SCIENCE AND TECHNOLOGY OF POLYMERIC SOIL STABILIZERS: FROM KILOMETERS TO NANO-METERS
Mojtaba (Babak) Abtahi1, Mariam Darestani2
1.
GRT(Global Road Technology), Brisbane, QLD, Australia
2.
Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD , Australia
Research on rapid soil stabilisers was initiated by military and dates back to World War II. This technology is now available for civilian
applications and wide range of new materials are now being used to seal road. In most of these techniques, traditional materials such as
lime and cement are being replaced with polymers. Traditional materials have been studied comprehensively and the science behind their
interaction with soil is understood. On the other hand, wide range of polymers have been used by a trial and error approach and for most of
the engineers it is not clear how these polymers work and what affects their performance.
It is reported that polymeric stabilisers can reduce road construction significantly by creating durable road foundations that can be built
several times quicker in comparison with traditional road. Our earlier research showed that performance of polymeric soil stabilisers is a
function of soil properties, polymer formulation and environmental factors. It is also believed that not only final properties of soil stabilizers
are dependent to soil type and characteristic, but also, performance of polymers can be undermined if the right polymeric formulation is not
selected for a specific soil type or climate.
In present study, we review polymeric soil stabilisers and the quest for finding the “magic Juice”. The latest polymeric stabilisers are then
introduced and a case study is presented. Performance of these polymers in a field test are correlated with the results of experiments in
laboratory scale. Mechanism of soil/polymer interaction in nano-scales is investigated using advanced technologies. These results show that
polymeric soil stabilisers can be engineered at molecular scales to achieve desired high performance in mega-scales.
A JOURNEY TOWARDS GREENER PAVEMENTS: HOW THE SURFACING INDUSTRY IS REDUCING GLOBAL CO2 EMISSIONS, NOW AND
INTO THE FUTURE.
Keith Allilomou1
1.
Downer Group, Port Melbourne, VIC, Australia
This paper provides an overview of the key initiatives enacted or underway within the Bituminous Surfacing industry that are working to
improve the overall sustainability of pavements and transport.
Various emission data sources and assessment tools (including Carbon Gauge, and various International studies) are evaluated and
combined with industry expertise to present a straightforward benefits assessment of developments in surfacing sustainability.
These initiatives, which include the increased use of RAP, reclaimed material use (such as crushed glass or Downer’s Tonerpave product),
and improvements in the production process, are evaluated in the context of the broader pavement life cycle and use.
This not only demonstrates the notable advancements made over the past twenty years, but also serves to highlight the importance that
‘pavement efficiency,’ as seen by the road user, will play in continuing our drive on green pavements.
NEW GENERATIONS OF CHIPSEAL (SPRAYSEAL) SURFACES FOR WATERPROOF AND RESILIENT ROADS USING EPOXY-BITUMEN
BINDERS.
Steve Bagshaw1, Phil Herrington1
1.
Opus Research, Lower Hutt, New Zealand
Chipseal road surfaces suffer from a wide range of limitations. At Opus Research we are investigating the next generations of binder
materials for the preparation of waterproof and resilient chipseals. One of the more promising candidates is epoxy-modified bitumen (EMB).
Our initial results suggest that EMB materials offer significant potential for providing improved performance of chipseals and significantly
improved value through increased longevity, chip retention and resistance to water ingress. A novel wheel tracker strategy showed that the
EMB chipseals were significantly more resilient than a range of three different penetration grade bitumens, so much so that the chipseal
layer supported itself against rutting, chip rollover and bitumen tracking. Chip adhesion studies using a modified Vialit plate adhesion test
demonstrated improved adhesion of chips and fines to the EMB over standard bitumen under a variety of conditions, including purely wet
conditions, without any additional adhesion agent. Film cohesion studies using an in-house designed apparatus have shown significant
differences over standard bitumen. We will describe our latest experimental strategies and present our results, and discuss implications for
introduction of EMB onto the roading network.
ANALYSIS OF THE TEMPERATURE PROFILE OF A DEEP LIFT ASPHALT PAVEMENT IN BRISBANE
Andrew Beecroft1, Laszlo Petho1, Erik Denneman1
1.
ARRB Group Ltd, Albion, QLD, Australia
As a part of the Queensland Enrobés à Module Elevé Class 2 (EME2) asphalt trial, a section of pavement in Brisbane was instrumented with a
number of temperature sensors. The sensors are providing pavement temperatures to a data-logging weather station, which also records
air temperature, solar radiation, rainfall, relative humidity and wind. This allows for a comprehensive summary of the weather parameters
and how they relate to the pavement temperature, and ultimately the performance, of asphalt pavements at various depths. At the one year
mark of monitoring these sensors, a comprehensive climate record at this site has been recorded, and a summary of pavement
temperatures over this year reveals a number of important observations.
A detailed distribution of asphalt temperatures at depth in Australian conditions will allow for a better informed design of asphalt
pavements. Two practical applications of this data set have been explored. The first matches the temperature profile with a traffic
distribution and provides a comprehensive matrix of the predicted damage to a pavement over one year at various times of day. The second
application provides a relationship between pavement temperature and the distribution of stiffness in asphalt layers. Both analyses
provides a more comprehensive insight into the behaviour of full-depth asphalt pavements. The implications of this study are that pavement
design will be better informed, allowing for more economic and efficient designs, and driving better value pavements that are specifically
tailored to the climate at a given location.
COMPACTION CHARACTERISTICS AND PERFORMANCE OF WARM MIX ASPHALT
Ambika Behl1, Satish Proff Chandra2
1.
Central Road Research Institute, New Delhi, DELHI, India
2.
Civil Engineering Department, Indian Institute of Technology , Roorkee, Uttrakhand, India
Compaction plays a very important role in the performance of hot mix asphalt (HMA) pavement. Most premature failures of asphalt
pavement are concerned with poor compaction. High quality compaction improves the bearing capacity, temperature stability and durability
of the pavement. This paper focuses on the laboratory investigation of the compaction characteristics and performance of warm mix asphalt
(WMA) using three different warm mix asphalt additives. Viscosity grade bitumen and polymer modified bitumen were used for this study
and the WMA additives used in this study were Evotherm J1, Rediset WMX and Sasobit. Viscosity tests of bitumen blended with the wma
(warm mix asphalt) additives indicated that these additives had a limited effect on viscosity reduction. Addition of Sasobit showed some
reduction in the viscosity of the base bitumen binders, whereas Evotherm J1 and Rediset WMX did not showed noticeable change in the
viscosity of the base bitumen binders. Investigation of the ease of compaction showed that the asphalt mixtures containing warm mix
additives allowed the compaction at lower temperatures and the design percentage of air voids of HMA were achieved for WMA in lesser
number of Marshall Blows. Data obtained from retained marshal strength test, indirect tensile strength test, static and dynamic creep test
showed that the mixes containing warm mix asphalt additives performed better in comparison to hot mix asphalt. Warm mix asphalt
samples showed lesser total permanent strain accumulation in comparison to hot mix asphalt samples, Sasobit modified warm mix asphalt
samples showed the least deformation.
THE PERFORMANCE OF A HIGHLY MODIFIED ASPHALT FOR HEAVY DUTY PAVEMENTS
Krzysztof Blazejowski1, Jacek Olszacki2, Hubert Peciakowski2
1.
R&D Dept., ORLEN Asfalt, Plock, Poland
2.
PKN ORLEN, Plock, Poland
The Highly Modified Asphalts (HiMA) are the new class of binders for paving applications. Based on a new Kraton developed polymers a new
family of binders has been developed in ORLEN Asfalt - hard (EN 25/55-80, PG 94-22), middle (EN 45/80-80, PG 82-28) and soft (EN 65/105-80,
PG 76-28). All binders were tested according to very wide test program, contained European (EN) and Superpave binder tests and hot-mix
basic testing - rutting and low temperature cracking with TSRST method. Results confirmed superior performance of tested binders and
their very positive influence on hot-mixtures. All tested properties have been improved. The paper presents tests results and analysis of
HiMA with comparison to conventional paving grade binders and polymer modified binders.
TEMPERATURE AND TRAFFIC SPEED EFFECTS ON ASPHALT PAVEMENT RESPONSE AND THE ELASTIC ASPHALT MODULUS
Didier D Bodin1, Erik E Denneman1, Olivier C Chupin
1.
ARRB, Vermont South, VIC, Australia
This paper provides theoretical basis with regard to the influence of temperature and traffic speed on pavement response and equivalent
asphalt resilient response. The effect of rolling wheel loads has been studied, using a viscoelastic pavement response to load model which
also includes asphalt temperature dependency. The responses of the asphalt layer for typical Australian temperatures have been computed
under speeds between 30 to 100 km/h. Both the modelled pavement deflection and asphalt strains exhibited dependency with temperature
and loading speed.
From the calculated strains at the bottom of the asphalt layer, an equivalent elastic modulus of the asphalt layer is determined. This
modulus can be used in a linear elastic pavement model and will lead to the same critical strain at the bottom of the asphalt layer under a
static load. The study confirmed previous findings and the equivalent modulus is dependant of the pavement structure (asphalt thickness
and underlying layers thickness).
The relative effect of asphalt temperature and traffic speed from the model was found consistent with the relationships used in the
Austroads guide used for pavement thickness design.
RWELAST®E : A SBS AND BITUMEN BASED ADDITIVE IN GRANULE FORM, FOR THE MODIFICATION OF ASPHALT CONCRETE MIXES
WITH SUPPLY CHAIN OPTIMIZATION.
Olivier Body1, Arnaud Claude1, Philippe Druot1, Marie Grange1, Serge Krafft2, Frédéric Loup2
1.
Roadway Solutions, Saint Pal De Mons, HAUTE LOIRE, France
2.
Central Binder Laboratory, Eiffage Travaux Publics, Corbas, Rhône, France
RWelast®E is an innovative and high performing additive in granule form, composed of pure bitumen and high content of elastomer SBS
(Styrene-Butadiene-Styrene). This product is used for the modification of asphalt concrete mixes and is ready-to-use by direct addition in the
coating plant mixers. RWelast®E granules can be added in both batch or continuous mixing plants without productivity loss.
Innovation and supply chain optimization:
RWelast®E is a new generation of Polymer modified Bitumen (PmB) avoiding the need to use binder plants. It also has many advantages
compared with traditional PmB : the supply is quicker and the quantity adapted to the performance required and the size of the job site. The
granules are ready-to-use : easy to transport, store, dose and handle.
High performing additives:
Adding RWelast®E is a solution to enhance the thermomechanical properties of asphalt concrete mixes and to improve long lasting surface
characteristics. Tests in laboratory were performed according to European Standards. They prove that the asphalt concrete mixes modified
with RWelast®E offer better resistance to rutting, thermal cracking and fatigue, in the same way as PmB. The modification of asphalt
concrete mixes with RWelast®E was performed in both continuous and batch plant mixers, in several sites. Asphalt mixes were mainly
implemented in wearing courses (continuous and open-graded asphalt concrete) in many job-sites (high level traffic trucks, round-abouts,
mountain motorway and tropical highways). After the manufacturing, a systematic monitoring of the asphalt concrete mixes modified with
RWelast®E granules was performed to check binder and SBS contents, and the grading curve. Then, microscopic analysis were led to
confirm the effective distribution of elastomer into the mixes.
