Asphalt Review - Volume 29 Number 2 (June / July 2010)
Asphalt Review - Volume 29 Number 2 (June / July 2010)
Asphalt Review - Volume 29 Number 2 (June / July 2010)
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<strong>Asphalt</strong><strong>Review</strong><br />
<strong>Volume</strong> <strong>29</strong> <strong>Number</strong> 2 <strong>June</strong>/<strong>July</strong> <strong>2010</strong><br />
From the AAPA CEO 16<br />
From the AAPA Chairman 17<br />
$1 million warm mix validation project 18<br />
GAPA widens membership 24<br />
Beyond warm mix 25<br />
Bitumen stabilisation in South Africa <strong>29</strong><br />
Smoothness brings cost savings 34<br />
Post graduate studies to<br />
maintain industry skill levels 36<br />
<strong>Asphalt</strong> in railway tracks 40
ASPHALT REVIEW<br />
CEO’s report<br />
I am writing this just as the 14th AAPA<br />
Road Construction and Surfacing<br />
Health and Safety Conference has<br />
concluded. There were many very<br />
interesting discussions and we will<br />
feature some of these in the next edition<br />
of <strong>Asphalt</strong> <strong>Review</strong>.<br />
The conference raised a range of<br />
issues from the structure of various<br />
bitumen hoses to the new national<br />
model health and safety laws. It<br />
also discussed a range of technical<br />
innovations and legislative issues such<br />
as the traffic management registration<br />
scheme in Queensland.<br />
One of the highlights of the<br />
conference was the papers on safety<br />
around road construction work sites,<br />
particularly on the benefits of reducing<br />
motorist speed around those sites to<br />
zero; that is to close the road. These<br />
discussions were followed by a panel<br />
discussion and workshop on working<br />
under traffic, speed management and<br />
enforcement.<br />
These discussions noted that some<br />
motorists may be distracted as they<br />
pass worksites. They may be using their<br />
mobile phone, changing their radio<br />
station or even having a morning coffee.<br />
Others may be affected by drink or<br />
drugs. In some cases, motorists are just<br />
in a hurry and ignore speed limits.<br />
The preferred safety option is therefore<br />
to close the road. Road closures not only<br />
increase safety, they also usually result<br />
in significant cost and time savings. But<br />
it is not always possible to close a road.<br />
In these cases, it is important that all<br />
those involved in the project continue<br />
to focus on safety with the aim always<br />
being zero incidents.<br />
To achieve this requires every<br />
person involved to be vigilant. Traffic<br />
controllers must be suitably trained<br />
and equipped, signage must be accurate<br />
and visible – and removed when it is<br />
not required. Protective barriers must<br />
be well positioned and designed –<br />
including filling plastic barriers with<br />
water and securing them together.<br />
Appropriate clothing is also essential,<br />
both day and night.<br />
Another significant part of the<br />
conference was a workshop for health<br />
John Lambert,<br />
CEO, AAPA<br />
and safety representatives from AAPA<br />
branches to meet and identify key areas<br />
that AAPA should focus on over the next<br />
two years. This workshop identified<br />
a number of potential opportunities<br />
including preparing an AAPA model<br />
check list to be used when closing a<br />
worksite to ensure signage is removed,<br />
better sharing of industry alerts and<br />
providing industry-relevant training to<br />
handle dangerous goods.<br />
A report on this workshop will be<br />
prepared for discussion in the AAPA<br />
State Branches.<br />
Many of the delegates at the conference<br />
commented that it was a great success<br />
and that they will be taking a lot of<br />
significant learnings from it. I would<br />
therefore like to thank Scott Mathews<br />
and Denise McQueen from Hallmark<br />
Editions, the conference organisers,<br />
for a great conference. I also thank<br />
the Platinum Sponsor, Fulton Hogan,<br />
and Bronze sponsor, Sparke Helmore<br />
Lawyers, as well as all the presenters<br />
who put so much into this conference.<br />
The other major event that has<br />
occurred recently in our industry is the<br />
commencement of the AAPA/Austroads<br />
Warm Mix Validation Project. This is a<br />
major project supported by AAPA and<br />
state road authorities to validate the<br />
hypothesis that warm mix is equal or<br />
better than hot mix asphalt. There is an<br />
article in this edition of <strong>Asphalt</strong> <strong>Review</strong><br />
detailing this project and I recommend<br />
that you read it.<br />
The project highlights the strength of<br />
AAPA to bring together both industry<br />
and state road authority members to<br />
work together for the common good of<br />
our industry.<br />
AAPA has successfully worked for 40<br />
years to support our industry and will<br />
continue to do so for many years to<br />
come. The warm mix project is just one<br />
example of many significant projects<br />
that have and are being undertaken<br />
nationally and in individual states. For<br />
example; at present AAPA is currently<br />
undertaking studies into perpetual<br />
pavements, sprayer calibration and<br />
skid resistance. It is also constantly<br />
updating its training courses and<br />
in conjunction with Austroads, the<br />
Pavement Work Tips series.<br />
Through its liaison groups, AAPA<br />
is bringing together industry and<br />
government agencies to help grow<br />
our industry and make even better<br />
roads. Most recently, this has led to a<br />
Bituminous Surfacing Working Group<br />
being established in the Northern<br />
Territory. A State Executive Officer is<br />
also being sought in Western Australia<br />
to support our industry in that state.<br />
An advertisement for that position is<br />
included in this <strong>Asphalt</strong> <strong>Review</strong>.<br />
AAPA is also working to produce<br />
a range of material to support our<br />
industry. This includes a publication<br />
on Environmental and Safety benefits<br />
of flexible pavements and a new DVD<br />
highlighting the importance of flexible<br />
pavements to the economic and social<br />
growth of Australia.<br />
AAPA also represents our industry<br />
in negotiations with the Federal<br />
Government over issues such as<br />
greenhouse reporting and through<br />
working in bodies such as Roads<br />
Australia. AAPA’s membership of the<br />
Global <strong>Asphalt</strong> Pavement Alliance<br />
allows it to make available the latest<br />
information on developments from<br />
around the world.<br />
AAPA will therefore continue to<br />
serve the flexible pavements industry<br />
to achieve a sustainable, growing, safe<br />
and knowledgeable industry.<br />
16 ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong>
Chairman’s report<br />
ASPHALT REVIEW<br />
The flexible pavements industry has a good<br />
health and safety record understanding<br />
we are working with hot bitumen, with<br />
heavy equipment and often near to<br />
moving traffic. However, we must strive<br />
to always improve, to always do better.<br />
Zero health and safety incidents must be<br />
the ultimately aim of our industry.<br />
AAPA’s successful Health and Safety<br />
Conference which has just finished is one<br />
of the initiatives our association leads<br />
to support our industry to continually<br />
improve its health and safety performance.<br />
Always considering road closure, managing<br />
signage, providing safe equipment and<br />
training are just some of the issues that<br />
were discussed at the conference and<br />
are issues we should always take into<br />
account.<br />
The conference also provided the<br />
opportunity for workshops to bring<br />
together experts across out industry and<br />
AAPA will be using those discussions to<br />
continue in its role of supporting our<br />
industry.<br />
The discussions at the Conference<br />
supported the need for everyone in our<br />
industry to always be vigilant and take<br />
responsibility for health and safety.<br />
With the support of our members we<br />
will soon be providing key lag indicators<br />
such as lost time injury and medical<br />
treatment frequency rates to provide an<br />
understanding of the actual performance<br />
of the overall industry, the trends, and<br />
allowing each member to understand how<br />
they compare.<br />
The AAPA Health and Safety<br />
conference highlighted just one of the<br />
Louis Nucifora,<br />
Chairman, AAPA<br />
ways that AAPA helps our industry.<br />
AAPA does a lot more for our industry<br />
than just holding successful conference.<br />
It also represents our industry in a<br />
number of ways including to state road<br />
authorities in each state and nationally.<br />
It also manages number of projects<br />
including the recent $1 million warm<br />
mix asphalt validation project which<br />
is featured in this edition of <strong>Asphalt</strong><br />
<strong>Review</strong>.<br />
AAPA and the AAPA Board is committed<br />
to supporting and growing our industry,<br />
achieving the goals set in its Strategic<br />
Plan. These focus on achieving a<br />
sustainable, profitable and safe industry<br />
that recognises the importance benefits<br />
of flexible pavements for the benefit of<br />
its members and all road users. Moving<br />
forward, I look forward to next reporting<br />
on our progress over the last year and<br />
the outlook for the year ahead.<br />
The <strong>Asphalt</strong> <strong>Review</strong> Magazine, prepared by the Australian <strong>Asphalt</strong><br />
Pavement Association (AAPA) is now also produced as a supplement<br />
in the ROADS magazine. To gain access to a broader readership,<br />
AAPA has undertaken to publish within ROADS, but its content will<br />
maintain the uniqueness and specialty focus on flexible pavements<br />
that <strong>Asphalt</strong> <strong>Review</strong> has provided for over 25 years. Availability<br />
of this and future issues of the <strong>Asphalt</strong> <strong>Review</strong> will continue via the<br />
AAPA web site: www.aapa.asn.au in addition to its inclusion in<br />
ROADS magazine.<br />
The publishing schedule is: February-March; <strong>June</strong>-<strong>July</strong>; and October-<br />
November.<br />
<strong>Asphalt</strong> <strong>Review</strong> reports on the<br />
flexible pavements and bituminous<br />
surfacing industry in Australia<br />
and New Zealand. It is published<br />
by ROADS Magazine on behalf<br />
of Australian <strong>Asphalt</strong> Pavement<br />
Association Limited (ABN 31 000<br />
770 123), a non-profit organisation<br />
formed to promote the economic<br />
use of asphalt and other bituminous<br />
bound products based on sound<br />
technical and commercial grounds<br />
for the benefit of its members, their<br />
customers and the community.<br />
Articles in <strong>Asphalt</strong> <strong>Review</strong><br />
may be reprinted provided<br />
acknowledgement is given.<br />
Contributions of a news or<br />
technical nature on all aspects of<br />
asphalt and bituminous surfacing<br />
are welcome.<br />
ADMINISTRATION<br />
AAPA Head Office<br />
Level 2, 5 Wellington Street<br />
Kew, Vic 3101<br />
Tel: (03) 9853 3595<br />
Fax: (03) 9853 3484<br />
Email: info@aapa.asn.au<br />
Website: www.aapa.asn.au<br />
<strong>Asphalt</strong> <strong>Review</strong><br />
Editor: Rex Pannell<br />
Email: rex.pannell@halledit.com.au<br />
Advertising: Yuri Mamistvalov<br />
Email yuri@halledit.com.au<br />
Tel: (03) 8534 5008<br />
ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong> 17
ASPHALT REVIEW<br />
$1 Million AAPA/Austroads Warm<br />
Mix <strong>Asphalt</strong> Validation Project<br />
In today’s world we must all<br />
take care of our environment.<br />
For those in the pavement<br />
industry, we must also ensure<br />
that pavements are safe,<br />
smooth and long lasting.<br />
<strong>Asphalt</strong> pavements are low<br />
emitters of greenhouse gas<br />
and the bitumen not consumed,<br />
remaining 100% recyclable.<br />
<strong>Asphalt</strong> pavements are also<br />
safe to drive on, easy and quick<br />
to resurface when required and<br />
are smooth to ride on.<br />
But as an industry, we recognise<br />
the importance of always<br />
seeking new ways to make even<br />
better roads. AAPA industry<br />
and government members are<br />
working together on a major<br />
project to validate warm mix<br />
asphalt for Australia.<br />
Warm mix asphalt uses less<br />
energy than hot mix during<br />
the production process. It also<br />
has a number of other potential<br />
benefits. The joint AAPA/<br />
Austroads Validation project<br />
is therefore a major project<br />
supporting the early adoption<br />
of this technology in Australia.<br />
• Improved safety benefits as the<br />
materials and asphalt are at lower<br />
temperatures compared to hot mix,<br />
creating a safer workplace;<br />
• Improved productivity as deep asphalt<br />
works can be opened to traffic more<br />
quickly. This benefits the transport<br />
industry and commuters by reducing<br />
the length of time roads are under<br />
repair;<br />
• Extended paving seasons; and<br />
• Longer haul distances.<br />
The effectiveness of this green<br />
technology has been proven through<br />
ongoing implementation in Europe and<br />
the United States, and in other countries<br />
around the world. It is also expected to<br />
become standard practice for asphalt<br />
production in these countries. However,<br />
state road authorities have advised<br />
that they want WMA to be validated in<br />
Australia, using normal material, plant<br />
and procedures, before it is used on<br />
major road projects.<br />
To validate WMA in Australia, AAPA in<br />
conjunction with state road authorities,<br />
developed an evaluation protocol to<br />
