledges with thanks the input and

assistance of the following in the compilation of the

documents, as well as their provision of visual materials

used in their illustration:

• Deon Pagel (National Asphalt);

• Morne Labuschagne (Colas SA);

• Herman Marais (Much Asphalt);

• Angela Broom (AJ Broom Road Products);

• Dave Collings (PDNA);

• Gerrie van Zyl (PDNA);

• Garth James (Kaytech) and

• Johan Hattingh (PH Bagale).

11

Sabita as an organisation and a brand has been in

existence for 30 years and is well known

throughout the Southern Africa road fraternity.

For a brand to remain relevant, it should not only live up

to its promise, but the image itself should evolve to stay

relative to contemporary “look and feel”.

To achieve both these objectives, Sabita’s basket of

imagery has been refreshed, ensuring that all the

projects or activities supported by Sabita have a specific

identity that is easily recognisable. At the same time a

new brand manual has been produced with clear and

concise specifications for Sabita's corporate identity to

support the association's marketing activities. The

manual covers all Sabita products, including a colour

palette for logos and stationery, and media design

applications for all publications.

Examples of the new logos are shown alongside.

Sabita's imagery basket refreshed

Diary event for KZN 2010

BitSafe “Train the Trainer” course

The next course in this highly successful member service is scheduled to be

held in the KwaZulu-Natal region in the first quarter of 2010.

A total of 48 Trainers have successfully completed the BitSafe "Train the

Trainer" course. The course trains delegates to assume an HSE trainer's role

in bitumen safety in their organisations.

The latest results of ongoing epidemiological

studies by the International Agency for

Research on Cancer (IARC), published in July

2009, confirm that no evidence was found of

an association between lung cancer and exposure to

bitumen fumes.

The project was launched in the late 1990s on a

cohort of workers exposed to bitumen fumes, and

reported in 2001 a slight incidence of lung cancer

among these workers, but did not identify a causal

link with exposure to bitumen fumes, and also did not

eliminate other causal factors.

As part of the long-standing international industry

commitment to occupational health and safety, the

study was sponsored by the associations representing

bitumen producers, Eurobitume, CONCAWE, and

users EAPA in Europe, and NAPA, ARMA and

NRCA in the USA.

The latest study, initiated in 2004, was a highly

focused follow-on nested case control study using the

same European asphalt workers who were cohort

members of the previous research. The purpose was

to disentangle the contributions of various agents to

the incidence of lung cancer, including bitumen

fumes, other agents occurring in the asphalt industry,

other occupational exposures, and tobacco smoking.

The extensive study analysed 433 lung cancer cases

and 1253 controls from Denmark, Finland, France,

Germany, Netherlands, Norway and Israel.

Results included:

• No evidence found of an association between lung

cancer and exposure to bitumen fumes;

• Factors identified as the likely contributors to the

slightly elevated incidence of cancer mortalities

were tobacco smoking and previous exposure to

coal tar;

• Other occupational exposures do not seem to play

a part;

• The study further acknowledged the importance

of the continuing trend towards minimising

inhalation and dermal exposures.

The latest study has not yet been peer reviewed, but the

study team intends publishing articles in peer reviewed

journals. At least two of these are currently in an

advanced stage of completion and should be published

before the end of 2009. However, the report is available

on the IARC website. The link is:

http:/www.iarc.fr/en/research-groups/LCA/

The original IARC study was instrumental in motivating

Sabita’s initiative to promote the discontinuation of the

use of coal tar products in South Africa as one arm of its

comprehensive commitment to implementing global

standards of worker health, safety and environmental

conservation. This remains one of Sabita’s dominant

focus areas.

(This article courtesy of Eurobitume)

12

Follow-up IARC study confirms

safety of bitumen fumes

Local Councillor Workshop

A successful Local Councillor Workshop

was held on 3 September in Klerksdorp,

North West Province, and was attended by

more than 80 local government councillors

and officials. This workshop was held in

partnership with the North West Branch of the

South African Local Government Association

(SALGA).

A key factor in the success of the workshop

was the involvement of Sabita members, who

set up exhibition stands and display tables to

familiarise councillors and officials with

available products and technology.

A continuing close relationship between Sabita

and SALGA is envisaged for the future.

LCWP cements Sabita-SALGA cooperation

At the Klerksdorp LCWP: (back l-r) Zodwa Shwabane,

Natasha Badenhorst and Lydia Moloi, (SALGA NW

office), (front l-r) Amogelang Motlhale (SALGA), Fani

Xaba (Aurecon), Cllr M Maphetlhe (Programme Director),

and Saied Solomons (Sabita)

The analysis of all the testing and monitoring

work undertaken as part of the second Warm

Mix Asphalt (WMA) trials is now complete

and shows a very positive outcome.

As reported in the August issue of asphaltNews,

the country’s second WMA trial was carried out in

Durban in late May, early June. Since then the

WMA Interest Group has been hard at work

collating the considerable volume of test results and

monitoring records into a comprehensive technical

report.

Template

It is evident that the strict adherence to the special

template developed for WMA trials, based largely

on lessons learned from the first WMA trials

carried out on Brackenhill Road, has paid off

handsomely. This template was used throughout the

trials and proved invaluable as a comprehensive

checklist. Another obvious reason for the success of

the trials was the importance given to managing all

aspects of the trials, in particular to ensure that

there were sufficient persons at various levels to

cope with the work, from overall management of

the project, management and supervision of the

manufacturing and paving processes, to the

monitoring of temperatures and roller passes.

Just to recap on the trials, they were carried out on

Leicester Road in the industrial area of Mobeni

over a total area of approximately 20 000 m2.

The trials included two WMA technologies,

SASOBIT®, which was used previously in the

Brackenhill road trials, and REDISET, an Akzo

Nobel product that was to be used for the first time

in this country. Conventional asphalt, manufactured

and paved at the usual temperatures, was included

as a control in the trials. All the mixes contained

10% reclaimed asphalt (RA).

Much Asphalt’s batch-type mixing plant at

Coedmore was used to manufacture all the mixes,

which were paved on the section of Leicester Road

between Grimsby Road and Pendlebury Road by

National Asphalt.

Figure 1 shows Much Asphalt plant’s two RA cold feed

bins in the foreground, with stockpiles of the two RA

fractions used in the mixes in the background.

As mentioned in a previous report in asphaltNEWS, a

feature of these trials was the use of two specialised

compaction technologies; Bomag demonstrated their

Asphalt Manager technology while Hamm displayed

their Oscillation Compaction technology.

