MA ModernAsphalts · 2020. 11. 17. · Modern Asphalts 6 Asphalt turns down the heat E fforts by...

S p r i n g 2 0 1 0 I s s u e n o 2 6

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Modern AsphaltsMA

THE MAGAZINE AND WEBSITE FOR HIGHWAYS AND AIRFIELDS ASPHALT PAVING

Inside this issue:

• Advocating a long view• Positive results for less heat• Answering emerging needs• Cold weather road fix• Value solved and sealed

T o o b t a i n m o r e d e t a i l s o f t h e p r o d u c t s a n d s e r v i c e s f e a t u r e d w i t h i n ,

p l e a s e e m a i l u s a t i n f o @ m o d e r n a s p h a l t s . c o m

2

Inside this issue:

M o d e r n A s p h a l t s 4Ringway is advocating

active asset managementfor more effective

maintenance

6A study led by Nynasis indicating positiveresults for reducedtemperature asphalt

10Colas’ Fibredec is ideal forrepairing roads andstrengthening them beforethe next cold weather

14Reviewing a selection ofkey asphalt surfacingdevelopments archived atwww.modernasphalts.com

12A new specialist

emulsion has beenlaunched by Bituchem

for sealing andpreserving roads

8After a decade of

development, ShellWAM® Foam is set tomeet emerging needs

M o d e r n A s p h a l t s

3

C l i e n t S i d e

Northern Ireland’s Roads Service is

seeking to reassure highway engineers

that thin surface course systems (TSCS)

are appropriate for surfacing principal

roads. The TSCS has to be designed

correctly for the site, however, with attention

paid to applied stress and quality of

substructure and workmanship in laying,

particularly around ironwork.

This is according to Roads Service

Consultancy (RSC) senior engineer and author

of a report on TSCS performance Geoff Lester.

Following publication of the report and further

developments, RSC is keen to ensure

engineers in Northern Ireland develop well

informed approaches.

“High profile failures of one or two TSCS

type surfacings had given the rest a bad name.

As a result a lot of engineers in Northern

Ireland had lost confidence in TSCS and gone

back to using hot rolled asphalt (HRA),” says

Lester. “The key message is specify TSCS but

get the design right because not all TSCS

surfacings are suitable for all locations.”

Contractors and asphalt manufacturers in

Northern Ireland moved to develop their own

proprietary TSCS materials from the late

1990s. By 2004 enough suppliers had gained

HAPAS (Highway Authorities Product Approval

Scheme) approval of their products to prompt

Roads Service to issue ‘Director of

Engineering Memorandum’ advice DEM

67/04 for designers of thin surfacings.

Increasing use and occasional problems

have since raised concerns over durability,

however, leading to RSC’s commission. The

work studied performance of proprietary TSCS

materials laid since 2004 at 120 sites. The

results find the majority of TSCS materials

performing well. Major failures had occurred at

two sites, while failures around ironwork were

found in 26 cases. Seven locations showed

evidence of isolated texture loss, fretting or

‘fattening up’, while a single site exhibited

rutting and potholing as a result of poor

underlying layers.

“There are several reasons found for these

problems, including use of 14mm materials at

high stress sites where a 10mm material may

be more appropriate,” Lester says.

Manufacturers produced TSCS materials

with 14mm aggregate primarily for generating

the 1.5mm minimum texture depth specified

by the Specification for Highway Works

(SHW).“Too much importance was attached

to texture depth. It’s not even the key

requirement of skid resistance,” says Lester.

The minimum texture required by the SHW

has since been amended to 1.3mm for thin

surfacings and use of 10mm materials has

become more prevalent. Designers still need

to be very careful when designing for high

stress levels.

“Some 10mm products with HAPAS

approval have been tested at lower thresholds

of traffic volume,” Lester says. “Overall,

proper design is essential, as is consideration

of the substrate and contractors should be

ensuring good compaction is achieved around

ironwork.”

More work is to be done including reissue

of DEM 67/04 for Roads Service engineers.

“Manufacturers also need to look at their

TSCS mixes to make them more durable and

compact better,” Lester says.

Changes beyond tight tolerances set by

HAPAS certificates would mean having to

apply again through the exhaustive HAPAS

approval process, but TSCS is now in the

European Standard for asphalt BS EN 13108.

“There is no reason why contractors cannot

use factory production control and type testing

for CE marking quality assurance instead,”

Lester says.

Thin surfacings in Northern Ireland:still favoured if designed correctlyInvestigation of thin surface course systems in Northern Ireland has found the

majority performing well, although occasional problems reveal a need to be

vigilant in design and construction.