PUTTING IT INTO PERSPECTIVE! AN INSIGHT TO AAPA’S “ASPHALT PAVEMENT SOLUTIONS – FOR LIFE” PROJECT. COMPLEX AND
RIGOROUS RESEARCH UNLOCKING SIMPLE BUT VITAL COMMUNITY BENEFITS FOR AUSTRALIA.
Dougall Broadfoot1
1.
Australian Asphalt Pavement Association, Parramatta, NSW, Australia
This paper provides an overview of the history, current status and projected deliverables of AAPA’s “Asphalt Pavement Solutions – for Life”
project, set in the context of the shared (and largely common) strategic objectives and values of all AAPA members and their stakeholder
groupings.
In lay terms, it covers the genesis, process of implementation and the outcomes of the project. It describes the linkages within the journey to
the vision and strategies of the industry participants driving it forwards and observes the alignment of the project with complementary
technology initiatives of the industry during the period.
It summarises the nature and extent of the compelling community benefits enabled by the project and the course to their realisation.
PAVEMENT ENGINEERING SERVICE LINE LEADER GHD IMPROVEMENTS IN ASPHALT SPECIFICATIONS AND CONSTRUCTION PRACTICES
IN THICK LIFT ASPHALT PAVEMENTS IN WESTERN AUSTRALIA
Russell Clayton1
1.
GHD, Hillarys, WA, Australia
Close to $2 billion dollars of major road construction in Western Australia over the last seven years has led to significant advances in the
design manufacture and construction of thick lift asphalt pavements. As each project progressed opportunities were identified for
improvements. After the fact investigations, lessons learnt investment in overseas studies and literature reviews indicated that further
improvements were required. Investigations into the performance of previous projects identified the presence of water in the pavement
structure despite considerable effort to build them in the dry.
The introduction of a new class of bitumen to Western Australia, and significant changes in specifications and construction practices led to a
marked improvement in the quality of the finished product and an $8.0 million dollar saving in asphalt costs.
Delivery contracts that are conducive to collaboration between the Client, Designer, Contractor, subcontractor and supplier was a key
element to the collaborative manner in which these outcomes were achieved in a relatively short period of time
This paper describes the processes that were followed that led to the Gateway WA project being a ground breaking innovative project in
terms of asphalt technology in Western Australia.
A NEW ERA IN SUSTAINABLE ROAD CONSTRUCTION USING ASPHALT IN WESTERN AUSTRALIAN
Russell Clayton1, Ryan Jansz2
1.
GHD, Perth, Western Australia, Australia
2.
Boral Asphalt, Port Melbourne, VIC, Australia
Great Eastern Highway upgrade in Western Australia was constructed with sustainability as one of its significant key performance indicators.
The City East Alliance undertook to explore as many sustainable opportunities to construct the project.
In the design phase there was significant corporation to establish practical inputs for pavement design based on production mix data, while
the opportunity for novel technologies was investigated.
The client had serious concerns about asphalt stripping and so the contract required that any asphalt layer exposed to rain before a
waterproof seal was applied had to be removed and replaced. The paper explores how this challenge was met through mix redesign,
logistics and treatment modification so as to avoid wasting high value resources. Trafficking of the waterproofing seal often through
intersections had to also be managed.
Every element of the pavement from subgrade to final asphalt wearing course was constructed using a sustainable material or technology.
Embankment fill was constructed from recycled sand derived from construction demolition waste, while crushed recycled concrete was used
as the subbase. Both recycled asphalt and warm mix asphalt were introduced with instrumented trial sections installed to study field
performance.
Trials of innovative temporary waterproofing seals were constructed, peer reviewed and used on very high trafficked areas with exceptional
performance.
The paper discusses new findings resulting from these trials and how demonstrated success has influenced subsequent projects that are
continuing the innovative practices.
The paper describes some aspects of how this remarkable achievement was met through, a suitable project delivery model, close
collaboration between the Client, Designer, Contractor and Suppliers. The Project was awarded an Infrastructure Sustainability Council of
Australia rating.
The use of these technologies also fitted the cultural values and economic sense of sustainability and recycling that can allow Western
Australia to achieve benefits well ahead of other states.
PUSHING THE BOUNDARIES WITH SBS BINDERS.
Vincent Conserva1
1.
Kraton Performance Polymers, EAST DONCASTER, VIC, Australia
SBS binders have been proven to work for over 35 years. However many factors including variability in bitumen quality, demands imposed
by climate change, traffic loadings and budget pressures have forced us to look at new ways to get more out of our pavements. Kraton
Polymers has led a multi year research and evaluation program together with various renowned institutes including Delft University of
Technology in The Netherlands and the National Center for Asphalt Technology (NCAT) in the United States to evaluate the performance of
full depth SBS modified flexible pavements. The study has given insight into new opportunities to construct thinner, tougher , sustainable
and more economical pavements. We will present the key research findings for our NCAT experimental pavement sections as reported in
the March 2015 Pavement Test Track meeting.
Early adopters often take risks and we will also present some case studies conducted in Australia and New Zealand over the past few years
and show how the new concepts are being used so you can see if they have applicability for the roads industry.
TOWARDS A MORE SERVICEABLE TECHNICAL SPECIFICATION FOR LOCAL GOVERNMENT ASPHALT SUPPLY
Russell Crabb1, Trevor Distin1
1.
Boral Asphalt, Wentworthville, NSW, Australia
Russell Crabb is the Technical Manager for Boral Asphalt NSW and has over 40 years experience in asphalt technical and production. He is
currently the Chairman of the AAPA NSW branch Technical Committee - a position he has held for several years. As part of that Committee
he has been involved in review and consultation for State Road Authority specifications, AUS-SPEC and ACT Government specifiations.
Over the years there has been many and varied differences in specifications between various local governments for asphalt supply. These
have deviated from the AUS-SPEC standard which has been developed in conjunction with Industry to meet the specific needs of the local
government environment. Changes in raw materials, mix design measures and production plants means that specifications need to be
continually updated to ensure that a consistent and durable product for road users and stakeholders is provided.
Some local government agencies have particular technical requirements that have been in existence for many years but which fail to
recognise the progress that has been made in both materials used and the design of asphalt.
The purpose of this paper is to:
• highlight some of the differences that are in practice
• demonstrate how there can be consistent technical requirements without impacting product performance
• clarify the most recent test methods used for quality control
This will allow Local Government to receive asphalt products that are of high standard, long lasting and value for money.
There has been much cooperative work done between NATSPEC and AAPA over the past two or three years on updating AUS-SPEC and this
paper aims to confirm the commitment to regularly review the document to keep it up to date with the latest technical knowledge and local
government expectations.
AIRPORT RUNWAY CONSTRUCTION USING ONLY SALT WATER
Troy Davis1, Paul Byard
1.
Shire of Ashburton, Tom Price, WA, Australia
The airport at Onslow was expected to play a critical role in moving the largely Chevron Wheatstone FIFO construction workforce to and
from their sites.
To handle the large increase in passenger numbers, in the number of flights and the size of aircraft being used, the Shire embarked upon
the Onslow Aerodrome Redevelopment project, part-funded by Chevron, which includes:
• Construction of a new 1900m long runway, taxiway and apron on tidal flats around an existing operational airport including
• the excavation, movement, conditioning, laying, compacting and grading of approximately 600,000 m3 of fill material; 75,000 tonnes of
base course rock;
• the production on site and laying of 12,500 tonnes of asphalt;
• the use of more than 100 million litres of salt water for conditioning the fill material;
• truck movements exceeded 1000 a day at peak construction;
Construction of the embankment for the new runway (105m wide at the base and extending 2200m in all) was expected to be carried out
using salt water out of necessity – the poor quality (sand) fill material required lots of water for conditioning before we could achieve the
level of compaction required; we had access to only very limited quantities of fresh water; and the site was surrounded by an everreplenished supply of salt water which we accessed through the construction of tide-filled sump off the end of the embankment:
Initially, we were expecting to use fresh water for the runway sub-base and base course but, as we were experiencing problems sourcing
that water for a realistic price, we approached the ARRB to investigate the option of using salt water throughout.
That investigation was carried out by Mr. Kym Neaylon who carried out a detailed risk analysis, proposed risk mitigation measures and then
worked closely with us on site for 6 weeks as unexpected sealing issues were encountered and subsequently overcome.
1. Managing the Risks of Using Seawater for Pavement Construction-Kym Neaylon, ARRB 26th ARRB Conference 2014
INCORPORATION EXPERIENCE AND KNOWLEDGE INTO SPRAY SEAL DESIGN
Bevan Sullivan1, Morrie Dellar1
1.
Fulton Hogan, Sydney
Publish consent withheld
IMPROVED DESIGN PROCEDURES FOR ASPHALT PAVEMENTS
Erik Denneman1
1.
ARRB, Albion
This paper presents the highlights of Austroads project TT1826 Improved design procedures for asphalt pavements, now in its third and final
year. Developments discussed in the paper include a methodology to predict asphalt pavement temperature from air temperature data.
Pavement temperature can be predicted at any time of day and any depth in the pavement structure. Further discussed are the influence of
load pulse and temperature on modulus and strain in the pavement structure. The paper also presents the improvements made to the
Austroads flexural beam test method for fatigue and stiffness. The method has been improved to allow characterisation of the fatigue
performance of asphalt mixes and to develop mix specific modulus master curves. An example is provided of how the temperature
distribution at depth information, combined with modulus master curve information can be used to perform a detailed evaluation of the
strain distributions in an asphalt pavement. The paper further outlines the proposed changes to the Austroads Guide to Pavement
Technology Part 2: Structural Design.
IMPLEMENTING NEW ROAD BUILDING TECHNOLOGIES: THE TIPES CERTIFICATION PROCESS
Erik Denneman1, Andrew Beecroft1, Jothi Ramanujam2
1.
ARRB Group, Brisbane, QLD, Australia
2.
Queensland Department of Transport and Main Roads, Brisbane, QLD, Australia
The road construction industry is often slow to embrace change due to an apprehension of the risks associated with innovation and a lack of
information about appropriate implementation strategies. Before we embark on a construction project we are faced with the task of
choosing from a wide variety of construction products that are available. Innovative, and what could be more efficient products, are often
overlooked for more established methods and processes. As our society changes there is a clear need for innovation and therefore a need
for any technical support that can be provided to our practitioners at both state and local government levels.
This paper illustrates the role of technical assessment (also known as Agrément) organisations in the international construction market, and
how the technical assessment and certification process can influence users to adopt innovative products that contribute to sustainability in
construction.
The paper covers the role that schemes such as the Transport Infrastructure Product Evaluation Scheme (TIPES) play in the introduction of
innovative construction products within the Australian road sector, by providing assurance to local government roads engineers and
practitioners, thus encouraging new products and building systems. TIPES purpose is to support and promote well-tested technologies to
improve the efficiency of road construction in investment and operations, and therefore creating consistency, reliability, safety and reduced
expenditures.