Mix temperature

Mix temperature, both during manufacture as well as at

the paving site, were strictly controlled within the

following limits:

Control Mix D + 10% RA

Temperature at weighbridge: 145oC to 160

oC

On arrival at paving site: 140oC to 160

oC

Warm mixes

Temperature at weighbridge: 120oC to 140

oC

On arrival at paving site: 120oC to 140

oC

As can be seen in Figure 2 this goal was in fact achieved,

with all the WMA mixes at least 20oC below the control

mix.

13

Second trials in Durban confirm bright

future for WMA

Figure 1. Reclaimed asphalt (RA) feedbins at theCoedmore batch-type mixing plant

As a means of gaining a better understanding of the

mix temperatures at various points in the

manufacturing and paving process, extensive use

was made of thermal imagery, Figure 3 shows the

distribution of temperatures in the WMA as the

delivery truck tips the mix into the paver hopper.

In Figure 4 the paver can be seen in the distance,

with the asphalt cooling down as it is compacted.

Getting back to the findings, the second WMA trials

on Leicester Road confirms the WMA Interest

Group’s core aim, to “produce WMA at the target

temperatures with a resulting pavement that is at least as

good as the control HMA”.

Other significant finds were that all six trial sections

were successfully compacted to achieve the required

minimum 92% MTRD level of compaction. There is

some indication that, in general, the WMA mixes

required fewer roller passes to reach density than the

control Type D mix.

The trials showed that asphalt mixes,

which contain 10% RA, could be

manufactured in Much Asphalt’s

batch-type mixing plant at both

normal mixing temperatures, as well

as at the reduced “warm mix”

temperatures, with residual moisture

contents well below the usual

maximum 0,5% moisture content

limit.

Cooperation

Excellent cooperation and technical

backup was received from both

WMA technology suppliers and

compaction technology suppliers

during the entire course of the trials.

Similarly the exceptionally good

relationship and team spirit that was

evident throughout the work between the client,

manufacturing and paving contractors no doubt

contributed to the success of these trials.

A comprehensive report covering all aspects of these

highly successful trials, compiled with the benefit of

extensive workshopping by the members of the WMA

Interest Group, is due to be posted on the Sabita website

in the near future.

Meanwhile, plans are already underway for the third set

of trials using several WMA technologies, intended to

push the boundaries with higher proportions of RA and

even lower manufacturing and paving temperatures.

With all the positive indications so far regarding the

practical use of WMA in this country, the WMA Interest

Group’s ultimate goal is to produce a guideline

document on Warm Mix Asphalt by the end of 2010.

14

Figure 2. Mix temperature controls plotted

Figure 3 Figure 4

Iconic South African “padmaker” Graham Ross,

whose name is synonymous with the design and

construction of roads in what used to be the Cape

Province, has published a Fourth Edition of his

comprehensive Guide to research on mountain passes,

roads and transportation in the Cape.

Ross is best known outside the roads sector for his

compilation The Romance of Cape Mountain Passes*

(based on his research for the guide), published in

2002 to mark the 100th

anniversary of the South

African Institution of Civil Engineering. The Fourth

Edition, the result of more than 15 years of meticulous

research and investigation and designed as a guide for

the use of future researchers in this field, is published

in electronic format and expands on information in

earlier publications.

Contents

The document is divided into four parts:

• Section A - Index of Cape mountain passes:

With an alphabetical listing of approximately 500

mountain passes and poorts in the Cape, this is the

most comprehensive index in existence. The index

includes the construction dates of listed passes in

the exhaustive Chronology in Section C;

• Section B - Schedule of pioneering and

construction dates: This section is a historical

summary of major roadmaking activities in the

Cape, and records the dates on which projects

were completed in a chronological

one-line-name-and-date schedule covering

mountain passes and major roads and bridges;

• Section C - Chronology: Entries in the

chronology summarise various cross-referenced

sources from which research information was

obtained to guide future researchers. “See also”

annotations list the dates of other chronological

entries, or indicate sources where additional

information may be obtained.

• Section D - Annotated bibliography: This lists

the comprehensive range of publications and other

relevant documents used in Ross’s research.

First mountain pass

Ross’s guide covers road construction beginning with a

description of the road built to haul timber from

Kirstenbosch in 1653 and the first mountain pass over

Constantia Neck in 1666, until 1994 – a record of more

than 300 years of road construction. While constituting

an invaluable tool for anyone interested in roads and

their ancillary features, the document also provides a

solid basis of information for civil engineers tasked with

upgrading existing roads or building additional roads and

structures. Its detail of what has happened in the past

enables accurate planning and design when undertaking

new or supplementary work on existing construction,

and explains where to look for the sort of information

needed during the planning phase.

In his Foreword to the Third Edition Ross Parry-Davies

notes that Ross’s research took him from various

archival records of South Africa’s history to “an

enormous number of engineering records and papers and

other published and unpublished documents in this

country, and to information stored in such far-flung

places as Scotland, the World Bank, the Highway

16

Research and reminiscences from roadmakers

New Graham Ross publication paves the

way for future historic research

The South African Road Federation (SARF) has chosen Graham Ross,

"a doyen of the roads industry in South Africa", as the first recipient of

its newly instituted President's Award to acknowledge and honour

excellence achieved by a person or persons in the roads sector over an

extended period.

The award was made at SARF's annual general meeting in Benoni on 5

November 2009. The citation described Ross's illustrious career, which

began in 1948 and included honorary membership of pavement

institutions throughout the world. In honour of his work in the highway

field he was awarded the Queen Elizabeth Coronation medal in 1953. He

was also elected Life Honorary Vice President of SARF in 1987.

SARF President's award 2009

* The Romance of Cape Mountain Passes may be ordered from SAICE Orders, Private Bag X200, Halfway House, 1685,

or direct from the publishers, David Philip, New Africa Books, 99 Garfield Road, Claremont, Cape Town.

Graham Ross

Research Board in the USA, the Public

Records Office in London and a host of

other sources of information.

“We as a nation owe a debt of gratitude

to Graham Ross, not only for his

contribution to the wealth of our

country, but also for his willingness to

share his experience and accumulated

knowledge with us in the form of this

document.”

The enormous number of books, papers,

documents and other publications

accumulated by Ross during his research

will be stored by the University of Cape

Town in due course and will be available

to future researchers.