Thin surface course systems at 120 sites have been investigated. The majority are performing well

email: [email protected]

Highway authorities facing backlogs of

emergency road repairs and with

limited budgets at their disposal may

be forgiven for concentrating their

efforts on delivering short term,

relatively inexpensive maintenance. But with

planning and the use of preventative

measures, road condition can be preserved

more cost effectively if clients and providers

can focus their efforts on carefully managing

their highway assets over the longer term.

This does not mean that potholes should

be left unfilled or reflective cracks ignored.

What the road maintenance contractor

Ringway is advocating is to use the

knowledge from asset inventory and

condition surveys and develop durable

products and construction processes across

a range of contracts and in a variety of

locations. This way the very best solutions

can be arrived at with both short term needs

and long term benefits in mind.

Ringway’s Group Bid Director Rob

Gillespie explains: “Asset management is all

about taking the known condition of the

network and deciding upon the standard of

highways you want to see, in terms of

structural composition, surface condition and

residual life. The asset and pavement

knowledge that Ringway has built up across

its Private Finance Initiative (PFI) activities

and European experience, allows us to work

with clients to deliver the most appropriate

construction and maintenance solutions. We

want authorities to make use of the best

new technology that offers durable materials

and value for money over the long term.”

Understanding how a highway performs

over time and intervening with a surface

treatment at the most appropriate point can

also help to prevent surface defects from

appearing in the first place, or being allowed

to get worse, Gillespie adds.

Highway asset management is not a new

idea, says Gillespie, but returning to the

process of preventative maintenance given

the backlog in maintenance over the last

three decades is a daunting thought for

network managers. The prospect of a

squeeze in maintenance funding after the

forthcoming General Election means clients

are likely to need to look more closely at

making savings. But by deploying more

durable products that perform well for many

years, the ‘whole life’ cost of roads – and

wider networks – could begin to come

down. It is the detailed knowledge of how

materials will perform over extended periods

that is critical to the decision making

process.


4

Calling for thelong term viewActive asset management is the key to highway authorities maintaining

roads more effectively and Ringway is well placed to bring its experience

of maintenance and materials to help clients achieve this.

R i n g w a y

“We want authorities to make use of

the best new technology that offers

durable materials and value for money

over the long term.” Rob Gillespie

Increased use of asset managementtechniques for delivery of long term roadmaintenance has led Ringway to developasphalt materials that reduce noise, areaesthetically pleasing, help combat vehicle

emissions and use less virgin stone.At Tonbridge in Kent, the company recently

specified its new Ultraphone asphalt surfacingthat reduces road noise after complaints fromlocal residents. In London, ‘Streetprint’surfacing has been laid to mimic theappearance of paving slabs without the needto employ specialist paving gangs.

The company has also developed a roadsurfacing designed to reduce traffic pollution.The ‘Noxer’ material contains titanium oxidethat accelerates the oxidation of nitrogenoxides emitted from cars to form stable,neutral oxides that are held on the surface andwashed away by rain.

Furthermore, trials are under way to createa high friction surfacing which blends togetherbauxite and lower grade aggregate to createan overall more cost efficient anti skid materialthat promises to deliver wider options foraccident reduction.

ASSET MANAGEMENT PROMPTS DEVELOPMENT

Road renewal under way in Enfield, north London


5

Durable road surfacing materials are being developed by Ringway as a result of its attention to asset management

Ringway has been maintaining local

authority roads in the UK for nearly 35 years

and in that time has built up a wealth of

knowledge on material composition and

performance. The company makes good use

of a pavement research facility in Warrington

and its world innovation centre in France

operated by parent company Eurovia to

develop new road construction and repair

products (see box). Clients are invited along

to help tailor materials that meet their long

term objectives.

Gillespie welcomes the introduction of

long term PFI highway maintenance and

management contracts, such as those in

Portsmouth and Birmingham. “These

arrangements allow road network condition

to be thoroughly assessed at the start of a

contract, brought up to standard using

durable materials during a core investment

period and maintained in the most effective

manner for the life of the concession,”

Gillespie says.

Ringway was unsuccessful in its recent

bid to manage Birmingham’s highways, but

the tendering process was not in vain and

formed part of Ringway’s long term strategic

development. It allowed engineers and

mathematicians from the company to further

develop their understanding of asset

management and more accurately predict

when a range of different carriageway

constructions would need to be renewed.

It allowed Ringway to match first hand

pavement condition information with the

materials and construction techniques

gathered from theoretical laboratory study.

Together with data from extended

monitoring of materials on long term

contracts, it has allowed the organisation to

fully appreciate the pavement management

decisions that clients have to face on a daily

basis, and develop long term asset

management strategies for Ringway itself.

The company is hopeful that this –

together with its experience of looking after

highway maintenance for authorities

including Worcestershire, Surrey, Kent and

Transport for London – will stand it in good

stead when bidding for further PFI roads

contracts and when studying options for

future highway financing models.