USE OF NEW AUSTROADS RAP BINDER CHARACTERISATION TEST METHODS IN THE RELIABLE DESIGN OF HIGH RAP CONTENT MIXES
Erik Denneman1, Jeffrey Lee1, Young Choi1, Laszlo Petho1, Jason Jones2
1.
ARRB, Albion
2.
Queensland Department of Transport and Main Roads, Herston
The re-use of reclaimed asphalt pavement (RAP) material in the production of new hot mix asphalt has become standard practice. In many
countries, including Australia, RAP is by far the most recycled construction waste product. Maximisation of the re-use of RAP in its highest
value application, i.e. as new asphalt product, has significant economic and environmental benefits. The inclusion of RAP in asphalt mixes
does however require due consideration during the mix design process to ensure satisfactory performance of the final product. Over the
past three years a research effort has been underway aimed at improving the design approach for Australian asphalt mixes containing
higher RAP contents. As part of this research new Austroads test methods (AGPT/T191, AGPT/T192 and AGPT/T193) were developed for the
extraction and characterisation of binder from RAP. The aim of this paper is to demonstrate the use of these methods to characterise the
viscosity of the binder blend in asphalt mixes containing RAP and how a mix designer may use these methods to select an appropriate grade
of ‘virgin’ binder to compensate for the RAP binder viscosity. Experimental results in the paper highlight the influence of oxidised RAP binder
on the viscosity of the binder blend as well as on the performance properties of asphalt mixes.
LATEST DEVELOPMENTS ON TMR QUARRY REGISTRATION SYSTEM (QRS) AND INCORPORATION INTO THE TMR STANDARD
SPECIFICATION SUITE
Ajith (Diss) Mr. Dissanayake, Peter Mr. Evans
The Queensland Department of Transport and Main Roads (TMR) manages a road network of over 33,500km, all of which is constructed of
either bound or unbound pavement material. Whether this material is constructed of concrete, asphalt or stabilised or unstabilised granular
pavement, the Department must manage the quality of the materials involved, to provide best value for the community Ensuring acceptable
quality of these materials has always been a one of the major challenges faced by the State Road Authorities.
To manage this quality, TMR was spending over $60M annually on quarry material testing. Faced with concerns that the quarry
testing frequencies for projects varied markedly between individual projects, particularly on some of the recent Alliance projects, and the
massive Transport Network Reconstruction Program (TNRP) the Department standardised its testing frequencies in 2012.
However, it was accepted that this was not an optimal approach, since source rock quality and consistency, quarry management, and
product consistency varies markedly between quarries. In this environment, it was obvious that some quarries were required to undertake
excessive testing to maintain their quality. Others may still not have been doing enough testing. The challenge for the Department was how
to address this issue.
This paper discusses the collaborative and innovative risk based approach that was developed in consultation with relevant quarry industry
stakeholders including the Cement Concrete and Aggregate Australia (CCAA) and the Institute of Quarrying Australia (IQA) to achieve an
innovative and more cost effective outcome for road construction quarry materials. Queensland will now be applying quarry specific testing
frequencies, which are self assessed by quarries based on guidelines developed jointly with industry. The paper also describes proposed
changes to the 20-year old TMR Quarry Assessment and Registration System (QARS).
While the cost saving from implementing the new innovative approach is difficult to quantify, a preliminary estimate is that this will reduce
testing costs for quarries, and ultimately to the road construction quarry material industry by $3M per year and the potential exists to
further refine the process to achieve even greater saving as more refinements are implemented.
EME2 THE JOURNEY TO AUSTRALIA
Rob Vos1, Laszlo Petho2, Trevor Distin
1.
AAPA, Brisbane, Qld, Australia
2.
ARRB, Brisbane, Qld, Australia
Enrobés à Module Élevé was developed in France in the late 1980’s as the need arose to build stronger pavements to carry 130 kN vehicle
axle loads. Whilst road pavements in Australia are designed and constructed to carry a maximum axle load of 85 kN, it was recognised that
this technology would have great benefits to our local transport network.
EME reduces the stresses and better spreads the traffic loading to the underlying pavement layers. This has the benefit of either reducing
the thickness of the structural asphalt required for a given load or extending the life of the pavement for the equivalent layer thickness.
What makes EME unique is that it uses a very stiff, higher binder content and small aggregate mixture.
The decision was made to introduce EME2 into Australia following the witnessing of the first paving trial on the AAPA tour to South Africa in
September 2011. This paper describes the journey embarked on to transfer EME2 technology to Australia which culminated with the
placement of the first demonstration trial in Brisbane in February 2014. In the delivery of this trial a number of challenges had to be
overcome involving the development of a local EME-style binder, development of asphalt performance criteria using local test methods and
a mix design which complied with French standards.
The execution of the manufacture and paving trial was the result of the joint efforts by many stakeholders. This involved the review of EME
technology by ARRB under the auspices of Austroads to ascertain its viability in Australian conditions.
The EME2 demonstration project was a big step in the technology transfer journey and has supported the development of an Australian
performance based mix design protocol and tentative specifications. EME2 can now be specified for use on the Australian transportation
network.
INNOVATIVE PRODUCT USE TO IMPROVE WOODEN DECK SURFACE SAFETY
Jason Eggleton1, John Lovell2
1.
Downer, Port Melbourne, VIC, Australia
2.
Knox City Council , Melbourne , VIC , Aust
Key Word Description
Knox City Council and Downer have successfully treated several wooden bridges within council area with the innovative BRP Road Patch to
address Cyclist/Pedestrian skidding accidents. There we numerous hurdles to overcome such as environment, access and the skepticism
born from numerous other alternative product failures which were able to be controlled enabling the dangers to be successfully overcome
with Downer, Knox and the bridge users all being extremely happy with the finished result. Knox and Downer believe this co-prepared paper
is a good representation of INNOVATIVE product to improve SAFETY, by addressing the dangers of Cyclist/Pedestrian skidding accidents on
their wooden bridge/boardwalks, with the added benefit of ASSET PRESERVATION. It is an ongoing program for Knox City Council which is
relevant to any Council who has wooden bridges or boardwalks used by pedestrians and cyclist.
RECENT ADVANCES IN PERFORMANCE BASED CHARACTERISATION OF ASPHALT MIXTURES – A REVIEW
Bayode Ero-Phillips
This paper reviews recent advances in performance based characterisation of asphalt mixes. A number of factors have necessitated the
requirement for performance based tests on asphalt mixes. The need to design long lasting asphalt pavements in order to preserve
resources and keep capital expenditure to a minimum is a major factor. Additionally, concerns about climate change as well as escalating
production costs have necessitated the use of a variety of new materials such as recycled asphalt and tyre rubber in asphalt pavements.
In the past, empirical properties derived from previous experience were generally used to predict the service performance of asphalt mixes.
Performance based tests however, provide engineering properties of asphalt mixes; these properties can be used to predict the service
performance of the mixes.
Performance based characterisation of asphalt mixes is therefore one of the most crucial steps in designing long lasting asphalt pavements.
Characteristics such as rutting potential, fatigue and thermal cracking behaviours can be analysed through performance based tests. Since
the implementation of Superpave in 1993, numerous tests such as wheel tracking and indirect tensile test have been used to investigate the
fundamental properties of asphalt mixes. However, recent analysis of some of these tests have shown their limitations, the most common
being that laboratory test data are at variance with field test data.
As a result, modifications to previous test methods and completely new test methods are being researched and introduced in order to
overcome the limitations of existing ones. The aim of this paper is to provide brief discussions on these limitations (showing the necessity of
developing new robust methods) as well as discussions on some of these new test methods.
HAMLET TREATMENTS.INNOVATIVE ROAD SURFACING TREATMENTS IN TOWNSHIP AREAS
John Esnouf1, Brian Hogan2
1.
VicRoads, Burwood East, VIC, Australia
2.
Northern Region, VicRoads, Bendigo, Victoria, Australia
The selection of road surfacing treatments in township areas is often a difficult choice.
This is especially the case in small rural townships.
Roads in these areas have often evolved over the years and may consist of several pavement types and strengths over the full width of the
road.
Also Traffic Engineers have invariably added central medians, turn slots, and pedestrian crossings etc often resulting in a complex section of
road.
These small towns which have been labelled 'Hamlets' for the purpose of this paper are nearly always surfaced with sprayed bituminous
seals. These sprayed seals have generally served well in the past in these locations, but are now often exceeding the limits of their
performance with the stresses created by modern traffic especially when parking with power steering, turning movements and the like.
The placement of asphalt overlay treatments often creates issues with level controls, and the strength of the old pavements may not be
sufficient to support an asphalt treatment, making asphalt surfacings impractical.
Also the expectations of people living in these 'Hamlets' and using the town centre often on a daily basis are an important part of selecting
an effective, appropriate, and affordable road surfacing treatment.
In the Northern Region of VicRoads there are many of these small towns and the issue of placing a suitable treatment when periodic
maintenance was required became increasingly important.
Over a period of time several thin surfacing treatments that were a combination of sprayed seal and asphalt type treatments were trialled
which resulted in the development of the Hamlet treatment. This consists of a combination of patching works where required, an asphalt
regulation layer to correct poor surface shape in some cases, placement of a geotextile reinforced seal in traffic running lanes, and
specialised thin asphalt surfaces for the final surface.
This paper discusses the evolution of Hamlet treatments in the Northern Region of VicRoads and looks at the advantages and disadvantages
of this treatment.
It also contains case studies of completed works, some of which have been placed and performing well for over 10 years.
USING INNOVATIVE IN-SITU MEASURING TOOLS TO BETTER UNDERSTAND ASPHALT PERFORMANCE
Christopher Gray1, Susan Tighe1, John Yeaman1
1.
University of Sunshine Coast, Maroochydore, QLD, Australia
Asphalt pavement is engineered to perform well under traffic and environmental loading. One of the most common methods of measuring
pavement temperature, within Australia is the Weighted Mean Annual Pavement Temperature (WMAPT). This paper will summarize some
of the key findings that came out of a research study that was recently conducted at the University of Sunshine Coast. It examined the direct
influence of solar radiation and the associated material thermal properties on the asphalt pavement. The research evaluated two
approaches including steady-state and simulative transient-state material analysis to examine the impact of solar radiation on the asphalt
pavement. A Calorimeter was constructed to provide a base for testing these procedures and designed to incorporate the requirements for
replicating in-situ pavement conditions including the concept of one-dimensional heat flow with adiabatic boundaries. The testing procedure
utilised the appropriate instrumentation to measure and record both the material thermal properties and the simulative temperature-depth
gradient.
The paper will present the results obtained for the steady-state analysis for albedo. In addition, the associated emissivity and conductivity
values will be presented which highlight the need to consider these factors and how they impact pavement performance. Analysis of the
transient-state condition presented accurate temperature-depth gradients for the seasonal cycles of summer, spring, winter and autumn
will also be presented. Mathematical regression produced second order polynomial functions for the associated seasons which were
sufficient in determining the temperature at any required depth. The significance of these findings was visibly evident when analysed in
conjunction with the Master Curve which correlated the values for stiffness to the seasonal temperature gradients. Overall, a procedure for
seasonally adjusted stiffness was developed which could be incorporated into mechanistic pavement design approach for pavement
optimisation resulting in a potential reduction in required thickness.