guide validation projects. This protocol<br />
was developed through the <strong>Asphalt</strong><br />
Research Reference Group (ARRG), a<br />
group comprising state road authorities<br />
and the AAPA National Technology<br />
Committee. ARRG advises the Austroads<br />
Pavement Technology <strong>Review</strong> Panel on a<br />
wide range of issues relevant to asphalt.<br />
Details of the protocol are provided at<br />
the end of this article.<br />
Having developed the validation<br />
project protocol, AAPA then worked<br />
with state road authorities and industry<br />
members to obtain support for a major<br />
validation project that would enable<br />
several different WMA processes to be<br />
validated against standard hot mix under<br />
heavy traffic conditions.<br />
After assessing a number of sites with<br />
staff from VicRoads, a suitable site was<br />
selected. This site is a heavily trafficked<br />
three lane section of the Hume Highway<br />
in northern Melbourne; a section that<br />
carries between 6,500 and 8,500 vehicles<br />
per day on each lane. The site was<br />
already scheduled to have a new wearing<br />
course under VicRoads programmed<br />
maintenance program.<br />
The decision to use a wearing course<br />
on a multiple lane urban highway with<br />
heavy traffic was made to ensure the<br />
project would demonstrate the field<br />
performance of WMA in a very difficult<br />
environment.<br />
VicRoads funded the costs of the asphalt<br />
materials under its maintenance budget<br />
and the three major asphalt producers<br />
– Boral <strong>Asphalt</strong>, Downer EDI Works<br />
and Fulton Hogan – agreed to provide<br />
AAPA, in conjunction with Austroads,<br />
has commenced a major project to<br />
validate the performance of Warm Mix<br />
<strong>Asphalt</strong> (WMA) in Australia. The AAPA/<br />
Austroads WMA Validation Project is a $1<br />
million project comparing several WMA<br />
materials against control sections of Hot<br />
Mix <strong>Asphalt</strong> (Hot Mix). The project aims<br />
to demonstrate that WMA has the same<br />
performance as hot mix asphalt and is<br />
managed jointly by AAPA and ARRB (on<br />
behalf of Austroads).<br />
WMA is asphalt made at lower<br />
temperatures than conventional hot mix.<br />
It requires less energy to manufacture<br />
and consequently produces less<br />
greenhouse gas. WMA also has a range<br />
of other significant benefits including:<br />
The WMA Validation Site prior to the start of works.<br />
18 ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong>
ASPHALT REVIEW<br />
a range of different WMA materials.<br />
The asphalt companies also agreed to<br />
fund the initial and ongoing extensive<br />
asphalt testing that was required under<br />
the Evaluation Protocol. The testing will<br />
be monitored by state road authority and<br />
ARRB personnel.<br />
To ensure consistency in placement<br />
reduce costs and enhance practicality,<br />
one company undertook all the<br />
placement. This highlighted the high<br />
level of cooperation between all the<br />
parties involved in this major project. It<br />
also ensured consistency in the laying of<br />
the samples and meant that all sections<br />
could be laid over three nights, reducing<br />
disruption to traffic.<br />
The Project required placing 21<br />
different WMA and hot mix wearing<br />
course sections of asphalt in a grid<br />
pattern on the section of the roadway<br />
and this was undertaken in April <strong>2010</strong>.<br />
Two foamed WMA processes and two<br />
additive WMA processes were used to<br />
produce the WMA materials. Some WMA<br />
materials were made with new aggregates<br />
and others with differing proportions of<br />
reclaimed asphalt pavement (RAP), from<br />
10% up to 50% RAP.<br />
Testing of the asphalt materials used<br />
could not be completed by a single<br />
laboratory given the large number of<br />
samples.<br />
As a result, each participating asphalt<br />
company prepared the specimens and<br />
completed testing for their own mixes.<br />
Representatives from Queensland<br />
Transport and Main Roads, NSW Roads<br />
and Traffic Authority, South Australian<br />
Department of Transport Energy and<br />
Infrastructure, VicRoads and ARRB<br />
were present during the preparation<br />
of samples and during the asphalt<br />
placement.<br />
The asphalt specimens are currently<br />
being tested by the asphalt companies<br />
with state road authority and ARRB<br />
observers monitoring that testing. The<br />
observers will continue to monitor<br />
all testing undertaken throughout<br />
this project to ensure accuracy and<br />
consistency.<br />
As outlined in the Validation Project<br />
Protocol, this project will continue<br />
for a period of at least two summers.<br />
During that time, industry, ARRB and<br />
state road authority members will<br />
continue to monitor the performance<br />
of the pavements. This will provide<br />
a clear understanding of the relative<br />
performance of WMA to hot mix.<br />
It is expected the outcomes of the<br />
validation project will confirm that<br />
WMA, with or without RAP, is as reliable<br />
as hot mix. But whatever the outcome,<br />
this project will enable both government<br />
and industry to better understand<br />
the opportunities to use WMA across<br />
Australia. It will also help to achieve<br />
greater consistency in specifications<br />
across Australia and will support the early<br />
use of WMA with all its environmental,<br />
economic and safety benefits.<br />
The project highlights the benefits<br />
of industry and Austroads/state road<br />
authorities working together through<br />
AAPA to achieve outcomes that benefit<br />
all parties. It not only reduces the costs<br />
to any single organisation, it significantly<br />
reduces the need for duplication.<br />
Importantly, the project also highlights<br />
how government and industry can work<br />
effectively together through AAPA.<br />
This is highlighted in a letter from<br />
Andrew Milazzo, Executive Director of<br />
the SA Department for Transport, Energy<br />
and Infrastructure, sent to the AAPA<br />
CEO, John Lambert, about the project:<br />
“The Department is delighted to be<br />
involved in a project such as this which<br />
encompasses the State Government’s<br />
strategic goals of attaining sustainability<br />
through greenhouse gas emissions<br />
reduction and improving wellbeing<br />
through greater safety at work.<br />
I appreciate the co-operative approach<br />
you have taken with the free flow<br />
of information, showing a genuine<br />
commitment from industry.” Further<br />
information on this project will be<br />
made available on the AAPA website<br />
and in future editions of <strong>Asphalt</strong> <strong>Review</strong>.<br />
Information can also be obtained from<br />
the joint project managers, Cassandra<br />
Simpson (AAPA) and Kieran Sharp<br />
(ARRB).<br />
20 ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong>
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ASPHALT REVIEW<br />
AAPA/Austroads Warm Mix <strong>Asphalt</strong> Validation Protocol<br />
In order to validate the performance<br />
of WMA (including WMA with varying<br />
amounts of RAP) against hot mix, AAPA<br />
and the sate roads authorities developed<br />
an evaluation protocol.<br />
This protocol was developed through<br />
the <strong>Asphalt</strong> Research Reference Group, a<br />
group comprising state road authorities and<br />
the AAPA National Technology Committee,<br />
which was established to advise the<br />
Austroads Pavement Technology <strong>Review</strong><br />
Panel.<br />
The scope of the protocol was confined<br />
to wearing courses consisting of densegraded<br />
asphalt and conventional binders.<br />
Recycled asphalt pavement (RAP), if<br />
included in the WMA, could also be<br />
addressed.<br />
The key issues addressed by the<br />
protocol were:<br />
• the testing of asphalt containing<br />
additives and surfactants, both in the<br />
laboratory and during production;<br />
• the testing of asphalt containing foamed<br />
bitumen: during production only;<br />
• desirable site conditions for a field trial;<br />
• the timeframe for the evaluation; and<br />
• data and information exchange.<br />
The Protocol specified four stages in a<br />
Validation Project – Initial Testing; Field<br />
Validation; Performance Monitoring,<br />
Reporting and Data Sharing.<br />
Initial Testing<br />
• WMA Incorporating Additives and<br />
Surfactants - Testing of (laboratory)<br />
design mixes.<br />
The Protocol proposed that a series<br />
of tests be conducted on both WMA with<br />
additives and surfactants, and the same<br />
asphalt mix composition without additives<br />
and surfactants (the control hot mix).<br />
The protocol includes the following<br />
asphalt tests:<br />
• resilient modulus (indirect tensile);<br />
• moisture sensitivity (stripping potential);<br />
• wheel tracking;<br />
• fatigue;<br />
• maximum density (voids free bulk<br />
density);<br />
• Marshall stability and flow;<br />
• air voids at the design binder content;<br />
• bulk density at the design binder<br />
content; and<br />
• recovered binder viscosity.<br />
Optimisation of an additive may then be<br />
further investigated by varying the amount<br />
of additive and reducing the production<br />
temperature.<br />
• WMA Incorporating a Foaming Process<br />
Foamed asphalt must be produced<br />
22 ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong><br />
through the asphalt plant as it cannot be<br />
readily replicated in the laboratory.<br />
Once the mix design and production<br />
criteria (i.e. production temperature) have<br />
been established, the same procedures<br />
as for WMA incorporating Additives and<br />
Surfactants should be adopted with the<br />
following two additions:<br />
• moisture content; and<br />
• moisture content of aggregates used in<br />
production mixes.<br />
Field Validation<br />
Site selection<br />
Field validation requires that a suitable<br />
site is identified that would enable the<br />
performance of the WMA materials to be<br />
compared against hot mix controls.<br />
Suitable sites should meet the following<br />
criteria:<br />
• minimum hot mix and WMA sections of<br />
length of 100 metres;<br />
• straight section, consistent crossfall and<br />
longitudinal grade;<br />
• reasonable shape (assessed visually<br />
and by roughness and shape testing<br />
using a Multi-Laser Profilometer (MLP);<br />
• strong structural condition (assessed<br />
visually and by pavement strength<br />
testing);<br />
• uniform distress condition;<br />
• known traffic counts and commercial<br />
vehicle percentage;<br />
• medium to heavy traffic conditions; and<br />
• minimum level of rutting and uniform<br />
rutting.<br />
Once a site is selected the following<br />
information should be recorded:<br />
• site ID (a suitable site ID should be<br />
assigned for easy reference);<br />
• road name and location;<br />
• lane number (where appropriate) and<br />
lane width;<br />
• direction of travel;<br />
• chainage; and<br />
• other relevant information, e.g.<br />
drawings, other reference points, the<br />
location of structures, intersections, etc.<br />
Production and Placement details<br />
Once a validation site has been selected,<br />
the following detailed information must be<br />
recorded on the production and placement<br />
of materials:<br />
• Production details:<br />
o mix and bitumen type;<br />
o bitumen content;<br />
o other additives used (if any);<br />
o WMA type and concentration;<br />
o date and time of production;<br />
o production temperature;<br />
o mix design details;<br />
o tonnage of asphalt produced; and<br />
o haulage time (from plant to site).<br />
• Placement details:<br />
o site details, eg. site ID, road name,<br />
etc;<br />
o overlay, or mill and replace;<br />
o thickness of asphalt laid;<br />
o asphalt temperature upon arrival at<br />
the site;<br />
o temperature at first compaction;<br />
o paver type;<br />
o shuttle buggy (if used); and<br />
o roller type and pattern.<br />
Performance Monitoring<br />
The field performance under traffic is the<br />
key factor in validating WMA. Trial sites<br />
must therefore be monitored for a number<br />
of critical performance parameters.<br />
Field monitoring<br />
Given the importance of demonstrating<br />
the viability of WMA and its adoption into<br />
practice by road authorities in Australia<br />
and New Zealand as soon as possible, the<br />
protocol recommended that validation sites<br />
initially be monitored for two summers.<br />
This recognised that should there be any<br />
early problems with WMA they would be<br />
identified during that period. At the end<br />
of that period, the following performance<br />
parameters would be measured and<br />
recorded:<br />
• cracking;<br />
• rutting at 10 metre interval;<br />
• texture at 10 metre interval; and<br />
• stripping potential.<br />
Reporting and Data Exchange<br />
It was noted in the introduction that the<br />
purpose of the protocol was to assess<br />
the performance of WMA and share data,<br />
experience and knowledge among the<br />
road authorities and industry in Australia<br />
and New Zealand using the Austroads<br />
framework. The Protocol recommended<br />
that all information be readily shared<br />
between all participants as a means of<br />
ensuring a consistent understanding of the<br />
performance of WMA.<br />
Reporting<br />
All information related to the evaluation of<br />
WMA should be collated for processing and<br />
to ensure a consistent and comprehensive<br />
report. This information includes:<br />
• Process type (eg. foamed, additive)<br />
and name of additive (if used) of WMA<br />
technology/processes considered;<br />
• asphalt mix type and aggregate size;<br />
• bitumen grade and percentage;<br />
continued on next page...
