PmB: A Sustainable Technology for Roads

TOTAL is the leader of the European and African bitumen markets as manufacturer of bitumen. TOTAL operates bitumen refineries as well as modified bitumen and emulsion plants producing a comprehensive and tailor-made range of products for road and industrial applications.

TOTAL provides innovative solutions to key societal issues such as road safety, the integration of roads in urban and rural landscapes and road construction with recyclable materials. TOTAL offers high-performance products providing sustainable and safe solutions.

• What kind of damages the roads face?

At the present time, the main damage observed on the roads in MENA is both thermal and mechanical cracking. With no maintenance works, those damages can quickly lead to important crazing (see below pictures 1^st line right & 2^nd line left) and finally to the formation of potholes (picture 2^nd line left). In specific zones, we may observe rutting (picture 1^st line right) - as a result to continuous heavy traffic on straight lanes - or ravelling (picture 1^st line left) - from low speed tangential stress on bends.

The deterioration of the pavement causes traffic disturbances, affects road user safety and leads to potential casualties and additional costs of road maintenance.

The fast appearance of those deteriorations is partly due to the use of normal paving grade bitumen for the wearing course which cannot meet the specific constraints of the pavement in the region:

• Intense traffic of heavy trucks
• severe climatic conditions

The combination of these two sets of factors determines how long a typical road design shall ensure a durable pavement without damage.

Basically, the first factor - number of passes of trucks with a gross weight exceeding 30 MT per day - causes mainly mechanical stress or fatigue throughout the whole pavement structure (sub-base, base and wearing courses).

The second one - highest and lowest temperatures combined with extreme variations between day and night - leads to thermal fatigue of the pavement layers, especially of the surface.

A road is mainly a set of layers with 2 components (binder and aggregates) defining the properties of the asphalt.

Among various solutions to improve the resistance under the mechanical stress as well as the thermal fatigue, an increase of the layer thickness and utilization of high properties raw materials with better are the most spread. Their implementation requires the binder specifications adaptation and/or the validation of mix-designs with new Asphalt Concrete formulas that guarantee higher performances complying with the local constraints.

In the case of port and industrial areas for instance, the regular and slow traffic of heavy trucks leads to quick crazing, stripping and puncturing in addition to thermal fatigue, whereas on highways, the classical deteriorations appear after a couple of years in service as longitudinal cracks or rutting.

Nowadays, both environment & sustainable development concerns push all players to find better solutions with notably new design structures using lower thickness. These mix-designs provide material savings up-to 30% with no reduction in pavement durability. High quality binders can also guarantee increased road durability for a given structure.

Various asphalt concrete formulas have been developed and validated after a survey of more than 10 years complying with the client expectations in term of durability, lower maintenance cost (extension of the wearing course renewal period) and quality of the wearing course: improvement of the grip for higher skid resistance, better drainage, reduction of the noise due to traffic (open porous asphalts).

• What solution has been already implemented in various regions?

In Europe and in North America where traffic and climatic constraints can also be quite severe, many works references showed how the life cycle of the road can endure more than 10 years or 30% longer life expectancy with neither maintenance, nor deterioration.

One major reason of this longer durability is the use of an adapted and performing bituminous binder such as Styrelf^®, the crosslinked Polymer modified Bitumen (PmB) of TOTAL.

Covered by more than 30 active patents worldwide, Styrelf^® has been continuously developed by Total to meet today's changing requirements (processes, products, applications...). Its performances have made Styrelf^® the leading technology of the PmB binders designed for roads with extreme characteristics ranging from Mount Evans (Colorado) at 4,359 meters altitude to the Formula 1 racetrack in Monaco and specifically adapted for highways. In more than 30 years, Styrelf^® has become a worldwide renowned brand: more than 10 million metric tons have been sold over the world.