BITUMEN IN NEW ZEALAND – PERFORMANCE BASED ASPHALT BINDER SPECIFICATION DRIVING ASPHALT INNOVATION
Glynn Holleran
This paper discusses a major innovation in New Zealand promoted by the industry and NZTA.
This paper discusses performance data from New Zealand bitumen over the last decade. It compares the rheological properties of bitumen
with the performance based mix properties and field performance. A new performance based binder specification is proposed that is not
intended to change the market place, but is aimed at lowering the risk to the contract. The specification applies to the material that actually
goes on the road. It specifies fundamental material properties that predict performance with respect to traffic and within the NZ
temperature
range.
The industry generally adopted rheological testing in 2007, particularly using Dynamic Shear Rheometer testing (DSR) .These methods are
not new but are well grounded in research and practical application over more than two decades in the USA. Data collected in New Zealand
from numerous unique bitumen sources has led to the establishment of a bitumen library by Fulton Hogan that allows samples from the
early 2000s to present day to be tested using these techniques. The use of performance based mix design that includes deformation and
fatigue type testing has allowed the rheological effects of these changes to be studied in mixes. Correlation with field performance has also
been carried out. The outcome is a specification based on fundamental rheological testing as used validated in USA that applies to New
Zealand conditions and practices.
COMPARATIVE DISCRETE ELEMENT MODELLING OF GEOGRID-STABILISED AGGREGATES AND PAVEMENT PERFORMANCE
John Buckley1, Rajesh Bhavsar2, Mike Horton3
1.
Tensar International, MORNINGSIDE, QLD, Australia
2.
Geofabrics Australasia, Melbourne
3.
Tensar International, Blackburn, England
The traditional method of specifying geogrids for subgrade reinforcement has relied upon defining such characteristics as ultimate strength
and strain with the inference that such properties are important when geogrid is incorporated in unbound aggregates in roads. This
particularly applies to roads designed to work with a geosynthetic acting as a tension membrane. However, such mechanisms rely on
deformation in order to support loads, which can lead to rutting at surface and damage to the formation at the sub-grade/geosyntheticaggregate interface. Design methods that use geogrids to stabilise, rather than reinforce an aggregate, are intended to largely avoid this
damaging deformation.
Whilst interlock and confinement of aggregate by stiff geogrid apertures appear to be important, recent discrete element modelling by
ITASCA in Germany of a moving wheel over biaxial and TriAx multi-axial geogrid-stabilised aggregate has shown that strength is not
important to the trafficking performance of a road designed to work with stabilisation as the geogrid function and that it is other features
that determine how well such a mechanically stabilised layer performs in use. This supports previous work that has also shown that
ultimate strength is not important to trafficking performance.
This paper briefly shows how such a geogrid-stabilised aggregate was modelled and comparative modelling of un-stabilised, biaxial and
TriAx stabilised aggregates under moving wheel loads. It shows comparative particle movements in different pavement construction and
the low strain developed within the geogrid structure under trafficking and also the importance of isotropic stiffness in the plane of the
geogrid, rather than strength, in providing optimum stabilisation performance. It discusses the development of tension rings within an
isotropic geogrid structure to accommodate the dynamic surface loads on the aggregate to help explain the performance of geogridstabilised pavements.
IMPACTS OF ASPHALT LABORATORY COMPACTION TECHNIQUES: DOES IT REALLY IMPACT THE MASTER CURVE?
Cody James-Johnston1, Susan Tighe1, John Yeaman1
1.
University of Sunshine Coast, Maroochydore, QLD, Australia
Sample preparation and evaluation is a critical component in quality control of asphalt materials. This paper describes a research project
which involved constructing a catalogue of Master Curves for typical asphalt mixes that are used in Queensland and in the Brisbane
area. The intent of the study was directed at better understanding the predicted performance and behavior of the mixture via different
laboratory compaction methods. The mixture selected, was produced by the Brisbane City Councils (BCC), Eagle Farm plant has a proven
history of being a good performer for the Queensland environment and has been used throughout the region. The mix, a B771 is one of
BCCs most commonly produced asphalt mixtures, which has incorporated the addition of 15% Reclaimed Asphalt Product (RAP) as an
aggregate substitute within the mix. This catalogue hopes to provide a better understanding of the mix characteristics for application in
mechanistic pavement design.
The research involved preparing the selected mixture using the following methods: the Marshall, Gyropac, Servopac and Shear Box
compaction methods. The Dynamic modulus of the samples was then tested and used to construct modulus Master Curves for the fourcompaction methods. The resulting data was then used to evaluate the mixes performance and behaviour characteristics for local
conditions. The produced catalogue hopes to provide a better understanding of the mix characteristics and performance capabilities in
Mechanistic-Empirical pavement design. The paper summarizes the outcomes of the research and provides practical guidance for
practitioners.
AMENDING THE AUSTROADS EMULSION SPRAY SEAL DESIGN METHOD FOR SUCCESSFUL PRACTICAL OUTCOME
Ryan Jansz1, Emanuel Popescu2
1.
Boral, Port Melbourne, VIC, Australia
2.
Boral Asphalt, Perth, WA, Australia
Emulsions spray seals have long eluded mainstream use in Australia, relegated to a second string option and used only by a few
organisations that build or maintain road assets.
Reluctance in using this product is partly due to limited practical experience and partly because of its impractical nature in some
circumstances.
By minor adjustment to the standard emulsion spray seal design method, the double, double emulsion spray seal has been turned into a
practical solution for clients especially when other treatments are unviable. This report relates how this alternative has been used for lightly
traffic roads in rural regions as well as highly trafficked roads for mine facilities. Both low and high level modification to emulsions is
discussed.
Early treatments are now several years old and still performing well. Such success might foster greater use of emulsion spray seals by road
managers and so also fulfil strategies towards cold applied products with less volatile material content.
Case studies are presented to demonstrate the success of the ‘adjusted’ emulsion, double, double design thereby leading the way to
adopting similar adjustments for other emulsion seal combinations.
The paper explores the value in this option as a way of expanding the use emulsions without all the attended application issues that usually
plague its adoption. The altered design process could be introduced as a qualification to the existing spray seal design method, thus
sanctioning its used by designers with impunity.
The change may also increase spray crew confidence in handling the product as job success rates increase. The resultant skill in applying
emulsion spray seals might translate into better field performance than had the standard approach been used with more attendant
challenges in prevailing conditions.
CASE STUDY: A COST EFFECTIVE APPROACH TO USE GROUND PENETRATING RADAR TO OBTAIN ACCURATE CONSTRUCTION
INFORMATION IN FLEXIBLE PAVEMENTS
Lalinda Karunaratne1
1.
Radar Portal Surveys Pte. Ltd., Brisbane, QLD, Australia
With tightening rehabilitation budgets, it is of paramount importance for road authorities and pavement designers to reduce the cost of
pavement investigations in flexible pavements without compromising accuracy and adequacy. Major part of those costs is likely to come
from destructive testing (DT) such as trenching. Number of testing locations can be significantly high if frequent changes in construction with
unknown boundaries are present and this is not unusual for flexible pavements in urban/ sub-urban areas. Non – destructive testing (NDT)
methods such as Ground Penetrating Radar (GPR), though cost – effective, can yield limited information sometimes with uncertain accuracy.
To obtain cost effective pavement data over lengthy sections with frequent construction changes, it is important to find an optimum mix of
both NDT and DT methods and to use limited DT data to improve the accuracy of NDT methods.
This case study presents tools and techniques, used in proposed upgrade for Pacific Motorway – Exit 54 in Coomera, QLD, for effective usage
of traffic speed GPR to identify different pavement construction types and accurately determine pavement layer thicknesses in flexible
pavements over larger area with minimum amount of trenching. The project area consists of nineteen road segments with varying
construction types with total length of over 7.5km. First, targeted trenching was done in homogeneous construction zones identified by GPR
reducing overall number of DT locations. Pavement layer depths over entire project area are then accurately predicted by compensating
dielectric constant values using actual construction materials during GPR processing.
This method also produces more accurate results than historical or as-constructed data which often are not updated or cannot be verified.
Case study will also discuss how this approach is currently being used for various other similar projects in Gold Coast, QLD as well as how to
effectively use at network-level.
PLANT BLENDED CRUMB RUBBER MODIFIED BITUMEN FOR SEALING APPLICATIONS
Jarryd King1
1.
SRS Roads Pty Ltd, Camellia, NSW, Australia
Advances in technology and manufacturing processes have given rise to more sophisticated crumb rubber products for use in the sealing
industry. Desirable properties such as, high elasticity, good initial adhesion to aggregate & Increased softening point provide many
advantageous when compared to traditional binders. These advantageous include, delaying reflective cracking in pavements, improved
shear resistance, improved aggregate retention & the ability to remove lose aggregate directly after application. With the specialised
stabilisation techniques used in the manufacture of crumb rubber product, these products now also have the ability to be stored for
extended periods of time and transported long distances which provide opportunities for use in more remote locations. The use of recycled
materials provides an environmentally sustainable product at an excellent cost/performance ratio.
QUICK SETTING MICROSURFACING SYSTEMS IN WESTERN AUSTRALIA
Michel Lenfant1, Kanjana Yindee2, Iulian Man2, Adrian Kroger3
1.
TIPCO Asphalt, Thailand, ., Thailand
2.
SAMI Bitumen Technologies, Australia
3.
Colas WA, WA
Microsurfacing is a surfacing material which is a fast and durable pavement preservation technique that utilizes the benefits of a cold mix
formulated with a polymer modified bitumen emulsion, aggregates and special additives.
The bitumen source and its chemical nature play a key role in setting and mix cohesion build-up.The mix curing time is shortened through
specific chemical reactions, allowing the traffic to be returned in a shorter time. Together with the mix design, the emulsion’s formulation is
fundamentally important in achieving faster setting and cohesion build-up.
The focus of the paper is the development of a quick setting microsurfacing system with the following characteristics:
·
Quick setting with quick traffic opening in less than 1 hour;
·
Suitable for high traffic situations;
·
Very good skid resistance;
·
Suitable for night time applications;
·
Rut filling applications;
·
High degree of durability;
·
Environmentally friendly.
GRITTING OF DENSE ASPHALT WITH CALCINED BAUXITE FOR IMPROVED LONG TERM SKID RESISTANCE IN HIGH SKID DEMAND AREAS.
Russell R Lowe1, Ed E Baran2, Robert R Pollock3
1.
Transport and Main Roads Qld, NATHAN, QLD, Australia
2.
Pavement Investigations, Ed Baran Pavement Investigations.com.au, Brisbane , Queensland , Australia
3.