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ASPHALT REVIEW<br />
...continued from previous page<br />
• mix design method;<br />
• design void content;<br />
• test results for design (laboratory mix);<br />
• test results for production mix;<br />
• field trial details; and<br />
• performance monitoring.<br />
Data Exchange<br />
Validation Projects should be undertaken jointly by industry and<br />
the road authorities. Any reports produced should therefore be<br />
provided to all participants for review. This will ensure that they<br />
are accurate and, where appropriate, do not divulge details of any<br />
proprietary products.<br />
The reports provided may then be used by road authorities, in<br />
consultation with industry, as a basis for consistent and appropriate<br />
specifications.<br />
Warm-mix asphalt position<br />
statement by GAPA<br />
The Global <strong>Asphalt</strong> Pavement Alliance (GAPA) is comprised<br />
of multi-national and national asphalt pavement associations<br />
throughout the world. We recognise the asphalt industry as<br />
the ultimate steward of our own product in terms of quality,<br />
performance, safety, and environmental benefit.<br />
In an effort to improve its already excellent environmental<br />
performance record, the GAPA supports the development and<br />
implementation of warm-mix asphalt.<br />
Warm-mix asphalt is the term used to describe a class of<br />
technologies employed to reduce the production and paving<br />
temperature of asphalt mixtures by 10 to 40 degrees centigrade.<br />
This temperature reduction may be effected through the use<br />
of mineral or organic additives or by mechanical means to<br />
introduce foaming into the production of asphalt mixtures.<br />
Warm-mix asphalt has been recognised as an environmentally<br />
friendly method to produce asphalt mixtures with the following<br />
benefits:<br />
• Higher product quality through better consistency and<br />
improved compaction;<br />
• Sustainability through reduced energy consumption and<br />
better performance;<br />
• Improved air quality through reduced emissions;<br />
• Reduced climate impact through reduced greenhouse gas<br />
generation;<br />
• Economic advantage through an extended paving season<br />
and longer haul distances;<br />
• Improved working conditions through the reduction of<br />
fumes and the reduction of temperature.<br />
The effectiveness of this green technology has been proven<br />
through ongoing implementation in Europe and the United<br />
States. This will inevitably become the standard practice for<br />
asphalt mixture production. We encourage others within the<br />
industry as well as our agency partners in all countries to<br />
become informed about warm-mix asphalt technology and to<br />
begin a path toward its implementation.<br />
Australian <strong>Asphalt</strong> Pavement Association<br />
European <strong>Asphalt</strong> Pavement Association<br />
Japan Road Contractors Association<br />
National <strong>Asphalt</strong> Pavement Association, USA<br />
Southern African Bitumen Association<br />
GAPA widens<br />
membership<br />
two years after<br />
formation<br />
At this time two years ago, the Global <strong>Asphalt</strong> Pavement<br />
Alliance (GAPA) came into being. The agreement to<br />
establish the alliance was signed in Copenhagen on 21<br />
May 2008 and reported in the <strong>June</strong>-<strong>July</strong> issue of Roads.<br />
The signatories to the alliance were:<br />
Australian <strong>Asphalt</strong> Pavement Association (AAPA);<br />
European <strong>Asphalt</strong> Pavement Association (EAPA);<br />
Japanese Road Contractors Association (JASA);<br />
(US) National <strong>Asphalt</strong> Pavement Association (NAPA)<br />
Southern African Bitumen Association (SABITA).<br />
The purpose of the Alliance was to build on existing<br />
links between the world asphalt associations to exchange<br />
information relevant to our industries. It recognised<br />
that there are many current and emerging issues such<br />
as sustainability and new technologies associated with<br />
pavement designs and materials. Most of these are<br />
relevant across the world and sharing information will be<br />
of benefit to all GAPA members.<br />
Under GAPA, the pavement associations can also<br />
provide consistent information to road authorities and<br />
the world community. This lead to a statement from the<br />
GAPA meeting held in January <strong>2010</strong> highlighting the<br />
importance of warm mix asphalt.<br />
In recent times, a lot of the information from research<br />
being undertaken in the US has been provided to AAPA and<br />
the other members. Information from Europe has also<br />
been provided, including on the use of asphalt in railway<br />
tracks that is highlighted in this edition of Roads.<br />
Recognising the benefits of the global alliance, two<br />
more asphalt associations have recently joined GAPA.<br />
They are Roading New Zealand and the Mexican <strong>Asphalt</strong><br />
Association [Asociación Mexicana del Asfalto, A.C. -<br />
(AMAAC)]. Other Associations are expected to join over<br />
the next few months.<br />
Currently Mike Acott, President of NAPA is the Executive<br />
Officer of GAPA.<br />
24 ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong>
Beyond Warm Mix <strong>Asphalt</strong><br />
Several new technologies have been<br />
developed that reduce energy usage for<br />
asphalt manufacture with a consequent<br />
lowering of production and placement<br />
temperatures. These materials are<br />
called “warm mix asphalt”, or WMA<br />
and the major Validation trial of these<br />
technologies is decribed in page 18 of this<br />
edition of <strong>Asphalt</strong> <strong>Review</strong>. However, trials<br />
are also being conducted in New Zealand<br />
into asphalt mixes that can be produced<br />
at even lower temperatures. These are<br />
referred to as half-warm asphalt.<br />
The following paper, prepared by Dr<br />
Bryan Pidwerbesky - Fulton Hogan, Alan<br />
Beuzenberg - Christchurch City Council,<br />
and John De Bono - Christchurch<br />
International Airport, reports on the<br />
reasons for using warm and half-warm<br />
mixes, including operational and technical<br />
benefits, reduction in greenhouse gas<br />
emissions and improvements to worker<br />
safety.<br />
The paper was delivered at AAPA’s 13th<br />
International Flexible Pavements Conference<br />
in November 2009 at Surfers Paradise in<br />
Queensland. (Condensed version - full<br />
version available from Conference papers<br />
2009 - aapa@asn,com.au)<br />
1. Introduction<br />
Climate change and the increased<br />
awareness of greenhouse gas emissions<br />
focusses industry and the community’s<br />
attention on the combustion of fossel<br />
fuels. Therefore although bitumen<br />
is not consumed in the production<br />
of flexible pavements, infact remains<br />
100% recyclable”, the industry does<br />
recognise that it must constantly look at<br />
technologies to even further reduce the<br />
energy concumed in producing asphalt<br />
materials. The industry also recognises<br />
the cost saving associated with lower<br />
fuel consumption. Recognising this,<br />
Fulton Hogan in New Zealand has<br />
identified an advanced Half Warm<br />
asphalt technology and has obtained a<br />
licence for its use.<br />
2. Background to Warm Mix<br />
<strong>Asphalt</strong>s<br />
The drive to reduce greenhouse gas<br />
emissions from hot-mix asphalt<br />
production by reducing fuel usage<br />
is not new. A number and variety of<br />
manufacturing techniques that reduce<br />
the energy used to manufacture asphalts<br />
have been developed beginning in the<br />
1990s. They are generally classified into<br />
two categories:<br />
- Additive based systems, where a<br />
proprietary additive is used to allow a<br />
reduction in energy usage; and<br />
- Alternative manufacturing techniques<br />
such as foaming.<br />
Some processes use a combination<br />
of both techniques, i.e. a proprietary<br />
additive in conjunction with modified<br />
manufacturing processes.<br />
Warm Mix asphalt offers a significant<br />
reduction in production temperature of<br />
up to 40 C and a reduction in greenhouse<br />
emissions associated with the production<br />
of in the order of 20%.<br />
3. Half-Warm Mixes<br />
In 2006, Fulton Hogan identified a<br />
new process that would use even less<br />
fuel for producing asphalt mixes. This<br />
process, developed in Europe, but<br />
licensed worldwide, combines the use<br />
of an additive with plant and process<br />
modifications, resulting in asphalt<br />
produced below 100°C, and able to be<br />
placed at temperatures as low as 60°C.<br />
This new process was radically<br />
different to the Warm-Mix asphalts<br />
previously considered. It involved a<br />
patented system, using proprietary<br />
chemical additives with a change to the<br />
asphalt production process. While the<br />
process change requires modification<br />
to asphalt plants, the degree of<br />
modification is substantially less than<br />
alternative processes and is hence more<br />
ASPHALT REVIEW<br />
A warm mix asphalt produces almost zero fumes and is safer to handle<br />
economically viable. Because the asphalt<br />
mix is produced at temperatures below<br />
100°C, energy demands are significantly<br />
reduced. Experience in Europe<br />
demonstrated that burner fuel savings in<br />
the order of 50% are achievable.<br />
Because this new process differs<br />
so significantly from previous Warm-<br />
Mix asphalts, a new term was coined<br />
to describe the material: “Half-Warm<br />
Mix <strong>Asphalt</strong>”. This term highlights the<br />
substantial reduction in production<br />
temperature of at least 70°C compared<br />
with similar hot-mix asphalts, and 30° C<br />
cooler than Warm-Mixes.<br />
The significant reduction in burner fuel<br />
usage reduces greenhouse gas emissions<br />
by as much as 50%. In addition, the<br />
cooler asphalt does not emit the “blue<br />
smoke” fumes from production and<br />
handling.<br />
Field crew also benefit from the Half-<br />
Warm asphalt process as the lack of<br />
blue smoke emissions reduces worker<br />
exposure to fumes, and the lowered<br />
placement temperatures virtually remove<br />
the risk of serious burns.<br />
Economically, the costs of the additive<br />
and plant modifications offset the<br />
savings in fuel usage. At the moment the<br />
process is borderline economic, but as<br />
fuel costs continue to rise, the use of the<br />
Half-Warm process will reduce the effect<br />
on the price of asphalt.<br />
Substantial quantities of Half-Warm<br />
asphalt pavements have been constructed<br />
in Europe and the United States. Much<br />
ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong> 25
ASPHALT REVIEW<br />
research and quality control testing has<br />
been carried out in association with this<br />
work, with considerable successes being<br />
obtained.<br />
4. Benefits of Half-Warm Mixes<br />
The two main benefits of Half-Warm<br />
asphalt mixes are:<br />
1. Reduction in greenhouse gas<br />
emissions; and<br />
2. Improvement in field crew health and<br />
safety.<br />
A closer examination of the technology<br />
reveals additional benefits for both<br />
producers and purchasers of Half-Warm<br />
asphalt mixes.<br />
4.1 For the producer<br />
Producing mix at a lower temperature<br />
means that the differential between<br />
ambient and mix temperature is reduced.<br />
This means that the Half-Warm asphalt<br />
mix will cool more slowly compared<br />
with hot mix asphalts. A slower rate of<br />
cooling allows longer cartage distances,<br />
extended workability time in the field<br />
and the ability to place and compact in<br />
cooler conditions.<br />
Because the Half-Warm asphalt cools<br />
more slowly, the formation of a chilled<br />
‘crust” on the surface of payloads does not<br />
form to the same degree. Another benefit<br />
of the Half-Warm asphalt technology is<br />
cleaner truck decks and hand tools.<br />
4.2 For the Client<br />
Conventional hot-mix asphalts are<br />
produced at around 165° C so that<br />
the viscosity of the bitumen binder is<br />
lowered enough to permit adequate<br />
workability of the mix. A negative effect<br />
of this high production temperature is<br />
the aging of the bitumen due to reaction<br />
with atmospheric oxygen. This is a well<br />
known phenomenon and is controlled<br />
by including aging tests in bitumen<br />
specifications<br />
The chemical additives in the Half-<br />
Warm process contain active adhesion<br />
promoters. Thus the risk of water<br />
damage in the asphalt pavement is<br />
reduced or eliminated. This use of<br />
adhesion promoters is contrasted with<br />
some Warm Mix systems that depend<br />
on the use of water, potentially trapping<br />
water in the mix and degrading longterm<br />
performance. The Half-Warm<br />
process provides for long-term adhesion<br />
of bitumen to the aggregate by including<br />
active chemistry in the additive<br />
chemicals.<br />
The reduction in temperature<br />
differential between the half-Warm<br />
asphalt and ambient temperatures,<br />
the extended workability and the<br />
minimisation of “crust” formation means<br />
that compaction is more readily achieved<br />
in the field minimising the risk of rutting,<br />
permeability and binder oxidation.<br />
The Half-Warm asphalt process is<br />
a means for the production of asphalt<br />
paving mixes. The same material is being<br />
manufactured and placed; it’s only the<br />
manufacturing process that has changed.<br />
5. New Zealand Experience with<br />
Half-Warm Mixes<br />
In 2005, Fulton Hogan began assessing<br />
warm mix and half-warm mix<br />
technologies available around the world,<br />
and selected the low emissions asphalt<br />
(LEA) process to implement in the<br />
company’s New Zealand asphalt plants.<br />
Following laboratory development and<br />
early pilot trials constructed on a haul<br />
road within one of Fulton Hogan’s<br />
quarries in Christchurch, some high<br />
profile/high-demand sites were paved:<br />
1. Buckley’s Road, Christchurch,<br />
December 2007<br />
2. Montreal Street, Christchurch,<br />
March/April 2008;<br />
3. Christchurch International Airport<br />
taxiway, February 2008.<br />
To date the performance of all the<br />
trials has been exemplary. Cores were<br />
taken of the trial sections in August<br />
2008 (4 months after they were laid),<br />
and tested in Fulton Hogan’s laboratory<br />
wheeltracking device. The AC14 initially<br />
had a higher rate of rut development<br />
compared with the CoolPave, but after<br />
10,000 passes they had similar rut<br />
depths.<br />
Our experience to date is that the<br />
Half-Warm process allows asphalt<br />
pavements to be placed at a quality<br />
equal to, or better than, conventional<br />
hot mix asphalt pavements.<br />
Fulton Hogan has produced Coolpave<br />
in 5 of its 14 fixed plants, all of which<br />
are continuous drum plants.<br />
Fulton Hogan has produced<br />
approximately 6000 tonnes of Coolpave,<br />
mostly a standard 14 mm dense mix.<br />
Small runs of 7mm and 10 mm mix<br />
have been produced for hand work trials<br />
which worked successfully.<br />
Mixes have been laid to date on minor<br />
city streets, multi-lane city arterials,<br />
airport taxiways and factory yards/<br />
carparks.<br />
Compaction results in the field show<br />
that Coolpave compacts similar to hot<br />
mix, and the workable time and time to<br />
compact increases using Coolpave.<br />
Minimal laboratory-based performance<br />
testing has been conducted, although<br />
one wheel tracking test showed that after<br />
10,000 passes the AC14 Coolpave had<br />
almost exactly the same degree of rutting<br />
as hot mix AC14. The Coolpave product<br />
reported total rutting equal to 96% of the<br />
hot mix value after 10,000 passes.<br />
6. Clients’ Perspectives<br />
6.1 Christchurch City<br />
Christchurch City Council leads and<br />
strongly supports local environmental<br />
initiatives in transportation and other<br />
fields – particularly where these initiatives<br />
may have benefits for the wider regional<br />
and national community.<br />
The production of standard asphalt<br />
has a high energy requirement due to<br />
the need for materials to be heated<br />
during production and the need for<br />
high temperatures to be maintained<br />
through to final placement. The high<br />