Before publication of the Fourth Edition of his

research, Graham Ross asked Bob Kingdon,

former president of the South African Road

Federation (SARF), to produce a short history of

South Africa’s blacktop roads and streets based on his

own research, experiences and recollections.

While too late for publication with Ross's Fourth

Edition, Kingdon’s submission is an outline for a more

rigorously researched paper for submission to the

SAICE’s Civil Engineering monthly. Kingdon writes:

The first asphalt roads in South Africa were laid in Cape

Town soon after the turn of the century. Arriving from

Wales in 1902 John Whitford Griffiths started a road

construction company in Cape Town in 1908. Called the

Union Granolithic and Asphalt Co., this company

surfaced several central city streets in 1910 with premix

asphalt using imported Val de Travers (Neuchatel,

Switzerland) asphalt as binder. The streets were

Church, Longmarket, Shortmarket, Hout and Castle.

After a pause in activity during the first World War,

the main road system in and around Cape Town was

progressively reconstructed with asphalt surfaces.

Shell Oil imported Trinidad Lake Asphalt as binder

and, as the City Council of Cape Town had ample

funds at the time, specifications based on sand seals to

penetration layers using granite aggregates became the

order of the day - for example Sir Lowry Road and

Somerset Road.

In 1924 Union Granolithic was joined by Arthur

Laver, Henry Rohr and Pat Stephens, who built main

arterial roads from central Cape Town to Sea Point

and to the boundaries of the southern suburbs. The

Typical pictures from Ross'sbook The Romance of Cape

Mountain Passes. Above isMeiringspoort, circa 1885(Cape Archives) and at leftthe same pass circa 1971

(Malcolm Watters)

A “sketchy” history of Cape Town's roads

17

company also built the road

between Kraaifontein and

Wellington in 1925, and in 1926

James Griffiths joined them and

the company asphalt surfaced the

streets of Worcester.

The plant used by these early

asphalt men merits comment.

Wolton Gray, who came to South

Africa in 1924 to sell steam rollers

for John Fowler of Leeds,

England, found few buyers so,

with two fellow steam men,

Lowman and Fishwick, he

launched Fowler Tar Spraying

(FTS) to hire out the rollers, and

eventually went on to undertake

road construction contracts. Early work included the

roads and wharves of Cape Town Docks for the S. A.

Railways & Harbours. The Fowler roller was unique

in that it had a tar kettle under the boiler and a chain

driven tar pump feeding a 9ft spray bar at the rear end.

It came equipped with a drawn hopper which spread

chips onto the freshly sprayed binder. In fact the

demand for road construction expertise and plant on

the African continent at this time was such that it took

Gray and his rollers as far afield as Takoradi in West

Africa to Mombasa on the east coast.

Specifications

The specifications of those years - the 1920s - are also

of interest. Basecourses usually consisted of 10in

granite spalls which were hand packed. The surface

was then sprayed with bitumen or tar followed by

successive applications of ‘binder’ and ‘choke’

aggregates - 3/4in (19mm), 1/2in (13mm) and finally

1/4in (6mm). (It is interesting to note

in passing that the 10in spalls

(“klipklop”) were first hand packed in

the back of the lorry or cart at the

quarry (Sea View Quarry, perhaps the

old Peak Quarry? … or Glencairn?)

where they were measured for

payment by the square yard. Once on

site they were duly unpacked and then

repacked onto the subgrade or, often,

directly onto the subbase. In the

1930’s the cost to the client of this

sort of specification was of the order

of £65 000 (sterling) per mile of urban

dual carriageway road. About half the

labour employed consisted of recent

immigrants from Europe almost

certainly prompted by the Depression.

Documenting the gradual expansion of companies

evolving in the road construction sector between the

1920s and 1960s (too voluminous to detail here),

Kingdon acknowledges that his catalogued history is

“inevitably sketchy and incomplete, even inaccurate.

However it is to be hoped that the foregoing account

gives the correct impression of the origins and

developments which are the basis of the current asphalt

road and street construction we see around us today in

South Africa.

We are part of an international technology and industry

and always have been. In fact it is appropriate to append

an addendum, namely that the early local history of

asphalt road surfacing contains the development of the

Cape Seal, a single 19mm seal followed by an

application of bituminous slurry, referred to on site as

“dagga”! The Cape Seal today is universally recognised

as an appropriate specification for certain conditions.

18

Bob Kingdon

Early bitumenspray operations

Anew package designed to

compare the impacts of various

road construction techniques on

the environment has been

launched by the Colas Group.

Marketed as EcologicieL® the package

was developed from the first comparison

of road construction impacts, named The

environmental road of the future, which

was released during the PIARC 2003

congress in Durban, and at a lecture given

during CAPSA’04 in Sun City.

The package, based on user-friendly

spread sheets, is not a Life Cycle

Analysis (LCA) tool, since it takes into

consideration only two major

environmental impacts, i.e. energy

consumption and green-house gas (GHG)

emissions. These constraints were

imposed because this data is most

accurately documented, and also since

these two parameters have a global

impact while others such as ecotoxicity, soil or

water pollution, although they may not be

negligible at all, have more local impacts.

However, the system does comply with LCA

requirements, and includes all components that

may be needed at any stage of construction and

maintenance. The end of life is also partly taken

into consideration, with the possibility to assess

material recycling.

Database

The heart of the package is its database for raw

materials, transportation, manufacture and laying

techniques. Most of the data gathered in this

database arise from published LCA results, e.g.

bitumen figures taken from an Eurobitume study in

1999, or from the Swiss Ecoinvent database. Other

data was obtained through energy consumption

measurements carried out in asphalt mixing plants

or binders and emulsion plants. An extension of

this data base is underway, to take into account the

specific conditions of various countries: for

example, electricity is mostly produced in France

through nuclear plants, with very few CO2

emissions. In Quebec, hydroelectricity does not

emit CO2 at all. Fuel, gas or coal based electric

plants do not have these advantages, and the

differences will impact on raw material production

each time electric energy is involved.

The system is based on the notion of a resources

network and construction steps (raw materials,

intermediate binders, manufactured mixes,

construction layers), and follows in fact the same

scheme as a price study, except that the output

consists of tons of CO2 or megajoules, instead of

Euros or Rands.

Analysis

The analysis programme has three basic stages:

• definition of raw materials sites from a wide

range of resources;

• definition of modified binders and emulsion

plants, together with the raw material

resources they’re supplied from, and the

recipes of the various binders or emulsions

produced;

• mixing plants, whether for hot mix asphalt,

cold mix asphalt or cement concrete. In the

case of hot mixing plants, energy can be

chosen between fuel oil and natural gas.