Resurfacing , Brisbane City Council -Works , Brisbane , Queensland , Australia
Gritting of Dense Graded Asphalt with Calcined Bauxite for Improved Long Term Skid Resistance in High Skid Demand Areas. Abstract To
date, Queensland Transport and Main Roads Department’s experience with gritting of asphalt surfaces has generally been to provide early
skid life skid resistance for stone mastic asphalts which if untreated may require up to 3 to 6 months of trafficking before the polymer
modified binder on the surface aggregate is worn off and the potential microtexture skid resistance is fully realised. Gritting of the stone
mastic surface had been found to both significantly increase early life skid resistance and also increase the longer term skid resistance. This
long term skid resistance gain has led to current trials using calcined bauxite as a grit to improve the skid resistance of the Department’s
standard Dense Graded Asphalt [14 mm] mix. In the past, calcined bauxite had only been applied in a post construction process as a
reactive measure in high demand areas with poor skid resistance. This paper presents the results of trials carried out, in the Metro South
East Regions of Queensland, on the skid resistance performance of both gritted and un-gritted dense graded asphalt surfaces and describes
the construction aspects involved in the calcined bauxite gritting process. Authors – Russell Lowe, Rob Pollock and Ed Baran
EVALUATION OF WARM MIX ASPHALT PERFORMANCE INCORPORATING HIGH RAP CONTENT.
Dai Lu1, Mofreh Saleh2
1.
Postgraduate student, University of Canterbury, Christchurch, New Zealand
2.
PhD, PE, FASCE, Associate Professor, University of Canterbury, Christchurch, New Zealand
Warm mix asphalt (WMA) is considered one of the sustainable and green technologies as it utilises low production temperatures. This
production procedure requires less energy to heat aggregates and bitumen before mixing compared to that of traditional hot mix asphalt
(HMA) and produce less emission in both mixing and compaction phases. However, lower mixing and compaction temperatures can result in
softer bitumen binder due to less ageing. Moreover, moisture resistance still remains as a concern as lower mixing temperatures may lead
to poor coating of bitumen to aggregates, thus, increasing moisture susceptibility. Reclaimed asphalt pavement (RAP) is a product removed
from old pavements. RAP contains aged binder, which can compensate for the softness of binder in WMA and may improve moisture
resistance of WMA mixes.This study is to investigate the rutting and moisture resistance of WMA incorporating high RAP contents based on
laboratory performance. The performance of WMA will be compared with hot mix asphalts (HMA).
NEW MODIFIED BINDER FOR AIRPORT ASPHALT
Stephen Emery1, Iulian Man2, Ivan Mihaljevic3
1.
Kubu Australia Pty Ltd, Kalamunda, WA, Australia
2.
SAMI Bitumen Technologies, Sydney, NSW, Australia
3.
Kamen Engineering Pty Ltd, Sydney, NSW, Australia
Working with industry, the Australian Airports Association developed a new airport asphalt binder. The binder was required to deliver good
asphalt mixture stiffness to cope with slow loading times and high temperatures, and higher resistance to viscous deformation such as
groove closure. The binder was required to have improved resistance to stripping, be easily constructible without requiring excessively high
temperatures for mixing and laying, and be robust and reliable such that it could be transported long distances by road. Historically, high
performance binders for airport applications have been associated with high level of polymer modification. While these generally
performed, the binder characteristics were not optimised in order to simultaneously address performance, cost-effectiveness, handling,
logistical and ease of workability issues. This paper focuses on the usage of SAMIfalt B380 bituminous binder for airport applications, which
is an elastoplastomeric modified binder with a mid-level of polymer modification. The performance is compared with conventional Class 320
unmodified bitumen, A10E PMB, and multigrade bitumen.
STABILISATION OF EXPANSIVE SOIL USING LIME AND POLYMER
Mariam Darestani1, Stuart Mcewan1, Abtahi Mojtaba1 , Tim Dargaville1, Graeme Millar1, Vincent Gomes2, Chaminda Gallage1
1.
Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD, Australia
2.
Chemical and Biomolecular Engineering , University of Sydney, Sydney, NSW, Australia
Expansive soils undergo significant volume change due to variation of their moisture content: soil heaves with increase in its moisture and
shrink as the moisture decreases. The lightweight structures such as pavements and shallow building foundations that are founded in these
soils are subjected to severe distresses. Further, as the soil heaves it loses its strength causing foundation failures of the structures founded
in/on expansive soil. . Therefore it is critical to stabilise such soil to minimise its moisture induced volume change to prevent structural
damages.. Stabilization of soils to improve strength and durability properties is traditionally achieved by adding cement, lime, fly ash, and
asphalt emulsion to soil. Non-traditional soil modification additives such as polymer emulsions, acids, lignin derivatives, enzymes, tree resin
emulsions, and silicates are also being used in the industry. Polymers are reported to be cost effective alternative to traditional soil
stabilisers that work with different soil types. The mechanism of lime stabilisation is well known but there is very little information on how
polymers work. Depending on their chemical and physical, soil-polymer interaction can range from a pure physical binding to formation of
covalent bonds between soil elements and polymer chain.
In the present study, one of the latest polymeric stabilising agent is examined for stabilising black soil which is widely spread expansive soil
in Queensland, Australia. Performance of the polymer stabilised back soil is compared with untreated and lime treated black soil using UCS
and soil swelling tests. Soil samples stabilised using water (as negative control), polymer and lime are also investigated. Stabilised soil
samples are further studied using advance imaging test to compare their fracture mechanism under load. Particle size, chemical and surface
charge analyses on polymer, soil and stabilised soil are performed to obtain information required to characterise soil-polymer interaction
mechanism.
DESIGN OF HIGH PERFORMANCE ASPHALT FOR AIRPORTS
Stephen Emery1, Ivan Mihaljevic2
1.
Kubu Australia Pty Ltd, Kalamunda, WA, Australia
2.
Kamen Engineering Pty Ltd, Sydney, NSW, Australia
Heavy duty pavements such as airport pavements carry much higher loads than highways. Experience in Australian and the Middle East has
shown the need for high performance asphalt mix design to cope with high loads in high ambient temperatures. Aircraft wheel loads and
pressures for the next generation of aircraft will increase to over 30 tonnes per tyre and 1650 kPa tyre pressure. Traditional Marshall Mix
Design Methods continue to be used, however these need to be supplemented in design by further tests. High performance mix design
criteria have been developed and applied overseas, and here were refined and applied to the development of an asphalt for runway
resurfacing works at Broome International Airport. This paper discusses the use of traditional Marshall Methods supplemented by
accelerated loading, wheel track testing and refusal density concepts in the development of high performance asphalt that is suitable for
airports in the challenging operational and environmental conditions of North West of Western Australia.
SPRAYED SEAL PERFORMANCE UNDER MULTIPLE-AXLE HEAVY VEHICLES
Kym L Neaylon1
1.
Opus International Consulting, Lower Hutt, WELLINGTON, NZ, New Zealand
The number of large heavy vehicles on major transportation routes in Australia has been increasing over the last decade, and reliance of a
thin flexible pavement network with a thin low-cost surfacing remains as strong as always.
In an effort to keep sprayed seal designs up-to-date and relevant, a study has been undertaken of the effects of single, tandem and triaxle
groupings on the macrotexture wear rate of a sprayed seal. It has been found that one pass of a triaxle does not necessarily cause the same
surface wear as three passes of a single axle group. It is now postulated that when multiple axle groupings are loaded such that they cause
the same pavement damage as each other (based on the 4th power law), they do not cause the same sprayed seal damage as each other.
It is also postulated that the flexible pavement load damage exponent of 4 does not apply to chip seals placed on these pavements, but
rather an exponent of 1.
These findings may be useful in future updates of the heavy vehicle seal design method.
Key words: seal design; sprayed seal; chip seal; heavy vehicle loadings; multiple axle groups
Bio: Kym Neaylon is a civil engineer who has been interested in sprayed sealing for over 20 years. He has held roles of a construction
engineer, surfacing's engineer, principal research engineer, manager materials and then national technical leader bituminous surfacing's at
the Australian Road Research Board. He currently holds the position of research manager, pavements, with Opus international
consultants. He is a final year candidate for a PhD in this paper's topic.
FIBRE REINFORCED ASPHALT CONCRETE
Stuart Neilson, Kamil Kaloush
Fiber Reinforced Asphalt Concrete (FRAC) mixtures continue to receive great attention from many transportation agencies world-wide
because of their ability to improve pavement performance compared to conventional designs. A number of studies reported on the unique
properties and characteristics of FRAC in terms of improved rutting, cracking, and raveling. Several agencies in the U.S. and countries around
the world have used, or are in the process of using FRAC mixtures in new pavement designs and rehabilitation programs. This paper
highlights findings from several research studies conducted at Arizona State University. The engineering properties of FRAC mixtures are
discussed along with a demonstration on how to use them in current pavement design procedures.
HUMAN-CENTRED DESIGN FOR ROAD CONSTRUCTION: OPTIMISING PRODUCTIVITY BY REDUCING SAFETY AND HEALTH RISKS
ASSOCIATED WITH THE OPERATION AND MAINTENANCE OF EQUIPMENT, TOOLS, ON-ROAD VEHICLES AND MOBILE PLANT.
Rob McGuire1, Sara Pazell3,2, Robin Burgess-Limerick4, Tim Horberry5
1.
BORAL Asphalt Queensland, BORAL Construction Materials, Kelvin Grove, QLD, Austraila
2.
BORAL Asphalt Queensland, BORAL Construction Materials, Kelvin Grove, QLD, Australia
3.
Minerals Institute Safety Health Centre, University of Queensland, Saint Lucia, QLD, Australia
4.
Minerals Institute Safety Health Centre, University of Queensland, Saint Lucia, QLD, Australia
5.
Minerals Institute Safety Health Centre, University of Queensland, Saint Lucia, QLD, Australia
A range of injury and health risks are associated with the operation and maintenance of tools and equipment used in road
construction. Hazardous conditions give rise to exposure to hazardous manual tasks, whole body vibration, severe thermal conditions,
uneven terrain, chemicals, heavy equipment, pinch points, fire, explosions, equipment roll-over, traffic conditions, and collisions. Risks are
prevalent for sprain and strain injury; slips, trips, and falls from ground or at height; chemical, bituminous, or heat burns; impact injuries;
fatality or severe disablement.
Through the study and application of the principles of participatory ergonomics and human factors design it is possible to eliminate and
reduce some of the health hazard risks, thereby providing great benefit to the road construction industry - innovation driving value.
Case vignettes will include discussion of the following:
·
Participatory ergonomics study and redesign of the diesel bath bucket and lug attachments, work method, and transit strategies.
·
Hazardous manual task risk assessment and subsequent change of the use a traditional broom, shovel, and wheelbarrow to clean the
work area of recycled asphalt product to the use of manual push brooms that led to greater productivity and satisfaction among operators
and labourers at an asphalt plant.
·
Design Operability and Maintainability Analysis Technique, a human factors engineering design review process, for the study of job
trucks and mobile plant equipment, with subsequent recommendations for after-market design changes, general design recommendations
for manufacturers and suppliers, and changes to procurement strategy.
Human factors design process will be disclosed in the discussion of these case vignettes.
HIGH MODULUS ASPHALT (EME2) PAVEMENT DESIGN IN QUEENSLAND
Laszlo Petho1, Peter Bryant2
1.
ARRB Group, Albion, QLD, Australia
2.