“By working closely with clients, we

believe that the skills of all maintenance

practitioners can work towards building

more robust management plans to balance

highway quality now with a durable

pavement which requires less maintenance

in the future,” says Gillespie.


[email protected]

Highway condition is often recorded for thepurposes of asset management usingroadmonitoring vehicles developed to theSCANNER (Surface ConditionAssessment for the National Network of

Roads) specification.There is currently no such nationally

recognised system for footways (althoughindustry groups are working on one) which aregenerally assessed visually to determine therepairs needed and to record the condition of theasset. On some contracts, Ringway and clientengineers working together operate ‘find and fix’

teams for identifying and repairing road defects.They use hand held electronic notebooksconnected via the Internet to a central roadmanagement inventory for logging reports ofproblems spotted.

‘Emergency’ defects are repaired immediatelyand the work recorded in the same system. Lessurgent programmes of refurbishment work arecarried out later by operatives on a scheduledmaintenance run, whose vehicles are directedfrom one site to another using satellite navigationwhich is linked to the task ordering system.

This blend of immediate repair and conditiondata gathering ensures the most cost effectiveapproach and guarantees safety defects areacted upon quickly.

MONITORING ON THE MOVE


6

Asphalt turns down the heat

Efforts by bitumen chemists to

develop durable asphalt material at

temperatures less than 180°C are

beginning to pay dividends. A range

of ‘Warm’ (100 - 140°C) and ‘Half

Warm’ (70 - 100°C) mix materials are now

available that not only offer a series of

social, economic and environmental

benefits – but are proven to be durable as

well.

A four year study into the performance of

three reduced temperature asphalt

techniques, including foamed bitumen, is

coming to a close in Belgium. Early results

from the study indicate there is little

difference between the performance of

warm and half warm asphalt compared to

hot mix material. The research project, led

by materials specialist Nynas and the

Belgian Road Research Centre, also points

to the conclusion that the same degree of

compaction can be achieved in a foamed

bitumen asphalt produced at 90°C as a hot

mix material produced at 150°C.

Publication of the Belgian study is

eagerly awaited by advocates of warm mix

technology, who are looking to substantiate

what they already claim: that asphalt

performance does not necessarily depend

on mix temperature.

They will also point to the numerous

benefits on offer by specifying warm mix

material. Financially, there are savings of up

to 50% to be had in fuel and energy costs

when choosing a half warm mix. Reduced

temperature asphalt can also be designed

to include recycled asphalt planings. This

leads to lower costs associated with mining

virgin material and reduced penalties for

disposing of unwanted aggregate.

Use of recycled material in warm mix

asphalt has its environmental benefits as

well. Substituting just 14% of primary

aggregate for recycled planings can reduce

carbon emissions in an asphalt by 4% and

cut a surfacing’s overall environmental

impact by 9%, according to a recent study

by the Waste & Resources Action

Programme.

There is also the not insignificant claim

that lower temperature asphalt reduces

carbon dioxide and nitrogen oxide

emissions by as much as 50%.

From a social point of view, reducing

asphalt temperature improves safety for

operatives, as there is less chance of

suffering burns when working with a warm,

rather than a hot, material. Disruption for

motorists around a warm mix roadworks

site is also said to ease, as construction

Reduced temperature asphalt production is being promoted by

Nynas to help highway authorities cut energy use and limit

greenhouse gas emissions.

N y n a s

“In the next 10 years, I believe a major

part of the UK’s asphalt market will

swap from using hot mix to warm mix.”

Dennis Day

Asphalt suppliers looking to develop and trialwarm mix asphalts can work with Nynas and itscomprehensive laboratory and testing facilities

programmes tend to be quicker when such

materials are specified.

One man with high hopes for the future

of warm mix material is Nynas’ product

application manager for cold paving

technology and surface treatments Dennis

Day. He says: “In the next 10 years, I

believe a major part of the UK’s asphalt

market will swap from using hot mix to

warm mix.”

Warm mix material offered by Nynas

makes use of the company’s foamed

bitumen binder Nyfoam. Foamed bitumen

is produced when water is introduced to

hot binder in small quantities. Water turns

to steam and the viscosity of the bitumen is

consequently reduced. This allows it to

flow more readily and coat stone more

effectively at a lower temperature than

conventional hot mix.

The foaming action can also increase the

length of time an asphalt remains workable

on site, without the use of chemical

additives. Bitumen can either be foamed

before it is added to a mix, or during the

mixing process.

“Use of foamed bitumen allows us to

manufacture a durable asphalt with the

performance characteristics of a material

created using a hot binder, but at a lower

temperature,” adds Day.

“We believe that our Nyfoam range of

binders has better and more consistent

foaming characteristics compared to other

binders, and is suitable for a wide range of

applications using half warm and warm mix

processes."