temperatures required to manufacture<br />
asphalt also result in high emissions<br />
to atmosphere as well as temperaturerelated<br />
safety issues for site staff and the<br />
public during the laying-down process.<br />
This initiative by Fulton Hogan meets<br />
council’s expectations for practical<br />
solutions to both environmental and<br />
safety issues. The material met initial<br />
trial requirements and meets all council<br />
asphalt test needs. The full scale trials at<br />
the two sites have to date demonstrated<br />
that material design, manufacture,<br />
cartage and laying methodologies are<br />
similar to standard asphalt; resulting in<br />
burner fuel savings during manufacture<br />
due to lower energy requirements,<br />
reduced emissions, easier achievement<br />
of density requirements when laying<br />
in cooler air temperatures and greater<br />
safety during placement.<br />
Council tendering and contract<br />
methodologies encourage innovation and<br />
Fulton Hogan’s proposal was developed<br />
within this framework. Council works<br />
with the local contracting industry to<br />
explore new initiatives. The local industry<br />
has demonstrated a willingness to work<br />
with council to meet both community<br />
and industry needs and has shown great<br />
passion in their endeavours.<br />
6.2 Christchurch International<br />
Airport<br />
Christchurch International Airport<br />
Limited (CIAL) has worked with Fulton<br />
Hogan for the last 18 years on Airfield<br />
Pavement Maintenance Works (APMW).<br />
In 2006, CIAL encouraged Fulton Hogan<br />
to undertake a process of innovation<br />
to reduce the total cost of ownership<br />
and reduce the carbon footprint in the<br />
delivery of the APMW programme. CIAL<br />
is a CarbonZero Airport, the first in the<br />
26 ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong>
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ASPHALT REVIEW<br />
southern hemisphere; CIAL supports any innovation that reduces<br />
the carbon footprint on a sustainable basis.<br />
CIAL has a rolling 20-year APMW program which makes it<br />
possible to look at paving opportunities that take advantage of<br />
these opportunities to trial several innovations.<br />
One of the innovations submitted to CIAL for approval was<br />
the trial CoolPave, on the airfield. Not only are there significant<br />
energy fuel savings, it is a much safer product to manage and<br />
compact. A trial section of CoolPave was laid on Taxiway A.<br />
Fulton Hogan laid 141 tonne (598m2) to a depth of 110mm<br />
on Taxiway A during February 2008. Subsequent testing and<br />
inspections of the CoolPave trial showed that CoolPave was<br />
as stable and as strong as the standard hot mix product used<br />
normally on the airfield.<br />
This first trial gave CIAL enough confidence to use CoolPave<br />
on a larger scale trial overlay on Taxiway F in February 2009.<br />
For this trial, 515 tonne (2,745m2) was laid. The full scale trial<br />
on Taxiway F is performing as designed. Testing and inspection<br />
are consistent with the small trial on Taxiway A. Handling the<br />
CoolPave was easier and much safer for the paving team than<br />
the standard hot mix product with no blue smoke and much<br />
lower temperatures.<br />
A smaller trial of 38 tonne using CoolPave with 30% Recycled<br />
<strong>Asphalt</strong> Pavement (RAP) was also completed on Taxiway F.<br />
The use of RAP reduces the amount of virgin binder required<br />
resulting in less cost and less fuel being used. The results of this<br />
trial are being assessed.<br />
CIAL is about to enter into a 5 year agreement with both<br />
Fulton Hogan and BECA to maximise the value of collaborating<br />
to reduce total cost of ownership in the delivery of APMW at<br />
CIAL. Part of this process is excelling at sustainable innovation<br />
for the benefit of all parties involved.<br />
CIAL is thrilled with the results from these trials. The trials<br />
pave the way for using CoolPave across more taxiway areas and<br />
possible trials on runway areas. CIAL will continue to work with<br />
Fulton Hogan on sustainable innovations within the APMW and<br />
any others areas within the Airport campus.<br />
7. Conclusions<br />
Recent advances have provided methods for the production of<br />
hot-mix asphalts at lower temperatures. These new production<br />
techniques have been termed “warm-mix asphalts” and more<br />
recent developments that further lower production and placement<br />
temperatures, “half-warm asphalts”.<br />
Fulton Hogan has implemented a “half-warm asphalt” technology<br />
under the CoolPave brand. Substantial tonnages of CoolPave-type<br />
half-warm asphalt pavements have been constructed in Europe<br />
and the United States. All evidence suggests that the CoolPave<br />
asphalt is at least as good as conventional hot-mix asphalt, if not<br />
better. Trials in New Zealand support these findings.<br />
There appear to be no technical barriers to the implementation<br />
of the CoolPave “half-warm” asphalt in New Zealand. There are<br />
economic constraints; plant upgrade and chemical costs are not<br />
insignificant. However, as fuel costs continue to rise, the economic<br />
barriers will disappear.<br />
It can sometimes be difficult to demonstrate the benefits of<br />
new technologies to clients. CoolPave is an exception to this; it<br />
is a manufacturing technique, which provides clients with a<br />
product essentially identical to conventional hot-mix asphalt. If<br />
there is a difference it is that the binder is aged less during the<br />
manufacturing processs.<br />
CoolPave half-warm asphalt is a significant advance in asphalt<br />
technology that provides benefits to the environment, the<br />
manufacturing and paving crews, the client and ultimately the<br />
tax-paying public.<br />
It is expected that hot-mix asphalts will be the exception in<br />
only a short time as evidenced by the substantial and enthusiastic<br />
uptake of half-warm asphalts in Europe and the United States.<br />
AAPA TRAINING COURSES FOR <strong>2010</strong><br />
Downloads of the<br />
<strong>2010</strong> program, course<br />
brochures, course<br />
outlines and course<br />
registration information<br />
are available from the<br />
website - www.aapa.<br />
asn.au/Training/AAPA<br />
Training Courses.<br />
If you require further<br />
information about courses<br />
or wish to discuss a<br />
customized course please<br />
contact:<br />
AAPA Training Centre.<br />
Phone: (03) 9853 5322<br />
Facsimile: (03) 9853 5914,<br />
E-mail: trainingcentre@<br />
aapa.asn.au<br />
Web: www.aapa.asn.au<br />
28 ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong>
BITUMEN<br />
STABILISATION IN<br />
SOUTH AFRICA<br />
To understand bitumen stabilisation technology (materials<br />
treated with bitumen emulsion or foamed bitumen), it is<br />
important to know the history of this technology.<br />
BSMs have been used in South Africa for more than 30 years.<br />
The concept of emulsion treatment came to the fore in the<br />
1970s when a newly constructed freeway suffered a catastrophic<br />
premature failure. The failed cemented base material was retreated<br />
with bitumen emulsion and most of those sections are<br />
still in a satisfactory condition today.<br />
The following paper, prepared by DC Collings, Loudon<br />
International, South Africa (davecol@iafrica.com), was also<br />
featured at AAPA’s 13th International Flexible Pavements<br />
Conference.<br />
Condensed version - full version available from Conference<br />
papers 2009 - aapa@asn,com.au<br />
The advent of foamed bitumen in South Africa<br />
During 1993, in pursuit of an alternative to bitumen emulsion,<br />
a Joint Venture (JV) between a large construction company,<br />
a small design firm and a foreign manufacturing company<br />
imported a specialised 400 t/hr foamed bitumen mixing plant<br />
from the foreign company. The mixing plant was duly established<br />
on site in April 1994. The anticipated construction period was<br />
four weeks.<br />
From the outset, everything that could have gone wrong did<br />
go wrong. On the odd occasion when foam was produced, the<br />
resulting bitumen stabilised material allowed the 150mm thick<br />
base layer to be successfully paved. A rudimentary method<br />
for operating the plant was eventually developed, allowing a<br />
satisfactory product to be mixed at an exceedingly slow rate.<br />
Despite this, the road is still in good condition 15 years later,<br />
in spite of the abusive loading it has received from timber<br />
haulage.<br />
Two major benefits did accrue from these expensive lessons:<br />
• foamed bitumen was shown to be a viable and highly<br />
attractive substitute for bitumen emulsion as a stabilising<br />
agent (the product was good, the equipment was flawed);<br />
and<br />
• an in-depth understanding of the problems encountered<br />
when using an expansion chamber to produce foamed<br />
bitumen.<br />
The new “properly engineered” system<br />
Following this project and a short but intensive research<br />
and development effort by the manufacturer’s engineering<br />
design team, the prototype spraybar for producing foamed<br />
bitumen was subjected to a series of trials in Germany in<br />
November 1995. The system was then mounted on a newgeneration<br />
recycler and shipped out to South Africa for<br />
field trials. Six weeks of continuous work followed before<br />
the Germans declared that the system was satisfactory. The<br />
system currently manufactured by this company, some 13<br />
years later, is exactly the same.<br />
Bitumen stabilisation in South Africa<br />
Within a year of completing these trials, four South African<br />
contractors had purchased large recycling machines equipped to<br />
apply foamed bitumen. These contractors quickly identified the<br />
economic advantages to be gained by substituting foamed bitumen<br />
for bitumen emulsion in tenders calling for the construction of<br />
an emulsion treated base (ETB). As a result, several contracts<br />
were awarded in favour of foamed bitumen, in spite of the Road<br />
Authority’s uncertainty as to whether or not foamed bitumen was<br />
indeed as effective as bitumen emulsion.<br />
Subsequent to developing the full-scale system for mounting on<br />
large recyclers, a small laboratory unit was developed to support<br />
the design aspect of this new technology.<br />
TG2 Second Edition and technology development<br />
Following the successful use of foamed bitumen the emulsion<br />
manufacturers supported the development of two documents<br />
through SABITA. However, these imposed a number of<br />
limitations. Subsequently a technical guidelines document<br />
TG2 was developed and released in 2002.<br />
Subsequently experience in South Africa and overseas<br />
highlighted deficiencies in TG2 and work was done to review<br />
those guidelines.<br />
This review took five years to complete with funding<br />
provided by SABITA and Gautrans and the new edition of<br />
TG2 was published in May 2009. It was titled TG 2 Second<br />
Edition, Bitumen Stabilised Materials, A Guideline for the<br />
Design and Construction of Bitumen Emulsion and Foamed<br />
Bitumen Stabilised Materials.<br />
TG2 Second Edition therefore replaces Sabita’s Manuals 14<br />
and 21 as well as the original TG2. Regardless of whether<br />
bitumen emulsion or foamed bitumen is applied as the<br />
stabilising agent, the same mix design and pavement design<br />
procedures are applicable to both and the new method for<br />
classifying BSMs takes no account of which stabilising agent<br />
was used in the mix.<br />
BSM CHARACTERISTICS AND<br />
PERFORMANCE<br />
BSMs are pavement materials that are treated with either<br />
bitumen emulsion or foamed bitumen. The materials treated<br />
are either those recovered from an existing pavement or fresh<br />
materials. Granular materials, previously cement treated<br />
materials or reclaimed asphalt (RA) layers are included.<br />
Where an existing pavement is recycled, old seals or asphalt<br />
surfacing is usually mixed with the underlying layer and<br />
treated to form a new base or sub-base layer.<br />
ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong> <strong>29</strong>
ASPHALT REVIEW<br />
Foamed bitumen<br />
The quantities of residual bitumen emulsion or foamed<br />
bitumen added do not typically exceed 3% by mass of dry<br />
aggregate. In many situations, active filler in the form of<br />
cement or hydrated lime is also added to the mix. The cement<br />
content should not exceed 1%, and should also never exceed<br />
the percentage of the bitumen stabiliser. If more cement than<br />
bitumen is added, then the material should be considered a<br />
cement treated material and the relevant guidelines for such<br />
materials followed.<br />
The addition of bitumen emulsion or foamed bitumen to<br />
produce a BSM results in an increase in material strength<br />
and a reduction in moisture susceptibility as a result of the<br />
manner in which the bitumen is dispersed amongst the finer<br />
aggregate particles. The “non-continuous” binding nature<br />
of the individual aggregate particles makes BSMs different<br />
from all other pavement materials. The dispersed bitumen<br />
changes the shear properties of the material by significantly<br />
increasing the cohesion value whilst effecting little change to<br />
the internal angle of friction. A compacted layer of BSM will<br />
have a void content similar to that of a granular layer, not<br />
an asphalt. BSMs are therefore granular in nature and are<br />
treated as such during construction. The failure mechanism<br />
for BSMs in a pavement structure subjected to repeated axle<br />
loads is permanent deformation, not fatigue cracking. BSMs<br />
are therefore more closely related to granular materials than<br />
to asphalt concrete.<br />
The behaviour of BSMs, relative to other pavement materials<br />
is illustrated in Figure 1.<br />
Condensed version - full version available from Conference<br />
papers 2009 - aapa@asn,com.au<br />
TG2, SECOND EDITION<br />
The research feeding into this publication took five years and<br />
was officially launched in May 2009 at a series of seminars<br />
held in the main cities around South Africa. The attendance<br />
of almost 300 delegates at these seminars was an indication<br />
of the level of interest shown by industry and subsequent<br />
feedback suggested that this technology will be adopted more<br />
widely in future, mainly as a result of a better understanding<br />
of material behaviour (especially the failure mechanism),<br />
coupled with the new simplified design procedures.<br />
Also appreciated was the decision taken to house the<br />
technology on <strong>Asphalt</strong> Academy’s website, allowing the 136-<br />
page manual to be downloaded in pdf format at no cost.<br />
All new and non-standard laboratory test methods for mix<br />
designs are also housed on the website rather than included<br />
in the manual.<br />
Another feature of the website is the inclusion of the<br />
programs for material classification and pavement design.<br />
Although these programs cannot be downloaded, users can<br />
access the website at any time, log on and use the software,<br />
free of charge. Input data and results can, however, be stored<br />
on the individual’s computer.<br />
It is envisaged that this website will receive ongoing<br />
development as more users provide feedback and additional<br />
information is obtained from research initiatives.<br />
The manual introduces the abbreviation BSM for a “bitumen<br />
stabilised material” and incorporates both bitumen emulsion<br />
treated material as “BSM-emulsion” and foamed bitumen<br />
treated material as “BSM-foam”. Regardless of which form<br />
of treatment is adopted, the resulting BSM is regarded as a<br />
generic product from a design and performance perspective.<br />
However, the most important feature of the new design<br />
approach is the direct relationship between the engineering<br />
properties of the materials in the various layer components<br />
and pavement performance.<br />
The new mix design procedures<br />
Figure 2 illustrates the three levels of tests that have been<br />
adopted for classifying the product into one of three BSM<br />
classes. The level of testing required is dictated by the design<br />
traffic (structural capacity requirement); the higher the level<br />
of testing, the greater the level of confidence achieved.<br />