Transport and Main Roads, Herston, QLD, Australia
Enrobés à module élevé (EME), which means high modulus asphalt, was developed in France over 30 years ago, and has been used
internationally for a wide range of heavy duty applications. It is primarily intended to reduce the thickness of full depth asphalt pavements
whilst still providing sound pavement performance through a combination of high modulus, and superior fatigue, deformation and moisture
resistance.
EME2, which is the highest class of EME in the French standards, is being introduced into Queensland through a collaborative effort involving
Transport and Main Roads (TMR), the Australian Road Research Board (ARRB), the Australian Asphalt Pavement Association (AAPA) and its
members, and Brisbane City Council (BCC). In addition, the implementation into Queensland leverages off related projects by Austroads and
other Australian road agencies.
An extensive research program was carried out under the TMR-ARRB NACoE project P9 for the development of structural design procedures
for pavements containing EME2. This included the positioning and function of EME2 layers in typical Queensland pavement designs,
procedures to characterise the modulus of EME2 at different temperatures and loading conditions, and the development and validation of
transfer functions for pavement structures containing EME2. While the French design system for flexible pavements directly applies inputs
from performance based mix design, immediate implementation of such a system in Queensland was inhibited by the existing Austroads
pavement design methodology which currently does not make such links to the mix design. The research project investigated the technical
solutions to overcome these issues; this paper summarises the technical basis of the implementation process.
Based on the background information collected in the research project a Technical Note was drafted, which is intended to facilitate the
timely implementation of EME2 on TMR projects. The paper also provides some practical guidance on the design of pavements
incorporating EME2.
3-D PAVING EXPERIENCE AT THE NATIONAL CORVETTE MUSEUM – MOTORSPORTS PARK
Chris Powell1
1.
Caterpillar of Australia Pty Ltd, Singapore
This paper covers some of the challenges in paving a 5.0 kilometer high-speed motorsports track to meet challenging materials and
construction specifications for ride quality and durability. The project was all new construction, starting with native base materials, over 77
000 tonnes of granular material and three lifts of asphalt pavement totaling over 54 000 tonnes. The existing clay sub-grade soil required
stabilization with lime to reduce the Plasticity Index. The sub-grade was stabilized to a depth of 30 cm, followed by a lift of dense-graded,
crushed limestone aggregate that was spread by asphalt pavers to a nominal depth of 20 cm. The base aggregate was trimmed to final
elevation by motors graders under 3-D blade control. The base lift of asphalt was then placed on the crushed limestone base using 3-D
screed control, followed by an intermediate asphalt layer placed under 2-D control and finally the surface lift of asphalt was placed using 2-D
grade control systems. The bituminous material used for the base course was a 19 mm, dense-graded Superpave warm mix asphalt. The
asphalt cement was a non-modified PG 64-22. The compacted depth of the base course was 50 mm. The design of the track specified a hoton-hot longitudinal joint to promote both increased joint density (durability) and joint appearance (precise match).
Before the start of paving, there was a significant amount of planning and training. Two wide paving kits (left and right) were ordered for the
paver set up for 6-metre wide paving. The crew practiced with the wide-width paving kit on parking areas at the Motorsports Park before
starting the racetrack. Paving speeds were carefully calculated so the two echelon pavers would be in balance and would consume the
hourly tonnage in a consistent fashion without stopping. This project was the first time that the paving crews were exposed to 3-D screed
control. The contractor’s technology team set up 17 Universal Total Stations (UTS) and installed 3-D controls on the paver when the crew
paved the parking areas. The paving crew was ready to go when production paving started on the racetrack. Finally, the quality control
team had the compaction process planned at the start of production paving. They confirmed that the rolling patterns would get the
required density and that the breakdown rollers could stay ahead of the tender zone.
This paper will focus on four main segments of base lift 3-D asphalt paving: first, a discussion of the planning needed for and
implementation of echelon paving with two asphalt pavers; second, an examination of a wide-width paving kit; third, an introduction to the
use of three-dimensional screed control used on the project; and finally, an analysis of the rolling patterns used by four double-drum,
vibratory asphalt compactors.
A NEW APPROACH TO QUALITY CERTIFICATION OF BITUMEN
Nigel Preston1
1.
Viva Energy, Melbourne, VIC, Australia
The 21st century has seen considerable changes take place to Australia’s bitumen supply Industry with a reduction to the local refining
footprint and an update to the specification for paving grade bitumen. In the early 2000s Australia was self-sufficient in bitumen production
but economic pressure through developments in international oil refining capacity has subsequently led to the closure of four Australian
refineries each of which were previously key bitumen supply points. In parallel with the reduction in domestic bitumen production, changes
have also taken place to the national specification for paving grade bitumen with the elimination of the old C50 grade and the introduction
of two new grades C240 and C450. In order maintain bitumen availability and offer the suite of grades described in AS2008, some supply
points have introduced in-line blending at the point of bitumen delivery into road tankers. This approach departs from the traditional means
of ‘batching’ and certifying individual storage tanks and adopts custody control systems to provide traceability on bitumen quality. This
paper describes the approach to in-line blending adopted by one supplier in Australia and details the quality control system that has
superseded the traditional bitumen certification process.
HOT IN-PLACE ASPHALT RECYCLING- TRANSPORT AND MAIN ROADS EXPERIENCE
Jothi m Ramanujam1
1.
Transport and Main Roads, Mount Ommaney, QLD, Australia
Many reasons have been put forward for insitu asphalt recycling. These include increasing costs of new pavement materials, shortage of
good quality aggregates, haulage costs from quarries, conservation of natural resources, energy conservation and geometric limitation of
existing urban roads. Recycling of asphalt pavements has long been recognised as worthwhile.
Hot In-Place Asphalt Recycling (HIPAR) in particular is used in many countries. In some countries this is a standard alternative to the
conventional milling and resurfacing or thin asphalt overlay rehabilitation treatment. HIPAR was first introduced to Queensland Transport
and Main Roads (QTMR) projects in 1990. During the period of ten years since this introduction, HIPAR gained wider usage in QTMR projects
as one of the options for rehabilitation treatment for aged asphalt surfacing. During this period an area of about 2 million m² was
recycled. TMR was extensively involved in the design, construction and performance monitoring of HIPAR treatments in order to obtain a
quality end product. However, the use of HIPAR has declined markedly over the last fourteen years.
Aim of this paper is to highlight the lessons learnt, analyse the reasons for the decline and suggest ways and means to reintroduce this
innovative technique which could lead to significant cost savings to QTMR.
SUSTAINABILITY IN ROAD PROJECTS- BUILDING THE BUSINESS CASE
Angela Reidy1, Arun Kumar2, Stephen Kajewski2
1.
Inxure Consulting, Melbourne, VIC, Australia
2.
Queensland University of Technology, Brisbane
Transport infrastructure is critical to well-functioning communities across the globe. The Productivity Commission has stated that public
infrastructure works, including road projects, contribute to economic productivity and quality of life. At the same time, the most pressing
sustainability issues associated with the transport sector include resource depletion and air pollution, with further impacts including
congestion, mobility impacts, human health impacts, community interactions, aesthetics and environmental impacts. In response to a series
of international commitments to sustainable development, many infrastructure agencies adopt sustainability objectives at a corporate
level and incorporate sustainability targets and indicators as part of corporate reporting processes. Whilst definitions and commitments to
sustainability vary widely between infrastructure providers, sustainability provides a means to deal with complexity particularly in respect to
climate change, political and economic changes but may also provide benefits around driving efficiency gains; compliance with legislation;
better management of risk; and managing reputation with internal and external stakeholders. Approaches to investment decision making
vary across jurisdictions and organisations, particularly when subject to regulatory review as part of funding processes. There is a need
to develop clear guidelines for investment decision making that better align with corporate sustainability objectives stated by infrastructure
providers. It is proposed that a more effective decision making process should involve the incorporation of sustainability goals from
corporate planning documents into the decision making process; problem definition and option generation using investment management
guidelines as evidenced by “best practice” investment management processes; comprehensive analysis of project options and impacts using
a range of assessment tools; and greater involvement from the public to accurately reflect community values.
BITUMINOUS BINDER TECHNOLOGIES OF THE FUTURE
Azeem Remtulla1
1.
SAMI Bitumen Technologies, Sydney, NSW, Australia
The concept of durable and a flexible pavement revolves around the use of a bituminous binder. In spray sealing applications durability,
adhesion, resistance to reflection cracking and ease of application are some of the fundamental attributes of a desirable binder. In asphalt
applications resistance to rutting and fatigue failure, workability of the mix and stripping are important parameters to consider. Additionally,
sustainability, safety and whole of cycle economics play an important part in the selection of “unique” technologies for consideration.
The paper discusses possible technologies of the future using composite and grafted polymer in modification of bitumen and the notion of
“Engineered” bitumen using processing mechanism to enhance the binders to deliver unique properties to ensure a balance of
performance, economics and sustainable outcomes.
Often existing and conventional specifications become barriers to entry for new technologies, the paper tries to articulate the possibilities
that are available in the field of innovation and new concepts that should be discussed and considered in the overall use of new products
and technologies in the maintenance and construction of pavements.
ADVANCES IN RUBBER-POLYMER HYBRID MODIFIED ASPHALT BINDER SYSTEMS
Tom Rosenmayer1
1.
Lehigh Technologies, Inc., Tucker, GEORGIA, United States
Rubber-modified asphalt (RMA) binders have been used successfully in many areas of the US for many years. RMA binders systems are
proven to improve performance, reduce costs, and provide a valuable use for end-of-life tire rubber materials. For example, they are used
to "grade-bump" a PG 64-22 binder to a PG 76-22 grade, as a cost-effective way to reduce pavement rutting in hot-climate
applications. However, RMA binders are sometimes limited in scope of application, or region of use, because they do not meet all of the
same performance requirements as polymer-modified asphalt (PMA) binders. These requirements may include storage stability, ODSR
phase angle, and RTFO-MSCR % recovery. New rubber-polymer hybrid technologies have been developed and successfully commercialized
that enable RMA binders to meet these requirements. Two such solutions are presented: 1) Conventional ground tire rubber (GTR)
combined with a novel stabilizing polymer, and 2) Micronized rubber powder (MRP) combined with conventional PMA polymers. It will be
shown that these new hybrids meet even the most strict PG/MSCR requirements for PMA binders. Compositions and complete PG/MSCR
test results are presented, as well as information relating to the successful commercial application of both systems.
FLEXIBLE PAVEMENTS STRUCTURAL CONDITION EVALUATION AT THE NETWORK LEVEL UTILISING FWD AND DEFLECTOGRAPH
DEFLECTION DATA
Mofreh Saleh1, Mena Souliman2, Kevin Reason3
1.
University of Canterbury, Ilam, NEW ZEALAND, New Zealand
2.
Departments of Civil Engineering and Construction Management , The University of Texas at Tyler, Tyler, Texas, USA
3.