All theses resources then lead to the construction

site, where more than twenty road techniques can

be selected, ranging from hot asphalt mixes, with

different manufacturing temperatures, to cold

asphalt mixes, in-situ recycling with emulsion,

surface dressing, micro-surfacing, concrete

pavements, or soil stabilisation. For each selected

technique, the user may determine the recipes, with

materials derived from the previously defined

resources.

Pavement structure selection

Finally, up to three different pavement structures

are designed, starting from earthworks up to

wearing course, with all intermediate layers.

The output of this study gives the comparison of

energy consumption and green house gas emissions

between the three pavement structures, accounting

for the allocation of these figures between binders,

aggregates, transport, manufacture and laying

phases.

20

New

environmental

assessment tool

targets responsible

development

Developing this tool also provided the opportunity to

analyse in greater detail the most consuming or polluting

factors within the production scheme, mainly for the

asphalt hot mixing plants. Two main factors were

identified, i.e. mixing temperature, where a reduction of

40°C leads to a decrease up to 20% in fuel or gas

consumption for the burner, and secondly, the aggregate

water content, for which a 2% variation will have a

similar 20% impact.

Reclaimed asphalt

In the asphalt industry increasing effort is currently

being focussed on the use of reclaimed asphalt materials

and the reduction of mixing temperature, and Figure 1

shows the gains that can be obtained, compared with a

traditional structure made of a 5cm wearing course on

top of a 14cm base course (surface: 100,000m2):

• the first alternate proposal is based on mix

designs that include 20% reclaimed materials for

the wearing course, and 30% for the base course;

• the second alternate

proposal foresees

moreover a reduction

of the mix

temperature by 40°C.

This leads to substantial

reductions in energy

consumption and GHG

emissions (Figure 2), ranging

up to 13% for the global

combined assessment, due to:

• binders, aggregates

and transportation

impacts when using

reclaimed materials;

• manufacture impacts

when reducing the

mixing temperature.

Although the package includes a wide range

of road construction techniques, studies

conducted in South Africa with single seals,

and a comparison between three different

binders, namely pure bitumen, SBS modified

bitumen, and bitumen emulsion, have shown

that use of this tool can achieve significant

reductions of energy consumption and GHG

emissions.

The analysis shows that emulsion seals

require much less energy and emit much less

GHG than traditional pure or modified

bitumen techniques, and it should be added

that the current version of the analysis

package does not take into account the need

for heating these binders on site to keep their

high temperature, which would even worsen

the comparison.

Accurate and user-friendly

On a moderate sized site

selected for analysis it was

found that savings equivalent

to the consumption of a light

vehicle travelling more than

180 000 km, or the average

production of one middle size

wind mill during 20 days,

could be achieved.

This product offers an

accurate, and yet user-friendly

tool for the environmental

assessment of projects,

including the selection of

alternative proposals and

priorities for new products or

techniques.

21

Figure 1: Comparison of energy consumption in Giga Joules (GJ)

Figure 2: Comparison of greenhouse gas emissions inequivalent tons CO2

Current procedures in South Africa for both the

determination of binder content and recovery of

binders cannot be sustained. According to a

research report A Guide to the safe use of solvents

in a bituminous/asphalt materials laboratory prepared

by the CSIR, a review of current practice should be

carried out without delay.

In the report, the authors J O’Connell and G Mturi state

that “best practice for any bituminous laboratory would

be to eliminate the use of solvents altogether for all test

methods, as well as for cleaning purposes.” Advances in

laboratory equipment over the last decade have made

this a viable option for some test methods such as the

determination of binder content, as well as for certain

cleaning requirements.

The specific test methods where solvents are used

routinely as reagents in an asphalt laboratory include:

• The determination of the binder content of

asphalt mixtures;

• The recovery of the binder from an asphalt

sample;

• The determination of the solubility of bitumen;

• The determination of the softening point of

bitumen where the softening point is expected to

exceed 85oC.

Benzene, once its toxicity was fully appreciated, was

replaced in the 1950s and 1960s by a range of mostly

chlorinated solvents still widely used today. These are:

• Trichloroethylene;

• 1,1,1-trichloroethane;

• Methylene chloride (or dichloromethane);

• Chloroform (or trichloromethane);

• Carbon tetrachloride;

• Toluene (methylbenzene).

A staged approach

While it may not be feasible to eliminate the use of

solvents altogether in the short term, the authors

recommend the following approach:

• The substitution of more hazardous solvents with

less hazardous ones. Severely toxic solvents such

as trichloroethylene could be replaced with less

toxic solvent combinations such as

toluene/ethanol (85/15) or blends of n-propyl

bromide (1-bromopropane);

• The substitution of more hazardous solvents

with new generation “non-toxic”,

environmentally friendly solvents. These

new generation solvents, based on blends of

naturally occurring compounds (e.g.

limonene blends from oils from lemon peels)

are easier to dispose of and are generally

biodegradable.

• Where it is not practical to replace a

hazardous solvent, measures to minimise

risk of exposure of a laboratory operator

should be adopted. Such risk management

(even for less toxic solvents) would entail:

� A set of general laboratory safety rules

to minimise the exposure of a laboratory

operator to any solvent as well as

minimise the risk of fire and explosion.

These general laboratory rules are

discussed in detail in the report and

cover details regarding personal

protective equipment (PPE), safety

training, laboratory signage,

maintenance and validation of safety

equipment such as fire extinguishers,

fume cupboards and extractor fans. The

requirements for fume cupboards and air

flow through the laboratory for the

various toxic solvents are also listed.

� Possession, interpretation and

management of the relevant Material

Safety Data Sheets;

� Compliance with the legislative

requirements of South Africa in terms of

the Occupational Health and Safety Act

of 1993 (with Amendments), the General

Safety Regulations of 1986 as per

Government Gazette Notice R1031, as

well as the Hazardous Chemical

Substances Regulations of 1995 as per

Government Gazette Notice R1179.

Ignition oven

The late 1990s and early 2000s have seen a

revolutionary step towards a solvent-free testing

through the development of new method for

determination of binder contents of HMA mixes –

the ignition oven procedure.