Nynas now hopes that warm mix

material using Nyfoam will begin to be

used in the upper layers of road pavement

in the UK. This would mark a departure for

the company, which until now has

promoted foaming binder for lower

pavement layer materials, mixed cold. For

over 20 years, Nynas has supplied bitumen

to the European market, which has been

used for foaming onto aggregate at

between two and three percent of volume

to enhance the characteristics of base

course material.

According to Day, if a higher percentage

of foamed bitumen is added to an asphalt –

matching the levels used in conventional

hot mix – the resulting material can be used

successfully in binder and surface courses.

The trick is to ensure aggregate particles

are coated fully. Asphalts mixed warm have

been used by Nynas' customers on road

construction projects in Holland since

2002. Products featuring the Nyfoam

binder include the lower temperature road

surfacing material LT-Asfalt.

Asphalt suppliers looking to develop and

trial warm mix products are welcome to

work alongside Nynas and make use of its

comprehensive laboratory and testing

facilities in the UK, Belgium and Sweden. In

some cases, asphalt mixing plants may

have to be modified to accommodate the

manufacture of warm mix materials.

Specialist staff from Nynas can help asphalt

suppliers to invest in upgrades to their

infrastructure wisely.

A four year research project led by Nynas is indicating little difference in performance between ‘warm’, ‘half warm’ and hot mix asphalt materials

7



[email protected]‘Half warm’ materials offer social, economic andenvironmental benefits

S h e l l B i t u m e n

8

Market conditions turnfavourable for warm mix

Demand is growing for asphalt solutions

that can help reduce energy

consumption and lower emissions.

Launch of asPECT (the asphalt

Pavement Embodied Carbon Tool) at

the Asphalt Industry Alliance conference

Carbon Innovation Ahead in October 2009,

plus a rapidly changing ‘carbon landscape’

means asphalt suppliers are increasingly

looking for lower energy options.

Shell Bitumen recognises this need. For

many years, Shell has been making use of

research and development resources to find

new technologies. One example is the Shell

WAM® Foam process, which helps asphalt

manufacturers to produce and lay asphalt at

lower temperatures than conventional hot

mix without compromising the performance

of the resulting road surface.

Shell Bitumen’s technical service manager

Lee O’Nions says: “Producing asphalt using

the Shell WAM® Foam process consumes

less energy than conventional hot mix

asphalt.

“Asphalt is mixed and manufactured up to

60°C lower with the Shell WAM® Foam

process, in comparison to conventional hot

mix, which offers a considerable saving in

carbon dioxide emissions of up to 35%.”

The Shell WAM® Foam process is suitable

for use in all layers including surface courses.

It is produced by mixing together soft and

hard grades of bitumen with aggregate.

The soft binder is mixed with the

aggregate to precoat it and then the hard

bitumen is introduced to the mixture as a

foam. Asphalt produced in this way can be

made to a range of penetration as with

traditional hot mixes.

As there are no additives involved in this

process there should be no specification

barrier to use of Shell WAM® Foam in

comparison to alternatives that make use of

chemical or organic additives as referenced in

the European Asphalt Pavement Association

Shell Bitumen has more than 10 years of experience developing its

warm mix asphalt process Shell WAM® Foam, which is now set to

help answer emerging needs.


The Carbon Reduction Commitment EnergyEfficiency Scheme (CRCEES) will operateas a 'cap and trade' mechanism,providing a financial incentive to reduceenergy use by putting a price on carbon

emissions. It will apply to all UK companies ororganisations whose half hourly electricityconsumption exceeds 6,000MWh during 2008,or have at least one electricity meter settled onthe half hourly market. The UK Department forEnergy & Climate Change has estimated around5000 organisations will fully qualify and around20,000 large public and private sectororganizations will be involved in some way.

Monitoring and reporting begins for theCRCEES in April 2010 with trading starting in2011. Organisations will buy credits relating totheir annual emissions. Reduction targets will

CARBON TRADINGEXPLAINED

be set by placing a ‘cap’ on the total allowancesavailable to each group of participants. Moneyraised will be recycled back according toperformance against the targets, which will beranked in an annual league table on energyefficiency.

With this incentive on its way, there is muchShell Bitumen’s UK business can learn from

customers and trials elsewhere in Europe.Shell’s Swiss business manager FelixLichtsteiner says: “My customers have alwaysbeen keen to ensure good performance in aproduct. Now they can also take advantage ofthe financial and environmental benefits affordedby low temperature options. Shell Bitumen canhelp them achieve success”.

Shell Bitumen has extensive experience of Shell WAM® Foam projects in Europe

position paper The Use of Warm Mix Asphalt

in June 2009.