Department of Transport and Main Roads, Sunshine Coast, Queensland, Australia
In order to make rational decisions for the maintenance and rehabilitation strategies, road asset managers will need to have reliable
classification of the structural condition of the pavement sections at the network level. Pavement surface deflection has been widely used by
several researchers and highway agencies to assess the structural condition of the pavement structure. Several deflection bowl parameters
were developed from the measured deflection to assess the pavement structural condition; however, there is no universal agreement on
these parameters. In this research paper, the normalised area ratio parameter is used to assess the structural condition of the pavement
network. Computer simulations for large number of pavement sections of different structural composition were undertaken. The
normalised area ratio derived from the synthetic computer simulations were validated with large field data extracted from the US Long Term
Performance Database (LTTP). The normalised area ratio provided good evaluation of the combined effect of the structural condition of
both the subgrade and the pavement layers.
PAVEMENT RECYCLING IS PART OF MANAGING BRISBANE CITY COUNCIL’S ROAD NETWORK
Greg Stephenson1, Inga Condric1
1.
Asset Management Branch, Brisbane Infrastructure Division, Brisbane City Council, Brisbane, QLD, Australia
Brisbane City Council, Australia’s largest local government authority, maintains a road network of 5,700 km, ranging from residential access
streets to major arterial roads. Pavement configurations include granular and cement stabilised granular with thin asphalt surface, concrete
and deep strength asphalt. Traffic loadings range from local residential streets through industrial access roads to arterial
roads. Approximately 93% of the network is asphalt surfaced and to construct and maintain these roads, Council operates two asphalt
plants, two quarries and a recycling facility.
As part of Brisbane Vision 2031 - Our Clean, Green City goal of Towards Zero Waste, Council actively uses recycled materials in its pavement
works. Recycling processes includes the use of Recycled Asphalt Pavement (RAP) and crushed glass in asphalt, recycled concrete as a
pavement material and strengthening of pavements by stabilising the existing pavement materials.
Through successful collaboration with local universities and other research organisations, Council has been able to extend its research into
the effective use of these recycled products to understand their performance and the resultant overall benefits to Council.
This paper highlights how pavement recycling is part of the normal practices to sustainably manage Council’s road network.
ESTABLISHMENT OF THE FATIGUE ENDURANCE LIMIT OF EME AND A5E MIXES FOR INCORPORATION INTO THE AAPA LONG LIFE
DESIGN PROCEDURE
Bevan Sullivan1, Alvin Prasad2, Tom Gabrawy3
1.
Fulton Hogan, Sydney
In 2012 the Australian Asphalt Pavement Association initiated the Asphalt Pavement Solution for Life Project (APS-fL), as part of this project a
draft supplementary guide to the AUSTROADS design guide has been developed for the design of Long Life Asphalt Pavements (LLAP). This
supplement uses the new concept of a Fatigue Endurance Limit (FEL) relationship to determine the limiting thickness of full depth asphalt
pavements, beyond which any increase in thickness results in no increases for freeway environments. Although, it was known that higher
FEL’s existed for non-conventional asphalt mixes, at the time of developing the supplement data was available both in terms of laboratory
testing and field performance data to include non-conventional mixes in the design supplement.
Over the past few years two new asphalt mixes have been introduced into the Australian market, EME and A5E asphalts, both of which have
shown significant benefits in optimizing conventional pavement design. However due to the LLAP design supplement, being limited to
conventional asphalts no benefits can be shown in determining the limiting thickness.
This paper sets out the procedure for the development of the FEL relationship for non-conventional asphalt mixes and provides guidance on
how the FEL can be incorporated into the LLAP design supplement.
INTER-CONVERSATION OF AUSTRALIAN MODULUS TESTS
Bevan Sullivan1, Erik Denneman2
1.
Fulton Hogan, Sydney
2.
Australian Road Research Board, Brisbane
The fundamental parameter required for the characterisation of an asphalt mix in any mechanistic design procedure is the modulus or
stiffness of the asphalt mix. Traditionally, in Australia two methods have existed for the measurement of the modulus of an asphalt mix, the
resilient modulus test and the flexural modulus test. Additionally, as part of the APS-fL project, AAPA introduced the dynamic modulus test
and the use of master curves for the characterization of asphalt mixes.
While all these test measure a modulus of the mix, none have the same definition of modulus or use the same loading shape. The result of
this is that different modulus values are obtained for the same “frequency” and temperature in the different test methods. The different
results, definition of modulus and definition of frequency, has led to confusion on how to report and convert modulus results obtained from
one test method to another.
The mathematics behind the conversion between modulus testing is complex and open to interpretation. Instead of trying to solve this
mathematics, this paper looked at the direct inter-conversion of the modulus tests and recommends a standard approach to converting and
reporting modulus results.
PERFORMANCE AND STRUCTURAL CHARACTERISTICS OF COLD CENTRAL PLANT RECYCLED ASPHALT CONCRETE
David Timm1
1.
Auburn University, Auburn, AL, United States
Cold central plant recycling (CCPR) has traditionally been a little-used technique in reclaiming asphalt pavements (RAP) in the U.S., especially
on higher-volume roadways. In 2012, the Virginia Department of Transportation (VDOT) sponsored three test sections at the National
Center for Asphalt Technology (NCAT) Pavement Test Track to evaluate CCPR under accelerated traffic conditions and to complement a field
project using CCPR on I-81 in Virginia. The three Test Track sections evaluated the effect of asphalt concrete (AC) thickness over the CCPR in
addition to using a cement-stabilized base layer versus an unbound granular base beneath the CCPR. The objective of this investigation was
to characterize the field performance and in situ structural characteristics of the CCPR sections at the Test Track. After 10 million equivalent
single axle loads (ESALs), all three sections exhibited excellent performance with no cracking, relatively little rutting (<7 mm) and very little
change in smoothness over time. This investigation clearly demonstrated the viability of CCPR under high traffic conditions. Further, this
study found that 1) the backcalculated AC/CCPR moduli resemble conventional AC materials while the stabilized base section appears to be
curing over time, 2) the measured tensile strain at the bottom of the CCPR layer clearly showed the structural benefit of including an
additional 50 mm of AC or the use of a stabilized base layer, and 3) the structural benefits of an additional 50 mm of AC are less pronounced
when examining the base and subgrade pressure levels.
PAVEMENT DESIGN - PAST, PRESENT AND A SUSTAINABLE FUTURE
David Timm1
1.
Auburn University, Auburn, AL, United States
Pavements are a vital component of healthy infrastructure. For the past 50 years, the design of pavement structures has been largely
empirical based on results from the AASHO Road Test held in the north-central U.S. in the 1950’s. The growing demand for higherperforming, longer-lasting pavements under extreme traffic conditions, all at reduced cost, has lead pavement engineers to re-evaluate
empirically-based methods and embrace mechanistic-empirical approaches. These approaches more readily accommodate innovations in
construction, materials and better predict pavement performance over time. This allows for the rational inclusion of green-technologies
such as reclaimed asphalt pavement, recycled asphalt shingles, ground tire rubber and warm-mix asphalt. Research at the National Center
for Asphalt Technology (NCAT) Pavement Test Track has demonstrated the viability of these technologies under high traffic conditions and
how they may be incorporated in modern pavement design methods. These methods include perpetual pavements which provides for long
life asphalt pavement with minimal structural improvements over time. Again, research from the NCAT Test Track, and other test sites, has
demonstrated the viability of perpetual pavement design as a valuable tool in achieving sustainable roadway infrastructure.
FIELD STUDY OF RESOURCE RESPONSIBLE MATERIALS
David Timm1
1.
Auburn University, Auburn, AL, United States
Resource responsible materials are being used in asphalt pavements to create high-performing, cost-effective pavements with minimal
environmental impact. These materials include: reclaimed asphalt pavement (RAP), recycled asphalt shingles (RAS), ground tire rubber (GTR),
and warm-mix asphalt (WMA). Although the implementation of resource responsible materials is increasing, wider use and acceptance will
be achieved through further performance monitoring and structural characterization. The 2012 “Green Group” experiment at the National
Center for Asphalt Technology (NCAT) Test Track was designed to address this need. The Green Group experiment was comprised of four
WMA sections: Conventional RAP, High RAP, RAP/RAS, and GTR. Performance was monitored – using in-situ strain gauges, falling weight
deflectometer testing (FWD), and weekly surface distress surveys – as the sections were trafficked by heavy triple-trailer trucks. This
research compiles construction, performance, forensic information to characterize performance and identify the mechanisms that led to the
observed distresses. Cracking was a primary distress observed in each section. The RAP/RAS and GTR sections significantly outperformed
the conventional RAP section. Early cracking failure was noted in the High RAP section, but was suspected to have resulted from slippage
between asphalt layers. Further forensic investigation (including coring and modelling) was initiated to explain the varying performance and
found layer interface bonding critically important, as is the case in any flexible pavement structure
INTELLIGENT ASPHALT COMPACTION WITH BOMAG ASPHALT MANAGER 2
Chye Cher Ting1
1.
BOMAG GmbH, Singapore
Abstract
In today’s competitive road construction market, we are always striving for high production output of a high standard to top of increased
profits as well. Thus, the concept of quality assurance and quality control(QA/QC) activities will also need to evolve.
Conventional methods of QA/QC programmes are too time-consuming and often disrupt construction schedules which will eventually lead
to increased costs. It may also not be representative of the entire pavement project.
The evolution of Intelligent Compaction or Continuous Compaction Control (IC/CCC) systems for the past 30 years has shown that it now
offers a more comprehensive and efficient QA/QC than conventional methods of testing.
This paper will focus on the concept of IC/CCC by introducing the BOMAG Asphalt Manager 2 and how this proven technology will improve
future infrastructure performance, reduce construction schedules, reduce costs and also improve overall site safety. 1
1. Kloubert H.J., Wallrath W., 2012 "Roller Integrated Surface Covering Dynamic Compaction Control" Job Report No. 05/12 PRE 108 070
2. Kloubert H.J., Wallrath W., 2010 "Intelligent Asphalt Compaction" Job Report No. 07/10 PRE 200 250
ASPHALT RUTTING PREVENTION IN AN APPLICATION OF HEAVY DUTY DENSE GRADED MIXES TOGETHER WITH PMB A5E
Johnny Tran1
1.
DPTI, Adelaide, SA, Australia
This paper presents the findings of Heavy Duty Asphalt Trials in South Australia with the application of Polymer Modified Binder temporarily
named as A5E using Kraton SBS D0243 for the purpose of Early Asphalt Rutting Prevention.
The trials have adopted RMS Specification PMB A5E properties with two based bitumen’s C170 & C320 to seek the critical properties of
stiffness and softening points. The analysed performance data of both PMB A5E & Heavy Duty Asphalt Mixes is presented and also
compared with both PMB A35P & A15E together with the field performance. The trial of PMB A5E is still ongoing and will be continuing
monitored over first 3 years.
INVESTIGATION OF SPRAY SEAL PAVEMENT FAILURE AT CALOUNDRA TENNIS CENTRE
Andrew White, Rhys Kilpatrick, John Tuxworth
Built Environment Collective was commissioned to provide Civil Services for the Caloundra Tennis Centre Redevelopment. The project
involved a 580 square metre car park extension. A two-coat spray seal pavement was determined appropriate with respect to budget
requirements and infrequent light vehicle usage.