Figure 2. Mix design flowchart Condensed version - full<br />
version available from Conference papers 2009 - aapa@<br />
asn,com.au<br />
TG2 Second Edition classifies BSMs into three classes,<br />
depending on the quality of the parent material, the effectiveness<br />
of stabilisation and the design traffic. The three classes are:<br />
BSM1: This material has a high shear strength<br />
BSM2: This material has moderately high shear strength<br />
BSM3: This material typically consists of soil-gravel and/or<br />
sand stabilised with higher bitumen contents.<br />
Table 1 summarises the boundary values for the various test<br />
results that are the primary indicators used to classify BSMs into<br />
one of three classes. Also shown are the CF values for each test.<br />
The new approach to pavement design<br />
The structural design of pavements in TG2 Second Edition<br />
utilises a knowledge-based approach that uses a Pavement<br />
<strong>Number</strong> (PN) that is based on AASHTO’s Structural <strong>Number</strong><br />
concept. However, the shortcomings of the Structural <strong>Number</strong><br />
method have been addressed in developing this PN method.<br />
This method was based on a plethora of data collected from<br />
numerous in-service pavements where the type and detail of the<br />
data suggested that a relatively simplistic method be adopted<br />
(it also precluded the use of a Mechanistic-Empirical design<br />
approach).<br />
Rules relating to pavement systems/ Rules relating to specific<br />
pavement layers:<br />
Condensed version - full version available from Conference<br />
papers 2009 - aapa@asn,com.au<br />
BSMs are assumed to act in a similar way to coarse granular<br />
materials but with a higher cohesive strength. Although not<br />
confirmed, the cohesive strength is presumed to reduce as a<br />
consequence of repeated loading and thus some softening may<br />
30 ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong>
ASPHALT REVIEW<br />
occur over time. However, such rate of softening is mainly<br />
determined by the stiffness of the support, which determines<br />
the degree of shear in the layer. However, owing to the higher<br />
cohesive strength, these layers are less sensitive to the support<br />
stiffness than unbound granular materials (higher modular ratio<br />
limit).<br />
Table 3 summarises the limits applicable to the modular ratio<br />
and maximum stiffness rules.<br />
Condensed version - full version available from Conference<br />
papers 2009 - aapa@asn,com.au<br />
Designing pavement using the PN method<br />
See full paper - Condensed version - full version available from<br />
Conference papers 2009 - aapa@asn,com.au<br />
The beauty of this method lies in its simplicity. The procedure<br />
commences by defining the pavement structure in terms of layer<br />
thickness and material class for each component layer.<br />
ECONOMIC AND ENVIRONMENTAL<br />
BENEFITS<br />
The benefits of using BSMs in pavement structures were shown<br />
by comparing different options for the rehabilitation of a specific<br />
pavement, each with the same structural capacity. The three<br />
options selected (illustrated in Figure 4) represent different<br />
technologies.<br />
Option 1 calls for the distressed asphalt layers to be removed<br />
by milling, the upper portion of the underlying base repaired<br />
before replacing the asphalt with fresh material.<br />
Option 2 reuses the existing pavement layers, recycled with<br />
cement as a new subbase layer.<br />
Option 3 reuses the existing pavement layers recycled with<br />
bitumen as a new BSM base layer, requiring only a relatively<br />
thin asphalt wearing course. .<br />
Economic comparison<br />
An estimate of the type and extent of maintenance work<br />
during a 20-year service life suggested that the asphalt<br />
surfacing layer would need replacing every seven to eight<br />
years for all options. Being susceptible to moisture ingress,<br />
an extra 35mm thickness of asphalt would be needed for<br />
Option 2 after some 14 years. Then, at the end of the service<br />
life, rehabilitation measures were determined, based on the<br />
failure condition of the various pavements:<br />
Option 1 (failure condition: fatigue cracks through the full<br />
thickness of asphalt over 10% of the length). Rehabilitate by<br />
applying a 60mm thick asphalt overlay plus a new asphalt<br />
surfacing;<br />
Option 2 (failure condition: moisture activated distress<br />
of the graded crushed stone base with potholes affecting<br />
10% of the road length). To be recycled to create a BSM<br />
base layer plus an asphalt surfacing (similar to the original<br />
rehabilitation Option 3);<br />
Option 3 (failure condition: permanent deformation of<br />
20mm in 10% of the total length of wheel paths). This can<br />
be addressed by milling off the asphalt surfacing, paving a<br />
levelling layer (35mm nominal thickness) and replacing the<br />
asphalt surfacing.<br />
Construction costs tend to be country specific and, in<br />
some cases, regional specific. A comparison of construction<br />
costs in money terms is therefore not a satisfactory means of<br />
comparing the three options. Determining the unit cost per<br />
kilometre for the life cycle (rehabilitation to rehabilitation)<br />
and reducing cost to a relative index does, however, provide a<br />
unit free basis for comparison. Accordingly, each option was<br />
priced using average unit contract rates in the South African<br />
construction industry (expressed in US$) and divided by the<br />
cost of Option 1 to obtain an index, as shown in Table 4.<br />
This exercise indicates that recycling with a bitumen<br />
stabilising agent is some 30% more cost efficient than the<br />
other two options where the initial rehabilitation called for<br />
a 20-year service.<br />
Energy consumption comparison<br />
The increased level of awareness of climate change is<br />
making society more aware of energy consumption. The<br />
construction industry is not exempt and several studies have<br />
been undertaken to estimate the amount of energy being<br />
consumed, particularly in the construction of roads where<br />
large machinery is employed and the quantities of material<br />
either consumed or moved is high.<br />
A detailed exercise carried out in New Zealand in 2008<br />
(Reference 8, Patrick) reported on the energy consumption<br />
data for various construction activities. Using this data, a<br />
similar exercise to that carried out above to determine costs<br />
was undertaken to estimate the total energy consumed for<br />
each option over a 20-year period. The results are shown in<br />
Table 5.<br />
This exercise indicates that combined construction activities<br />
over a 20-year cycle are almost 30% more energy efficient for the<br />
BSM option (Option 3) than Option 1 which, in turn, is some<br />
30% more energy efficient than Option 2.<br />
CONCLUSIONS<br />
The publication of TG2 Second Edition has provided a refreshing<br />
new insight into the behaviour of BSMs and introduced a new<br />
separate class of material for use in pavement structures.<br />
In recognising that the end product is similar regardless of<br />
whether the bitumen is applied in an emulsified or foamed<br />
state, this publication has effectively eliminated the conflict<br />
between the bitumen emulsion and foamed bitumen lobbies.<br />
In addition, TG2 Second Edition provides a relatively simple<br />
set of guidelines for the competent design and construction of<br />
pavements that include these materials.<br />
Maximising the reuse of existing pavement materials by<br />
recycling minimises the consumption of new materials,<br />
thereby providing both economic and environmental<br />
benefits. The addition of a bitumen stabilising agent<br />
enhances the performance of the recycled material, providing<br />
both flexibility and durability. Due to their durability<br />
properties, BSMs offer a lower whole-of-life cost through<br />
lower maintenance and other interventions required to<br />
achieve an acceptable level of service over the design life of<br />
the pavement, as well as the cost of rehabilitation when the<br />
terminal condition is reached. The true value of BSMs is only<br />
now starting to receive the attention they deserve. Meanwhile,<br />
environmental considerations are receiving more attention<br />
in the provision of pavements, a long overdue focus brought<br />
about by global concerns over climate change. Increasing<br />
emphasis on the environmental impact of road construction<br />
and rehabilitation has led to sufficient data becoming<br />
available for use in analysis and decision making. Decisions<br />
based solely on initial construction costs will, in future, be<br />
replaced by a more complex model that incorporates both<br />
energy consumption and whole-of-life costs.<br />
32 ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong>
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ASPHALT REVIEW<br />
Smoothness Matters<br />
The US <strong>Asphalt</strong> Pavement Alliance has released a publication “Smoothness Matters”. This emphasises<br />
the importance of well maintained flexible pavements to save costs for the community and reduce<br />
emissions to the environment. It is therefore as relevant to Australia as it is to the US.<br />
The US <strong>Asphalt</strong> Pavement Alliance<br />
(ACA) publication “Smoothness Matters”<br />
comments that pavement smoothness<br />
is a significant determinant of vehicle<br />
fuel economy. That is, the smoother<br />
the pavement, the lower a vehicle’s<br />
fuel consumption. This is as pavement<br />
smoothness affects the rolling resistance<br />
by influencing friction between the tyre<br />
and the pavement.<br />
This makes common sense – the less<br />
rolling resistance, the less energy necessary<br />
to drive a vehicle along the pavement.<br />
However, how much difference can<br />
the pavement smoothness make to fuel<br />
consumption?<br />
Smoothness Matters refers to a full<br />
scale field study conducted – it was a fullscale<br />
field study conducted by the Federal<br />
Highway Administration at the WesTrack<br />
pavement test track in Nevada. This study<br />
indicated that trucks running on slightly<br />
smoother pavement could reduce fuel<br />
consumption by 4.5 percent. Other studies<br />
show similar or sometimes greater fuel<br />
savings with cars running on smoother<br />
pavements.<br />
Studies also show that the savings<br />
are even greater when one compares<br />
the roughest pavements in a highway<br />
network with the smoothest. Some experts<br />
estimate that it is possible to reduce fuel<br />
RoadsJobs consumption 15/6/10 by as 12:40 much PM as Page 10% 1 by<br />
rehabilitating the roughest pavements.<br />
Not only do smoother pavements reduce<br />
fuel consumption, they also reduce vehicle<br />
operating costs and driver fatigue by<br />
minimizing tyre bounce and load impacts.<br />
According to figures developed by the US<br />
Road Information Program (TRIP), driving<br />
on rough roads costs the US motorists $23<br />
billion annually in extra vehicle operating<br />
costs.<br />
Smoother pavements also last longer as<br />
truck tyres roll along the pavement instead<br />
of bouncing on each bump.<br />
Even small bumps, accelerate the rate of<br />
road deterioration. Studies in the US show<br />
that improving pavement smoothness by<br />
25% results in almost a 10% increase in<br />
pavement longevity. This saves taxpayers<br />
money and conserves natural resources.<br />
Keeping a road smooth begins with a<br />
well-engineered foundation and pavement<br />
structure. An asphalt “perpetual pavement”<br />
is designed and built to ensure that the<br />
structure lasts virtually indefinitely.<br />
Routine maintenance is simply a matter<br />
of infrequently milling the surface for<br />
recycling, followed by placing a smooth<br />
new asphalt overlay, a task that can be<br />
done quickly with short road or lane<br />
closures and little impact on traffic.<br />
It has been determined that if the roads<br />
across the US could be made slightly<br />
smoother there would be a saving of at<br />
least 4 percent of the fuel consumed.<br />
This would reduce annual vehicle fuel<br />
consumption by about 7 billion gallons,<br />
equivalent to taking over 10 million<br />
vehicles off the road every year, reducing<br />
fuel and vehicle maintenance<br />
While we don’t use as much fuel as<br />
the US, smoother roads in Australia<br />
would have a significant impact on<br />
fuel consumption. The use of asphalt<br />
pavements is the most effective means of<br />
achieving and maintaining smooth roads.<br />
<strong>Asphalt</strong> surfaces can also be made to<br />
meet a range of requirements such as low<br />
noise, skid resistance and to minimise<br />
water spray and can be readily maintained<br />
at low cost and minimal disruption.<br />
The ACA document can be downloaed<br />
in full from http://asphaltroads.org.<br />
For a full discussion of studies on<br />
this topic, Marks, Howard, PhD. 2009.<br />
Smoothness Matters: The Influence of<br />
Pavement on Fuel Consumption. Hot<br />
Mix <strong>Asphalt</strong> Technology Vol. 14, No. 6,<br />
pp. 18-<strong>29</strong>, available at www.nxtbook.<br />
com/nxtbooks/naylor/NAPS0609/index.<br />
php#/18.<br />
The US <strong>Asphalt</strong> Pavement Alliance is<br />
a joint venture between the US National<br />
<strong>Asphalt</strong> Pavement Association (NAPA), the<br />
US Bitumen Institute and US State <strong>Asphalt</strong><br />
Pavement Associations. APA has just<br />
released a new publication highlighting<br />
the benefits of asphalt pavement, lower<br />
fuel consumption.<br />
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ASPHALT REVIEW<br />
Post Graduate Studies<br />
through Distance Learning -<br />
NEW ENROLLMENTS NOW BEING ACCEPTED<br />
Those of us involved in road construction<br />
understand the very important role<br />
flexible pavements play in our economy<br />
and society. Without high quality flexible<br />
pavements linking communities and<br />
providing all important transport routes<br />
our society would be a lot poorer.<br />
High quality roads are also beneficial<br />
to the environment, reducing the risk<br />
of accidents, lowering noise and even<br />
reducing fuel consumption and wear<br />
and tear on vehicles. The travel time is<br />
also reduced on well constructed and<br />
maintained flexible pavement surfaces.<br />
The Australian flexible pavement<br />
industry has shown that it can produce<br />
world class roads. However, to continue<br />
to do this we must ensure that staff are<br />
well trained. For this reason, AAPA offers<br />
a range of practical and relevant training<br />
courses We also need highly trained<br />
engineers and pavement designers. For<br />
this reason AAPA and Austroads support<br />
the Centre for Pavement Engineer<br />
Education (CPEE) in its offering of post<br />
graduate courses. The following article<br />
highlights the work of CPEE in offering<br />
high quality training through distance<br />
education.<br />
There is a continuing need for increased<br />
capability and knowledge in the work<br />
environment particularly in technical areas<br />
associated with the design, construction<br />
and maintenance of road pavements<br />
and other major infrastructure assets.<br />
Yet there is also increasing pressure on<br />
time and it is frequently not possible or<br />
convenient to undertake study via face to<br />
face courses at universities.<br />
The distance education courses offered<br />
by the Centre for Pavement Engineering<br />
Education (CPEE) provide a unique<br />
and convenient option to learn and gain<br />
relevant knowledge and qualifications<br />
without the need to attend classrooms<br />
CPEE’s targeted distance education<br />
approach is now in its 14th year and<br />
is well regarded by the whole of the<br />
pavement industry, including state and<br />
local government. It is also strongly<br />
supported by Austroads and AAPA.<br />
CPEE offers a Graduate Certificate<br />
of Pavement Technology, Master of<br />
Technology and Master of Engineering<br />
in Pavements, and applications are now<br />
being accepted for these courses for study<br />
period 2, <strong>2010</strong>.<br />
The Graduate Certificate of Pavement<br />
Technology comprises four units. The<br />
LaTrobe University accredited Master of<br />
Technology comprises eight units and the<br />
Master of Engineering in Pavements, 12<br />