This method employs the principle of a decrease in

mass of hot mix asphalt, after combustion of the

binder. The report states that the cost savings in

22

A review urged on the use of

solvents in asphalt laboratories

terms of solvent acquisition and HSE considerations

make this a most cost effective method.

Correction factors

While it is recognised that a number of correction

factors or calibrations need to be effected to

compensate for factors such as mass loss of

aggregate, moisture and mass balance temperature

corrections, the ignition test has been formalised in

ASTM D6307 - 05: Standard test method for

asphalt content of hot mix asphalt by ignition

method.

In addition to obvious HSE and cost benefits

already mentioned, the method also results in

substantial time savings compared to the solvent

extraction method. Furthermore laboratory

proficiency testing conducted in the USA has found

that ignition oven testing results in better

repeatability and accuracy than solvent extraction

testing in terms of both the grading of the recovered

aggregate and the binder content. The report states

that “coefficients of variation of less than 2% are

obtained for the proficiency testing”.

Notwithstanding these undeniable advantages of the

ignition oven method circumstances may arise

where solvent extractions are necessary. Such

circumstances may comprise cases where

aggregates degrade substantially during ignition,

where HMA samples are removed from a site some

time after construction and no samples are available

to determine the appropriate correction factors and,

clearly, where the binder of the hot mix asphalt

needs to be recovered for further analysis.

New generation solvents

In the search for safer and more

environmentally friendly solvents, a

number of new solvents have been

developed, or introduced into the

bituminous product industry from

other sectors in the economy. Such

solvents include:

• D-limonene: Obtained by distilling

the oil from orange peels (a

by-product from the orange juice

processing industry), this product is

also used in a variety of

applications, including the

cosmetics, food and pharmaceutical

industry. Limited amounts can be

disposed of via the water drainage

system. With a flash point of 50oC,

D-limonene has a higher

fire/explosion risk than the other

new solvents that have entered the

market;

• Florasolvs solvent range: These

consist of a range of products from

ethoxylated macadamia nut oil to

ethoxylated jojoba oil, which not only serve as

solvents, but also as non-ionic surfactants (i.e.

soaps/cleaning agents). They have high boiling

points and flash points, resulting in lower risk of

fire and explosion;

• N-propyl bromide solvents (nPB): While various

studies have shown that nPB is a safe solvent in

comparison with chlorinated solvents, others

maintain that more research into side-effects is

required to make definitive statements.

From a purely technical perspective, a number of

advantages attach to the use of nPB. It would appear that

nPB scores when the properties of the recovered binder

are compared with those of the original binder. Also, the

use of nPB leads to a significant reduction in extraction

and recovery times (30-40% less).

Furthermore, nPB has been shown to be amenable to

recycling and reusing in the extraction/recovery process.

These advantages have resulted in a number of states in

the USA adopting nPB as their solvent of choice for the

determination of binder content as well as binder

recovery.

Cleaning options

In similar vein to the use of the ignition oven for the

determination of binder content of hot mix asphalt

without resorting to solvents, the development of high

temperature ovens for cleaning glassware and equipment

will lead to decreased dependency by laboratories on

cleaning solvents. An example of such an oven is the

PYRO-CLEAN series of ovens from M&L Testing

Equipment (Inc).

23

The Troxler New Technology Oven (NTO)(Picture courtesy of Troxler)

Typical solvents used for cleaning in South Africa

include:

• Paraffin;

• Diesel;

• Toluene;

• Xylene;

• Hexane.

These solvents vary in their toxicity and risk of fire

or explosion, and if a laboratory should use any one

of these the necessary precautionary procedures

should be adopted.

The alternative ‘safety solvents’ discussed above

have been adopted by many laboratories

internationally for cleaning purposes.

Recommendations

In conclusion, the authors recommend that:

• The ignition oven method, being a proven

accurate, safe, cost-effective, environmentally

friendly and time-saving method for binder

content determinations of asphalt should become

the standard test method for routine quality

assurance testing in South Africa;

• In circumstances where it is required that the

binder be recovered from the asphalt, the use of

benzene and chlorinated solvents, being

carcinogens, are no longer acceptable and should

be phased out in South Africa in the interests of

health and safety and environmental

considerations;

• Any number of safer and more environmentally

friendly solvents can be proposed as replacement

for those currently used nationally, but such

replacement/s must conform to the legislative

requirements of South Africa as well as the

requirements for technical performance.

• In order to limit the coefficient of variation of test

results obtained from binders recovered from hot

mix asphalt, it is recommended that one single

extraction procedure be prescribed for South

Africa. The authors propose that an enhanced

solvent extraction and binder recovery method as

set out in AASHTO T319, be considered.

Alternatively, ASTM D5404 (rotary evaporator

method), amended to include a two-flask system

for lower binder hardening could be considered.

• For enhanced testing proficiency, only one

specific solvent - a toluene/ethanol blend - should

be prescribed in South Africa. This

recommendation is based on the acceptable

technical performance of this solvent combination

as seen in the literature review as well as the low

health and safety risks associated with its use.

Alternatively, nPB, may be considered as the

national standard solvent based on the fact that

internationally the trend seems to be in this

direction.

24

As a resident engineer on a construction unit you get

involved in peculiar happenings.

The surfacing of the N2 in the Knysna area during

1950/51 entailed establishing a teerkamp, with all

bitumen, road tar, stone and crusher dust stockpiled in an

area near the Goukamma railway siding. Some of the

bitumen drums had been in stock for years. As there had

been very little roadworks during WWII, the drums had

deteriorated badly - the 33 gallon drums were of poor

quality in any case - so that handling them had caused

split drums and leakage.

Now, the farm owner had pens of large white pigs and

on a certain day I received an angry phone call from him,

that some of his pigs had got into the teerkamp and were

now stuck in the bitumen. He was convinced the pigs

would die. In those days there was no radio

communication so off I went to Goukamma, to find six

large pigs, now mostly black, firmly stuck and

exhausted, with a ganger and labourers trying to get

them out. My first thought was the “please explain”

letter I would get from head-office!

There was only one way to get then clean: that was

to wash them with power paraffin we had in stock.

My ganger said the pigs would die, and I said if we

don’t clean them they’ll die anyway, and he then

had the good idea that we could scrub them with

soap and water after the paraffin.

And so one engineer, a ganger, and labourers

cleaned up the now-totally-exhausted pigs. The

scrubbing certainly revived them - a pig can really

make a hellish noise when it is man-handled, and it

was said that it could be heard miles away!

Since then I’ve enjoyed eating bacon!