Styrelf^® is produced by in situ crosslinking thermoplastic elastomers within bitumen. Its continuous polymer network, within a bitumen matrix, provides a very fine and homogeneous microstructure and results in outstanding properties (picture 3):

-          increased durability and resistance against fatigue

-          excellent cohesion of the binder leading in particular to a good resistance to tangential forces

-          decreased thermal sensitivity

-          increased adhesiveness with aggregates of various mineralogical types

-          high level of elasticity dealing to creep and rutting resistance (2 times less rutting at 60°C versus pure bitumen)

-          excellent stability during storage and transport

Thanks to all these performances, the Styrelf^® technology meets the requirements for pavements submitted to high mechanical stresses (highway, racetrack, roundabouts...) and exposed to extreme thermal and climatic conditions. It particularly suits to open porous asphalt (better ravelling resistance), thin and ultra-thin surfaces (materials savings and high roughness for a better grip), anti-rutting asphalt mixture, stone mastic asphalt, fuel resistance asphalt mixes (Styrelf^®IntaKt^® range)... It can also be used with different techniques from high modulus asphalt (increasing fatigue life up to 60 % and reducing the thickness of the layer), to surface treatment when fluxed or emulsified.

• How TOTAL participates in the development of technology and in the sustainability approach?

(from the Round Table, MENA INFRA N°2, speaker from Total: Jean-Pascal PLANCHE)

To address all bitumen industry challenges and in particular performances and sustainability as drivers, TOTAL looks at various levels of the bitumen life:

-          bitumen production: selection of crudes, compliance to health measures and regulations, use of biomass or appropriate wastes, improvement of processes,

-          bitumen application: improvement of handling bitumen considering safety, environment, energy and gas emissions reduction,

-          bitumen service life: pavement design with the appropriate binder, economics and durability depending on the traffic, climatic and economic conditions and available techniques,

-          bitumen end of life: recycling of pavement and/or bitumen, use of appropriate wastes without health risks.

The international Research and Development team of Total Bitumen is located in Lyon (France). Five other regional technical centres closely work with customers on their specific needs. These teams were at the origin of Styrelf^® technology and today works on performance related test methods, new crude sources for bitumen, durability, reduction of energy and emissions when producing and using bitumen, recycling, high performances binders (highly modified Styrelf^®), resistance to chemical products (Styrelf^® IntaKt^®, coloured binders (Kromatis^®)...

Partnerships between Total Bitumen and universities or other actors of the road industry have lead to interesting technical progress, for example:

-          Laboratoire des Ponts et Chaussées (LCPC - FR), to develop Styrelf^® technology,

-          LAVOC, laboratory from Ecole Polytechnique Fédérale de Lausanne (CH), which carried out a 14 years study on PmB's comparing their performances and durability. Styrelf^® was considered as excellent,

-          PennState University (USA) to characterize Styrelf^® according to the latest available performance oriented test methods.

Moreover, TOTAL sets bridges within the industry:

-          CEN/TC 336, European technical committee for the standardisation of bituminous binders, Eurobitume, AAPT, TRB, Rilem, Asphalt Institute....

-          Following occupational health studies on the effects of bitumen fumes in preparation of the new IARC bitumen monograph

-          Reduction of application temperatures

And believing that communication and transparency is the key of success for further development, TOTAL initiated in 2006 the 360° sustainable development approach, where a wide cross-section of stakeholders have been interviewed to know their expectations vis-à-vis our company.

TOTAL is the world fifth-largest oil and gas company and operates in more than 130 countries and has over 94,500 employees.

TOTAL is the leader of the European Bitumen market and a major player in US, India and Africa as manufacturer of petroleum bitumen and high performance modified bitumen. Total operates bitumen refineries and Polymer modified Bitumen (PmB) plants producing a comprehensive range of products for road and industrial applications.

Total Middle East (TME) is the subsidiary of the Refining & Marketing division of TOTAL in the region. TME is a leading regional player in manufacturing & sales of lubricants through its state-of-the-art blending plant located in Jebel Ali, U.A.E. TME is also active in Aviation and Special Fluids activities.

Contacts:

TOTAL MIDDLE EAST F.Z.E.

Arnaud Bourhis - Bitumen Manager

Al Masaood Tower, P.O. Box 14871

Dubai - U.A.E.

T: +971 4 260 9800 - F: +971 4 294 0447

E: arnaud.bourhis@total.com

www.totalmiddleeast.com