units.<br />
In conjunction with the University<br />
of Tasmania and the Institute of Public<br />
Works and Engineering Association<br />
(IPWEA), CPEE has also launched a new<br />
Graduate Certificate in Infrastructure<br />
Asset Management.<br />
This provides a unique and relevant<br />
course directed at infrastructure<br />
managers and those seeking to work in<br />
this increasingly important area. The<br />
significant number of enrolments to date<br />
indicates this new offering has been very<br />
well received and contains the content<br />
practitioners are seeking.<br />
All CPEE courses are very practical<br />
and encourage direct application of<br />
the skills and knowledge acquired. The<br />
application of learning to problems in the<br />
workplace is facilitated by the distance<br />
education format, which does not require<br />
attendance at a university or attend<br />
face-to-face sessions, but encourages<br />
those undertaking courses to apply their<br />
knowledge in their workplace wherever<br />
possible.<br />
With most of the units incorporating<br />
the latest revised Austroads Guides, each<br />
provides up to date technical content.<br />
Units may also be selected to suit the<br />
needs of individuals wishing to update<br />
specific knowledge. This means students<br />
are able to apply what they learn directly<br />
and immediately to their day-to-day<br />
activities, providing benefits to both the<br />
student and the employer.<br />
It is also possible just to undertake a<br />
single unit on a specific topic for those<br />
wishing to gain a focused learning<br />
immediately.<br />
For further information, email info@<br />
pavementeducation.edu.au or visit the<br />
CPEE website www.pavementeducation.<br />
edu.au<br />
36 ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong>
PMS
ASPHALT REVIEW<br />
Focus on spray sealing<br />
As those involved in the flexible pavement<br />
industry in Australia are aware, this<br />
country along with New Zealand and<br />
South Africa, place vast amounts of spray<br />
seal. Indeed most of our rural roads are<br />
spray sealed.<br />
It is therefore appropriate that Australia<br />
hosts an international conference on this<br />
form of surfacing.<br />
Recognising this, ARRB held the first<br />
International Spray Sealing Conference<br />
in Adelaide in 2008. This was an excellent<br />
conference attracting delegates from<br />
around the world. It included delegates<br />
from developing countries where spray<br />
sealing may be an opportunity to provide<br />
safe and reliable surfaces in areas that are<br />
currently not sealed. The conference also<br />
provided an opportunity for Australian,<br />
New Zealand, South African and other<br />
international experts to discuss a wide<br />
range of issues.<br />
The second Sprayed Sealing Conference<br />
is to be held in October this year. AAPA is<br />
a strong supporter of this conference and<br />
the associated ARRB Conference.<br />
2nd International Sprayed Sealing<br />
Conference (10-12 October <strong>2010</strong>)<br />
The 2nd International Sprayed Sealing<br />
Conference will be held at the Sebel Hotel,<br />
Albert Park, Melbourne. The theme of the<br />
Conference is ‘Sustaining sprayed sealing<br />
practice’.<br />
The conference will provide an<br />
opportunity for practitioners and<br />
policy makers to keep abreast of new<br />
developments in sprayed seal design,<br />
material selection and construction<br />
techniques. It will focus on maintenance<br />
of sprayed seal performance in a climate<br />
of increasing expectations and demands,<br />
combined with depletion of known<br />
quality materials.<br />
It will contribute to the continued<br />
development of sprayed sealing<br />
procedures and technologies which<br />
are vital to improving the performance<br />
of a significant proportion of the road<br />
network.<br />
For further enquiries, please contact Ms<br />
Khar Yean Khoo, Technical Secretary - 2nd<br />
International Sprayed Sealing Conference,<br />
at ssc<strong>2010</strong>@arrb.com.au<br />
24th ARRB Conference (13-15<br />
October <strong>2010</strong>)<br />
The 24th ARRB Conference will be held<br />
immediately after the 2nd International<br />
Sprayed Sealing Conference, also at the<br />
Sebel Hotel. The theme of the conference is<br />
‘Building on 50 years of road and transport<br />
research’.<br />
Since their commencement in 1962,<br />
ARRB Conferences have brought together<br />
a broad range of experience and expertise<br />
from Australia, New Zealand and around<br />
the world, creating a stimulating and<br />
thought-provoking setting for discussion<br />
and interchange.<br />
The <strong>2010</strong> Conference will include papers<br />
and discussion under key topics reflected in<br />
the National Transport Strategy including:<br />
• congestion, freight and productivity;<br />
• Safe Systems;<br />
• sustainable infrastructure sciences and<br />
technology; and<br />
• sustainable infrastructure management.<br />
For further enquiries, please contact Ms<br />
Tariro Makwasha, Technical Secretary -<br />
24th ARRB Conference, at 24conf@arrb.<br />
com.au<br />
Registrations are now open. Please visit<br />
the ARRB <strong>2010</strong> Conference website for<br />
updates and to register online www.arrb.<br />
com.au/conferences.<br />
Sponsorship and exhibition<br />
opportunities at both conferences are also<br />
available. Please contact our Sponsorship<br />
Coordinator: sponsorconf@arrb.com.au<br />
or 03 9881 1555, or visit the ARRB <strong>2010</strong><br />
Conference website.<br />
Vacancy – AAPA State Executive Officer<br />
The Australian <strong>Asphalt</strong> Pavement Association was formed in 1969 as a nonprofit<br />
organisation to promote the economic use of asphalt and bitumen bound<br />
products based on sound technical and commercial grounds.<br />
AAPA members include all major participants in the field of asphalt and<br />
bituminous pavements including asphalt producers, spray sealing organisations,<br />
bitumen suppliers and State Road Authorities as well as a wide range of associate<br />
members representing all facets of the industry<br />
The AAPA Board, State Branches and members are supported by a small<br />
national office based in Melbourne headed by the AAPA Chief Executive. The<br />
Queensland, NSW and Victorian Branches are also supported by a Regional<br />
Executive Officer in each of those states.<br />
Due to increasing opportunities in Western Australia, it is proposed to appoint<br />
a Regional Executive in Western Australia (Perth).<br />
This is a newly created position reporting jointly to the Chief Executive and the<br />
WA State Branch Chairman. He or she will be the principal contact for activities<br />
in Western Australia and, with the support of the National Office, will manage the<br />
affairs of the Western Australian Branch.<br />
The successful candidate must have knowledge of the pavement industry and<br />
be able to represent AAPA and its members at all levels of government, industry<br />
and the community. He or she must also be a self-starter with a commitment to<br />
the successfull growth of flexible pavements in Western Australia.<br />
The position may be offered either on a full time or part time basis. For a full<br />
time position the salary is negotiable but is expected to be a package in excess of<br />
$120,000.<br />
Further Information<br />
For a confidential discussion about this position call:<br />
John Lambert, AAPA Chief Executive<br />
Phone (03) 9853 3595 or 0419 822 114<br />
Applications should be marked confidential and sent to<br />
John Lambert Level 2, 5 Wellington St Kew 3101<br />
38 ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong>
Boral <strong>Asphalt</strong><br />
Boral’s LoCarb asphalt<br />
Paving the way towards a more sustainable future<br />
Boral is an industry leader in the manufacture and application of construction<br />
materials and is committed to providing sustainable asphalt solutions.<br />
Boral has introduced a LoCarb asphalt which is the result of many years of<br />
research to satisfy the desire by road authorities and communities worldwide<br />
to use more friendly technologies to preserve and sustain the environment.<br />
These new developments have led to a reduction in the amount of energy<br />
used and green house gases emitted in the asphalt production process.<br />
LoCarb asphalt is achieved by reducing the temperature of asphalt<br />
in manufacturing and application, using a proven ‘warm mix’ technology<br />
while also allowing greater quantities of recycled asphalt to be used.<br />
LoCarb asphalt has excellent long term performance with the additional<br />
benefit of reducing the carbon footprint of road maintenance.<br />
For more asphalt information<br />
visit www.boral.com.au/<br />
asphaltproducts or call:<br />
NSW (02) 8801 2000<br />
VIC (03) 9508 7144<br />
QLD (03) 3268 8011<br />
SA (08) 8425 0400<br />
WA (08) 9451 6466
ASPHALT REVIEW<br />
<strong>Asphalt</strong> in Railway Tracks<br />
The following article has been modified from a European <strong>Asphalt</strong> Pavement Association (EAPA)<br />
paper and is produced with their permission. EAPA is the European industry association representing<br />
the manufacturers of bituminous mixtures and companies engaged in asphalt road construction and<br />
maintenance across Europe. It is also a part of the Global <strong>Asphalt</strong> Pavement Alliance (GAPA).<br />
The feature follows an article produced in the October/November 2009 Roads which provided<br />
information on the use of asphalt in rail construction in the US. Given the rapid growth of rail<br />
demand across Australia, rail authorities and construction companies should consider the many<br />
advantages associated with the use of asphalt as described in these articles.<br />
Introduction<br />
In railway design, as in highway design,<br />
increasing traffic loads and volumes<br />
and particularly the introduction of<br />
high-speed trains, have resulted in the<br />
need for new approaches. In addition,<br />
concern for the environment requires<br />
sustainability to be taken into account in<br />
the design process.<br />
<strong>Asphalt</strong> mixtures have been shown to<br />
provide good technical alternatives for<br />
several elements of traditional railway<br />
construction. In particular, experience<br />
with asphalt in the track superstructure<br />
(the traditional superstructure consists of<br />
the rails, the sleepers, fastenings and the<br />
ballast) and in the sub ballast layer has<br />
shown that these types of construction<br />
are able to fully meet the requirements of<br />
modern railway tracks.<br />
Application of asphalt in railway<br />
construction<br />
The properties of bitumen and asphalt<br />
offer good opportunities in railway track<br />
construction. This has been proven in<br />
various applications, both for heavy<br />
loaded tracks and for high-speed tracks.<br />
The use of asphalt in railway<br />
construction provides a positive<br />
contribution to the bearing capacity of the<br />
structure. It improves both the stability<br />
and the durability of the structure, which<br />
contributes to the reduction in the need<br />
for maintenance. In addition, the use of<br />
asphalt helps to reduce vibration and noise,<br />
and may reduce the total construction<br />
height of the superstructure, which is<br />
of importance in the case of tunnels and<br />
bridges.<br />
Applications of asphalt in railway<br />
construction can be divided between use<br />
as sub-ballast layers and use as full depth<br />
(asphalt) construction, also called the<br />
ballast-less track.<br />
<strong>Asphalt</strong> as sub-ballast layer.<br />
The rail ballast absorbs the train weight<br />
and distributes it from the rails to<br />
the sub-grade, thereby avoiding any<br />
deformation. The railroad can thus keep<br />
its geometrical features.<br />
The rapid decay of the railroad level<br />
which occurs with traditional ballast<br />
construction is mainly due to the<br />
unsatisfactory “fatigue behaviour” of<br />
the ballast and this is mostly due to<br />
embankment settling.<br />
By interposing a semi-rigid layer<br />
(the so-called “sub-ballast”) in the area<br />
between the ballast and the embankment,<br />
the behaviour of the overall structure<br />
is greatly improved. The sub-ballast is<br />
normally laid on a highly compacted<br />
embankment layer.<br />
A railway structure with sub-ballast<br />
works almost exclusively on compression<br />
and, therefore, differs from a traditional<br />
structure. This consequently eliminates<br />
fatigue cracking.<br />
Especially on high-speed tracks,<br />
maintaining levels and profile is of high<br />
importance. This can be achieved by<br />
increasing the stiffness of the structure<br />
to achieve better load distribution to the<br />
ballast and sub-ballast material. This<br />
will prevent an early deterioration of<br />
the rail geometric. In this case the use<br />
of asphalt in a sub-ballast layer can offer<br />
the solution.<br />
The application of asphalt as a subballast<br />
layer will contribute to the<br />
following aspects:<br />
- Bearing capacity<br />
The application of a monolithic layer<br />
(0.1 – 0.2 m) of asphalt, as a sub-ballast<br />
layer will increase the stiffness of the<br />
total structure. The fact that an asphalt<br />
layer is also capable of withstanding<br />
tensile forces gives an extra positive<br />
contribution to this effect.<br />
- Geotechnical stability<br />
The relatively high stiffness of the asphalt<br />
sub-ballast layer will make a positive<br />
contribution to the compaction of the<br />
layers on top of the asphalt layer. This<br />
improves the total stability. So the asphalt<br />
mix sub-ballast contributes to keeping<br />
the railroad geometry unaltered.<br />
- Resistance to vertical deformation<br />
The relatively high stiffness of the asphalt<br />
layer compared to granular material<br />
will lead to less permanent vertical<br />
deformation. The vertical loading<br />
conditions and the relatively short<br />
loading time are relatively small, so there<br />
will be no permanent deformation in the<br />
asphalt layer.<br />
- Drainage<br />
When a layer of dense asphaltic concrete<br />
is used as a sub-ballast layer, optimal<br />
drainage of the total structure will be<br />
realised. The impermeable asphalt<br />
sub-ballast layer can prevent possible<br />
contamination of the sub-structure by<br />
vertical hydraulic transport of mud and<br />
fines.<br />
- Durability<br />
Because of the confinement of the ballast<br />
by the asphalt layer, the ballast layer is<br />
strengthened and deterioration of the<br />
ballast is reduced. The asphalt sub-ballast<br />
layer increases the foundation modulus,<br />
providing a more rigid foundation, with<br />
the effect that there is a reduction of<br />
tension and shearing stress inside the<br />
ballast material, with consequently less<br />
fatigue and less degradation and wear of<br />
the individual aggregate particles.<br />
Because of the low air voids in the<br />
asphalt mix (1 – 3%) and because the<br />
asphalt layer is buried, weather effects<br />
(temperature changes, Ultra Violet<br />
radiation, oxygen) will not affect the hot<br />
mix, so no deterioration (aging) of the<br />
asphalt or bitumen will take place.<br />
40 ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong>
Even if limited deformation of the subsoil<br />
does take place, this will not affect<br />
the asphalt layer because it is capable of<br />
withstanding the deformation without<br />
loosing its integrity because of the viscoelastic<br />
properties of asphalt.<br />
- Noise and vibrations<br />
The mechanical properties of the asphalt<br />
layer will lead to a reduction in the<br />
vibrations and noise produced by passing<br />
trains. The use of modified asphalt<br />
(polymer modified bitumen, rubber<br />
crumb) can further improve the vibration<br />
dampening effect of the sub-ballast.<br />
- The ballast-less track / the direct<br />
application of the sleepers on the<br />
asphalt<br />
For many years there have been<br />
developments aimed at improving the<br />
stability of the traditional rail-track<br />
structure of rail, sleepers and ballast. The<br />
introduction of high-speed trains and<br />
the desire for less maintenance led to the<br />
development of the ballast-less track. In<br />
this form of construction the ballast is<br />