“Blending grades of bitumen for use in

asphalt is not unusual,” says O’Nions. “But

in the Shell WAM® Foam process, the two

grades of binder need to be injected

separately into the asphalt mixing plant. To

achieve this, a specially designed foam bar is

attached to the mixing plant to deliver the

correct quantities of binder at precisely the

right time.”

According to O’Nions, asphalt

manufactured using the Shell WAM® Foam

process is produced to a similar recipe as

conventional hot mix asphalt and no special

variety of aggregate or filler materials are

required. Clients can make use of secondary

aggregates, recycled asphalt planings or

crushed glass in the mix.

A patented process, Shell WAM® Foam

was first started in 1995 in conjunction with

Norwegian contractor Kolo Veidekke in

Norway. Since then, more than 90,000

tonnes of asphalt mixtures using the Shell

WAM® Foam process have been laid in trials

and commercial jobs throughout Norway,

Switzerland, Italy and the UK, each

demonstrating that WAM® foam mixtures

give equivalent performance to hot mix

asphalt in different road categories and in

different climates.

One specific trial in the UK has been

carefully monitored by O’Nions. “This UK

road has performed well over the years. The

site has been checked over time and cores

taken; the road is performing at least

equivalent to that of a hot mix asphalt.”

In 2008 the Swiss government distributed

carbon allowances to companies that opted

out of a national CO2 levy on heating fuels in

favour of an emissions trading scheme.

“In the last three to four years we’ve seen

an increase in customers’ interest in low

temperature options, but incentive to use

these innovations was low,” says Shell’s

business manager for Switzerland Felix

Lichtsteiner. “Today, partly as a result of

recent increases in taxation, low temperature

technologies are becoming increasingly

recognised in Switzerland as attractive

solutions which not only help reduce energy

consumption and emissions efficiently, but in

turn, reduce fuel and tax costs.

“Since 2008, customers are increasingly

coming to Shell as the Shell WAM® Foam

process is one of the few solutions that

enable them to continue to use the same

recipes, which is a big benefit to them.

Industry working groups have been set up to

accelerate implementation and we expect to

see an even bigger increase in use of warm

mix asphalts by 2011.”

Although in the UK there may have been

less financial incentive to encourage use of

lower temperature solutions, from April 2010

the Government is introducing mandatory

carbon trading which may give UK highway

authorities, their contractors and asphalt

suppliers monetary reasons to consider

lower temperature solutions.

The Government initiative, the Carbon

Reduction Energy Efficiency Scheme

(CRCEES), is designed to encourage large

organisations to reduce their carbon

footprint. Firms exceeding an annual carbon

emission target will be penalised while well

performing businesses will be rewarded (see

box left). Although it is not clear to what

extent organisations within the asphalt

industry will be involved, more than 20,000

companies in the UK are expected to

participate in some way.


99

Shell Bitumen’s warm mix process Shell WAM® Foam offers carbon emissions savings of up to 35% and produces asphalts suitable for all pavement layers

“Industry working groups have been set

up to accelerate implementation and we

expect to see an even bigger increase in

use of warm mix asphalts by 2011.”

Felix Lichtsteiner


[email protected]


1 0

Versatile treatment answerscold weather problems

Recent inclement weather across the

UK has resulted in numerous

potholes and cracks in the nation’s

roads; bringing home with a

vengeance the need to prepare

highways adequately prior to the next cold

snap.

The answer to this problem is simple,

according to Colas’ Fibredec consultant

Arthur Thompson. Authorities should be

making better use of Fibredec, a proven

material specifically developed to arrest

cracking and crazing of road surfaces.

Left unchecked, the freeze and thaw

action of water often causes cracks in the

surface to become larger and turn into

potholes. Use of Fibredec on weather

damaged carriageways inhibits further

ingress of water and protects the

foundation layers of a road.

Fibredec is a process whereby bitumen

emulsion, aggregate and chopped glass

fibres are combined to form a versatile

treatment that is very quick to apply and is

ideal for sealing cracked surfaces on either

concrete or asphalt.

The treatment is applied through

specially designed and patented equipment

which simultaneously sprays two films of

binder and sandwiches a layer of chopped

glass fibre between the films. The total

binder application rate depends on the

nominal aggregate size, the site category

and the rate of spread of glass fibre.

“The glass fibre gives Fibredec greater

tensile strength. It can reduce pre-patching

normally associated with conventional

surface dressing programmes by as much

as 40%, which ultimately means less time,

cost and waste” says Thompson.

Fibredec is highly versatile and can be

used in its own right as an enhanced

Colas’ Fibredec, developed as the ultimate stress absorbing membrane,

is an ideal inlay or surface treatment for repairing damaged roads and

strengthening them in preparation for cold weather.

C o l a s

“There’s no doubt that Fibredec hasproven to be the most efficientsolution for cracked roads,” saysColas’ Fibredec consultant ArthurThompson. “We’ve done

numerous projects and once the preparatorywork has been completed, Fibredec can beapplied quickly and efficiently.”