PS: The pigs all survived, and our teerkamp was

made “mouse-proof”!

John A de Kock

Reminiscences of a padmaker

The day of pigs

The Society for Asphalt Technology is going

from strength to strength with membership

numbers now standing at 445 and growing,

reflecting SAT’s success in promoting

competence in the use of bituminous products.

In becoming a sponsor member of the Road Pavements

Forum SAT recently established another landmark in

the evolution of its efforts to provide continuing

excellent service to its members. The November 2009

RPF was the first such meeting to which all SAT

members received invitations to attend.

The 16th Annual General Meeting of the Society for

Asphalt Technology was held on 10 November 2009

in tandem with the RPF in Pretoria. Main items for

discussion were the acceptance of the financial

statements for the year 2008 as well as the ratification

of membership subscriptions for 2010. A below

inflation increase of 5% was proposed for the

membership subscriptions for 2010.

CAPSA’11 Steering Committee

At SAT’s last Council/Exco meeting held on 18

August 2009, SAT president, John Onraët was elected

to represent the Society on the CAPSA’11 Steering

Committee. It is envisaged that the CAPSA’11

Steering Committee could utilise SAT, with its strong

member base, as a reservoir of knowledgeable people

to draw upon when necessary, particularly for

technical workshops and paper peer reviews.

Julian Wise Asphalt Education Trust

Commemorating Julian Wise, a SAT life honorary

member and industry stalwart, the establishment of a

Julian Wise Asphalt Education Trust scholarship is

being explored. The SAT Council believes this is an

appropriate way to deliver on its value proposition to

promote the knowledge of asphalt technology and to

make it available to all members.

SAT director receives award

Cape Town based engineer Dr Lucas-Jan Ebels, a

director and honorary treasurer of SAT, was recently

named the 2009 Young Engineer of the Year by

Consulting Engineers South Africa (CESA).

This award recognises the contribution of engineers of

less than 35 years of age to the industry and to the

future of the profession. As a result of his selection

Lucas attended the international Federation of

Consulting Engineers (FIDIC) convention in London

in September 2009, and will serve on CESA's Young

Professionals Forum for 12 months.

Ebels was appointed a director of SAT in

2005, at a time when the society was

struggling to re-establish its service

value to its members, and to achieve

financial viability.

"He has steered SAT from the brink of

insolvency to a position of sound

financial health," according to SAT

President John Onraët. "With his recognised technical

skills Lucas is an integral part of SAT and a highly

valued member of the executive."

SAT Central Region

SAT Central Region under chairmanship of Basil

Jonsson, has held several successful seminars and

workshops during the year:

• A co-hosted seminar with the CSIR and the

RMPD group, held during March 2009 and with 9

international professors presenting, was

oversubscribed as the venue could only

accommodate 130 delegates;

• A seminar on Developments with warm mix

asphalt in southern Africa was held on 28 May

2009 with 110 delegates attending;

• A seminar on the Gauteng Freeway Improvement

Project was held on 27 August 2009 with 90

delegates attending. An interesting presentation

with project details was delivered by Alex van

Niekerk and the SANRAL team of engineers;

• A workshop on A practical approach to bitumen

and its uses was held on 7 October 2009 with

127 delegates attending;

27

Dr Lucas-Jan Ebels

SAT’s landmark membership of the

RPF underscores service value

• A workshop on A practical approach to

aggregates and its uses was held on 4 November

2009 with 72 delegates attending.

SAT Eastern Region

Activities of the SAT Eastern Region under

chairmanship of Craig Bradley, included:

• A seminar on Design and use of

slurry/microsurfacing was held on 12 February

2009 – together with the regional AGM - with 38

delegates attending;

• A seminar on Development with warm mix

asphalt (WMA) in RSA was held on 6 April 2009

with 42 delegates attending;

• A site visit to the new King Shaka International

Airport on 6 August was attended by 45

delegates.

• A workshop on A practical approach to bitumen

and its uses was held on 6 October 2009 with 57

delegates attending;

• A workshop on A practical approach to

aggregates and its uses was held on 5 November

2009, together with a site visit to Ridgeview

Quarry.

SAT Southern Region

Seminars and workshops held by SAT Southern Region

under chairmanship of Ockert Keyser, included:

• A seminar on Design and use of

slurry/microsurfacing was held in 5 February

2009 with 132 delegates attending;

• A seminar on Development with warm mix

asphalt (WMA) in RSA was held on 29 May 2009

with 75 delegates attending;

• A workshop on A practical approach to bitumen

and its uses was held on 5 October 2009 with 54

delegates attending.

• A workshop on A practical approach to

aggregates and its uses was held on 2 November

2009.

SAT membership

SAT membership is open to all persons working with or

having an interest in asphalt technology. Details on

membership, as well as a downloadable membership

application form, are available on the SAT website

www.socsat.co.za.

28

Local events 2009

NEPAD Transport Summit and Africa Expo:

25 - 26 November, Gallagher Convention Centre,

Gauteng.

International events 2009

Asphalt Rubber 2009:

2 - 4 November, Nanjing, China.

International Conference on Rural Roads:

25 - 27 November, Tanzania.

Local events 2010

Road Pavements Forum (RPF):

4 - 5 May, North Coast, KwaZulu-Natal

29th

Annual Southern African Transport Conference

- SATC 2010:

9 - 12 August, CSIR, Pretoria.

International events 2010

NAPA 2010 55th

Annual Meeting:

17 - 20 January, Maui, Hawaii, USA.

GSAAPA Meeting:

21 - 22 January, Maui, Hawaii, USA.

First International Conference on Pavement

Preservation:

12 - 16 April, Newport Beach, California.

16th IRF World Road Meeting:

25 - 28 May, Lisbon, Portugal.

11th ISAP Conference (ISAP NAGOYA 2010):

1 - 6 August, Nagoya, Japan.

2nd International Spray Seal Conference 2010:

11 - 12 October, ARRB, Australia.

World of Emulsions (IBEF and SFERB):

11 October, Lyon, France.

CME World Emulsions Conference:

12 - 14 October, Lyon, France.

Local events 2011

Conference on Asphalt Pavements for Southern

Africa (CAPSA'11):

11 - 14 September, Drakensberg, South Africa.