Three months into the on-maintenance period it showed significant wear and aggregate stripping. The performance of the two-coat spray
seal as-constructed was reviewed to determine suitability and method of failure. Response was also provided to the sub-contractor’s claims
that:
-
2-coat seal should not be employed for use in a carpark situation
-
The pavement performance (and failure) was indicative of a 2-coat seal application
This paper compares the as-constructed two-coat spray seal with:
-
the nominated Sunshine Coast Regional Council Specification,
-
Austroad,
-
industry best-practice.
The two coat seal pavement was designed according to Austroads and Sunshine Coast specifications. It was noted in Austroads AP-T236-13
and the AAPAA pavement selection table that the use of a two-coat spray seal is suitable for high stress areas with low volumes of heavy
vehicles.
The sub-contractor’s proposed two-coat spray seal application rates/quantities were provided and reviewed after failure. As interpreted the
binder application rate was too low, and the proportion of aggregate too high compared to Austroads specifications. Choice of aggregate
size was also questioned. The AAPA ‘Work Tip No.38; Sprayed Sealing – Surface Enrichment’, was referenced and nominated as a rectification
method for providing enhanced binding and extended design life.
In this instance deviation from best practice specification has resulted in a poorly finished surface and inadequate aggregate binding.
Despite differing industry opinions, a number of guidelines and literature sources identify that spray-seal can be utilised as a carpark
pavement surface for light vehicle use, providing an economical and appropriately durable asset.
FOAMED BITUMEN STABILISATION AND CASE STUDY - SMITH STREET MOTORWAY AND OLSEN AVENUE INTERCHANGE UPGRADE
PROJECT, GOLD COAST
Tanmay Vaidya1, Damian Volker2
1.
Parsons Brinckerhoff, Brisbane, QLD, Australia
2.
Engineering and Technology, Queensland Department of Transport and Main Roads, Brisbane, QLD, Australia
This paper will provide information about methodology, design and construction of TMR Foamed Bitumen stabilisation process. Besides, a
detail case study will be presented.
Foamed Bitumen is a specialist pavement stabilisation method of incorporating hot bitumen into gravel by means of adding a small
percentage of water. The addition of water causes bitumen to expand 10 – 20 times in volume. While in its expanded state, foamed bitumen
has the ability to disperse amongst a larger surface area coating finer particles. These fine bitumen particles create millions of individual
elastic points giving foam bitumen pavements excellent flexibility and flood resilience.
The case study project is located at the doorstep of the flexible pavement conference. This $57 million road upgrade involved insitu foamed
bitumen on 2.4 km of eastbound carriageway. The stabilised sub-base was then overlaid by intermediate and surfacing asphalt layers. The
foamed bitumen provided a sustainable and cost effective pavement. This paper will discuss design, construction processes, and key
learning outcomes. Pavement investigation data of before and after the rehabilitation work will be analysed and presented.
DESIGN OF HIGH PERCENTAGE RAP MIXES IN SOUTH AUSTRALIA
Hugo Van Loon1, Peter Hughes2, Johnny Tran1
1.
DPTI, Adelaide, SA, Australia
2.
Downer, Adelaide
This paper explores the technical and specification requirements of incorporating varying percentages of RAP up to 50% into asphalt mixes
in South Australia. The improved quality of asphalt plants makes this a reality while environmental and cost benefits make this essential for
South Australia.
The rejuvenation of aged RAP is explored, and data from one asphalt plant is analysed and presented with a range of findings including a
limited role for direct viscosity testing of RAP stockpiles and use of stiffness testing on a daily basis is discussed. A proposed specification
update is also presented.
THE USE OF WARM ASPHALT SURFACING ON A HEAVY VEHICLE ROUTE: A CASE STUDY IN SOUTH AFRICA
Ian Van Wijk1, Jan Louw1, Anton Hartman1
1.
Aurecon, Brisbane, QLD, Australia
Warm Mix technology was used on a road carrying very heavy coal trucks through the town of Bethal in South Africa. Long hauling distances
created a challenge and warm mix technologies were used to produce a suitably compactable, but also (paradoxically) highly rut resistant
surfacing. One of the main advantages when implementing the warm mix is the shift and extension of the available compaction window,
providing contractors with an extended workability period. The paper will provide information on the traffic loading, the mix design, rut
resistance measurements, construction and performance.
BUILDING BETTER ROADS AT LOWER COSTS
Willem Vonk1, Bob Klutz
1.
Kraton Polymers Research B.V., Amsterdam, Netherlands
Polymer Modified Binders (PMB) have by now captured about 15% of the global bitumen market in paving and the trend is still going up.
Besides comparative trials, there are not many extensive evaluations whether the investment in higher priced PMBs is worth the money. It
wasn’t until 2005 that the US Asphalt Institute actually provided evidence that PMBs did perform better, leading to reduced maintenance
schemes and longer lifetimes, which results in improved NPVs. It has to be realized that these data were based on typical US formulations
that normally have relatively low polymer loadings and tend to be applied in the wearing course only.
Another known fact is that the effectivity of polymer modification of bitumen is non-linear: at a certain minimum concentration, the polymer
is able to form a continuous network throughout the binder. If one then combines binders with a polymer concentration above that
threshold with modifying the full depth asphalt, the performance improvement is such that one may expect either perpetual pavement
performance at standard thickness or it is allowed to reduce the standard thickness to a level that the performance is still premium while
the cost of the pavement is lower than when based on unmodified bitumen. This paper provides the latest information on data generated in
NCAT and demonstrates the effect of the improved performance in the outcome of different pavement design methods.
NEXT GENERATION BINDER FOR AIRPORT ASPHALT
Greg White
Most of Australia’s runways are surfaced with Marshall designed, dense graded, hot mix asphalt. There surfaces are typically replaced by
asphalt overlay every 10-15 years. Traditionally, conventional C320 bitumen was used as the binder. To address a number of perceived
performance issues, since the start of the 21st century, airport asphalt in Australia has often included premium binders. There is a
perception of a reduction in performance of binders in Australia and overseas. Aircraft and their operation at major airports have also
become ever more severe with continued growth in wheel loads and tyre pressures. The field performance of airport asphalt has been
questioned with a number of failures being well documented.
Binder comprises only 5-6% of the mass of airport-quality asphalt. However, its influence on the performance of the mixture cannot be
disputed. This critical element of this mix is, however, one of the least transparently monitored elements. Aggregates are subject to an array
of independent testing and petrographic analysis, quarry faces are inspected and source rock approved ahead of time. Bitumen, by contrast,
is required only to pass through empirical ‘gates’ for viscosity and other parameters, which vary for different grades and binder types.
In an effort to improve airport asphalt’s field performance a new proprietary binder was developed called JetBind. JetBind was developed to
meet the specific demands of airport pavements in Australia’s generally hot climate. The high temperature/high shear performance of the
JetBind was compared to that of commonly specified products. Comparisons were made using the USA’s Performance Grading test known
as the Multiple Stress Creep Recovery protocol for the Dynamic Shear Rheometer. Comparisons were also made for Marshall and other
properties. The test results show the benefits of JetBind in comparison to the current grades of binder for Australia airports.
THE ADEQUACY OF RUNWAY ASPHALT OVERLAY INTERFACE CONSTRUCTION
Greg White
Most of Australia’s runways are surfaced with Marshall designed, dense graded, hot mix asphalt. The common approach to runway
resurfacing is to remove at least the top 5 mm of the existing surface layer prior to cleaning and tack coating. The exposed surface is cleaned
and tack coated prior to the new (typically 50-60 mm thick) layer being constructed. These processes are commonly performed all in the
same shift, which is often a short night time period. This places pressure on construction processes, including those relating to the bond
achieved at the interface between the existing pavement and the new surface.
The interface between asphalt layers is critical to good pavement performance and has been shown to be the cause of significant surface
failures on airports around the world, including Australia. The interface condition can be tested in the field or in the laboratory using a range
of monotonic direct shear and cyclic shear loading regimes. Factors that affect interface adequacy include tack coat type and application
rate, interface texture, contamination and service temperature. Where the achieved interface strength is exceeded by aircraft induced shear
stresses, the interface will fail and delamination or shoving may occur.
For aircraft loads and tyre pressures, these shear stresses are significant. They also peak 40-60 mm below the surface of the pavement, right
where the interface is commonly located. This paper presents and review of airport asphalt overlay construction methods and risks. The
testing of a number of interfaces from real airports is detailed as well as the calculation of aircraft induced shear stresses under various
braking conditions. The adequacy of interface shear resistance is then assessed based on the measured interface strengths and the typical
stresses induced. Finally, potential improvements are suggested for the future of airport asphalt overlay design, specification and
construction.
A PREVENTATIVE MAINTENANCE TREATMENT – SEALCOAT
Jason Williams1
1.
SRS Roads Pty Ltd, Brisbane, Queensland, Australia
Sealcoat is a preventative maintenance treatment designed to preserve asphalt and spray seal pavements in an as new condition for as long
as possible and thereby reduce the need for expensive rehabilitation and reconstruction.
Sealcoat treatments are designed to seal the pavement surface against the intrusion of air and water, thereby slowing the oxidation process.
SealCoat involves the application of a polymer-modified bitumen emulsion containing specially graded aggregates, fillers, latex, rubber and
pigment adjusters, with sand and water being post added on site prior to application. Custom built sprayers with larger nozzles than
conventional sprayers, specialist pumps and mixing paddles help to keep the material in suspension. Being an emulsion it is not heated but
applied at ambient temperature.
Advantages over conventional treatments include the speed of application with an average shift spraying over 6,000m2 in urban streets and
a fast drying time of between 30 mins and 2 hours. Disadvantages include no shape correction and a relatively short life span of about 5
years between applications.
The finished treatment provides a rich black colour that seals and extends the pavement life at a low cost and has been successfully applied
at most major airports, Defence bases and on local government roads in Australia.
DEVELOPING A FRAMEWORK FOR INNOVATIVE RESEARCH AND EDUCATION WHICH IMPROVES PAVEMENT LIFE CYCLE AND REDUCES
COSTS
Susan Tighe1, John Yeaman1
1.
University of Sunshine Coast, Maroochydore, QLD, Australia
There are many exciting innovations currently occurring in the pavement engineering and management field. It is apparent that these
innovations in design, material selection, construction practices, maintenance procedures and management of road networks present many
opportunities for the Australian Asphalt community to implement these innovations to provide technical, economic and in many cases
environmental benefits. It also means there can be costs to implementing some of these innovations so these need to be managed properly
and efficiently.
This paper summarizes a framework on how innovative asphalt technologies can be assessed in a quantitative manner. It is based on some
on-going research that is currently underway at the Queensland Pavement Centre located at the University of the Sunshine Coast and
various industry partners. More specifically, it is directed at integrating laboratory and field testing in an engineered way to determine how
effective various materials, designs and technologies are. The paper initially describes how a technology can be assessed in a factorial
manner. It then identifies how key performance indicators can be selected and subsequently examined. This analysis is presented in a
decision tree matrix. Finally guidelines are presented on how an engineered test section might be designed and constructed to ensure all
the important parameters are tested while all parties are able to manage risk. The paper is directed at both public and private sector
stakeholders in the industry who may be looking at testing a new material or technology.
Overall, this paper shares some best practices on key aspects to quantifying costs and benefits and provides a few examples of how recent
technologies have been assessed under this framework.