A recent example is a contract carried outon behalf of Redcar & Cleveland Council whichapproached Colas to overlay a badly potholedroad. This adopted road leads from a mainhighway to a group of houses and farms andcovers a distance of around 1600m.

“It was in a particularly bad state withnumerous potholes and lots of cracks,”

explains Thompson. “The only viablealternative to Fibredec would’ve been to planeoff the entire surface and relay it. Our methodwas by far the most cost effective solution.”

On this project Colas’ first task was to simplyfill all of the road’s potholes using road planingsto form a good profile for the Fibredecapplication. The preparatory work took one dayand a second day was used to apply a doubleapplication of Fibredec to the cleaned surface;finished with two coats of grey chippings.

FIBREDEC - THE COST EFFECTIVE SOLUTION

A badly potholed road in Redcar & Cleveland has been treated with Colas’ glass fibre reinforced surfacing Fibredec to produce a cost effective solution


1 1surface dressing, or – where that technique

may not be appropriate – alongside other

forms of road treatment as a stress

absorbing membrane. For instance,

Fibredec can be specified in combination

with a micro asphalt surfacing or applied

prior to the application of thin surfacing

systems.

Fibredec’s high tensile strength and

durability have been proved through

independent research by Ulster University.

The Northern Ireland institution evaluated

Fibredec and concluded that its use as a

stress absorbing membrane interlay (SAMI)

significantly inhibits the propagation of

reflective cracking in an asphalt overlay.

In each of the three tests carried out the

samples using Fibredec out performed the

samples where no SAMI was used. The

use of Fibredec was shown to enhance the

overall performance of an overlay by

approximately 30% and slow the wheel

tracking rate by 300%.

“Increasing pressure on highway

budgets is likely to result in a greater

portion of maintenance programmes being

delivered through more cost effective

surface dressing techniques in place of full

resurfacing. Fibredec provides clients with

a versatile solution with added whole life

cost and sustainability benefits,” says Colas

specialist treatments business manager

Carl Fergusson.

Given the deteriorating structural

condition of many roads, highways

authorities will be looking for surface

treatments that have inherent strength for

resisting cracking and ultimately prevent

the recurrence of potholes.

“Fibredec will figure in this because it

prevents onset of these problems occurring

again,” adds Fergusson.

1 11 1

Before and after with Fibredec: Deteriorating roads can be provided with a cost effective and high strength treatment to arrest surface cracking and crazing


[email protected] for surface dressing techniques with inherent strength is likely to increase due topressures on budgets

“The glass fibre gives Fibredec greater

tensile strength. It can reduce pre-

patching normally associated with

conventional surface dressing

programmes by as much as 40%.”

Arthur Thompson


1 2

Long term valuesolved and sealed

Innovative solutions are available to help

highway authorities overcome challenges

of deteriorating road condition during times

of static or decreasing budgets. The

bitumen technology specialist Bituchem

has several products on offer to help,

including a newly launched, environmentally

beneficial and very cost effective material –

FortSeal.

This a specialist fast setting emulsion that

when spray applied to an asphalt or surface

dressed road surface, covers small cracks and

surface voids; sealing and preserving the

pavement. The condition of treated

carriageway is effectively fixed at the time of

application of FortSeal and at a cost of only

80p per square metre.

“In comparison, relaying a road of fairly low

classification costs about £12/m2 and every

individual area of patching is £7 to £8,” says

Bituchem director Roger Lord. “Local

authorities had greater funds available 10 or

even five years ago and now their budgets are

likely to reduce further. FortSeal is relatively

cheap and holds road surface together at least

for the next five years when FortSeal should

be reapplied and it is the cheapest option

available for doing this.”

FortSeal is also a water based emulsion,

adds Lord, and therefore has the edge in

environmental terms on similar pavement

preservatives that derive from solvents.

“Compared to digging up and resurfacing

roads, FortSeal saves a lot of energy costs and

emissions. Use of the preservative is not

going to fix defects in road condition, but a

very good approach can be pothole filling or

patching followed by application of FortSeal

with a hand held spray gun to make road

repairs last much longer,” says Lord.

“It is usually the joints between road

surfaces and in-laid patches that are

vulnerable to water getting in and causing

premature or repeat failures. FortSeal helps to

seal joints and surfaces. Long term studies

have shown early treatment of the

preservative on a newly laid road surface,

before deterioration has become significant,

gives a life expectancy four times that usually

expected.”

Bituchem’s preservative was developed in

North America where a substantial weight of

evidence of the material’s performance has

built up over a period of 40 years. In Kansas in

the United States, for instance, a county road

surfaced with a bituminous surface course in

1969 was treated in part a year later with the

preservative – known then as General

Pavement Management – before being tested

for deterioration over the next seven years.