Local and international events calendar

29

Index of articles in last three issues of asphaltNEWS

Volume 22, Issue 3, November 2008

CEO comments

Sabita funds HiMA research

N3 rehabilitation at Marianhill

Sabita directors

Warm mix asphalt trials for KZN

Sabita's Code of Conduct

Local and international events

Asphalt rideability - a contractor's perspective

Asphalt Academy initiatives gain momentum

Gradings and new sieve sizes

Feedback from international conferences

Sabita focus on safety issues

Sabita publications

New Sabita members

Sabita members

Volume 23, Issue 3, March 2009

CEO comments

Letters to the Editor

First two BitCert certificates issued

TG2 now covers foam and emulsions

Report on Durban's WMA trials

New insights into HMA rutting

Asphalt reinforcement guideline launched

IS#2: A case for surfacing gravel roads

Sabita publications

Updated manual on bitumen rubber asphalt

TMH1 review approaches completion

New Spray Seals Information website

Solution offered to flushing problems

Local and international events

Slurry sealing manual in the pipeline

AsAc roadmaps industry skills

Sabita members' conference announced

MMLS protocol now available

New Sabita members

Sabita members

Volume 23, Issue 2, August 2009

CEO comments

Reader opinion: Asphalt mix gradations

Local and international events calendar

Sabita celebrates 30 years

Sabita Outstanding Achievement Award

CAPSA'11 steering committee convened

Warm mix asphalt trial outcomes

GFIP road network

Reducing the asphalt industry's carbon footprint

Sabita conference on sustainability

Sabita publications

Australian Ball Penetration device tested

Response to AsAc's Pavement Engineering course

The benefits of trade associations

Reducing road maintenance costs

SARF rescue plan for provincial roads

Obituary - Julian Wise

Update on revisions of TMH1

SA's inaugural RMPD editorial meeting

Sabita members

30

AG Thomas (Pty) Ltd P.O. Box 100 Manzini M200 Swaziland Tel +268 5184499 Fax +268 5186363

AJ Broom Road Products (Pty) Ltd P.O. Box 16421 Dowerglen 1612 Tel 011 4543102 Fax 011 4542790

Akasia Road Surfacing (Pty) Ltd P.O. Box 259 Bon Accord 0009 Tel 012 5620921 Fax 012 5620530

Asphalt Services cc P.O. Box 1765 East London 5200 Tel 043 7451014 Fax 043 7451245

Astec – Asphalt Technology P.O. Box 589 Rothdene 1964 Tel 016 3621310 Fax 016 3623024

Bitumen Constr. Services (Pvt) Ltd P.O. Box M78 Harare Zimbabwe Tel +263 4 305506 Fax +263 4 305507

Bitumen Supplies & Services (Pty) Ltd P.O. Box 1028 Sunninghill 2157 Tel 011 8039338 Fax 011 8039881

Colas SA (Pty) Ltd P.O. Box 82 Eppindust 7475 Tel 021 5316406 Fax 021 5315514

Concor Roads & Earthworks P.O. Box 8259 Johannesburg 2000 Tel 011 4952221 Fax 011 4952496

Group Five Civil Engineering P.O. Box 1750 Bedfordview 2008 Tel 011 4096607 Fax 011 4096789

Javseal (Pty) Ltd P.O. Box 26317 Isipingo Beach 4115 Tel 031 9025988 Fax 031 9022457

Milling Techniks (Pty) Ltd P.O. Box 779 Gillits 3603 Tel 031 7929580 Fax 031 7004447

More Asphalt P.O. Box 2180 Durbanville 7550 Tel 021 9750784 Fax 021 9750792

Much Asphalt (Pty) Ltd P.O. Box 49 Eerste Rivier 7100 Tel 021 9004411 Fax 021 9004446

National Asphalt P.O. Box 1657 Hillcrest 3650 Tel 031 7362146 Fax 031 7361938

Phambili Road Surfacing (Pty) Ltd P.O. Box 145 Mkondeni 3204 Tel 033 3461982 Fax 033 3461995

Polokwane Surfacing (Pty) Ltd P.O. Box 288 Ladanna 0704 Tel 015 2931221 Fax 015 2931258

Power Construction (Pty) Ltd P.O. Box 129 Blackheath 7581 Tel 021 9071300 Fax 021 9056912

Rand Roads (div. of Grinaker LTA) Private Bag X030 Kempton Park 1620 Tel 011 9235304 Fax 011 3976294

Roadmac Surfacing (Pty) Ltd P.O. Box 8378 Bloemfontein 9300 Tel 051 4300404 Fax 051 4300400

Roadsmart (Pty) Ltd P.O. Box 30344 Tokai 7966 Tel 021 7130129 Fax 021 7130128

Roadspan Surfaces (Pty) Ltd P.O. Box 30550 Jet Park 1469 Tel 082 4112267 Fax 011 5188584

Sanyati Roads (Pty) Ltd P.O. Box 477 Botha's Hill 3660 Tel 031 777 1905 Fax 031 777 1972

Spray Pave (Pty) Ltd P.O. Box 647 Alberton 1450 Tel 011 868 5451 Fax 011 900 1470

Tarfix (Pty) Ltd P.O. Box 77354 Fontainebleau 2032 Tel 011 7084794 Fax 011 7084797

Tarspray cc Suite327,P.B.X09WeltevredenPark1715 Tel 012 6690003 Fax 012 6690110

Tor Construction cc P.O. Box 914 Hartenbos 6520 Tel 044 6940008 Fax 044 694 0006

Tosas (Pty) Ltd P.O. Box 14159 Wadeville 1422 Tel 011 3232000 Fax 011 9022755

Van Wyk Tarmac cc P.O. Box 12535 Onderstepoort 0110 Tel 012 5611871 Fax 011 5611321

Zebra Bituminous Surfacing cc P.O. Box 14335 Kenwyn 7790 Tel 021 7613474 Fax 021 7971151

BP SA (Pty) Ltd

P.O. Box 1806, Durban 4000

Tel 031 2758867 Fax 031 2652701

Chevron SA (Pty) Ltd

P .O. Box 714 Cape Town 8000

Tel 021 4037242 Fax 021 4030380

Engen Petroleum Ltd

P.O. Box 1043, Jhb 2000

Tel 011 4806202 Fax 011 4806003

Sasol Oil (Pty) Ltd

P.O. Box 4211, Randburg 2125

Tel 011 8899773 Fax 011 8899859

Shell SA Marketing

(Pty) Ltd

6 Ipivi Road, Kloof 361

Tel 031 5711000 Fax 031 7646208

Total SA (Pty) Ltd

P.O. Box 579, Saxonwold 2132

Tel 011 7782376 Fax 011 6876381

SPONSOR MEMBERS

ORDINARY MEMBERS

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Afrisam SA (Pty) Ltd P O Box 6367 Weltevreden Park 1715 Tel 011 6705500 Fax 011 4759326