replaced by a rigid monolithic element<br />
that directly supports the sleepers. This<br />
can be achieved by placing the track frame<br />
of rail and sleepers directly on an asphalt<br />
construction.<br />
The most important requirement is<br />
to have a perfectly flat and level asphalt<br />
surface to comply with the narrow<br />
tolerances that are required for rail<br />
level (+/- 2 mm). Modern asphalt laying<br />
machines can fulfil this requirement using<br />
modern levelling equipment.<br />
The advantages of these systems are the<br />
elasticity of the asphalt layer, especially<br />
when polymer modified asphalt is<br />
used, and the ease of construction and<br />
maintenance. Another important factor<br />
in favour of this system is the ability<br />
to carry out minor corrections without<br />
demolishing and reconstructing the base.<br />
Because these systems eliminate the use<br />
of ballast they have the great advantage<br />
of lowering the track base, allowing the<br />
construction of tunnels with smaller<br />
diameter. The first successful application<br />
of the ballast-less tracks dates back to the<br />
beginning of the 1990s, in Germany. Other<br />
experimental tracks have been built since<br />
then, mostly in Germany.<br />
Experiences in Italy and Germany<br />
Italy<br />
The first experience with asphalt mixes<br />
in high-speed railway construction in<br />
Italy date from the early 1970s. Since<br />
then hundreds of kilometres have been<br />
RAIL.ONE. All rights reserved<br />
built and the results have been very<br />
satisfactory with the application of an<br />
asphalt sub-ballast layer contributing<br />
to the stability of the rail geometry.<br />
In particular, at critical points such as<br />
switch points, expansion joints, level<br />
crossings and in areas between concrete<br />
structures (bridges) and embankments,<br />
where dynamic forces are substantial,<br />
the asphalt sub-ballast layer introduced<br />
a remarkable improvement of the<br />
superstructure stability.<br />
The sub-ballast is made up of an<br />
asphalt mix (100-140 mm thickness)<br />
laid by normal paving machines. It has<br />
the typical behaviour and well-known<br />
advantages of visco-elastic materials.<br />
When the asphalt mix solution is<br />
compared with cement mix solutions<br />
for the sub-ballast, the following<br />
advantages are evident in favour of<br />
asphalt:<br />
• reduced use of aggregates due to<br />
the lesser thickness of the asphalt<br />
sub-ballast layer (average 120 mm<br />
thickness compared to at least 200<br />
mm);<br />
• cracks are less likely to emerge;<br />
• there is no need to protect the<br />
finished surface by means of<br />
bitumen membranes or emulsion<br />
spray;<br />
• time for “hardening” is much<br />
shorter.<br />
Experience shows that the presence<br />
of an asphalt sub-ballast layer in<br />
the railway structure also results in<br />
a reduction in noise and vibrations<br />
transmitted to the surrounding<br />
environment and to passengers.<br />
Germany - Solid Railway Trackbed<br />
General Issues<br />
The rail web (rails and sleepers) with<br />
ballast bedding type of construction has<br />
reached a level that is hardly capable of<br />
improvement as a classical construction<br />
method for railway track. Furthermore,<br />
in the case of routes designed for very<br />
rapid passenger traffic, it has been<br />
found that wear and tear takes place<br />
much more quickly than expected<br />
through stone displacement, breakage<br />
and abrasion because of the dynamic<br />
traffic loads on the railway ballast.<br />
As a result, track bed deterioration<br />
occurs more frequently and requires<br />
maintenance work at more frequent<br />
intervals. This maintenance work is<br />
costly and disrupts normal railway<br />
operations.<br />
ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong> 41
ASPHALT REVIEW NEWS<br />
Replacing load-bearing ballast with asphalt was used for the<br />
first time in Germany around 25 years ago, with an asphalt<br />
base course. Since then, seven different systems of the asphalt<br />
construction method have been developed and constructed in<br />
Germany.<br />
Requirements for the asphalt layers<br />
In general, the requirements for the asphalt are determined<br />
by the load type. In the case of the solid railway trackbed,<br />
loading frequency is at a lower level than with asphalt roads.<br />
In contrast, the axle loads, and consequently the wheel loads,<br />
are far higher. On roads, the actual distributed load results<br />
in a wheel load of 5.75 tons for a truck with an 11.5-ton axle,<br />
which works out to around 0.8 MPa for a surface area of<br />
around 710 cm². For railways, however, there is a considerable<br />
load distribution over the rail and the sleeper. The wheel load<br />
of 11.25 tons results in stress on the bottom of the sleeper of<br />
around 0.25 MPa, and thus only around one-third of the load<br />
experienced on roads.<br />
The asphalt needs to be designed to be permanent, flexible<br />
and dense in order to avoid the need for maintenance work<br />
and subsequent improvements. The lifetime of the solid<br />
railway trackbed has been estimated to be around 60 years.<br />
Experience in Germany has shown that asphalt types with a<br />
high binder content and a low void content have proven to be<br />
reliable.<br />
Advantages<br />
The solid railway trackbed laid in Germany to date has been<br />
shown to be very successful due to the reliability of the paving<br />
and by the material-specific characteristics of the asphalt:<br />
• <strong>Asphalt</strong> can be paved without joints due to its visco-elastic<br />
characteristics; stresses arising from the effects of load and<br />
temperature are reduced.<br />
• <strong>Asphalt</strong> can also be used with extreme super-elevation<br />
because no separation arises from the high internal friction<br />
in the paved state.<br />
• <strong>Asphalt</strong> can be paved at a precise tolerance (± 2 mm) due to<br />
its material characteristics.<br />
• Load can be put on the asphalt immediately after it cools<br />
down; shorter construction times are achieved because of<br />
this.<br />
• Corrections in the position that may be needed (e.g. due<br />
to settlement of the embankment) can be quickly and easily<br />
made either by milling off or by putting on another layer.<br />
The preceding article highlights some of the Europe<br />
experience in using asphalt in rail track construction. In<br />
Australia asphalt has not been used, but with the increasing<br />
demands on our rail network and with the construction of<br />
new railways, the Australian Transport industry should look<br />
at the advantages of asphalt.<br />
The use of asphalt in the construction of tram lines also<br />
offers many potential advantages including smoother rides,<br />
lower noise, quick track rehabilitation and maintenance times<br />
and potentially less maintenance of wheels and suspensions.<br />
If there is interest in using asphalt in railways or tramways,<br />
AAPA will consider inviting experts from both Europe and the<br />
US to participate in workshops to discuss the technical and<br />
commercial advantages of this material.<br />
For further information about EAPA and contact details<br />
refer to www.eapa.org<br />
SAMI expands its boundaries<br />
May 5, <strong>2010</strong>, saw the opening of SAMI Bitumen Technologies’<br />
new bitumen import terminal facility at the Port of Brisbane.<br />
The terminal complements the company’s high standard of<br />
product and service delivery, and significantly expands its<br />
reach.<br />
Bulk bitumen is usually imported into Brisbane from Asia<br />
via purpose built ships and the new bitumen storage and<br />
processing terminal facility has a pipeline that connects the<br />
bulk storage tanks to the new general purpose wharf. But it’s<br />
not simply about making the process of unloading and storage<br />
easier.<br />
SAMI’s new import terminal incorporates some of the most<br />
advanced technology of its kind in the world. The facility is<br />
capable of producing a variety of high performance bitumen<br />
grades used in road construction and maintenance, as well as<br />
bitumen product for various industrial applications.<br />
This one-stop import and production approach makes the<br />
terminal one of the most efficient in Australia. It is in addition<br />
to the company’s terminals at Geelong in Victoria and at North<br />
Fremantle in Western Australia.<br />
Pioneering new technologies has been part and parcel of the<br />
SAMI approach to business since the company’s inception 32<br />
years ago. In 1978, it was formed because there was a need to<br />
develop new technology; a way by which a polymer modified<br />
bitumen could be used as a stress absorbing membrane interlayer<br />
under asphalt overlays in road pavements.<br />
SAMI not only succeeded in developing a polymer modified<br />
bitumen for use as a sprayed seal and as an asphalt overlay<br />
binder, but also created a new market in Australia. This was<br />
just the beginning for SAMI and from that starting point<br />
the company focused its resources on developing innovative<br />
road technologies, products and securing other contracting<br />
services.<br />
In 2008, SAMI significantly expanded its global reach beyond<br />
Australia by establishing a formal collaborative relationship<br />
with Colas SA. It was a natural development as SAMI had<br />
been exchanging technical information over the previous 16<br />
years with the French company in what was described at the<br />
time as a ‘long term mutual courtship’.<br />
Interestingly, there were other similarities between the<br />
two companies. Both Colas and SAMI are company names<br />
that have their origin in the innovative products created by<br />
each entity and both companies began life in the pursuit of<br />
a bitumen related solution which led to the creation of those<br />
particular products.<br />
Bulk Bitumen Cargo being off loaded at the General Purpose wharf,<br />
Port of Brisbane<br />
42 ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong>
Part of SAMI Bitumen Technologies Bitumen<br />
Import Terminal<br />
SAMI was named after its first product<br />
– Stress Absorbing Membrane Interlayer<br />
– and Colas, which was established<br />
in 19<strong>29</strong> to specifically develop a new<br />
emulsion technology for road surfacing,<br />
was named after its first product<br />
commonly referred to as ‘Cold <strong>Asphalt</strong>’.<br />
Strategically, the new union was a tour<br />
de force as Colas was already operational<br />
in 40 countries around the globe and<br />
employed around 66,000 employees<br />
across 1400 business units. This further<br />
strengthened SAMI’s reach in terms of<br />
operational geography and technology.<br />
Colas had already earned a reputation<br />
as a leading international player in<br />
bitumen related technology and with<br />
SAMI’s in-house technical expertise and<br />
manufacturing base know-how, it would<br />
prove to be an innovative combination.<br />
The new Port of Brisbane import<br />
terminal is an example of SAMI’s<br />
continuing strategic expansion to ensure<br />
bulk bitumen supply in this region.<br />
The official opening was held at<br />
the Port of Brisbane Visitors Centre<br />
Auditorium and Brisbane’s Lord<br />
Mayor, Campbell Newman, officiated<br />
accompanied by the Deputy Mayor,<br />
Councillor Graham Quirk, and senior<br />
managers of Brisbane City Works. The<br />
official party was welcomed by Mr<br />
Jacques Pastor, Chairman of SAMI’s<br />
Board of Directors, Mr Ian Willis<br />
Brisbane’s Lord Mayor, Campbell Newman<br />
(right) and SAMI’s CEO Ian Willis after<br />
unveiling the commemorative plaque<br />
CEO and General Manager, Mr Azeem<br />
Remtulla.<br />
Representatives of Brisbane City<br />
Council, Brisbane City Works, Port<br />
of Brisbane Corporation, Queensland<br />
Transport and Main Roads Department<br />
and the asphalt industry also attended.<br />
They toured the new terminal after the<br />
opening ceremony.<br />
SAMI continues to expand its scope<br />
with manufacturing plants in Sydney,<br />
Brisbane and Perth. There is also a<br />
new plant on the drawing board for<br />
Melbourne and these bases allow SAMI<br />
to focus on the ongoing development<br />
of new polymer modified bitumen<br />
products, emulsions and other specialty<br />
bitumen products for the Australian and<br />
Asian markets.<br />
To ensure that SAMI maintains its<br />
leading edge within the global bitumen<br />
industry, research and development<br />
are key operational components. For<br />
that reason the company maintains<br />
a comprehensive NATA registered<br />
laboratory with a significant inventory of<br />
bitumen and asphalt testing equipment.<br />
SAMI also regularly conducts trials<br />
of new products with various road<br />
authorities throughout Australia.<br />
A more sustainable future with Boral LoCarb <strong>Asphalt</strong><br />
New developments in asphalt production have led to a reduction<br />
in the amount of energy consumed and green house gasses<br />
emitted when asphalt is produced.<br />
As an industry leader in the supply and application of<br />
construction materials, Boral is committed to providing<br />
sustainable asphalt solutions which ensure superior pavement<br />
performance.<br />
LoCarb asphalt has been developed incorporating the latest<br />
innovations in asphalt technology in an effort to reduce the<br />
carbon footprint of asphalt roads. This has been achieved<br />
largely by reducing the manufacturing and application<br />
temperatures and optimising the use of recycled asphalt.<br />
In some instances, additives are incorporated into asphalt<br />
at normal mixing temperatures to improve or extend<br />
workability. This is done so that the hot mixed asphalt can be<br />
transported longer distances or paved in thinner lifts without<br />
compromising the compaction of the asphalt layer.<br />
When LoCarb is produced, a reduction in mixing<br />
temperature is achieved by lowering the binder’s equiviscous<br />
temperature. This means that the temperature to which<br />
the aggregate is heated to achieve complete coating with<br />
binder can significantly be reduced. An important factor<br />
in this new technology is that temperatures can be lowered<br />
without affecting the workability of the asphalt during its<br />
placement.<br />
During asphalt manufacture the bitumen properties harden<br />
when it is exposed to the heated aggregates in thin films. As a<br />
consequence of the mixing temperature being reduced, less<br />
hardening of the binder takes place which facilitates the use<br />
of reclaimed asphalt pavement (RAP).<br />
The use of RAP in conventional hot mixed asphalt is common<br />
practice but there have been some concerns regarding the<br />
possible impact the use of a high percentage of recycled<br />
asphalt could have on the long term durability of the asphalt<br />
surfacing. With the advent of LoCarb, less aging of the new<br />
binder takes place which comingles with the aged binder in<br />
the RAP to produce a mix with less aged binder overall.<br />
ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong> 43
ASPHALT REVIEW<br />
See Table 1. for a comparison of<br />
typical temperatures (degrees C)<br />
measured on a trial carried out on 10<br />
March <strong>2010</strong> in Queen Street for the<br />
Parramatta Council.<br />
More benefits with LoCarb<br />
“LoCarb is a win-win for the environment<br />
and from a sustainability perspective,<br />
with a simultaneous reduction in energy<br />
consumed and emissions generated<br />
during the manufacturing process,” says<br />
Boral’s <strong>Asphalt</strong> Technology Manager,<br />
Trevor Distin.<br />
There is also a saving in the amount<br />
of non-renewable raw materials such<br />
as bitumen and aggregates required to<br />
produce asphalt.<br />
The benefits of using LoCarb asphalt<br />
extend further than those already<br />
mentioned.<br />
“The lowering of application<br />
temperatures means that we are now<br />
able to achieve the same, if not better,<br />
compaction and production rates in the<br />
field. This is because the mix compacts<br />
more uniformly and allows us to open it<br />
to traffic sooner,” Mr Distin says.<br />
“On a recent job the temperature was<br />
measured behind the paver for both a<br />
traditional hot mix and LoCarb asphalt<br />
using an infrared thermal imaging<br />