Core samples were taken from treated and

untreated sections after which the bitumen

was extracted and analysed using standard

methods at Iowa State University. Tests

showed viscosity was increasing at a far

greater rate in untreated sections which were

therefore oxidising and ageing more rapidly.

Likewise, penetration values remained higher

in treated areas, confirming that over a seven

year period, where applied, the preservative

had extended the life of the surfacing (see

graphs, right).

“A lot of performance testing of roads

treated with this preservative has been carried

out in the US,” says Lord. “Also backing up

the test results is the visual appearance of

carriageway surfaces five to seven years after

treatment. Sizeable cracks and potholes do

not appear because the binder in the road

surface has not become brittle.

“Minute cracking may start to appear at this

stage in the pavement’s life but with another

application of FortSeal the voids are resealed

and the bitumen ageing is slowed again. It is

the binder in asphalt surfaces that fails as it

ages, but with a simple and inexpensive

preservative treatment, problems with

potholes, repeat failures and disintegrating

road structures can be prevented.”

Bituchem is applying FortSeal in association

with one or two UK highway authorities and

their contractors this year, including Surrey

County Council which is hoping to see its

New developments in surfacing technology have arrived from North

America, including a bitumen emulsion that will seal and preserve

asphalt against the effects of ageing.

B i t u c h e m

“Long term studies have shown early

treatment of the preservative on a

newly laid road surface, before

deterioration has become significant,

gives a life expectancy four times that

usually expected.” Roger Lord

The FortSeal preservative provides a finishedsurface that will last longer and looks good

carriageway assets protected over a longer

term than conventionally seen. “Ideally we

would like to see it written into tenders that all

new road surfaces will have application of

preservative to protect the surface from

ageing,” says Lord. “Highway authorities

invest large sums of money in their networks

and have more reason than ever to want to

see that money go further over the long term.

It makes perfect sense to seal in the

investment.”

There is more to come from Bituchem

including an innovation that allows

‘sweepings’ to be used in new applications of

surface dressing. This is another bitumen

emulsion developed and proven in the US and

being used in the UK this year. It answers the

question of what to do with ‘dirty’ chippings

that would otherwise be considered and

stockpiled as waste; promising significant

savings in costs for highway authorities.

“Surface dressing is likely to account for a

greater proportion of road surfacing

treatments carried out over this and coming

years as budgets get tighter and authorities

look to seal carriageway surfaces,” Lord says.

“Opening up use of recycled aggregates and

sweepings in surface dressing will be a

significant step forward for efficiency, as will

use of FortSeal on surface dressings, which is

how a lot of preservative is used in the US.

“Authorities in the States like to spray

preservative on new dressings to hold

chippings in place and to show a nice black

finish. Public perception is always an issue

with surface dressing, mostly due to loose

chippings and the generally unimpressive

stone coloured end product,” Lord says. “The

low cost of applying FortSeal is worth paying

for a surface that looks good and attracts a

positive response, and lasts much longer.”

1 31 31 3

Bituchem’s FortSeal preservative has been proven over a period of 40 years in North America, to protect asphalt surfaces from the effects of ageing


[email protected]


TreatedUntreated

100

80

60

40

20

01969 1970 1971 1972 1973 1974 1975 1976 1977

Penetrationat25

°C

76543210

1969 1970 1971 1972 1973 1974 1975 1976 1977

Millinew

tonseconds/m

2

Penetration over time in treated and untreated roads

Viscosity of bitumen extracted from treated and untreated roads


On-line archive documentsthe key developmentsAll current and previous articles published in Modern Asphalts can be

viewed and downloaded from the magazine’s website. The following is a

digest of recent developments archived at www.modernasphalts.com

1 4

R i n g w a y , M A 2 3 , a u t u m n 2 0 0 8 –

Performance assured by design precision

Environmental targets, landfill charges

and aggregate tax – all are increasing

interest in asphalt recycling as a

financially prudent solution for road

resurfacing projects. According to

Ringway Infrastructure Services, such

incentive is driving up demand for its

Foambase recycling process, with the

manner in which the technique is applied

ensuring its success.

Each Foambase asphalt mix is designed

specifically for the individual application

after the existing pavement has been

tested to ascertain its nature. The exact mix

constituents can then be determined for

getting precisely the desired outcome, as

demonstrated on the A338 in Wiltshire.

Ringway laid 7000t of Foambase along a

1.1km section of the A338 in May 2008 for

Wiltshire County Council. The authority had

not used Foambase before but was aware

of its performance and financial benefits.

“We felt that this scheme was big

enough to make recycling with Foambase

worthwhile doing,” says Wiltshire’s

Highway Network Maintenance Manager

Peter Binley.