Arcus Gibb (Pty) Ltd P.O. Box 3965 Cape Town 8000 Tel 021 4699172 Fax 021 4245571

Asch Professional Services (Pty) Ltd P.O. Box 51121 V&A Waterfront 8002 Tel 021 4184988 Fax 021 4195187

Aurecon (Pty) Ltd P.O. Box 1347 Cape Town 8000 Tel 021 481 2400 Fax 021 424 5558

BKS (Pty) Ltd P.O. Box 3173 Pretoria 0001 Tel 012 421 3667 Fax 012 421 3679

CapePeninsulaUniv.ofTechnology P.O. Box 652 Cape Town 8000 Tel 021 4603074 Fax 021 4603710

Dick King Lab Supplies (Pty) Ltd P.O. Box 82138 Southdale 2135 Tel 011 4999400 Fax 011 4936349

DuPont de Nemours Int SA P.O. Box 3332 Halfway House 1635 Tel 012 683 5600 Fax 012 683 5663

GMH/CPP Cons. Eng. P.O. Box 2201 Randburg 2125 Tel 011 4620601 Fax 011 4620672

Goba (Pty) Ltd P.O. Box 180 Sunninghill 2157 Tel 011 2363331 Fax 011 8078535

HHO Africa P.O. Box 6502 Roggebaai 8012 Tel 021 4252870 Fax 021 4194689

Iliso Consulting (Pty) Ltd P.O. Box 686 Gillits 3603 Tel 031 2662600 Fax 031 2662616

Jeffares & Green (Pty) Ltd P.O. Box 1109 Sunninghill 2157 Tel 011 8070660 Fax 011 8071607

Kantey & Templer (Pty) Ltd P.O. Box 3132 Cape Town 8000 Tel 021 4059600 Fax 021 4196774

Kaymac (Pty) Ltd T/A Kaytech P.O. Box 116 Pinetown 3600 Tel 031 7172300 Fax 031 7023173

Kwezi V3 Engineers (Pty) Ltd P.O. Box 36155 Menlo Park 0102 Tel 012 4256300 Fax 012 4601336

Lafarge Industries SA (Pty) Ltd P.O. Box 139 Paarden Eiland 7420 Tel 021 5088000 Fax 021 5088120

Lidwala Cons. Engineers (Pty) Ltd P.O. Box 2930 Nelspruit 1200 Tel 013 7532864 Fax 012 7532816

Namibia Technical Services cc P.O. Box 30623 Windhoek Namibia Tel +264 61 215324 Fax +264 61 215327

PD Naidoo & Assoc. (Pty) Ltd P.O. Box 7786 Roggebaai 8012 Tel 021 4182929 Fax 021 4186440

Rankin Engineering Consultants P.O. Box 50566 Lusaka Zambia Tel +260 1 290562 Fax +260 1 293156

Sasol Technology Fuels Research P.O. Box 1 Sasolburg 1947 Tel 016 9604068 Fax 016 5224835

Sasol Wax (a div. of SCI) Chemcity 2 P.O. Box 1 Sasolburg 1947 Tel 016 9602126 Fax 016 5222063

SRT (Pty) Ltd P.O. Box 15324 Westmead 3608 Tel 031 7004510 Fax 031 7003165

SSI Eng. & Env. Cons. (Pty) Ltd P.O. Box 867 Gallo Manor 2146 Tel 011 7986051 Fax 011 7986005

TPA Consulting (Pty) Ltd P.O. Box 1575 Westville 3630 Tel 031 7651907 Fax 031 7652551

Tshepega Engineering (Pty) Ltd P.O. Box 33783 Glenstantia 0010 Tel 012 6652722 Fax 012 6655597

Unitrans Fuel & Chem. (Pty) Ltd P.O. Box 31 Tableview 7439 Tel 021 5510636 Fax 021 5511996

Vela VKE Cons. Eng. (Pty) Ltd P.O. Box 72927 Lynnwood Ridge 0040 Tel 012 4813821 Fax 012 8034411

WSPSACivil&Struct.Eng.(Pty)Ltd P.O. Box 2330 Edenvale 1610 Tel 011 4502290 Fax 011 4502294

ASSOCIATE MEMBERS

Beosumbar & Associates cc P.O. Box 605 Westville 3600 Tel 031 2667494 Fax 031 2667404

Chemimpo (Pty) Ltd P.O. Box 1378 Randburg 2125 Tel 011 2932058 Fax 011 7873513

DMV Harrismith (Pty) Ltd P.O. Box 912 Harrismith 9880 Tel 058 6222676 Fax 058 6230271

Letaba Lab (Pty) Ltd P.O. Box 739 White River 1240 Tel 013 7527663 Fax 086 6754843

Mdubane Energy Services (Pty) Ltd P.O. Box 4876 Durban 4000 Tel 031 3042470 Fax 031 3019302

Meckow Ltd (SA) P.O. Box 12614 Mill Street 8010 Tel 083 7891565 Fax 021 4617783

MTTC (Pty) Ltd P.O. Box 912-387 Silverton 0127 Tel 012 8003018 Fax 012 8004381

N3TC (Pty) Ltd P.O. Box 2063 Bedfordview 2008 Tel 011 4543596 Fax 011 454077

Salphalt (Pty) Ltd P.O. Box 234 Isando 1600 Tel 011 8232218 Fax 011 8262239

AFFILIATE MEMBERS

32

Asphalt News is published by the Southern African Bitumen Association (Sabita),a non-profit organisation sponsored by its members to serve all stakeholders

through engineering, service and education.

Sabita together with the associations listed below, have founded aglobal strategic alliance of asphalt pavement associations and are working

jointly towards a full, open and productive partnership:

Australian Asphalt Pavement Association (AAPA)National Asphalt Pavement Association (NAPA)European Asphalt Pavement Association (EAPAJapanese Road Contractors Association (JRCA)

The contents of this publication may be reproduced without any changes andfree of charge, provided the source is acknowledged

Southern African Bitumen Association (Sabita)

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Howard Place 7450

South Africa

Tel: +27 21 531 2718

Fax: +27 21 531 2606

email: info@sabita.co.za

www.sabita.co.za