camera. The temperature readings<br />
recorded across the mat supported our<br />
belief that there was far less variation<br />
for LoCarb than hot mixed asphalt<br />
and this is a key factor to achieving a<br />
uniform density in the mat after final<br />
compaction.”<br />
The temperature profile measured by<br />
Thermovision Services across the mat<br />
behind the paver for HMA vs LoCarb.<br />
There is also a significant reduction<br />
in fumes and odours generated because<br />
LoCarb is produced and placed<br />
below the fuming temperature of<br />
bitumen. Bitumen typically fumes at a<br />
temperature around 135 degrees C and<br />
the rate of fuming doubles with every<br />
10 degree increase in temperature.<br />
This helps improve the quality of air<br />
for people living within the vicinity of<br />
an asphalt plant and for the asphalt<br />
workers placing LoCarb.<br />
LoCarb Trials<br />
Since the first trial section in 2006, Boral<br />
has placed LoCarb on many streets<br />
across Australia. In 2009 an extensive<br />
trial was undertaken on the Deer Park<br />
bypass with the properties of the mix<br />
thoroughly evaluated. Further trial<br />
sections of LoCarb were placed on the<br />
Hume Highway in Melbourne in April<br />
this year as part of the national Warm<br />
Mix <strong>Asphalt</strong> validation project organised<br />
by AAPA in conjunction with all the State<br />
Road Authorities.<br />
Laboratory tests carried out to date<br />
have shown that the performance of<br />
LoCarb is on par with that of hot mixed<br />
asphalt. LoCarb technology is also very<br />
versatile and can be applied to most<br />
mixes from wearing course to base<br />
courses.<br />
On a recent job in Perth, 2000 tons of<br />
LoCarb was placed on the Great Eastern<br />
Highway as a patching material because<br />
Main Roads Western Australia wanted a<br />
mix that could be trafficked immediately<br />
after it was placed and compacted.<br />
Given the benefits to both the<br />
environment and the road provider<br />
there is a compelling argument that<br />
LoCarb should be considered as an<br />
asphalt material of first choice for your<br />
next road project.<br />
Plant LoCarb Hot mixed<br />
asphalt<br />
<strong>Asphalt</strong> temperature directly after mixing 138 172 34<br />
Stack temperature 103 119 16<br />
Paving Site<br />
<strong>Asphalt</strong> temperature in the truck at site 105 137 37<br />
<strong>Asphalt</strong> temperature behind the paver 90 116 26<br />
difference<br />
FULTON HOGAN PAVES<br />
THE ROAD TO SUCCESS<br />
Fulton Hogan, a Trans–Tasman leader in<br />
the construction and asphalt industries<br />
is using its Astec plant and equipment<br />
as an advantage to build a multi-million<br />
dollar road project in South Australia –<br />
possibly the state’s largest.<br />
To ensure that it was equipped to<br />
deliver on the project’s tight product<br />
specification and aggressive productivity<br />
targets, Fulton Hogan engaged Astec<br />
Australia to establish a modern asphalt<br />
production facility and paving equipment<br />
for the Northern Expressway Project<br />
(NEXY)<br />
The project is a 23 kilometre route that<br />
will connect key areas of metropolitan<br />
Adelaide and is considered a “benchmark<br />
for modern road construction in<br />
Australia”.<br />
From the start, Astec Australia worked<br />
in a partnering type relationship with<br />
Fulton Hogan, to understand and provide<br />
solutions for its exact project needs.<br />
A few years ago Fulton Hogan used<br />
Astec’s plant and equipment with great<br />
success on its high profile Eastlink<br />
Project in Victoria, so with those good<br />
experiences fresh in its mind, Fulton<br />
Hogan didn’t hesitate to engage Astec<br />
in the supply of a T200 M Pack Double<br />
Barrel <strong>Asphalt</strong> Plant, a SB1500 Material<br />
Transfer Vehicle and a RP 190 Roadtec<br />
Highway Paver.<br />
Astec Australia provided a ‘turnkey’<br />
solution for Fulton Hogan. Fulton Hogan<br />
provided the hard stand area, gas and<br />
power and Astec Australia did the rest.<br />
Through its partnering arrangement with<br />
Fulton Hogan, Astec constructed the civil<br />
works for the plant site, and then used its<br />
in house expertise to manufacture, ship,<br />
install and commission the T200 Double<br />
Barrel <strong>Asphalt</strong> Plant equipped with<br />
Warm Mix and 50% RAP Technology.<br />
To handle the project’s productivity<br />
demands and the need for providing<br />
various mix types on any given day,<br />
Fulton Hogan opted for Astec’s Long<br />
Term Storage Silos. Three 150 tonne silos<br />
provide Fulton Hogan with the ability to<br />
store 450 tonnes of hot mix for 72 hours<br />
without loss of temperature or quality.<br />
Fulton Hogan has used the storage<br />
system to great advantage, increasing its<br />
productivity through those short winter<br />
Table 1<br />
44 ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong>
days in South Australia to over 2500<br />
tonnes per day.<br />
Fulton Hogan, whose Australian<br />
headquarters are based in Melbourne,<br />
is a major civil contracting company<br />
which offers services in civil<br />
contracting, construction, infrastructure<br />
maintenance, quarrying and asphalt<br />
production and surfacing.<br />
The company’s <strong>Asphalt</strong> Manager<br />
NEXY Project, Morrie Deller, says the<br />
Astec equipment has enabled Fulton<br />
Hogan to manufacture more than<br />
400,000 tonnes since February 2009,<br />
and the project is on track for early<br />
completion in August – four months<br />
ahead of schedule.<br />
“Astec drives us to that high quality<br />
of performance maintenance. We have<br />
had very, very little down time on this<br />
project due to break down,” he says.<br />
“It gives us the most state-of-the-art<br />
plant in the world. These double barrel<br />
drum plants are top of the tree from a<br />
technology point of view.<br />
“There are very minimal issues with<br />
EPA – we can recycle material from the<br />
works back into the works so there is<br />
minimal waste.”<br />
Mr Deller, who brought the first Astec<br />
plant into Australia in 1996, is one of<br />
the most familiar in the country with<br />
the brand.<br />
“On this job we’ve got silos for asphalt<br />
storage where we can hold more than<br />
400 tonnes of product for several days<br />
and we’ve got four bitumen kettles of<br />
about 50 tonnes each,” he says.<br />
“With Astec, it is the fact that they do<br />
the whole deal. They’ll put it all together<br />
for you.<br />
“We buy Astec equipment because it<br />
performs and because of the back up<br />
that we get from Astec in Brisbane.”<br />
Astec Australia General Manager,<br />
David Smale, says the challenge for<br />
Astec Australia since it acquired Q-Pave<br />
in 2008 is to not only demonstrate to<br />
industry that standards haven’t dropped<br />
but to exceed expectations.<br />
He says the contract with Fulton<br />
Hogan is one of Astec Australia’s biggest<br />
deals in relation to a relocatable plant<br />
and project equipment.<br />
“The NEXY Project is up there with<br />
some of the largest infrastructure projects<br />
in Australia, and in terms of being on time<br />
and being commissioned on spec, the<br />
delivery of the asphalt plant was certainly<br />
extremely important,” he says.<br />
“We worked with Fulton Hogan’s site<br />
people to have the whole site prepared.<br />
When building a plant there are 45<br />
trailers of structures and equipment. We<br />
bring them in, in sequence, and as we<br />
take them off the trailers we stand them<br />
all on the concrete pads and everything<br />
is set out while people set it up. “Our<br />
business is fortunate to have a very<br />
capable service team, which had the<br />
whole plant standing in seven days and<br />
commissioned in 28 days – for a plant of<br />
this size that is pretty impressive”<br />
When work is finished on the NEXY<br />
project, the equipment is expected to be<br />
relocated.<br />
David Smale says his company focuses<br />
and delivers on the after sales service and<br />
support that Fulton Hogan requires to<br />
ensure their NEXY project is successful.<br />
Mr Smale says the relationship with<br />
Fulton Hogan began a number of years<br />
ago and included work on the 600,000<br />
tonne EastLink project in Melbourne.<br />
“That proved to be a successful<br />
relationship in terms of Astec Australia<br />
providing solutions in asphalt plant<br />
installation and maintenance,” he says.<br />
“It gives the customer that complete<br />
confidence he won’t have any dreaded<br />
down time – I may not have this number<br />
exactly right, but I am told by Fulton<br />
Hogan that they only had 13 hours of<br />
down time on their Nexy Project during<br />
its two-years of construction.“<br />
Australian <strong>Asphalt</strong> Pavement<br />
Association Queensland Executive, Rob<br />
Vos, says that the NEXY Project is one<br />
of South Australia’s largest infrastructure<br />
projects and is designed with deep<br />
lift asphalt pavement. South East<br />
Queensland has a number of these types<br />
of full depth asphalt projects which are<br />
a good design solution for long lasting<br />
pavement.<br />
Mr Smale says Astec’s “first and<br />
foremost” strategy is to maintain and<br />
improve on its core asphalt business,<br />
and to help the industry itself improve<br />
the market by providing solutions for<br />
sustainability. Astec Australia will also<br />
work on capitalising on its relationship<br />
with Astec’s Aggregate and Mining Group<br />
of companies and their products to<br />
develop the aggregate arm of its business<br />
in Australia.<br />
ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong> 45
ASPHALT REVIEW<br />
New paver constructs<br />
or rehabilitates<br />
VÖGELE’s SUPER 3000-2 tracked paver<br />
features “dash 2” technology which makes<br />
it a top class paver in terms of performance,<br />
technology and ergonomics.<br />
With a laydown rate of up to 1,600<br />
tonnes per hour and pave widths up to<br />
16m, large-scale construction projects<br />
can be completed in the shortest possible<br />
time and large widths can be paved<br />
without joints.<br />
Paving bituminous and nonbituminous<br />
mixes<br />
The modern technical concept<br />
underlying the SUPER 3000-2 allows<br />
road construction and civil engineering<br />
contractors to cover an extremely<br />
wide range of paving applications. The<br />
laydown rate means its is capable of<br />
paving large quantities of mix to the<br />
highest quality standards.<br />
This is not merely a theoretical value,<br />
as the technical parameters for material<br />
handling prove. The paver comes with a<br />
material hopper holding 17.5 tonnes. The<br />
conveyor tunnel is 1.62m wide and 40cm<br />
high.<br />
Combined with conveyors, for which<br />
separate hydraulic drives are provided, and<br />
high-performance augers, large quantities<br />
of mix can be transferred in front of the<br />
screed in the shortest possible time.<br />
The tracked SUPER 3000-2 leads of the<br />
world’s largest fleet of road pavers.<br />
Heavy-duty equipment for very<br />
abrasive materials<br />
High material throughput is important<br />
not only when building asphalt<br />
pavements up to 16m wide without<br />
joints. It is also important for sub-base<br />
paving jobs where large quantities of<br />
non-bituminous materials are involved.<br />
SUPER 3000-2 is ideally equipped for<br />
this kind of work. The bottom plates of<br />
the conveyors and the return pulleys<br />
for conveyor chains are highly wearresistant,<br />
even in the standard version.<br />
If the machine is used primarily for<br />
sub-base and base course construction,<br />
a Heavy-Duty Kit is available as an<br />
option, which effectively counteracts<br />
abrasive wear with reinforced guards<br />
for the conveyor tunnel and the chassis,<br />
and modified auger blades.<br />
With a laydown rate of 1,600t/h and pave<br />
widths up to 16m, large-scale construction<br />
projects can be completed within a short<br />
period of time.<br />
PowerPack for the SUPER 3000-2<br />
The VÖGELE machine comes with a<br />
powerful drive system for tough jobs.<br />
The paver is powered by an ultramodern<br />
6-cylinder DEUTZ diesel engine type<br />
TCD 2105 V06 4V with a maximum<br />
power output of 300kW at 1,800 rpm.<br />
Fuel consumption is very low compared<br />
to other large pavers in this class,<br />
amounting to no more than 217g/kWh.<br />
Like all “dash 2” generation pavers,<br />
SUPER 3000-2 can also be operated<br />
in “ECO Mode” to further reduce fuel<br />
consumption and noise levels (282kW<br />
at 1,500 rpm). With a capacity of 600<br />
litres, the paver’s fuel tank is big enough<br />
to see it through long working days.<br />
The paver is equipped with a<br />
high-performance transfer gearbox,<br />
supplying all hydraulic systems with<br />
exactly the power needed for the job in<br />
hand. The generator is directly flanged<br />
to the transfer gearbox, which provides<br />
for a maintenance-free drive. The high<br />
generator output guarantees rapid<br />
electric screed heating.<br />
High power requires optimum cooling.<br />
VÖGELE traditionally install an efficient,<br />
low-noise cooling system. SUPER 3000-2<br />
VÖGELE offer a Heavy-Duty Kit (option) for<br />
particularly abrasive applications. The kit<br />
includes wear-resistant, reinforced guards<br />
for the conveyor tunnel and modified auger<br />
blades to counteract abrasive wear.<br />
is equipped with a cooler assembly for<br />
engine coolant, charge air and hydraulic<br />
oil, making it WAT-compliant and allowing<br />
it to be used without restrictions in all<br />
climate zones.<br />
SUPER 3000-is equipped with the latest<br />
version of the ErgoPlus® operating concept<br />
featuring a high-contrast display.<br />
The ErgoPlus® operating concept<br />
SUPER 3000-2 is equipped with the<br />
latest version of the ErgoPlus® operating<br />
concept featuring a high-contrast display.<br />
All information is clearly legible on the<br />
display panel.<br />
The ErgoPlus® concept is made up of<br />
several components focusing on clearly<br />
structured operating consoles allowing the<br />
user to quickly learn and access all machine<br />
functions. Four different operating modes<br />
can be selected at the push of a button:<br />
“Neutral”, “Job Site Mode”, “Positioning<br />
Mode” and “Pave Mode”. A “Memory”<br />
feature stores last settings when exiting<br />
“Pave Mode” and settings are retrieved<br />
automatically after the paver’s move on<br />
the job site.<br />
The system also guarantees an<br />
unobstructed view of all vital points on the<br />
paver. Everything is within the operator’s<br />
field of vision.<br />
New SB 300-2 Fixed-Width Screed<br />
for pave widths up to 16m<br />
A new SB 300-2 Fixed-Width Screed has<br />
been developed to match the SUPER<br />
3000-2 paver’s wide range of applications.<br />
The screed can be built up to pave widths<br />
up to 16 metres. The screeds are ideal for<br />
high-quality paving in constant widths. For<br />
jobs requiring paving in varying widths,<br />
hydraulic bolt-on extensions (HE) are<br />
available. The hydraulic extensions allow<br />
variation of the pave width within a range<br />
of 0.75m on either side of the screed.<br />
A new SB 300-2 Fixed-Width Screed can be<br />
built up to a maximum pave width of 16m.<br />
46 ROADS JUNE <strong>2010</strong>/JULY <strong>2010</strong>
VÖGELE VISION 5103-2<br />
FEATURING HIGH POWER AND SUPERIOR<br />
COOLING AND OPERATING SYSTEMS<br />
8-Foot Class<br />
Superior Technology<br />
Provides cool and quiet operation<br />
Large Fuel Tank<br />
Holding 250 liters<br />
Electronic Traction Management<br />
Ensures optimum tractive effort<br />
High Horsepower Tier III CUMMINS Engine<br />
127kW at 2,000 rpm<br />
ErgoPlus ® Operating Concept<br />
For simplicity and unobstructed operator visibility<br />
Very Narrow Conveyor Chain Guard<br />
Provides uniform flow of mix<br />
ROAD AND MINERAL TECHNOLOGIES<br />
www.wirtgen-group.com<br />
JOSEPH VÖGELE AG<br />
Joseph-Vögele-Straße 1 · 67075 Ludwigshafen, Germany<br />
Telephone: +49 (0)621 8105 0 · Telefax: +49 (0)621 8105 461<br />
E-Mail: marketing@voegele.info<br />
WIRTGEN Australia Pty Ltd<br />
2-12 Sommerville Circuit · Emu Plains NSW 2750<br />
Telephone: +61 2 4735 2699 · Telefax: +61 2 4735 6711<br />
E-Mail: sales@wirtgen-aust.com.au