“The technique is providing a new way

for us to make the budget go further by

saving money on new materials and

potential landfill costs” – as well as helping

the council and other authorities meet their

environmental targets on recycling...

www.modernasphalts.com/archive/23/articles/MA23ringway.pdf


1 5

N y n a s , M A 2 5 , a u t u m n 2 0 0 9 –

Modif ied binder benefits spelled out simply

S h e l l B i t u m e n , M A 2 1 , a u t u m n 2 0 0 7 –

Upping surface outputs with Shell S Grade

Highway authorities interviewed by

Modern Asphalts are claiming to have

‘got on top’ of pothole issues aided by a

high performing repair product. The

material – Colas’ Colpatch – is giving

certainty that pothole repairs will last.

This has been mostly in Scotland thus far,

although the benefits of Colpatch relate only

in small part to geography. The crucial

attribute is the product’s durability in all

weathers, gained from its composition and

reported ‘tenacious bond’ to the bottom and

sides of any pothole...

www.modernasphalts.com/archive/25/articles/MA25colas.pdf

C o l a s , M A 2 5 , a u t u m n 2 0 0 9 –

Staying power proves potholes repair product

Asphalt producers looking for enhanced

durability from their road surfacing

materials are becoming more aware of

the benefits of selecting polymer

modified bitumens. These special

binders contain additives designed to make

an asphalt more workable during application,

and – once in situ – more resistant to

deformation, fatigue or cracking.

Nynas Bitumen has rebranded its entire

range of bitumen products including its

polymer modified binders, or PMBs. Nynas

now offers three categories of bitumen

binder as part of an initiative it calls the

‘Performance Programme’...

www.modernasphalts.com/archive/25/articles/MA25nynas.pdf

Much of the UK’s pavement surfacing

is now carried out at night to keep

disruption to a minimum.

Restriction on working hours brings

logistical difficulty, which has driven

Shell Bitumen to develop its Shell S Grades

for increasing volumes of surfacing possible

in a given time.

Asphalt mixes containing Shell S Grades

are more workable at a given temperature –

or can be laid at lower temperatures. Any

Shell binder can be modified to provide the

tangible benefits of Shell S Grades...

www.modernasphalts.com/archive/21/articles/MA21Shell.pdf

Sponsors:RingwayAlbion House, Springfield Road,Horsham RH12 2RWcontact: Tracey Elmsphone: 01403 [email protected]

Nynas UK ABNorth Road, Ellesmere Port,Cheshire CH65 1AJcontact: Paul Adbyphone: 0151 327 [email protected]

Shell BitumenRowlandsway House, Rowlandsway,Wythenshawe, Manchester M22 5SBcontact: Emma Mallinsonphone: 07976 [email protected]/bitumen

ColasColas Limited, Rowfant, Crawley,West Sussex RH10 4NFcontact: Palvinder Kaurphone: 01342 [email protected]@colas.co.uk

Bituchem GroupLaymore Road, Forest Vale Industrial Estate,Cinderford, Gloucestershire GL14 2YHcontact: Tom Ellsmorephone: 01594 [email protected]

If you would like any further information about the products or companies featuredin this magazine please forward your enquiries to [email protected]

The Modern Asphalts website – www.modernasphalts.com– is the premier on-line source of information on UK asphaltpaving.

All current and previous articles published in Modern Asphaltscan be viewed and downloaded individually from the website’sarchive, using an index that sorts articles by subject, magazineissue and sponsor.

There is also a section for contacting the editorial team atModern Asphalts and for obtaining free subscription to themagazine. So if you wish to add your name to the distribution,go to www.modernasphalts.com

• Ringway is advocating active asset managementfor more effective maintenance

• A study led by Nynas Bitumen is indicatingpositive results for reduced temperature asphalt

• After a decade of development, Shell WAM® Foamis set to meet emerging needs

• Colas’ Fibredec is ideal for repairing roads andstrengthening them before the next cold weather

• A new specialist emulsion has been launched byBituchem for sealing and preserving roads

• Reviewing a selection of key asphalt surfacingdevelopments archived atwww.modernasphalts.com

Click on the front cover to open a pdf of the entiremagazine or right click to download it. Click on'CURRENT ISSUE' above to download individual stories.

Published by:

Barrett, Byrd AssociatesLinden House, Linden Close,Tunbridge Wells, Kent TN4 8HHcontact: Jon Masters,phone: 01892 [email protected]

Client Side articlecontributed by:

Printed by:Pureprint GroupBellbrook Park, Uckfield,East Sussex TN22 1PL

No part of this publication may bereproduced stored in a retrieval systemor recorded by any other means withoutprior permission of the publisher. © 2010

THEBITUCHEMGROUP

MA ModernAsphalts · 2020. 11. 17. · Modern Asphalts 6 Asphalt turns down the heat E fforts by...

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